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CHEMISTRY OF SCHIFF BASES:
The consideration products of carbonyl compounds and primary amines are
often named as Schiff bases. They are also known as azomethines or anils or imines.
Schiff bases can be prepared by (i) The reaction of carbonyl groups with
amino groups are related reaction, (ii) nitroso-methylene condensation, (iii) formation
of oximes via c-nitro sations, (iv) diazonium salt-methylene condensations,
(v) additions to carbon-carbon double or triple bonds, (vi) formation of >C=N bands
through ylids, (vii) tautomerization of amides and thioamides are related reactions,
(viii) addition reactions to nitriles, isonitriles, nitrile oxides and related compounds,
(ix) oxidation and elimination from nitrogen compounds, (x) reduction of nitro
compounds, (xi) formation of azomethine by rearrangements and photochemical
reactions and (xii) electrochemical synthesis at lead electrode.
The condensation of primary amines with carbonyl compounds was first
reported by Schiff [1]. The reaction was reviewed [8, 286]. The experimental
conditions depend on the nature of the amine and the carbonyl compounds which
determine the position of the equilibrium.
The reaction was reviewed [4, 55]. The experimental conditions depend on
the nature of the amine and the carbonyl compounds which determine the position of
the equilibrium.
RR’CO+R”NH2⇐⇐⇐⇐⇒⇒⇒⇒ RR” C=NR”+H2O
Usually, it is advisable to remove the water as it is formed by distillation or by
using an azetrope forming solvent [10,18,211]. This is necessary with diaryl or aryl
alkyl ketones, but aldehydes and dialkyl ketones can usually be condensed with
amines without removing the water. Aromatic aldehydes react smoothly under mild
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conditions and at relatively low temperatures in a suitable solvent or without it. In
condensations of aromatic amines with aromatic aldehydes, electron attracting
substituents in the para position of the amine decrease the rate of the reaction, while
increasing it when on the aldehyde [50]. In both cases a linear sigma-rho relationship
was observed. With ketones, especially with aromatic ones, higher temperatures,
longer reaction times and a catalyst are usually required in addition to the removal of
water it is formed.
The reaction is acid catalysed. However, only aldehydes and ketones which do
not aldolize easily in acidic media can be condensed with amines in the presence of
strong acid catalyst, eg., concentrated protic acid [39], BF3 – ETHERATE [49, 219],
Zncl2 [2, 18, 20, 39, 55] or POCl3 [51]. For methyl ketones, only weak acids should
be used, while for methylene ketones, which are less sensitive to acid catalyzed
aldolizations, stronger acids may be used as catalysts[4]. Ultraviolet irradiation is
reported [20] to promote the formation of azomethines from aldehydes. This is
explained [57] as a light promoted auto oxidation of part of the aldehyde to the
corresponding acid, which in turn acts as catalyst. Schiff bases have also been
prepared using piperidine [215], dimethylacetamide and 5% lithium chloride [265]
and platinum group elements [335] as catalysts. Aromatic aldehydes and aliphatic or
aromatic ketones give with the amines quite stable azomethines. Primay apliphatic
aldehydes can give azomethines with various amines if the reaction is carried out at
00C, and the product’ is distilled from KOH [11, 17]. The effect of solvent in the
preparation of Schiff bases was also studied as a function of the Reichardt ETN and
modified Kamlet-Taft BKT parameters by Nagy et al [313].
The intra nuclear distance quoted for the >C=N-double bond is 1.29A0 for the
non-conjugated group and 1.35 or 1.36 A0 for azo-aromatic compounds [37]. Symth
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[3. 25] estimated the dipole moment of >C=N-to be 0.9 D.Cottrell [40] calculated the
bond energy for C=N-bond from the original data of Coates and Sutton [12] and
found to be 147.0K.cal/mole. Palmer’s book [42] gave some detailed examples of the
calculation of bond energies from thermochemical data and found to be
142.0K.cal/mole
The IR data found in the literature revealed that the acyclic >C=N- bond most
commonly encountered in Schiff’s bases (azomethines) absorb in the 1690-1640 cm-1
region. In most cases it is a strong and fairly sharp band located at somewhat lower
frequencies than the bands of carbonyl groups and close to >C=C, stretching
frequencies. In the absence of strain, steric hindrance or other complicated factors and
in dilute solutions, prepared from neutral solvent, the stretching frequency of >C=N-is
found to be 1670 cm-1 the corresponding force constant, 10.6 dynes cm-1 is in the
harmonic oscillator approximation. If there are one or more groups conjugated with
the >C=N- group the frequency is usually lowered. Generally speaking there is very
little difference between infrared and Raman frequencies and between the spectra of
pure liquids and solids and their solutions in CCl4 or other not very associative
solvents. In general >C=N-vibrations exhibit a lesser degree of localization than
>C=O vibrations.
Little is known about the electronic spectrum of the C=N group itself in a
purely aliphatic environment.Platt [31]and Sidman [38] estimated that ∏-n transition
lies at 2100 A0 if the >C=N-group carries only aliphatic substances, at 2500 A0 if
conjugated with vinyl group and at 2900 A0 on a benzene ring. Much more is known
about the spectra of compounds in which the >C=N-group is substituted by aromatic
rings. Charette, Faltlhanal and Teyssie [55] studied the ultraviolet spectra of a series
of N-salicylidene alkyl amines and their aryl-substituted derivatives in different
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solvents. Spectacular changes occur when the inert solvents are replaced by hydrogen
bonding solvents. Gawinecki, Ryazard et al prepared some Schiff Bases derived from
aryl groups and carried out the UV studies [189]. Kinetics and mechanism of
hydrolysis of Schiff bases were studies by Pishchugin et al [261, 262]. Hydrolysis of
various oxazolidines and N-acylated oxazolidines was carried out to explosure that
suitability as potential prodrugs [285]. Mohammed et al. reported the kinetics of
hyrolysis of Schiff bases and indicated that the rate-determining step is changed from
–OH attack on the free Schiff base in alkaline media to attack by water on the
protonated Schiff base in neutral and weakly acidic media. The results of study of
solvent effect on base hydrolysis rates suggest that specific solute-solvent
interactions, viz., dispersion forces and intermolecular hydrogen bonding play
important roles [287]. Pramila and coworkers examined the rates of hydrolysis of
Schiff bases at pH 4-13 in a 10% dioxime water system and in various non-ionic
surfactant systems [433]. Angles et al studied the hydrolysis of Schiff bases in
aqueous and non-aqueous media [440].
Determination proton-ligand stability and stability of Schiff bases were
reported in the literature [62,72,122,123,130,154,317,358]. Salman et al [441] studied
some new o-hydroxy Schiff bases in four solvents using UV spectra and reported that
the appearance and intensity of band at >400 nm which belongs to the keto form of
the Schiff base depends on the electronic and not the steric effect of the substituent.
Potentiometric investigation of effects of several electron donating and withdrawing
substitutents on the basicity of azomethine group of salicyalidene aniline in
nitrobenzene was carried out by Gunduz et al [336]. Potentiometric study of some
Schiff base ligands was reported in the literature [337] Madhav et al [419] studied
some Schiff bases using HMDE, square wave and cyclic Volta metric techniques and
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explained the results in terms of electron withdrawing and releasing effects of the
substituted groups. Effects of supporting electrolytes, solvents and acid concentration
on salicyladehyde tris Schiff base have been studied polagraphically by Sreenivasulu
et al [420].
By virtue of the presence of lone-pair of electron on the nitrogen atom and of
the general electron donating tendency of the double bond, compounds containing the
azomethine group should possess basic properties. The most characteristic aspect of
the compounds containing the >C=N-group which show basic properties lies in the
formation of complexes with metals. These complexes provide some very
characteristic series of coordination compound. The basic strength of the >C=N-group
is inadequate by itself to permit the formation of stable complexes by simple
coordination of the lone pair of electrons to a metal ion. Therefore, in order that stable
compounds to be formed it is necessary that there should also be present in the
molecule a functional group with a replaceable hydrogen atom, preferably a hydroxyl
group near enough to the >C=N- group to permit the formation of a five or six
membered ring by chelation to the metal atom.
Physico-chemical studies of Metal-Schiff base complexes:
A perusual of literature revealed that Schiff bases behave as monodentate,
bidentate and polydentate ligands towards many metal ions in the formation of
complexes. Metal chelates of azomethines mostly with transitional metals, lanthanides
and rare earths have been prepared and characterized using elemental analysis,
conductometry, magnetic susceptibility, thermal (TG, DTA, DSC), X-ray diffraction,
X-ray fluorescence, infrared, ultraviolet visible, mass, nuclear magnetic resonance,
electron spin resonance and proton resonancespectra [61, 67, 70, 80, 82, 93, 97, 100,
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103, 110, 121, 125, 132, 136, 139, 140, 146, 152, 156, 162, 163, 169-172, 174-185,
197, -212, 215-234, 236-239, 241-248, 252-254, 256-260, 298-301, 319, 363, 479].
The characterization of metal Schiff base complexes synthesized electro-
chemically has also been reported [293, 318, 401, 422, 434, 436]. Formation of
polynuclear and mixed-ligand copper (II) complexes with Schiff base have been
envisaged in the literature [303, 475].
Studies of metal-azomethine complexes in solution have been carried out by
several authors. Metal –to-ligand ratio and stability constants for the complexes were
computed using pH metric and potentiometric [62, 72-74, 88, 96, 122-125, 129, 133,
148, 155, 157, 168, 196, 235, 316, 336, 352, 383, 397-399, spectrophotometric [60,
75, 104, 150, 196, 260, 262, 317] and conducto metric [408] techniques.
Solvent extraction, thin layer chromatography and spectro electrochemical
studies were carried out to study Cu(II), Zr(IV), U(VI), Co(II) and Th (IV) Schiff base
complexes [64, 126, 195, 233]. Schiff bases were also used in the fluoremetric
determination of beryllium [228] and aluminium [281]. Aoki et al studied the effect of
metal-to-liand ratio on fluorescence properties of Zn(II) and Be(II) Schiff base
Complexes[314]. The same authors have also determined ethylenediamine
fluoremetrically by forming a fluorescent Be(II)-Schiff base complex [396].
Polarographic technique has also been employed by various authors in the
study of metal-azomethine complexes to determine coordination number, stability
constants, kinetic parameters and stereochemical behavior in solution for reversible
and irreversible systems [9, 64, 87, 127, 130, 131, 134, 135, 137, 143, b147, 149,
158, 159, 186, 190, 193, 222, 249, 250, 287, 291, 307, 350, 407, 412, 442].
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Applications of Schiff bases and their metal complexes:
The >C=N-group is present in may organic molecules of fundamental
importance. They have got extensive application in biological and industrial fields.
Schiff bases with potential pharmaceutical use were synthesized [26,29,46].
Anticataract pharmaceutical Schiff bases have been reported by Elsmer et al [292].
Azomethines prepared by Nakahara and his coworkers were used as catalysts
providing dental composites with excellent hardens, adhesion, on dentin and enamel,
and discolouration resistance [306]. Thirty seven pharmaceutical anils were reported
in the literature possessing anti inflammatory, antipyretic and analgesic properties
[84]. Neomycin derivatives were recovered by converting them to Schiff bases with
aromatic aldehydes at PH<7.0. These Schiff bases themselves are useful in human and
verterinary medicine [46]. A potentcy of 725 streptomycin units/mg was reported for
a number of Schiff bases prepared from salt of streptomycin [47]. Compounds of
pencillin with Schiff bases of amphetamine were reported [23]. Therapeutically
effective Schiff bases exhibiting cardio tonic and diuretic actions have also been
prepared [8, 36, 114]. Schiff bases having anti inflammatory property have been
synthesized [41, 220, 227]. Sivam et al prepared some Schiff bases useful as raw
materials for drugs, agrochemicals and electron devices by reduction of them with
molecular hydrogen in presence of palladium containing catalyst and tertiary amines.
Tuberculostatically active Schiff bases were condensed from aldehydes and
amines with activity at 10-6, 10-7 concentration [19, 35, 98]. Shah et al reported
potential tuberculostatic azomethines which inhibited growth of mycobacterium
tuberculosis in vitro [283].
Antiviral active anils were prepared in presence of zinc and acetic acid by
Auelbekov et al [229]. Iridium (III) Schiff base complexes also behaved as
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antivirucides [312]. Substituted salicyladehyde Schiff bases of 1-amino-3hydroxy
guamidine tosylate acted as antiviral against cornovirus.
Fifty seven Schiff bases used as anticancer agents were reported by Chaudari
and his coworkers [105]. Anticancer activity of Schiff bases was also cited in the
literature [161]. Schiff bases of uracil-6-carboxaldehyde were synthesized and
evaluated as potential antitumour agents by Kim et al [445]. Metal-Schiff base
complexes studied by Zishen et al also exhibited anticancer activity against Ehrlich
ascites carcinoma, with the Cu(II)complexes having the highest activity [358].
Pronounced anticarcinogenic reactivity of copper-di-Schiff bases has been studied
[389]. Antineoplastic properties of different Schiff bases have been examined both in
vitro and in vivo and reported as useful future anticancer agents [391]. Copper
complexes of di-Schiff bases were used as neoplasm inhibitors and antirheumatics
[361, 392]. Schiff bases derived from salicylaldehyde and 2-substituted aniline and
their metal chelates with Cu(II), Ni(II) and Co(II) ions were screened for antiulcer
activity. The copper complexes showed an increased activity [309].
Insecticidal compositions containing Schiff base as an active ingredient was
reported [5]. The anils alone did not exhibit grater insecticidal action prepared by
West [6] but exerted enhanced effect on non-aqueous solutions containing pyrethrum
or rotenone. Thirteen azomethines tested against several pathogenic fungi were
reported [22]. Schiff bases possessing pesticidal and fungicidal activity were reported
by Gradon and coworkers[160]. Quantitative estimation of azomethine containing
insecticides and fungicides was carried out polarographically [142]. Synthesis of
some more Schiff bases of fungicidal activity were also reported [49, 144, 175, 187,
275-277, 298, 322, 347, 348, 359, 362]. Siddique et al. [329] evaluated the toxicities
9
of Schiff bases and their complexes against insects and also reported the greater
efficacy for the complexes than the Schiff bases.
Complexes with bidentate Schiff bases were reported to possess biocidal
activity against bacteria and fungi [194, 577]. Singh and his coworkers synthesized
some boran complexes with Schiff bases and found to possess antifungal and
antibacterial activity [352]. Schiff bases derived from methylcyclo propyl ketones on
addition with dialkyl phosphates showed aphicidal activity [380]. Twenty six thiazole
Schiff bases and derivatives prepared by Mehapatra showed antifungal activity
curvularia species [214] “Schiff base complex of copper possessing considerable high
fungi toxicity was reported by Satpahty et al “[465]. The antifungal property of some
nickel-Schiff base complexes was studied. The complexes were more active than the
free ligands against all the fungi tested [290]. Fifteen transition metal complexes with
three Schiff bases have been screened against some fungal pathogens. Among these,
Cu(II) and Co(II) complexes with one of the three Schiff bases, namely benzyl-
touldine ligand showed high fungi toxic results [360]. Schiff bases derived from
5-nitro and 5-chloro salicylaldehyde and their complexes with Mn(II), Fe(III), Ni(II)
and Cu(II) have been studied for fungicidal activity using the growth method
[321., 346]. A serried of sixteen methylated polyfluoro aromatic Schiff bases and their
salts were tested as acaricides, fungicidies and insecticides. Fluorination on the
aldehyde part of the molecule enhanced the insecto acaricidal activity over that caused
by fluorination on amine part [375]. Schiff base obtained from Tries and glyoxal was
studied for its pesticidal activity by Nicolae et al [188]. Pesticidal active phosphonium
salts of C-phosphorous (III) substituted azomethines were synthesized [441].
Bactericidal and chemotherapeutical active Schiff bases were prepared from
sulfaphyridine [8, 114]. Schiff bases with antibacterial activity derived from different
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aldehydes and amines were cited in the literature [13,14, 83-85]. Of the seventy-three
azomethines prepared by Tottistrov et al, only salicylaldehyde component possessed
Schiff bases were found to contain antimicro biological activity [65]. Schiff bases
having antibacterial activity were prepared and reported by various workers
[28,239,294, 297, 315, 49, 354,355,384, 388,394,410,421,424,430].
Amino acid Schiff base complexes of dimethyl dichlorosilane were prepared
and studied their antibacterial activity. The data showed that the silane complexes
were better inhibitors than the corresponding free ligands [213]. Antibacterial activity
of Schiff bases and their metal complexes, varied from inacntive to highly active, was
discussed with regards to ligands and metal content [263]. Antimicrobial activity of
coordination compounds of some 3d elements with Schiff bases was tested against
strains of staphylococcus, proteus, salmonella, shigella and vaccine strains of a
Bacillus authraris [356]. Schiff base complexes of uranium and ziroconium were
examined for antibacterial activity in vitro [296].The antimicrobial activity four
bacteria strains were studied using diffusion test procedure [295].Mester et al.
prepared ten Schiff bases possessing trypnosomical activity [307].
Schiff bases possessing herbicidal activity were prepared by Sinha et al [320].
Azomethines were also used as starting material and intermediates in the preparation
of herbicides[270, 27]. It is found that Schiff bases have been employed as growth
regulators [106]. D’Amico prepared six Schiff bases and found to be useful as plant
growth regulators. Schiff base of aminohydroxy tetrahydronaphalene was found to
possess growth regulating activity [31].Growth regulating activity of Schiff bases on
cucumbers and tomatos [273] have been studied. Some azomethine compounds used
as growth stimulants were also reported [230].
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Salicyladehyde - tryptohan complex of copper (II) has been used as a tool for
immobilization of protein [339, 340]. Synthesis of new cataionic Schiff base complex
of copper (I) and their selective binding with DNA was reported by Janak et al [481].
Radio labeled Schiff bases were used brain studies and their lipophilicity and protein
binding capacity have been demonstrated [226]. The role of cell-surface Schiff base
forming ligands in the inductive interaction between Class II*antigen Presenting cells
(APC) and murine T cells was investigated [382]. A review with 47 references was
presented on bioinorganic chemistry of metal-Schiff base chelates as vitamin B6
analogs [92].Azomethines with anticoagulant properties were reported in the literature
[316, 385-387, 415].
Mixtures of linear poly Schiff bases of low molecular weight were synthesized
from aliphatic diamines and terephthaldehyde [30]. Soluble and insoluble polymeric
Schiff bases were synthesized and their Co(II), Cu(II) and Ni(II) complexes were
characterized [173]. Diamagnetic polymeric Schiff base complex of Zn and Uo2+
Complexes were prepared by Mishra and his coworkers [475]. Cross linked polymers
from Schiff bases have been derived and reported by Barbara andhis coworkers [278].
Al-Dujali et al synthesized liquid crystalline poly Schiff base polymers [430, 404].
Polymers of azomethine group containing methyl acrylate esters were prepared by
Ohashi et al [438, 439] and used for second harmonic generation devices in opto-
electronics.
Mixtures of azomethines and diazomethane pigments were used for PVC,
printing inks and coasting with good migration resistance [99,138]. Azomethines and
their metal complexes with Cu(II), Ni(II), Zn(II) and Co(II) reported by Hunger were
used as pigments [145]. The Schiff base derived from salicylaldehyde and
diaminomaleonitrile and its metal complexes were used as pigments [138, 279]. Some
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azomethine transitional metal chelates useful as pigments for plastics were also cited
in the literature [84]. Theodar [108] synthesized fast greenish yellow to bluish red
diazomethane pigments. Azomethine-metal complexed pigments from bibenzyl series
have been prepared [405].
Paints containing drying oils with conjugated double bonds and Schiff bases
were reported [34]. Property to Schiff bases increasing the drying rate of paints was
cited in the literature [33]. Schiff base compounds useful for electrophoretic coating
[309] and corrosion inhibitors [324, 447] were also reported.
Polyazomethine dyes were synthesized by Streel and Reindl [44].
Azomethines were used for dyeing and printing of fibrous material from polymers or
copolymers of acrylonitrile or dicyanethylene [28]. Schiff base metal complexes
containing azo groups have been prepared and used as dyes for cotton, polyster, wool
and leather [222, 224]. Chromium Schiff base complexes have been used as fast
brown dye for wooll and leather [223]. Metal chelates of Group IV elements with
Schiff base ligands have been synthesized and reported as colouring material for
resins [305]. Complexes of O-phenylenediamine bis {salicylaldimine with Fe(III),
Ni(II), Cu(II) useful as intermediates for drugs, agro chemicals, porphyrins and dyes
[375, 413]. Bis (hydroxyl benzylidene amino) benzene sulfonamide derivatives of
metal complexes were used for mass dyeing of polyester fibres [225]. Schiff bases
were also used to promote the light-fastness of syntheitic threads, fibres and foils [41].
Complexes of azomethines useful for improving the light fastness of dyed leathers
were synthesized [264]. Schiff bases as luminescent dyes for solar collectors were
also reported [402]. Copper complexes of Schiff bases derived from Phenolic
aldehydes with aliphatic diamines were used as good light stabilizers for dyed and
undyed polyamide Fibres [373]. In photography, a yellow Schiff base was used
13
inirreversibly dischargeable photographic filter and antihelation layers as filtering
agents [24]. Anils formed yellow styryl dyes particularly useful for colour correction
masks for the cyan layer of colour film [27]. Photographic developers incorporating
azomethine group were also described [15]. Certain Schiff baes of dialdehyde and
diamino compound, when mixed with gelatin were used as colour filter in making
colour films [16]. Schiff bases prepared by Mariko and Sadao showed goodmiscibility
in various resins, have good solubility and were used in the charge transferring layer
of electrophotographic photoreceptors [267]. Substituted azomethines were also
employed in the coating of electrophotographic paper [45]. Some caionic technetium
complexes o f Schiff base ligands were studied as myocardial imaging agents [269].
Schiff base compounds useful as aroma and taste enhancers in perfurmes,
cosmetics, food stuff, chewing gums and beverages were prepared [328, 344,345].
Schiff bases derived from amines and organoleptically acceptable aldehydes were
employed as deodorants for removing aldehyde associate off flavor in fats, oils [374]
and odourous air from refrigerators or raw garbage [342, 415].
Aromatic polyazomethines were used in the manufacture of filaments [265].
Dicarboxylic acid azomethines were reported and used in the preparation of high glass
temperature materials from apoxy resins [272]. Heat and fire resistant
polyazomethines have also have also been prepared [326, 343, 372, 416]. Rajan
carried out studies on the application of Schiff bases for high temperature lubrication
[409]. Heat resistant polyazomethines with good electrical properties and useful for
manufacturing printed circuit boards were prepared by Kihara et al [414]. The
polymeric Schiff bases synthesized were found to posses semiconducting properties
[76]. A review with seven references on organic semiconductors prepared from
polymeric Schiff bases was discuassed [218]. Yasuo et al prepared six thermostable
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and semiconducting polyazomethines by poly condensation of diamines with
dialdehydes [379]. Nishikawa et al prepared Schiff base type epoxy compounds with
excellent heat resistance, mechanical strength and optical characteristics and were
used for laminates, coating and semi conduction sealants [377, 378,443]. Schiff bases
were also used in the preparation of automobile antiglare mirros [266]. Anils derived
from heterocyclic carbonyl compounds with 2,6-diethylamine were used as rubber
antioxidants [219]. Modified rubber compositions with improved green strength and
cured properties and useful for tires, were manufactured by treating unsaturated
rubbers with Schiff bases in the presence of a Friedel-Crafts catalyst and then adding
carbon black [325].
Schiff bases was used as catalysts in accelerating the formation of the factice
[21, 86, 109]. Organic compound containing an azomethine group was used as a
catalyst for the polymerization of H2CO in an inert medium [48]. The catalytic and
oxidative activities of azomethines and their corresponding copper, nickel chelates
were discussed by Aptekar et al [71]. Rhodium- salicylidene complexes and nickel-
azomethine complexes used as catalysts for isomerization and dimerization of
α-olefins respectively were reported [86, 109]. The liquid phase oxidation of
2,3,6-trimethyphenol to 2,3,6-trimethyal-pquinone with molecular oxygen catalyzed
by metal- Schiff base complexes were performed in various solvents by Mizukami et
al [318]. Titanium (IV)-Schiff base complexes were employed as catalysts in the
oxidation of thianisole [282]. Optically active quadridentate Schiffbases and their
titanium (IV) complexes were prepared by Caoriet al and employed as catalyst in the
asymmetric oxidation of methyl phenyl sulphide with organic hydroperoxides [425].
Ring opening reactions of epoxides with trimethylsilyl cyanide catalyzed by titanium
alkoxide - Schiff base complexes were studied by hayashi et al [446]. Catalytic
15
dehydrogenation of hydrozones to diazo compounds was carried out with cobalt
Schiff base complex-oxygen system [280]. Catalytic efficiency of Cobalt (II)
complexes of tetra and unique denate Schiff base ligands had been tested towards the
oxidation of 2,6-di-tert-butyl phenol by molecular oxygen [320, 341]. In the oxidation
of 3,5-di-tert-butyl catechol to 3,5-di-tert-butyl cquinone, complexes of UO2(II),
Cu(II) and Ni(II) with complexes which are less active than their Cu(II) analogs and
used as catalysts in the oxidation of 3,5-di-tert-butyl catechol by oxygen [423]. The
mechanism of oxygen binding by cobalt (II) complexes with bidentate Schiff bases
was considered by Vogt et al. [217]. Pallidum complexes of Schiff bases derived from
heterocyclic aldehydes were used as catalysts for the hydrogenation and isomerization
of allul benzene in methanol in presence of NaBH4 [304]. Stable peroxo Schiff base
complexes of thorium [364] and Zirconium [365] were tested for their catalytic
activity. Bis (salicylidene)-1,2-diaminocyclohexane-Mn(III) complex was synthesized
and its catalytic property was studied [371]. Cobalt-Schiff base complexes were used
as metal complex carriers of oxygen [217, 368]. Du, Wen et al carried out the
catalytic oxidiation of phenols by cobalt-Schiff base complexes [370]. Epoxidation of
olefins catalysed by mono-and bi-nuclear Schiff base complexes was reported and the
catalytic activity was correlated with the structure of the ligand, the redox potential of
the metal ion and the binuclear character of the complex [367, 369, 400]. Reductive
carbonylation of nitrobenzene to phenyl urethane catalyzed by ruthenium (III) Schiff
base complex was reported by Khan et al [366]. Schiff base complex of ruthenium
(III), useful as catalytic organic oxidant was prepared [437]. Epoxidation of alkenes
with iodosylbenzene using mono-and binuclear ruthenium (III) Schiff base complex
catalysts is studied by Upadhyay et al [444].
16
In addition to the above mentioned applications, Schiff bases have been
employed in preparative uses, (e.g.heterocyclic compounds) [381] for the
identification, detection and determination of aldehydes or ketones, for the
purification of carbonyl or amino compounds (amino acids in protein hydrolysats) [7],
or for the protection of these groups during complex of sensitive reactions (e.g.amino
acids during peptide synthesis) [53]. Primary amines were determined by Fluorescent
high performance liquid chromatography and chemiluminescene flow injection
methods after converting them s Schiff bases [406, 431,432]. The condensed project
of salicylaldehyde with o-amino phenol was used as a gravimetric reagent for copper
(II) [107]. Metallic impurities, such as copper from petroleum products were removed
using Schiffbases [32]. In bioprosthetic tissue, residual aldehyde levels, which when
high may cause implantation problems such as inflammation and other adverse
reactions, were reduced in the form of Schiff base by contacting the tissue with a
rinsing solution containing a primary amine [323].
Iron is the fourth most abundant element in the earth´s crust occurring in
nearly all types of rock and soil minerals as both Fe Iron is the fourth most abundant
element in the earth´s crust occurring in nearly all types of rock and soil minerals as
Fe 2+ both Fe3+ Iron plays a central role in the biosphere, serving as the active center
of proteins responsible for O and electron transfer and of metalloenzymes such as
oxidases, reductases and dehydrases [476].
In recent years several studies have linked the concentrations of specific
transition metal ions to various diseases. Low serum copper level is used as a marker
for wilson´s disease. Serum copper levels are elevated in a large number of chronic
and acute illnesses such as Hodgkin´s disease, leukemia, and many other
malignancies [439]. Zinc is an important nutritive factor as well as a cofactor for
17
many metalloenzymes. Zinc is necessary for the growth and division of cells,
especially during the stages of life when growth rates are high. Zinc deficiency is
associated with syndromes that cause short stature and dwarfism [113]. Also, iron and
cobalt are all trace essential elements for human bodies. Lack of these essential
elements can induce some diseases while it is harmful and deleterious for overtaken
[506].
A new modeling study of the role of transition metal ions on cloud chemistry
has been performed. Developments of the model of multiphase cloud chemistry are
described, including the transition metal ions reactivity emission, deposition processes
and variable photolysis in the aqueous phase [56]. In the present work, Compounds
containing an azomethine group (>C=N-), Schiff bases, are used for determination of
the studied transition metal ions. Schiff bases are generally bi or tri dentate ligands
capable of forming very stable complexes with transition metal ions. The wide use of
antibiotics in man and animals and their extensive use in areas other than the
treatment and prophylaxis of disease have resulted in a serious problem of drug
resistance. Many of the well- known antibiotics, penicillin, streptomycine,
tetracycline ect; are chelating agents, their action is improved by the presence of small
amounts of metal ions. The antimicrobial activity of the ligands and their transition
metal complexes against different bacteria are also reported. Copper complexes have
more antibacterial activity against the bacteria staphyloccus aureus,klebsiella
pneumonia[216,579].
Schiff base can be used in dyestuff production, liquid crystal industries and
also in pharmacology. They are synthetic oxygen carriers and they have been
produced from intermediate products in enzymatic reactions and used as antitumor’s,
therefore, it is very important to prepare its transition metal complexes [510] Schiff
18
bases are organic compounds with great utility in important fields as: medicine
agriculture, cosmetic products [511, 583].
Some Schiff bases present anticancer [512], antitumor [116], antibacterial
[53,580] activity; they play a prominent part in the enzymatic or unenzymatic
transaminating reactions of the carbonyl compounds with amino acids [542,513]. In
the coordinate chemistry field, a lot of Schiff bases operate as ligands [529, 584].
Some of the Schiff bases complex combinations with metals are used as insecticides,
fungicides, herbicides [546]. Can be remarked the large field of the biological action
presented by the Schiff bases derived from aromatic 2-hydroxyaldehydes [543].
Schiff bases have a large number of synthetic uses in organic chemistry
[585,586]. Acylation of Schiff bases by acid anhydrides, acid chlorides and acyl
cyanides is initiated by attack at the nitrogen atom and leads to net addition of the
acylating agent to the carbon-nitrogen double bond. Reactions of this type have been
put to good use in natural product synthesis.
Schiff bases appear to be an important intermediate in a number of enzymatic
reactions involving interaction of an enzyme with an amino or a carbonyl group of the
substrate. One of the most important types of catalytic mechanism is the biochemical
process which involves the condensation of a primary amine in an enzyme usually
that of a lysine residue, with a carbonyl group of the substrate to form an imines or
Schiff base. Stereo chemical investigation carried out with the aid of molecular model
showed that Schiff base formed between methylglyoxal and the amino group of the
lysine side chains of proteins can bent back in such a way towards the N atom of
peptide groups that a charge transfer can occur between these groups and oxygen
atoms of the Schiff bases. In this respect pyridoxal Schiff bases derived from
pyridoxal and amino acids have been prepared and studied from the biological point
19
of view. Transition metal complexes of such ligands are important enzyme models.
The rapid development of these ligands resulted in an enhance research activity in the
field of coordination chemistry leading to very interesting conclusions.
The carbon-nitrogen double bond of Schiff bases like the carbon-oxygen
double bond is readily reduced by complex metal hydrides [530,525]. Reduction of
this type is probably the most efficient and convenient method for the conversion of
C=N into amino compounds. Thus lithium aluminium hydride in THF at room
temperature (or in difficult cases at elevated temperature) smoothly reduces Schiff
bases in high yield (> 90 %) to secondary amines. Sodium borohydride is an equally
effective reducing agent and is preferred to lithium aluminium hydride because of its
inertness to a wider range of solvent media and because of its greater specificity in
that other substituents such as nitro or chloro reducible by lithium aluminium hydride
are unaffected by sodium borohydride. reagent of this type is sodium
cyanoborohydride (NaBH3CN) .
When heterocyclic compounds played an important role in regulating
biological activities. Many Schiff base metal complexes are known to be medicinally
important and are used to design medicinal compounds. Nitro and halo derivatives of
Schiff bases are reported to have antimicrobial and antitumor activities [562].
Antimicrobial and antifungal activities of various Schiff bases have also been reported
[563,582]. Fungi toxicity of some Schiff bases have investigated by Sahu et al.[73].
Gawad et al. reported high antimicrobial activities of some Schiff bases [533]. Many
Schiff bases are known to be medicinally important and are used to design medicinal
compounds [551]. Cinnamldehyde is a well-established natural antimicrobial
compound. It is probable for cinnamaldehyde to react with amino acid forming Schiff
base adducts in real food system. The main advantage of cinnamaldehyde is that
20
direct contact is not required for being active as antimicrobial. Cinnamaldehyde has
been shown to be active against a range of food borne pathogents bacteria.
Wei et al. have prepared some adducts by the direct reaction of amino acids
with cinnamaldehyde at room temperature. Their antimicrobial activities were
evaluated with benzoic acid as a reference. Both cinnamaldehyde and their adducts
were more active against three microbial strains at low pH. They were more active
than benzoic acid at the same conditions, also [568] . Parekh and co-workers have
synthesized Schiff bases derived from 4-aminobenzoic acid and cinnamaldehyde.
They were screened as potential antibacterial agents against a number of medically
important bacterial strains [262] . They concluded that different response of the
synthesized Schiff bases arise because of their structural differences and are also
solvent dependent. Srikar et al. used p-dimethyl amino cinnamaldehyde to form
desired Schiff base, which used for quantitative estimation of Sparfloxacin in bulk
and pharmaceutical dosage forms [466].
The antibacterial activities of chitosan and the Schiff base derived from
chitosan and cinnamaldehyde were investigated by Xioa and co-workers [115]. The
results indicate that the antibacterial activity of the Schiff base is stronger than that of
chitosan. It was found that antibacterial activity increases with the increase of Schiff
base concentration.
CORROSION INHIBITORS:
An interesting application of Schiff bases is their use as an effective corrosion
inhibitor which is based on their ability to spontaneously form a monolayer on the
surface to be protected [478]. Schiff bases have been found to posses more inhibitor
efficiency than their constituent carbonyls and amines [518]. The results indicated that
these Schiff bases inhibited the corrosion efficiently. Some authors have attributed
21
these considerably stronger inhibition efficiencies to the presence of unoccupied
p*- orbitals in the Schiff base molecules, which enable electron back donation from
the metal d-orbitals and thereby stabilize the existing metal-inhibitor bond, which is
not possible with the constituent amines [574].
MISCELLANEOUS APPLICATIONS:
Interest due to their thermal stability similar to polyamides and their using as
solid stationary phase for gas chromatography [526], their semiconductor properties
[552], mechanical strength, electrochemical and nonlinear optical properties [564],
and useful catenation ligand, where the coordination polymeric Schiff bases are
extensively studies[519] .
Schiff base polymers are produced by the polycondensation of diamines with
various dicarbonylcompounds [517]. Khuhawar et al. synthesized and characterized
Schiff base polymers derived from 4,4’- methylenebis(cinnamaldehyde) with various
diamines [575]. Due to various applications of silver(I) complexes, for example as
reagents in organic and inorganic synthesis[217] , in photography or electrochemical
silver plating , and as free radical scavengers in industrial processes [50], these
complexes have received considerable attention in recent years[522]. Limited work
related to the silver (I) complexes with mixed ligands.
Amirnasr et al. have synthesized and determined crystal structure of two
mixed ligand silver(I) complexes, [Ag(ca en = is a bidentate Schiff base that prepared
from cinnamaldehyde and ethylendiamine, and X= N and SCN[507] 1,3- diene)iron
complexes have found many useful applications in organic synthesis[508]. Although a
large number of these compounds have been reported and their activity investigated
[539], less is known of the corresponding heterodynes compounds. In such
compounds, which may be regarded as derived from the basic butadiene unit by the
22
replacement of one or more of the carbon atoms by the oxygen or nitrogen, the
possibility arises that the lone pair of electrons of the heteroatom is involved with the
metal-ligand bond [126] .The 1-aza-1,3-butadienes and their tricarbonyl complexes
are readily available by condensation of cinnamaldehyde with the corresponding
arylamine followed by complexation with the ennacarbonyldi-iron. Jarrahpour et al,.
have synthesized the 1-(2-aminopyridine)-4-phenyl-1,3-diene and
1-(3-aminopyridine)-4-phenyl-1,3-diene as heterodynes for iron carbonyl
complexes[498] . Knölker et al. have reported that (η1-aza-1,3-butadiene)
tricarbonyliron complexes are highly efficient for the transfer of the tricarbonyliron
fragment [499] .
Cyclometallation reactions are well-established for many of the metals in the
periodic table, especially where the metallation has occurred at an aromatic carbon
atom [534]. However examplesinvolving cyclometallation of sp-(1,2,4-triphenyl-1-
aza-cyclohexadienyl)Re(CO)3. The crystal structure and properties of copper(I)
complexes with multidentate ligands has a growing interest in recent years [527], for
their potential applications in metallosupramolecular assemblies[535], bioinorganic
chemistry [503] and catalysis[524]. Morshedi et al. have designed and prepared
tetradentate N donor Schiff base ligand with using of cinnamaldehyde. They have
studied the coordination chemistry of their copper(I) complexes[565].
Khalaji and Welter react N,N'-bis(ß-phenyl-cinnamaldehyde)-1,2-
diiminoethane (Phca2en) with a mixture of CuI and AgNO3 to yields the
mononuclear [Cu(Phca2en)2][AgI2] complex. The X-ray crystallography showed that
this complex consists of a [Cu(Phca2en)2]+ cation and a [AgI2]- anion. Phca2en acts
as a bidentate ligand coordinating via two N atoms. Bolz et al. prepared Schiff bases
with multiple binding sites for supramolecular assemblies by condensation of para-
23
nitro- and para-N,N dimethylaminocinnamaldehyde with 1,3-dimethyl- and 1-butyl-
5-aminobarbituric acid [540]. The investigation of keto-enol tautomorism of
synthesized Schiff bases by FTIR spectroscopy confirmed that in the solid state this
compounds exist only in the enol form. In all sighted species, the absorption of light
by the cis – retinal Schiff base rhodospin results in the cis – trans isomerization of its
chromophore as an important step[528]. Under different conditions, p-substtuted
cinnamaldehyde undergo a variety of different photoprocesses including cis – trans
isomerization[523]. The photobehavior of rhodospin is dependent on molecular
environment[600]. Kanthimiathi and Dhathathreyan have studied the photoreaction of
monolayers synthesized Shiff bases drived from condensation reaction of p-nitro
cinnamaldehyde with ethylene diamine and o-phenylene diamine at air /water
interface[479].
24
REFERENCES:
1. Schiff, H., Ann. Chem. 131, 118 (1864).
2. Reddelion, G., Ber. 43, 2476 (1910).
3. Smyth, C.P., J. Am. Chem. Soc. 60, 183 (1938).
4. Sprung, H.M., Chem. Rev. 26, 297 (1940).
5. Satteford, A. and Sons Ltd. and West, T.F., Brit. 538, 523 (1941).
6. West, T.F., J.Soc. Chem. Ind. 61, 158 (1942).
7. Brand, E. and Sand Berg, M., Org. Synth. Coll. Vol. 2, 49 (1943).
8. James, R., U.S. 2, 393, 271 (1946).
9. Moffett, R.B. and Hoehn, W.M., J. Am. Chem. Soc. 69, 1792 (1947).
Moffett, R.B., Org. Synth. Coll. Vol. 4, 605 (1963);
Freifelder, M., J. Org. Chem. 31, 3875 (1966).
10. Tiollais, R., Bull. Soc. Chim. France 708 (1947).
11. Coates, G.E. and Sutton, L.E., J. Chem. Soc. 1187 (1948).
12. Rao, H.K.S., Chandran, K.R. and Basu, U.P., J. Indian Chem. Soc. 26, 133
(1949).
13. Castel, G., Gazz. Chim. ital, 80, 812 (1950).
14. Kodak-Pathe, Fr. 983, 022 (1951).
15. Kodak-Pathe, Fr. 983, 109 (1951).
16. Hurwitz, M.D., U.S. Pat. 2,582,128 (1952).
17. Crewe, R., Mamann, R., Jacobsen, G., Nolte, E. and Riecke, K., Ann., Chem.
581, 85 (1953).
18. Muslin, L., Roth, W. and Frlenmeyer, H., Helv. Chim. Acta. 36, 886 (1953).
19. Kolsa, J., Arch. Chem. 287, 62 (1954).
20. Hermann, B. and Co., Ger. 841, 359 (1954).
25
21. Farrow, W.M. Calvin, H. and Schueler, F.W., J. Am. Pharm. Assoc. 43, 370
(1954).
22. Charles, B.B., U.S. 2,696,427 (1954).
23. Roger, R. and Nicoles, G., Rev. farm (Buenos Aires). 96, 5 (1954).
24. Vsevolod, T., U.S. 2,687,353 (1954).
25. Smyth, C.P., Dielectric behaviour and structure, Mc-Graw Hill, New York
(1955).
26. Charles, D. Lowry, Jr., U.S. 2,715,073 (1955).
27. Runti, C., 11 Farmaco (Pavis) Ed. Sci. 10,579 (1955).
28. Platt, J.R. in Radiation Biology (Ed. A. Hollaender), Vol. 3, Chap. 2, Mc-Graw
Hill, New York (1956).
29. Compagnic Franosisede reaffinage, Fr. 1,122,357 (1956).
30. Agfa Akt-Ges. Ger. 950, 617 (1956).
31. Farben Fabriken Bayer A-C (Roderich Rane and Werner Mueller), Ger.
1,108,659 (1956).
32. Nicolas, G., Rev. Assoc. Bioquim, Agr. 21,150 (1956).
33. Krassig, H. and Creber, G., Macromol. Chem. 17, 131 (1956).
34. Rohm and Hass G.m.b.H (by Theodor Volker and Herbet Zinna) Ger.
1,020,320 (1957).
35. Farbwerke Hoechst Akt-Ges. Vorm. Meister Lucius and Bruning (by Friedrich
Erbe). Ger. 965, 261 (1957).
36. Farbwerke Hoechst Akt. 2 Ges. Vorm. Meister Lucius and Bruning. Ger.
1,007,915 (1957).
37. Trefilove, L.F. and Postovskiv, I. Ya., Doklady Akad. Nauk. S.S.S.R. 114, 116
(1957).
26
38. Coro, Y., Japan. 13,823 ('61) (1957).
39. Tables of Interatomic distances adn configuration in molecules and ions (Ed.
L.R. Sutton), special publication No. 11, London, The Chemical Society
(1958).
40. Sidman, J.W., Chem. Rev. 58, 689 (1958).
41. Billman, J.H. and Tai, K.M. J. Org. Chem, 23, 533 (1958).
42. Farben Fabriken Bayer Akt-Ges (by Max Pestemer and Herbert J. Exner). Ger.
1,043,577 (1958).
43. Cottrell, T.L., The strength of Chemical Bonds, 2nd Ed., Butterworths, London
(1958).
44. Palmer, W.G., Valency, Second Edition, Cambridge University Press, P. 125
(1959).
45. Brunner, R., Craf, A. and Scheibe, G., Z. Wiss Phot. 53, 214 (1959).
46. Farben Fabriken Bayer, A-G Brit. 873, 673 (1960).
47. Upjohn Co., Brit. 839, 023 (1960).
48. John, D.S. and Harrykroll., U.S. 2,928,876 (1960).
49. Distillers Co. Ltd. (by Reginald H. Hall and Donald P. Young) Brit. 846, 168
(1960).
50. Strel, M. and Reindl, S., Arch. Pharm. 293, 984 (1960). Kenny CN,chem. Ind
1960:880-4.
51. Kalle, A.G., Brit. 836, 151 (1960).
52. Pratt, E.F. and Kamlet, M.J., J. Org. Chem. 26, 4029 (1961).
53. Taylore, M.E. and Fletcher, T.J., J. Org. Chem. 26, 940 (1961).
Popp, F.D. (1961) J. Org. Chem. 26, 1566
54. Curtin D.Y. and Hausser, J.W., J. Am. Chem. Soc. 83, 3474 (1961).
27
55. Badische Anilin - and Soda-Fabrik A-G (by Guanther Nottes). Ger. 1,117,805
(1961).
56. Dane E., Drees, F., Konrad, P. and Drockner, T., Angew-Chem. 84, 873
(1962), Sheehan, J.C. and Grenda, V.J., J. Am. Chem. Soc. 84, 2417 (1962).
57. Layer, R.W. Chem. Rev. 63, 489 (1963).
58. Reeves, R.L. in Chemistry of the carbonyl group (Ed. S. Patal), Interscience, P.
567 (1966).
59. Rotmistrov, M.M., Kulik, G.V. Corbonous, T.V. and Bredikhina, A.N.,
Microbiol. Zh. (Kiev). 32, 510 (1970).
60. Satapathi, S. and Sahoo, B., J. In org. Nucl. Chem. 32, 2223 (1970).
61. Aptekar, M.D., Matskevich, T.N., Trailina, E.P. and Savich, I.A., Zh. Obsch.
Khim. 41,652 (1971).
62. Ali, M. Akbar, Livingston, S.E. and Phillips David, John; Inorg. Chim. Acta,
5,493 (1971).
63. Biradar, N.S., Pujar, M.A. and Marathi, V.R., Indian J. Chem 9,712 (1971).
64. Bascuman, R., Cetina, R. and Gomer-Lara, J., J. Inorg. Nucl. Chem. 33,1013
(1972).
65. Prashar, P. and Tundon, J.P., Z., Inorg, Allg. Chem. 383, 81 (1971).
Kano S, Yakugaku, Zasshi. 1972; 92 (8): 935-944.
66. Menecke, G., Wille, W.E. and Kosamehl. G., Makromol, Chem. 160, 111
(1972).
67. Surray, A.R., U.S. 3,772,370 (1973).
68. Inman, E.R., Mc Cree, J.M. and Stirling, J.A., Ger. Offen, 2,313,225 (1973).
69. Rottistrow, M.N., Kulik, G.V. Skrynik, E.M., Corbones, T.V., Bredikhina,
A.N. and Taranova, L.A., Fiziol, Aktiv. Veshchestva. 5,123 (1973).
28
70. Yagi, Y., Kobayashi, A., Hirata, I. Japan. 734,564 (1973).
71. Mehta, R.K. and Gupta, R.K., Indian J. Chem. 11,56 (1973).
72. Rao, G.N. and Rustogi, S.C., Indian J. Chem. 11,1181 (1973).
73. Uhleman, E. and Plath, M., Z. Anorg. Allg. Chem. 403, 279 (1973).
74. Juraik, F. and Hajek, B., Chem. Listy. 68, 23 (1974).
75. Yamada, S., Kuma, H. and Yamanouch, K., Inorg. Chim. Acta. 10, 151 (1974).
76. Thaker, B.T. and Bhattacharya, P.K., Proc. Int. Conf. Coord. Chem.
R. 40, 3 (1974).
77. Dey, K. and Sen, S.K., J. Indian Chem. Soc. 52, 261 (1975).
78. Ozha, D.D., Singhvi, B.R. and Mehtra, R.K., J. Indian Chem. Soc. 52, 1104
(1975).
79. Rustogi, S.C. and Rao, G.N., Indian J. Chem. 13, 702 (1975).
80. Lehtinen, M., Halmekoski, J., Farm. Aikak, 84, 107 (1975).
81. Papenfuhs, T., Ger. Offen., 2,415,550 (1975).
82. Saxena, R.C., J. Sci. Res. 6,13 (1975).
83. Dash, B. and Mahapatra, S.K., J. Inorg. Nucl. Chem. 37, 271 (1975).
84. Zyzyck, L.A., Frumner, H. and Villa, J.F., J. Inorg. Nucl. Chem. 37, 1655
(1975).
85. Hill, H.A.O. and Zarb-Adami, N., J. Inorg. Nucl. Chem. 37, 2443 (1975).
86. Chaudari, D.T. and Sabnis, S.S., Bull. Haffkine Inst. 4, 85 (1976).
87. D'Amico, J.J., U.S. 3,992,191 (1976).
88. Wazir, B.L. and Kachru, C.N., Chem. Ers. 12,188 (1976).
89. Papenfuhs, T., Volk, W., Ger. Offen. 2,460,396 (1976).
90. Startseva, G.P., Rogachev, B.G., Khidekel, M.L., Hatkovskil, P.E. Carasina,
M.P., USSR, 534, 244 (1976).
29
91. Ozha, D.D., Raul, K.N. and Mehtra, R.K., Indian J. Chem. 14A, 61 (1976).
92. Narang, K.K. and Lal, R.A., Indian J. Chem. 14A, 442 (1976).
93. Parikh, P.C. and Bhattacharya, P.K., Indian J. Chem. 14A, 617 (1976).
94. Thaker, B.T. and Bhattacharya, P.K. Indian J. Chem. 14A, 619 (1976).
95. Sondhi, S.M., Sharma, R.S. and Ralhan, N.K., Indian J. Chem. 14B, 633
(1976).
96. Lindoy, L.F. Lip, H.C., Power, L.F. and Rea, J.H., Inorg. Chem. 15, 1724
(1976).
97. Perey, G.C. and Stenton, H.S., J. Inorg. Nucl. Chem. 38, 1255 (1976).
98. Hodgson, J.B. and Perey, G.C., Spectrochim. Acta. 32A, 1291 (1976).
99. Singh, O.P. and Tandon, Jagdessh, P., Monatch. Chem. 107, 1235 (1976).
100. Narang, Krishnan, K. and Lalram, A., Transition Met. Chem. (Weinheimi,
Ger.). 1,260 (1976).
101. Gupta, S. and Theriot, L.J., J. Coord. Chem. 5,153 (1976).
102. Biradar, N.S., Kulkarni, H.V. and Havinale, B.R., J. Karnatak Univ. Sci.
21,150 (1976).
103. Rothkopf, H.W. and Wochrle, D., Ger. Offen. 2,611,697 (1977).
104. Treopolskaya, T.V., Tkachenko, F.L., Munin, F.N. and Kitaev, Yu. P., Izv.
Akad. Nauk. SSSR. Ser. Khim. 1,7 (1977).
105. Biradar, N.S. and Patil, Basavaraj, R., Monatch. Chem. 108, 581 (1977).
106. Kohli, Rakesh Kumar and Bhattacharya, P.K., J. Indian Chem. Soc. 54,340
(1977).
107. Seshadri Naidu, R. and Raghava Naidu, R., Indian J. Chem. 15A, 652 (1977).
108. Smyth, H.R. and Osteryoung, J.G., Anal. Chem. 50,1632 (1978).
109. Joshi, P. and Joshi, P.C. J. Indian Chem. Soc., 55,1267 (1978).
30
110. Hunger, K., U.S. 4,096,157 (1978).
111. Srivastava, T.N., Chauhan, A.K.S., Agarwal and Manjula, Transition met.
Chem. (Weinheimi Ger) 3,378 (1978).
112. Cradon, E., Krassowaka, B., Eckstein, Z., Przem. Chem. 58, 662 (1979).
Eladwy MA, Shams SA, Dine E, Breenbaly KM, Pharmazine. 1979;
34(3):144-7.
113. Takeuchi, S., Kochi, M., Rewarada, A., Esumi, S., Sasaki, K., Kewabata, S.,
Saito, T., Inoue, Y., Yamamoto, M., Sekine, K., Japan Koki Tokyo Koho.
7970, 428 (1979).
Schuster, I.S. and Robert, J.D. (1979) J. Org. Chem. 44, 2658.
114. Sankhla, N.K., Ranungo, P.K. and Mehtra, R.K., J. Indian Chem. Soc. 56,99
(1979).
Dine E, Breenbaly KM, Pharmazine. 1979, 34(3):144-7.
115. Patel, M.N., Patel, M.M. and Patel, C.B., J. Indian Chem. Soc. 56,1255 (1979).
Sahu K, Behera RK, Pathaik RC, Nayak A, Behera GB, Indian J. Chem. 1979;
18B: 557
116. Patel, N.A., Shah, J.R. and Patel, R.P., Indian J. Chem. 19A, 236 (1980).
Alcock, N.W., Cook, D.F., McKenzie, E.D. and Worthington, J.M. (1980)
Inorg. Chem. Acta 38, 107.
Pearson AJ, Acc. Chem. Res. 1980;13: 463.
117. Dorutiu, Aurel and Lochli, Iliana (Rom)., Stud. Univ. Babes-Bolyai (Ser)
Chem. 25, 56 (1980). Barnish IT, Cross PE, Dickinson RP et al. J. Med.
Chem. 1980; 23: 117-121.
118. Karanpurwale, A.M., Patel, R.P. and Shah, J.R., J. Macromol. Sci. Chem. A15,
439 (1981).
31
119. Takahasi, Masashi and Iwamoto, Toschitake., J. Inorg. Nucl. Chem. 43, 253
(1981).
120. Patil, M.S. and Shah, J.R., J. Indian Chem., Soc. 58, 944 (1981).
121. Ramanijam, V.V. and Sivashakar, B., J. Indian Chem. Soc. 58, 1152 (1981).
122. Bied Charreton, C., Frostin-Rio, M., Pujol, D., Gaudemer, A., Andebert, R.
and Idoux, J.R., J. Mol. Catel. 16, 335 (1982).
123. Rana, A.K. and Shah, J.R., Indian J. Chem. 21A, 929 (1982).
124. (Miss) Vasudha Atre, Venkat Reddy, G.,
(Miss) Sarada, L.N. and Ganorkar, M.C., Indian J. Chem 21A, 934 (1982).
125. Mostafa, M.M., Shallaby, A.M. and El. Asmy, A.A., J. Indian Chem. Soc. 60,
109 (1983).
126. (Mrs) Shukla, P.R. and Jayanth Bhargava; J. Indian Chem. Soc. 60, 287
(1983).
Mehrotra R, Bohra R, Metal Carboxylates, Academic Press, London. 1983
127. (Mrs) Shukla, P.R. Singh, V.R., Jaiswal, A.M. and Gopal Narain; J. Indian
Chem. Soc. 60, 321 (1983).
128. Aggarwal, R.C. Singh, N.K. and Singh, R.P., J. Indian Chem. Soc. 60, 789
(1983).
129. Patil, M.S., Deore, H.O., Kulkarai, M.M. and Shah, J.R. J. Indian Chem. Soc.
60, 817 (1983).
130. (Mrs) Padmaja, R. Shukla, Akhilesh, M. Jaiswal and Gopal Harain,
J. Indian Chem. Soc. 60, 1014 (1983).
131. Siddiqi, K.S. Shah, M.A.A. and Zaidi, S.A.A., Indian J. Chem. 22A, 812
(1983).
132. Kushekar, B.A. and Khanolkar, D.D., Indian J. Chem. 22A, 881 (1983).
32
133. Biradar, N.S. Divakar, M.C. and Aminabhavi, T.M., Indian J. Chem. 23A, 586
(1984).
134. Uma Agarwal and Greesh Saxena J. Indian Chem. Soc. 61, 698 (1984).
135. Elered, A. Jordan and Fedrick, B. , Leader US 2-880. 120 (1959)
136. Sterl, M. and Reindel.S., Arch. Pharm. 293, 984 (1960)
137. Kalle, A.g., Brit., 836, 151 (1960)
138. Vogel, A.I., A Text book of Quantitative Inorganic Analysis, Longman, P. 389
(1961)
139. Charette, J.J., Falthansal, G. and Teyssie, P., Spectrochim.Acta, 20, 597
(1984)
140. Pfloumer Arther, E.V.S. 3-511, 637 (C1 71-106Ad)Appl.29, 6(1964)
141. Hauptmann, S. and Grabler, W., Z.Naturforsch, 623, 111 (1968)
142. Vogel, A.I., A text Book of Practical Organic Chemsity including Qualitative
Organic Analysis, ELBS and Longman Group Ltd., Ed.(1968)
143. Saxena, R.C. and Malik, W.U., J. Indian Chem. Soc., 46 1071 (1969)
144. Satapathi, S. and Sahoo, B., J. Inorg. Nucl.Chem., 32, 2223 (1970)
145. Felty, W.L., Ekstrom, C.G. and Leussign., D.L., J. Am. Chem.Soc., 92, 3006
146. Aggett, J., Richardson, R.A., Anal.Chim.Acta, 50, 269 (1970)
147. Prashar, P. and Tandon, J.P., Z.Anorg. Allg.Chem., 383, 81 (1971)
148. Aptekar, M.D., Nateskevich, T.N., Trailina, E.P. and Savich, I.A., Zh.Obsch.
Khim., 41, 652 (1971)
149. Mehta, R.K., Gupta, R.L., Indian J. Chem., 9, 1150 (1971)
150. Mehta, R.K., Gupta, R.K. and Singhvi, V.C., J. Prakt.Cchem., 313, 371 (1971)
151. Kogan, V.A., Dorokhova, N.I. and Osipov, O.A., Zh.Neorg.Khim., 16, 179
(1971)
33
152. Gershuns, A.L. and Rastrepina, I.A., Visn.Kharkiv.Univ.Khim., 73, 56 (1971)
153. Manecke, G., Wille, W.E. and Kosamehl, G., Makromol. Chem., 160, 111
(1972)
154. Panomarev, A.A. and U.N. Dyukaneva, Zr. Org. Khim., 8(3), 527-8(1972)
(Russia)
155. Nickel, Hast, Schendehuette, and Kari, H., Ger.Offer., 2, 051, 303, Appl.20-51
(1972)
156. Bohac Stanley, Josoc Cosmet Chem.23 (2), 125-37 (1972) (Eng.)
157. Mehta, R.K. and Gupta, R.K. Indian J.Chem., 11, 56 (1973).
158. Rao, G.N. and Rustogi, S.C., Indian J. Chem., 11, 1181 (1973)
159. Uhleman, E. and Plath, M., Anorg. Allg.Chem., 403, 279 (1973)
160. Surray, A.R., U.S., 3, 772, 370 (1973)
161. Imman, E.R., Mc Cree, J.M. and Stirling, J.A., Ger., Offen., 2, 13, 225 (1973).
162. Rottistrov, M.N., Mulik, G.V., Skrynik, E.M., Corbonos, T.V., Bredikhina,
A.N. and Taranova, L.A., Fiziol.Aktiv., Veshchestva, 5, 123 (1973)
163. Yagi, Y.,Kobayashi, A., Hirata, I., Japan, 734, 564 (1973).
164. Rajendra, P.S. and Khan, A.A., J.Inorg.Nucl.Chem., 35, 3865 (1973)
165. Pania, S.L., Kaul, K.N., Mehta, S. and Mehta, R.K., Curr. Sci., 42, 819 (1973).
166. Eanty Chanlees, J. Frost Johan, R., Horyak, John, Rasano, and Henil, J., 45(2),
243-5 (1973) (Eng.).
167. Sakaguchi, Kafei, Takemoto, and Hirotaka, Japan Appl., 74 3687 (1973) 23
pp.
168. Cauntry Charles, J., Frost, Jphn.R Haryak, John Rasano and Henri, L.,
J.Colloided Interface Sci., 45 (2), 242-5(1973) (Eng.)
169. Jursik, F. and Hajesk, B., Chem.Listy, 68, 23 (1974)
34
170. Yamada, S., Kuma, H. and Yamanouch, K., Inorg. Chim.Acta, 10, 151(1974)
171. Thaker, B.T. and Bhattacharya, P.K., Proc.Int.Conf.Coord.Chem., R40, 3
(1974)
172. Dey, K. and Sen, S.K., J. Indian Chem.Soc., 52, 261 (1975)
173. Osha, D.A., Singhvi, B.R. and Mehta, R.K., J. Indian Chem.Soc., 52,
1104(1975)
174. Lehtinen, M., Halmekoshi, J. Farm. Aikak., 84, 107 (1975)
175. Papenfuhs, T., Ger.Offen, 2, 415, 550 (1975)
176. Jain, P. and Chaturvedi, K.K., J. Indian Chem.Soc., 52, 1220 (1975)
177. Narang, Krishnan, K. and Lalram, A., Transition Met. Chem. (Weinheimi,
Ger.), 1, 260 (1976)
178. Jain, P.and Chaturvedi, K.K., J. Indian Chem.Soc., 53, 863 (1976)
179. Parikh, P.C., J. Maharaja Sayaji Rao Univ.Baroda, 24, 57 (1976)
180. Debey, K.P., Puri, M.K. and Wazir, B.L., Rev.Chim.Miner., 13, 343 (1976)
181. Kohil, Rakesh, K. and Bhattacharya, P.K., Bull. Chem. Soc., Japan, 49, 2872
(1976)
182. Patel, M.S., Trivedi, T. and Vyas, D.N., J. Electrochem. Soc. India, 25, 159
(1976)
183. Chifnik Sheidor, and Oho Ferdinand, US 4, 292, 186, Appl.727, 197, 6 pp
(1976)
184. Singhvi, B.R., Kanungo, P.K. and Mehta, R.K., Curr. Sci., 46, 222 91976)
185. Patel, M.S., Trivedi, T. and Vyas, D.N., J. Electrochem. Soc. India, 26, 21
(1977)
186. Vyas, D.N., Trivedi, T. and Patel, M.S., Chem.Era 13, 163 (1977)
187. Patel, M.S, Trivedi, T. and Vyas, D.N., J. Indian Chem.Soc., 54, 353 (1977)
35
188. Trivedi, T., Patel, M.S. and Vyas, D.N.J Indian Chem Soc., 54, 762 (1977)
189. Seshadri Naidu, R. and Raghava Naidu, R., Indian J. Chem., 15 A, 1051
(1977)
190. Myroyama, Stanlay, T. Appl. 813-381, 4 (1977)
191. Trivedi, T., PATEL, M.S. and Vyas, D.N., J. Indian Chem. Soc., 55, 980
(1978)
192. Trivedi, T., Patel, M.S. and VyasD.N., Indian J. Chem., 16 A, 449 (1978)
193. Patel, M.S, Trivedi, T. and Vyas, D.N., J. Indian Chem. 724 (1978)
194. Trivedi, T., Patel, M.S. and VyasD.N., Indian J. Chem., 13, 20 (1978)
195. Patel, M.S., Trivedi, T. and Vyas, D.N., J. Electrochem. Soc. India, 27,67
(1978)
196. Sankhla, N.K., Kanungo, P.K. and Mehta, P.K., J. Inidan Chem.Soc., 56, 99
(1979)
197. Vyas, D.N., Patel, M.S. and Trivedi, T., J. Indian Chem.Soc., 56, 126 (1979)
198. Bera, C.r., Chattopdhyay, S. and Sen Gupta, G.P., J. Indian Chem.Soc., 56,
416 (1979)
199. Mayadeo, N.S. and Hussain, S.N., J. Indian Chem. Soc., 56, 1255 (1979)
200. Patel, M.S., Trivedi, T. and Vyas, D.N., J. Def. Sci., 29, 7 (1979)
201. Trivedi, T., Patel, M.S. and Vysa, D.N., J. Electrochem.Soc.India, 28,
151(1979)
202. Cradon, E., Krassowaka, B. and Eckstein, Z.Przem. Chem., 58, 662 (1979)
203. Takeuchi, S., Kochi, M., Kawarada, A., Esumi, S., Sasaki, K., Kewabata, S.,
Saito, T., Inoue, Y., Yamamoto, M., Sekhine, K., Japan Kokai Tokyo Koho
7970, 428 (1979)
204. Patel, N.A., Shah, J.R. and Patel, R.P., Indian J. Chem., 19 A 236 (1980)
36
205. Dorutiu, Aurel, and Lochil, Iiana(Rom)., Stud., Univ.Babes-Bolyai
(Ser).Chem., 25, 56 (1980)
206. Malik, W.U., Bembi, R., Bhargava, P.P., Sushila and Tandan, O.P.,J.Indian
Chem. Soc., 57, 455 (1980)
207. Dean Harold, E., Halloram-Raoswmony, O. AND Winany Esther, D., Rjujack,
Braisstanly, J.US Apll.109, 800; pp. 6 (1980)
208. Ryer, Jack, Bloch and Ricordo, US Appl, 220, 457, pp. 6 (1980).
209. Lal, K. and Singh, R.P., Indian J.Chem., 20 A853 (1981)
210. Karanpurwale, A.M., Patel, R.P. and Shah, J.R., J. Macromol.Sci.Chem., 15,
439 (1981)
211. Vasudha Atre, Venkat Reddy, G., Sarada, L.N. and Ganorkar, M.C., Indian J.
Chem., 21 A, 934 (1982)
212. Sreenivasulu, R., Rao, V.S.Raghavendra, Reddy, K. Hussain, J. Indian
Inst.Sci., 65, 127 (1984)
213. Dash,., Mahapatra, P.K., Panda, Dand Pattnaik, J.M. Mrs., J. Indian Chem
Soc., 61, 1061 (1984)
214. Barabulescu, Nicolaw., Moga-Gheorghe, Spiridon, Sintamanian, Ana.,
Barbulesu, Emilia., Cuza, Olga, Pateu, Maria, Vasilescu, Ro.Ro. 85, 084
(1984).
215. Gawinecki, Ryszard; Muzalawski, Filiks, Pol.J. Chem., 58, 1091 (1984)
216. Sreenivasulu, R., Raghavendra Rao, V.S. and Hussain Redy, K., Analyst, 110,
411 (1985), Davarski, K., Vasilev, G. and Khalachev, N. (1985)
Dokl.Bolg.Akad. Nauk 38(5), 655; C.A. (1985), 10366674 f.
217. Sreenivasulu, R., Raghavendra Rao, V.S. and Hussain Redy, K., Analyst, 24A,
249 (1985)
37
218. Bhal, Laxmi, Tandon, J.P., Indian J. Chem., 24 A 562 (1985) Grunes R,
Sawondy W, J. Chromatogr. 1985; 122: 63–9
219. Panda, C.R., Chakravortty, V., and Dash, K.C., Indian J.Chem., 24 , 807
(1985)
220. Masoud, Mamdouh, S., Akelah, Ahmed, and Kandil Samir, S., IndianJ.
Chem., 24 A, 855 (1985)
221. Parikh, P.M. and Shah, J.R., Synth. React.Inorg. Met-Org. Chem., 15, 769
(1985)
222. Kuge, Y. and Yamada, S., Synth.React.Inorg.Met-Org.Chem., 15; 1085 (1985)
223. Soni, H.K. and Shah, J.R., Synth.React.Inorg.Met-Org.Chem, 15,1157(1985)
224. Varshney, ANIL, and Tandon, J.P., Proc.Indian Acad.Sci.Chem.Sci., 94,
509(1985)
225. Jezierska, Julia, Jezowska-trzebiatowska, and Boguslawa, Bull. Pol. Acad. Sci.
Chem., 33, 227 (1985)
226. Takeuchi, Akira; Yamada, Shichiro, Bull. Chem. Soc., Jpn., 58, 2990 (1985)
227. Mahmouid, M.R., Hmaed, M.A., Kamel, M.S., and El-Gyar, S.A., Monatsh.
Chem., 116, 129 (1985)
228. Zelentsov, V.V. and Suvorova, K.M., Teor.Prikl.Khim.B. Diketonatov. Met.,
25 (1985)
229. Narain, Gopal, Niadu, S., Sufal Kumar, Shukla, Pdmaja R., J. Inst.
Chem.(India), 57, 227 (1985)
230. Engel, Alank, Yoden, Tomoko; Sanni, Kohei; Ogata Naoya; J. Am. Chem.
Soc., 107, 8308 (1985)
231. Morimoto, Toshiaki; Sekiya, Minoru; Chem.Lett., 9, 1371 (1985)
38
232. Taploo, CL., Kumar, V., Dua, O.P., Singh, Y., Chamoli, R.P., and Dhar, D.N.,
Himalayan Chem.Pharm. Bull., 2, 49 (1985)
233. Masir ur Rahman; athar, Mohammad, Ahmad, Naseer; J. Chem.Soc. Pak., 7,
145 (1985)
234. He, Yongbing; Wu, Chngtai; Wang, Xiaojing; Yu, Kaichao; Yu, Kaichao.,
Wuhan Daxue, Xueabo, Ziran Kexueban, 3, 114 (1985)
235. Sakuntala, E.N., and Vasanta, E.N., Z. Naturforsch.B.,
Anorg.Chem.Org.Chem., 40 B, 1173 (1985)
236. Cros, Gerard; Laurent, Jean Pierre, Inorg. Chem.Acta, 105, 63 (1985)
237. Aninabhavi, T.M., Biradar, N.S., Patil, S.B., Roddabasanagoudar, V.L. and
Rudzinski, W.E., Inorg.Chim.Aacta, 107, 231 (1985)
238. Dash, B., Paatra, M. and Mohapatra, P.K., J.Indian Chem.Soc., 62, 734 (1985)
239. Ramanjuam, V.V. and Sivasankar, B., J. Indian Chem.Soc., 62, 734 (1985)
240. Mizukami, Fujio; Satoh, Kenichi; Niwa, Suuichi, Tsuchiya, Tohru; Shimizu,
Kazuo; Imamura, Juichi; Sekiyu GAKKAISHI, 28, 293 (1985)
241. Chmielewski, P., Vogt, A., and Jezowska-Trzebiatowska, B., Proc. Sch-
Symp.Inorg.Biochem.Mol.Biophys., 106 (1985)
242. Syromyatnikov, V.G., Zagnil, V.V., Kuz’min, R.N., Yatskiv, E.L. and
Eleckron, Org. Mater., 210 (1985)
243. Ishizaki, Masahiko, Kato, and Shozo; Jpn., Koaki Tokkyo, Koho, JP 60, 12,
929 (1985)
244. Shinozaki , Katsuo; Okazaki, Tokuji; Sagai, Saburo Akaboshi, Mitsuya;
Ikegami, Shiro; Kajiwara, Yoshio; Kimura, Tomonori; Kanbara, Toshibumi;
Naito. Yasuo; Jpn. Kokai Tokkyo Koho JP 60, 606, 158, 113 (1989).
245. Ermakov, S.S. and Krasikov, B.S., Fiz., Khim., 4,57(1985).
39
246. Fabio, B., Eur.Pat.Appl.EP. 148 120 (1986)
247. Befia Fabio (Ciba-Geigy A-G), Eup. Pat. EP. 150,576 (1985)
248. Dehnert, J. and Juenemann, W., Ger.Offen. DE 3,375,591 (1985)
249. Kaul, Dansilal, Ger.Offen.DE 3, 413, 603 (1985)
250. Varvarigou, D., Chiotellies, E. and Evagelatos, G., Dev. Nucl., Med. 9 (Prog.
Radio Pharma Col.), 131 (1985)
251. Nouguier Robert; Crozet, Michel; Vanellie, Patrice; Maldonado, Jose;
Tetrahedron Lett., 26,5523 (1985)
252. Watanabe, Kumihiru, and Aoki Izuo; Bunseki Kagaku, 34, 497 (1985)
253. Auelbekov, S.A., Mirzaabdullaev, A.B., Aslanova, d.Kh., Kuchkarov, S. and
Achilova, G. Sh., Khim-Farm Zh. 19, 829 (1985).
254. Davarski, K., Vasilew, G. and Khalachev, N., Dokl. Bolg. Akad. Nauk., 38
(5), 655 (1985).
255. Mikhailov, V. and Vasilev, G., Dokl.Bolg. Akad. Nauk., 38, 1551 (1985)
256. Csaszar, J., Morvaj, J. and Hercxeg, O., Acta. Phys. Chem., 31, 717 (1985)
257. Panda, C.R., Chkravorthy, V. and Dash, K.C., Solvent Extr. Ion Exch., 3, 857
(1985).
258. Kasuga, Kuminogu; Kuramitsu, Hiroshi, Kadowaki, Mayumi; Nagahara,
Takeo; Yamamato Yasuo, Bull.Chem. Soc. Jpn., 59, 1467 (1986)
259. El-ezaby, Mohammed, S., Marafie, Hayat, M., abu-Soud, Husam, M.,
Polyhedron, 5, 973 (1986)
260. Varshney, Anil; and Tandon, J.P., Polyhedron, 5, 1853 (1986).
261. Casellato, U., Fregona, D., Sitran, S., Vigato, P.A. and Fenton, D.E., j. Less
Common Met., 122 249 (1986).
40
262. Varshney, Anil; and Tandon, J.P.Proc.Indian Acad. Sci Chem. Sci., 97, 141
(1986) Chaudhari TD, Subnis SS, Bull. Haskine Inst. 1986; 4: 85
263. Inoyatov, M.D. and Mirzaev, U.M., Uzb Khim. Zh. 2,23 (1986)
264. Gol’dfarb, Ya. L. Kalik, M.A., Zavyalova, V.K., Agarunova, Yu.S.,
Kozlovskaya, E.A. Izv.Akad.Nauk, SSSR Ser.Khim., 7, 1620 (1986)
265. Nelson, S. Martin; Lavery, Aidan; Drew, Michael, G.B., J.Chem.Soc.Dalton
Trans., 5, 911 (1986)
266. Nishida, Yuzo; Kida, Sigeo, J. Chem.Soc. Dalton Trans., 12, 2633 91986)
267. Casella, Luigi, Gullotti, Michele, Inorg. Chem., 25, 1293 (1986).
268. Shyamal, Arun, Mayura, Manna Ram; Transition Met.Chem. (Weinheim,
Ger.),
269. Rao, V. Sudhakar, Darbarwar, Mallesswar, Indian J. Chem., 25B, 540 (1986)
270. Dashora, R., Singh, R.V. and Tandon, J.P., Inidan J. Chem. 25 A, 188 (1986)
271. Bhaskare, C.K. and More, P.GIndian J. Chem. 25 A188 (1986)
272. Syamal, Arun; Ahmed, Saeed; Maurya, Mannar; R., Indian J. Chem 25 A, 683
(1986)
273. Sreenivasulu, R., Raghavendra Rao, V.S. and Hussain Reddy, K., J. Indian
Inst.Sci., 66, 95 (1986)
274. Sreenivasulu, R., Sreenivasulu, B. and Sreeramulu, J., S.K. Univ.Res.J., 1, 77
(1986)
275. Sasaki, I., Gaudemer, A., Chiaroni, A. and Riche, C., Inorg. Chim. Acta, 112,
119 (1986)
276. Alteparmakian, Vart; Robinson, Stephen, D., Inorg.Chim.Acta, 116, L37
(1986)
277. Calienni, James J., Brittain Harry, G., Inorg. Chim. Acta, 116, 163 (1986)
41
278. Patel, M.N., Patel, M.M., Cassidy, P.E., Fitch. John, W., Inorg.Chim.Acta,
118, 33 (1986).
279. Casollato, U., Guerriere, P., Tamburrimi, S., Vigato, P.A.and Graziani, R.,
Inorg. Chim. Acta, 199, 215 (1986)
280. Patel, M.N. and Jani, B.N., J. Indian Chem. Soc., 63 278 (1986)
281. Singh, R.V., Synth. React. Inorg. Met –Org. Chem., 16, 21 (1986).
282. Ghose, B.N. and Lasisi, K.M., Synth. React. Inorg. Met-Org. Chem., 16, 1121
(1986)
283. Ortego, J. Dale; Meying Jeffrey, J. Chem. Engg. Data 31, 365 (1986).
284. Al-Dilaimi, Sobhi, K. and Mutor, A.A., Thermochim.Acta, 97, 267 (1986)
285. Pishehugin, F.V., Sharshenalieva, Z.Sh., and Dakenova, N.S., Zh.
Obshch.Khim., 56, 953 (1986).
286. Pishchugin, F.V., Sharshenalieva, Z.Sh., and Dakenova, N.S., IIzv.Akad.Nauk
Kirg.SSSR, 6, 65 (1986)
287. Pujar, M.A., Hadimani, B.S., Kumari, S. Meena; Gaddad, S.M. and Neelgund,
Y.F., Curr. Sci., 55, 353 (1986)
288. Puentener, Alois; Back, Gerhard, Koller, and Josef, Eur. Pat. EP 181, 236
(1986)
289. Koltot, V.N., Chernykh, T.E., Shugaeva, T.V., Batik’yan, D.A., Shchetinin,
A.M., Kudryavtesv, G.I., Khim.Volokna, 4, 30 (1986).
290. Omi, Shinya; Suzuki, Yasutoshi; Ito, Hiroshi; Hara, Kunihiko; Jpn. Kokai
Tokkyo, Koho, J.P., 6, 107, 383 (1986)
291. Kajiura, Sadao; Maeda, Mariko; Jpn.Kokai Tokkyo KohoJ.P., 6, 137, 844
(1986)
42
292. Tanaka, Masato; Kobayashi, Toshiaki; Jpn.Kokai Tokkyo Koho, J.P., 61, 257,
954 (1986)
293. Vanderheyden, Jean Luc, E., Avail Univ. Microfilms Int., Order No. DA
8518119, From Diss. Abstr.Int.B. 46, 1898 (1986)
294. Kato, Shozo; Igami, Satyoshi; Jpn.Kokai Tokkyo Koho, J.P. 61, 137, 859
(1986)
295. Kato, Shozo; Igami, Satyoshi; Jpn.Kokai Tokkyo Koho, J.P. 61, 151, 161
(1986)
296. Chattha, Mohinder, S., U.S. 4, 595, 761 (1986)
297. Serzhanina, V.A., Kacherovskaya, F.B., RozHKNOVA, n.g., Smirnova, G.K.,
Amdeeva, E.I., Veststi Akad. Navuk BSSR Ser Khim, Navuk 1, 116 (1986)
298. Kozlov, N.S., Korotyshova, G.P., Rozhkova, N.G., Simrnova, G.K., Andeeva,
E.I., Vestsi Akad. Navuk 2, 54 (1986)
299. Barbulesu, Nicolae; Moga, Gheorghe Spirideu; Sintamarian, Ana; Rom.RO
88, 605 (1986)
300. Sintamarian, Ana., Moga, Gheorghe, S., Rom. RO 89, 359 (1986)
301. Sintamarian, Ana., Moga, Gheorghe, S., Rom. RO, 89, 360 91986).
302. Wulft, Guenter; Heide, Barbara; Helfmeier, Georg., J. Am. Chem.Soc., 108,
1089 (1986)
303. Lotsch, Wolfganag; Bock, Gustav; Neumann, Peter., (BASF A-G) Gen.Offen
DE 3, 503, 776 (1986)
304. Nishinaga, Akira; Yamazaki, Shigekazu, Matsuura, Terue; Chem.Lett.(4) 505
(1986)
305. Watanabe, Kunihiro; Aoki, Izuo; Bunseki Kagaku, 35, 484 (1986)
43
306. Colombo, Anna; Marturano, Giorgio; Pasini, Alessando, Gazz.Chim.Ital., 116,
35 (1986)
307. Shah, S.R. Shah, S.J., Gol, D.D., Thakur, K.A., J. Inst.Chem.(India), 58, 49
(1986)
308. Martin, M.A., Alberto Ben and S.A. Basat, Energia (Madrid), 12 (5), 99-103
(1986)
309. Burr, Anders; Bundgaard, Hans, Arch .Pharm. Chem. Sci. Ed., 15, 76 (1987)
310. Shankar, Ravi; Rout, A.K., Sahoo, B., Indian J. Chem., 26 A, 156 (1987)
311. Mahmoud, M.R., El-Nady, A.M., Hamed, M.M.A., Inidan J.Chem., 26 A, 596
(1987)
312. Rao, N. Rama; Rao, P.Venkateswar, Reddy, G. Venkata; Ganorkar, M.C.,
Indian j. Chem ., 26 A, 887 (1987)
313. Saxena, G.C., Shrivastaa, V.S., J. Indian Chem.Soc., 64, 633 (1987)
314. Dhakarey, Rajesh; Saxena, Greesh, J. Indian Chem.Soc., 64, 685 (1987)
315. Sreenivasulu, R., Raghavendra Rao, V.S.and Sreeramulu, J., J. Electrochem.
Soc. India, 36, 131 (1987)
316. Elstner, Erich, F., Ger, Offen. DE, 3, 617, 711 (1987)
317. Duran, M.L., Rodriguez, A., Romero, J., Sousa, A,, Synth.React.Inorg.Met
Org.Chem., 17, 681 (1987).
318. Mishra, V., Saksena, D.K., Jain, M.C., Synth. React.Inorg. Met-Org.Chem.,
17, 987(1987).
319. Prop, Radu Dumitru, Donea, Adriana; Chiorean, Vasile; Farcasan, Valer;
stud.Univ.Babes-Bolyai, Chem., 32, 85 (1987)
320. Jain, I., Chaturvedi, Kamal, K., Res.J.Sci.Devi Ahilya Vishwavidyalaya,
Indore, 9, 84 (1987).
44
321. Bharamagoudar, T.D., Pujar, M.A., Alagawadi, A.R., Curr.Sci., 56, 889
(1987).
322. Kennedy, B.J., Mc Grath, Anthony, C., Murray, Keith, S., Sketton Brain, W.,
White, Allan, H., Inorg. Chem., 26, 483 (1987)
323. Casella, L., Gullotti, M., Pintar, A., Messori, L., Rockenbauer, A., Gyor, M.,
Inorg.Chem., 26, 1031 (1987)
324. Nepveu, Francoise, Inorg. Chim. Acta 134, 43 (1987).
325. Costes, Jean Pierre; Cros, Gerard; Murattet, Francois; Barbiew, Marie-Heiene;
Polyhedron, 6, 996 (1987).
326. Sasaki, I., Pujol, D., Gaudemer, A., Riche, C., Polydedron, 6, 2103 (1987)
327. Amirrov, R.R., Saprykova, Z.A., Zh. Ubshch.Khim., 57, 1526 (1987)
328. Nesterov, M.A., Laxer, L.I., Dykh.Zh.L. Sharj, V.Z., Yakerson, V.I.,
Izv.Akad.Nauk.USSR, Ser.Khim., (1), 27 (1987)
329. Misono, Takahisa; Kikuchi, Testuro; Sawamura, Katsuhiko; Nago, Yukinori;
Abe, Yoshimoto; Shikizai Kyokaishi, 60, 27 (1987)
330. Nakahara, Tekshi., Kasumoto Koji., Yuasa , Shigeki; Jpn.Kokai Tokkyo Koho
JP 62, 132, 904 (1987).
331. Mester, B., Elguero, J., Claramunt, R.M., Castanys, S., Mascaro, M.L., Osuna,
A, Vilaplana, M.J., Molina, P., Arch. Pharm (Weinheim), Ger.320.115 (1987).
332. Isuchi, Yoshie, Kokai Tokkyo, Koho JP Appl. 80/11503,3 (1987)
333. Anthony, T.J. and Joseph, L.P., US, 4, 665, 146(1987)
334. Zayed, Salem, E., Pak.J.Sci.Ind.Res. 30 (6), 432-8 (1987).
335. Isuchi, Yoshie, Kokai tokkyo, Koho JP Appl. 80/11503,3 (1987)
336. Sharma, V.K., Pandey, O.P., Sengupta, S.K., J.Inorg. Biochem., 34, 253
(1988)
45
337. Nagy, P., Herzfeld, R., Acta.Phys.Chem., 34, 51 (1988)
338. Aoki, Izuo, Watanabe, Kunihiro; Bunseki Kagaku, 37, 333 (1988)
339. Ranga, S.P., Sharma, Shobha; Chowdary, Vimala; Parihar, Manju; Mehta,
R.K., J. Curr.Bio.Sci., 5, 98 (1988)
340. Mayadeo, M.S., Nalgirkar, Jyothi, V., Indian J. Chem ., 27 A, 456 (1988)
341. Mitra, Jayati; Metzler, David E., Biochem.Biophys.Acta, 965, 93 (1988)
342. Rodriguez, a., Duran, M.L., Romero, J., Sonsa, A., An.Quim.Ser.B. 84, 198
(1988)
343. Sharma, Niro; Zutshi, K., Trans,. SAEST, 23, 393 (1988)
344. Sinha, A.I.P., Bala, Manju, Acta.Cience.Indica, Chem., 14, 5 (1988)
345. Goyal, S., Lal, k., Acta Cienc.Indica, Chem., 14, 265(1988)
346. Singh, Waikhom Mangi; Bash, B.C., Pesticides, 22, 44 (1988)
347. Nahef, Aws., Dieck, Ronald, Eur.Pat., 267, 434 (1988)
348. Monticelli; C., Brunoro, G., Frignani, A., Marchi, A., Korroz.Figy, 28, 118
(1988)
349. Kitahara, Shizuo; Nakakawaji, Fujito; Fujii, Toshihiro, (Nippon Zeon
Co.Ltd.), Jpn.Kokai Tokkyo Koho, 63, 7, 954 (1988)
350. Mita, Toshihiro; Jpn.Kokai Tokkyo Koho, JP 63, 234, 030 (1988)
351. Serin, Selahattin; Gok. Yasar. Doga; Turk.Kin.Derg., 12, 325 (1988)
352. Mookherjee, Braja; Sands, KEITH, p., Hagedom, Myrna, L., US, 4, 755720
(1988).
353. Siddiqui, K.S., Kureshy,R.I., Khan, P., Hagedom, Myrna, L., US, 4, 775720
(1988)
354. Bair Kenneth, W., US Appl. (496-85), pp 15 (1988).
355. Bair Kenneth, W., US 4, 720,5797; US Appl.496-833; pp 15 (1988)
46
356. Bair Kenneth, W., US 4, 719,049; GB Appl. Pp. 24 (1988)
357. Bair Kenneth, W., US 4, 720,587 (1988)
358. Kabayashi, Kazuhiro, Koboshi, Shigbharh, Kuze, Satora, and Ishikawa Masao,
Japan Kokai, Tokkyo, Koho JP, 65, 104, 049 (88, 104), 049), PP 20 (1988)
359. Bringmann, Gerhrd; Geisler, Joerg.Peter; Jansen, Johannes Rudolf (BASF a-
G), Ger Offen. DE 3, 819 (1989)
360. Gunduz, Turgut; Kilic, Esma; Atakol. Orhan., Koseoglu, Fitnat., Analyst
(London), 114, 475 (1989)
361. Sevilla, J.M., Blazquex, M., Garcia-Blanco, F., Dominguez, M., J. Chim Phys.
Phys-Chim.Biol., 86, 1143 (1989)
362. Galyametdinov, Yu.G., Zakieva, D.Z., Ulakhovich, N.A., Budnikov, G.K.,
Izv. Vyssh.Uchebn.Zaved.Khim.Khim.Tekhnol., 32, 50 (1989)
363. Moriya, Katushiro; Tanizawa, Kazutaka; Kanaoka, Yuichi; Chem. Pharm.
Bull., 37, 2849 (1989)
364. Moriya, Katushiro; Tanizawa, Kazutaka; Kanaoka, Yuichi; BioChem.
Biophys. Res.Commun., 161, 52 (1989)
365. Sasaki, Isabelle; Pujol, Daniele; Gaudemer, Alain; Thurey, Pierre; Calude,
Renee; Zarembowitch, Jacqueline; New J. Chem., 13, 843 (1989)
366. Osawa, Yasuko; Narutomi, Yuji, Uchikuga, Baburo (Sogo Pharmaceutical Co.
Ltd.)Jp 01, 20, 852 (1989)
367. Muneto, Toshikhiko; Miyazawa, Masashi; ,atsumoto, Toshikiko, Kurosaki,
Yuichi (Kuraray Co. Ltd.), Jpn, Kokai Tokkyo Koho, JP, 01, 158,037(1989)
368. Mookkherjee Braja, D., Trenkle, Robert, W., Calderone, Nicholas; Schreck,
Lisa; Sands Keith, P.US, 4, 853, 369 (1989)
47
369. Mookkherjee Braja, D., Trenkle, Robert, W., Calderone, Nicholas;
Fenn.Ronald, S.US, 4, 853, 369 (1989)
370. Goyal, Sudha; Lal, KEEMTI, j. Indian Chem.Soc., 66, 477 91989)
371. Patel, V.K., Vasanwala, A.M., Jejurkar, C.R., Indian J. Chem., 28 (A) 719
(1989)
372. Siddiqui, K.S., Tabassum, S., Zaidi, S.A.A., Kurshy, R.I., Khan, N.H., Indian
J. Chem., 28 (A), 1074 (1989).
373. Shinkonenko, S.V., Opanasenko, E.P., Volyanskii, Yu.L., Shul’ga, N.N.,
Peprepichka, M.P., Bunyatyan, N.D., Khim-Farm.Zh., 23, 59 (1989).
374. Sreenivasulu, R., Babu Prasad, G., Hari Haranath, B., J. Electrochem. Soc.
India, 38, 213 (1989)
375. Skwarski, Dionizy Musial, Eugeniusz; Maltowska, Jolanta; Poznan. Rocz.Med
10, 89 (1989)
376. Singh, V.P., Singh, R.V., Natl.Acad.Sci.Lett. (India), 12, 311 (1989)
377. Chondhekar, T.K., Dhuley, D.C, J. Inst.Chem.(India ), 61, 9 (1989) . Mohan J,
Anjaneyulu G S R, Kiran. . J.Indian chem. Soc 1989; 66:118-22.
378. Agarwal, U., Saxena, G.C., Proc. NATL.Acad.Sci.India, Sect A, 59, 373
(1989)
379. Shlyakhov, E.N., Tomnatik, L.E., Burdenko, T.A., Chaika, T.S., Tsapkov,
V.I., Samus, N.M., Khim-Farm.Zh.23, 186 91989)
380. Samus, N.M., Shlyakhov, E.N., Velishko, N.G., Burdenko, T.A., Chaika, T.S.,
Taspkov, V.I., Bodyu, V.G., Borozenets, S.P., Khim.Farm.Zh. 23, 1098
(1989).
381. Viguera, Ana Rosa Villa, Maria, Jesus; Goni, Felix, M., J. Biol.Chem., 265,
2527 (1990)
48
382. Wu, Ziishen; Gui, Ziqi; Yen, Zhenhuan., Synth React.Inorg.Net-Org. Chem.,
20, 335 (1990)
383. Siddiqui, K.S., Tabassum, S., Kureshy, R.I., Khan, N.H., Zaidi, S.A.A.,
Synth.React. Inorg. Met-Org.Chem., 20, 133 (1990)
384. Sahu, Kanak, L., Prasad, Prasanna, K., Panda, Ashok, K., Guru, Sarweshar.,
Transition Met.Chem.(London ), 15, 270 (1990)
385. Cherayath, S., Alice, J., Pabhakaran, Chathakudam, P., Transition
Met.Chem(LONDON), 15, 449 (1990).
386. Kassum, Emad, M.M., Kamel, Mohsen, M., Khir-Eldin,Nahed, Y., Pak.J.Sci.
Ind.Res., 33, 315 (1990)
387. Kwik, W.L., Tay, Alice, W.N., Polyhedron, 9, 1293 (1990)
388. Agarwal, D.D., Srivastava, Savita; Chandha, Poonam; Polyhedron, 9, 1401
(1990)
389. Agarwal, D.D., Jain, Rajeev, Bhatnagar, R.P., Srivastava, Savita; Polyhedron,
9, 1405 (1990)
390. Khan, M.M., Taqui., Halligudi, S.B., Shukla, Sumita; Shaik, Z.A., J. Mol.
Catal., 57, 301 (1990)
391. Agarwal, D.D., Bhatnagar, R.P., Jain, ajeev, Srivastava, Savita; J. Mol. Catal.,
59,385 (1990)
392. Kamizawa, Chiyoshi; Matsuda, Masaji; Lee, Woo Tai; Mizukami, Fujio,
Niwa, Shuichi; Maku, 15, 34 (1990)
393. Bhattacharya, P.K., Proc.Indian Acad.Sci., Chem.Sci., 102, 247 (1990).
394. Du, Wen; Wang, Guixia; XI, Zuwei; Fenzi Cuihua, 4, 306(1990).
395. Oki, Aderemi, R., Hodgson, Derek, J.Inorg. Chim. Acta, 170,65(1990).
49
396. Mercier, Regis, Sillon Bernard; Pascal, Thierry;Fr. DemandeFR
2,645,158(1990).
397. Huber-Emden, Helnut; Reinert; Eur.Pat.Ep,362,139 (1990).
398. Behan, John Martin; Perring, keith Douglas; Eur. Pat. Ep,393,619(1990).
399. Yagihara, Tomia; Matsui, Nobuo; Hmamoto, Isami: PCT int. Wo 90 02 734
(1990).
400. Sivam, Gowsala,p., Reed, Michael, W., Srinivasan, Ananthachari, Morgan, A.
charles,Jr., Brisner,Diana, I., Vrudhula, Vivekanda,M., Comezogu F.Taha:
PCT Int.Appl. WO 90 03 401 (1990).
401. Nishikawa, Akio; Koyama, Toru; Asano, Hiodeki., Jpn. Kokai Tokkyo Koho
JP 02 45 519 (1990).
402. Nishikawa, Akio; Koyama, Toru; Asano, Hiodeki., Jpn. Kokai Tokkyo Koho
JP02 88 623 (1990)
403. Saequsa, Yasuo; Sekiba, Kazuhiro; Nakamura, Shigeo; Kenkyu Hokoku-Asahi
Garasu Zaidan, 56, 139 (1990)
404. Minbeav, B.V., Mataeva, S.O., Abiyurov, B.D., Zh.Obshch.Khim. 60, 1070
(1990)
405. Kuznetsov, V.V., Prostakov, N.S., Khim.Geterotsiki. Seodin, 1, 5, (1990)
406. Gao, Ziao Ming; Rhodes, John; J. Immunol., 144, 2883 (1990)
407. Goyal, Sudha; Lal, Keemeti., Trans SAEST, 25, 1 (1990).
408. Goel, Sudha; Lal, Keemeti., Asian J.Chem., 2, 271 (1990)
409. Bagwe, V.T., Pandey, H.N., Rao., A.P., Mayadeo, M.S., Trans.SAEST, 25,
147 (1990)
410. Bagwe, V.T., Pandey, H.N., Mayadeo, M.S., Acta Cienc Indica Chem.16c,
205 (1990).
50
411. Pandey, H.N., Bagwe, V.T., Mayadeo, M.S., Acta Cienc Indica Chem. 16C,
273 (1990)
412. Sharma, Anju; Bhardwaj, Upasana; Jain, Lata; Kacchawaha, G.R.,
Kacchawaha, Meenakshi, Mehta, R.K., J. Curr. Bio.Sci., 7, 149 (1990)
413. Miesel, Ralf; Weser, Ulrich, Free Radical Res.Commun., 11, 39 (1990)
414. Parashar, R.K., Sharma, R.C., Mohan, Govind; Biol Trace Elem. Res., 23, 145
(1990)
415. Sur, Bimanesh; Chatterjecc, Shyama Prasad; Sur, Pratima; Maity, Tapas;
Roychoudhury, Shyamal; Oncology, 47, 433 (1990)
416. Weser, Ulrich; Miesel, Ralf; Ger.Offen DE 3, 912, 642 (1990)
417. Wang, Pou Hsiung; Keck, James, G., Lien., Eric, J., Lal, Michael, M.C., J.
Med. Chem., 33, 608 (1990).
418. Zelenin, K.N., Khorseeva, L.A., Alkseev, V.U., Korolynk, A.M., Sivoldskii,
E.P., Sofronov, G.A., Kutsenko, S.A., Khim-Farm.Zh. 24, 40 (1990)
419. Mathur, S.C., Sethi, P.D., Jain, C.L., J.Indian Chem.Soc., 67, 981 (1990)
420. Aoki, Izuo, Takahashi, Akira, Watanabe, Kunihiro, Bull Chem.Soc., Jpn., 63,
1973 (1990).
421. Chowdary, V., Parihar, M., Mehta, R.K., Phys. Chem., (Leipzig), 271, 413
(1990)
422. Devadas, M., Om Prakash, K.L., Pal, A.V., Chandra; Indian J. Cham., 29A,
192 (1990).
423. Dobrynina, N.A., Agranovich, A.M., Isaeva, S.V., Martynenko, L.I., Evseev,
A.M., Zh . Neorg. Khim., 35, 1748 (1990).
424. Agarwal, Dau D., Bhatnagar, Rajendra, P., Jain, Rajeev, Sivastaa, Savita, J.
Chem. Soc. Perkin Trans., 6, 989 (1990).
51
425. Bastida, Rutina; Lage, Teresa; Parrado, Concepcion; Rodrigueze, Teresa;
Sousa, ANTONIO Fenton, David, E., J. Chem.Soc., Dalton Trans., 7, 2101
(1990)
426. Sharma, K.S., Bhushan, Kul; Singh, G.P., J. Photochem.Photo Biol., 52, 478
(1990)
427. Al-Dujaili, Amar, H., Shalash, Raidhth, J.A., Yasagh, Thaiy S., Eur.Polym.J.,
26, 947 (1990)
428. Abd-Alla, Mohamed, A., Aly.Kamal, I., High Perform Poly. 2, 181 (1990)
429. Manukain, Badrig, K., Huber, Walter., Glanzman, Ernst; Gazz.Chim.Ital., 120,
315 (1990)
430. Adachi, Kyoko; Ihinose, Norio, Fresenius; J.Anal.Chem., 338, 265 (1990)
431. Sreenivasulu, R. and Sreeramulu, J.J., Electrochem.Soc.India, 39, 247 (1990)
432. Liu, Jianhua; Masuda, Yoshitaka,; Sekido,Eiichi; Analyst (London ), 115,
1089 (1990)
433. Rajan, K.S., Report (1990)
434. Kunesch, N., Barbier, M.P., Dalkafouki, A., Poission, J.E., Ann.Pharm.Fr. 48,
1, (1990)
435. Kabachink, M.M., Chadnaya, I.A., Novikova, Z.S., Vestn Mosk.Univ.Ser.Z.
Khim, 32, 405(1991)
436. Shagisultanova, G.A., Ivanova, M.E., Popeko, I.E., Timonov, A.M., Zh.
Neorg. Khim., 36, 3096 (1991)
437. Yamazaki, Shigeru; Jpn.Kokai Tokkyo Jp 03, 103, 477 (1991).
438. Kihara, Yasuo; Yamamoto, Michiharo; Shiraj; Mitusuyoshi; Jpn.Kokai
Tokkyo Koho JP 03, 162, 450 (1991)
52
439. Baudin, Josianne, PCT Int. Appl. WO 91 17 139 (1991) Mirkin, M.V. and
Bard, A.J. (1991) J. Anal. Chem. 63, 532
440. Wada, Keiichiro; Cassidy, Patrick, E., Hager, WILLIAM, S., U.S. 5, 066, 765
(1991)
441. Gotmare, Suslekha, R., Mayadeo, M.S., Acta Cience.India Chem., 17 © 255
(1991)
442. Mishra, Pradeep, Gupta, P.N., Shakya, Ashok, K., J. Indian Chem.Soc.68, 681
(1991)
443. Madhava, A., Seshu; Patil, C.J., Vyas, D.N., Ramachandraiah, G., Bull.
Electrochem., 7, 283 (1991)
444. Sreenivasulu, R. , Sudhakar Babu, K. and Hari Haranath, B., J. Electrochem.
Soc. India, 40, 59 (1991)
445. Lauer, Manfred,; Zipperer, Berhard, Goetz. Norbert., Lorenz., Giesela,
Ammermann, Eberhard., Eur.PAT. Appl. EP 409, 077 (1991)
446. Arulsamy, Naramoney, Zacharias, Panthapally, S., Transition Met.
Chem.(London), 16, 255 (1991)
447. Srinivas, Bhamid; Zacharias, Panthapally, S., Transiton Met.Chem.(London),
16, 521 (1991)
448. Satpathy, Krishna, C., Panda, Ashok, K., Mishra, Rushabha; Chopdar, Aditya,
P., Pradhan, Sarda, K., Transition Met. Chem.(London), 16, 628 (1991).
449. Sasaki, Caori, Nakajima, Kiyohiko; Kojima, Massaki, Fujita, Junnosuke; Bull.
Chem,Soc. Jpn., 64, 1318 (1991)
450. Soni, U.C. and Perkin, A.R., Indian Journal of Hetrocyclic Chemistry 1, 133-
136 (1991) Eng.
53
451. Bair Kenneth, W., C. Andews, Webstery Tutile Richond, L. Knick, Vincent,
C.Cory, Michael, Mckee, Bavid, R.J. Med.Chem.34 (7), 1993-90 (1991)
(Eng.)
452. Mecham George Victon, West Michale, Pet. Inst. Appl. WO 91, 12, 232, PP
27 (1991)
453. Bair Kenneth, W., Pat. Appl.(A, 2, 012, 626) c1c07d491), 53(1991).
454. Ali, Mohammad Akbark; Haroon, Chowday, M., Nazimuddin, T.H.,
Transition Met. Chem (London), 17, 133 (1992).
455. Hayashi, Juniro; Yamada, Masaaki,; Hobo, Toshiyuki, Anal.Chim. Acta, 259,
67 (1992).
456. Hayashi, Juniro; Yamada, Masaaki,; Hobo, Toshiyuki, Anal.Chim. Acta, 266,
359 (1992)
457. Mishra, Pramila; Mishtra, Bijay, K., Behera, Gopa, B., Int.J. Chem.Kinet.24,
593 (1992)
458. Labisbal, Elena; De Blas, Andres; Garcia-Vazques, Jose, A., Romero, Jaine;
Duran, Maria,. L., Sousa,Antonio; Bailey Neil A., Fenton, David, E., Lesson,
Philip, B., Parish, R.V., Polyhedron, 11, 53 (1992)
459. Labisbal, Elena; De Blas, Andres; Garcia-Vazques, Jose, A., Romero, Jaine;
Duran, Maria,. L., Sousa,Antonio; Bailey Neil A., Fenton, David, E., Lesson,
Philip, B., Parish, R.V., Polyhedron, 11, 227 (1992).
460. Castro, J.A., Romero, J., Garcia-Vazquez, J.A., Duran, M.L., Sousa, A.,
Castellano, E.E., Zukerman-Schpector, J., Polydedron, 11, 235 (1992)
461. El-Hendawy, Ahmed, M., El-Kourashy; El-Ghany., Shanab, Mai, M.,
Polyhdedron, 11, 523 (1992).
54
462. Ohashi, Toyoyoji; Kojima, takashi; Itsubo, AKIRA; Jpn. KokaiTokkyo Koho
JP 04 63 805 (1992).
463. Ohashi, Toyoyoji; Kojima, takashi; Itsubo, AKIRA; Jpn. KokaiTokkyo Koho
JP 04 63 815 (1992).
464. Garcia del Vado, M. Angeles; Echevarria, Gerardo; Vazques, Miguel, A.,
Garcia Balnco, Francisco; J. Chem.Soc., Perkin 2 Trans.6, 915 (1992)
465. Salman, Salman, R., Shawkat, Swwasan, H., Kamounh, Fadhil, S., Can.J.
Appl. Spectrosc., 37, 46 (1992).
466. Abdel-Hamaid, Refat; El-Haty, Mohamed, T., Can. J. Chem., 70, 877 (1992)
Shah S, Vyas R, Mehta RH, J. Indian Chem. Soc. 1992; 69: 590
467. Montheard, J.P., Bionon, B., Zerroukhi, A., Cachard, A., Polymer 33, 3756
(1992)
468. Upadhyaya, Mukehs, J., Bhattacharya, Pbitra Krishna, Ganeshppure, Pralhad,
A., Satish, Sheo., J.Mol.Catal,., 73, 277 (1992).
469. Kim, Jack, C., Lee, Young, H.C., Korean J. Med. Chem., 2, 64 (1992)
470. Hayashi, Masahiko; Tamura, Mayumi; Oguni, Mobuki; Syn.Lett., 8, 663
(1992).
471. Braig, Adalbert; Philips, Emyr, Ger.Offen DE 4, 141, 634 (1992).
472. Frings, Rainer, B., Grehe, Gerwald, F., Ger.Offen.DE 4, 042-386, C1 CO7
(233/16) (1992) 5 PP.
473. Branca Quirico, Heitz Marie Paule, Ncidhart, Werner, Stalder, Heirh, Veira
Enicwost, WolfganEr. Pat. EP 509, 354 91992), 50 pp
474. Peters AT Maxs, Dyes and Pigments, 20, ISS4, 291-305 (1992 ) (Eng.)
475. Yoshida, Kurnihiko-Mimura, Tomio, Shimojo, Shiguru; Karasaki Mustunori,
Jwima Masaki, Scto.Touru; Mitsouka, Shigeaki, Eur.Pat Appl (EP 558 019).
55
476. Uchama, Hiroshi, Tanno Kyottiko Jpn. Kokai, Tokkyo Koho JP 0592661 (93-
92-661) (1993), 40 pp. . Rauhut, G., Clark, T. and Steinke, T. (1993) J. Amer.
Chem. Soc. 115, 9174
477. Chou, Chihyuch, Malcha, Robert, E., Nocito, Vincen DCT IntAppl. WO 93,
04, 136, (1993), 40 pp. Destevens G, Eager M, Tarby C. Heterocyclic. 1993;
35 (2), 763-773.
478. Kurutau, Takahiro, Tiho, Hiroyuks, Sakuma, Sadatoshi, PCT Inst Appl. WO
93. 08.685 10 pp. Abdul-Gawad M, Issa YM, Abd-Alhamid SM, Egypt J.
Pharm. Sci. 1993; 34: 219
479. Israila, L. 93. 820 (cl 607 D 8404), APPL 20, 55 pp (1993)
Solomon EI, Jones PM, Maj JA, Chem. Rev. 1993; 93: 2623
480. Saitoemi, Sugajuko, Takaide Fumi, Jpn Kokai Tokkyo Koho JP 05, 125, 306
(93, 125, 306) (1993) 10 pp
481. Koo Noryoki, Kojimh, Akihiko Fuku Da, Hideyoki, Jpn. Kaki Tokkyo Koho
JP 06-263.766 (CI CO7 d 501/57), 79 (1994).
482. Kao, Noryoki, Kojima Akihiko, Fukuda, Deyoki, H., Jpn-Kaki Tokkyo Koho
JP 06, 263.766 (CI CO7D 501/57), 79 (1994).
483. Philippe, Michel, tuloup, Remy; De Servet. Armelle, Sera, Domiel, Fodorpie
RRE (SA), Eur. Pat EP 709-081 (CI A 61 K7 142 ) 94/12 68t (1994), 9 pp.
484. Banio, M. Font-J.Lopez, DO, Muntaseu-J, Tamarit-JLI Hoget-Y, journal DE
Chime, Physique, Et, DE, Physico-Chime Biologigue, 91, 189-202 (1994)
485. Barrio, m. front, J., Lopez, Do Muntaseu-J, Tamarit-J.L., Journal of hermal
Analysis, 41, 1171-1175 (1994).
486. Gerstein Terry, US 37, 420 (Cl-424-70-11 A61 K7/11)(1994).
56
487. Yoshioka, Masato, Apachi, Takashi Jpn, Kokai, Tokkyo, Koho, JP 06122-611
(94-122-611), 91994) 19 PP.
488. Mondet, Jean, Sturia, Jean, Michel Lion Bertrnd, Dupuls, Christine Cazeneuve
Colete, PCT Int. Appl. WO, 94, 09,749(1994)-32 pp.
489. Krushna, C., Sataphy, Ashok, K., Panda, Rusabha, Mishra ADITHY, p.,
Chopdar and Miss SARADA, k. Pradhan, J. Indian Chem.Soc., 71, 593-596
(1994).
490. Tegeler, J.J., Meriman, G.H., Heilyer, L., Ontengans, M., Baile, B.Abstracts of
the Paper of American Chemical Soc., 209, 179m (1995).
491. Clas, Sophie, Dorothee, Bccrand, Simon, R. Brit. UKPat, Appl. US Appl. 22
(1995).
492. Pan Chert Eugene Joseph (Procter & Gamble Co.), Brit UKP Appl. GB 2,
281-076, (1995), USAppl. 15pp.
493. Clas, Sophie, Dorothee, Bccrand, Simon, R. Brit. UK. Pat, Appl. GB
2,285,989, O2 Aug (1995) US Appl. 188-546-22pp.
494. Clas, Sophie, Dorothee, Bccrand, Simon, R. Brit. UK. Pat, Appl. GB
2,285,989, US Appl.188-546(1995)22pp.
495. Valerie, Piotbertrand (SA), Eur Pat Appl. EP. 637-600(1995) 23 pp.
496. Mougin Nathalic, Mondet, Jean Plot Bertrand, Jumino, Alex Patraud Jeanue,
Eur. Pat. Appl EP 663-20 (1995), 10 pp
497. Collin Nahtalic-Quemin, Eric (SA), Fr Demande FR 2, 714, 545, Appl. 91995)
14 pp.
498. Garg, R.K. and Sharma,L.M., J. Indian Chem. Soc. 72, 251 (1995).
Navon, Golub G, Cohen H, Meyerstein D, Organometallics. 1995; 14: 5670
499. Mishra, V. and Parmar, D.S., J. Indian Chem.Soc., 72, 811-813 (1995)
57
Navon N, Golub G, Cohen H, Meyerstein D, Organometallics. 1995; 14: 5670
500. Kato, Yasuo, Yamada, Hideaki, Asano, Yas Unisa (Bioatech), Jol. Mol. Catal.
B. enzyme. 913-6), 151-160 (1996) (Eng.) Mihai Barboiu, Marilena
Cimpoesu, Comelia Guran, Claudiu Supuran, Metal based drug. 1996; 3(5),
227-232.
501. Sandosham, Tessie, Hicbel, Johann Kallmann, Hermanna, Cuthbertson,
AlanFisher, Peter, Hartmann, Michael, Kremningh, Peter Rovenskes, Frans,
Heibyn, Mette. Pet, Inst. App. WO, 96, 19, 455 CI (O7D21181)Gb Appl 50
(1996)
502. Kobayashi, Shin, Fursue, Tsuyoshi, Yuasa, Sathosh, Micro, Naka, Iwaki,
Akashi Tomido Yasvko. Eur. Pat. Appl. EP. 736-890 (CI Hoiji 130)JP Appl.,
78 (1996).
503. Singh, B.and Srivastav, A.K., J. Indian Chem.Soc. 73, 602-694 (1996).
Knölker H, Goesmann H, Gonser P, Tetrahdron Letters; 1996;37 (36):6543-
6546
504. Aly, M.A., Hassan, Fonad, Taha, Ahmed, Eloudi and Mohammed, T.A.,
Quenaway, J. Indian Chem. Soc., 73, 325-328(19960
505. Tanaka, J., Tsureutone, K., Komatsu, A., Ito, T., Kalida, Y., Fujii, Y., Nakana,
Y, Usui, Y., Fukuda and Chikira, Bull.Chem.Soc., Jan, 70, 615-629 (1997).
506. Kong,D.,Zhang,X.,Zhu,Q.,Xie,J.andZhou,X.(1998) Zhongguo Yaown Huaxue
Zazhi 8(4), 245 ;. C.A. (1999), 131, 53640 p.
507. Wang R, Wang Y, Li S. Gaofenzi Tonghaa. 1998; 1:33–40
508. Khuhawar MY, Channar AH, Shah SW, Eur Polym J. 1998; 34: 133–5
509. Pandeya SN, Sriram D, Nath G, DeClerq E. . Eur J Pharm Sci. 1999;9:25-31.
510. Pessoa, J.C., Cavaco, J., Covreia, J., Costa, D., Henriques, R.T. and Gillard,
58
R.D. (2000) Inorg. Chim. Acta., 305(1), 7.
511. Zhu, T.L., Tong, J. and Chon, M.X. (2000) J. Chem. Soc. Dalton Trans., 4182
512. Pui, A and Berdan, I. (2000) Rev. Chim (Bucure ti) 53, 9.
513. Lu S M and R Y Chen Organic Preparations and Procedures International
2000; 32(3): 302-306.
514. Lu S M and R Y Chen Organic Preparations and Procedures International
2000; 32(3): 302-306.
515. Sridhar SK, Saravanan M, Ramesh A Eur J Med Chem. 2001;36:615-625
516. Ammar YA, Ismail MMF, El-Gaby MSA, Zahran MA . Indian J Chem.
2001;41B:1486- 1491
517. Bilgic S, Cabiskan N, J. Appl. Electrochem. 2001; 31: 79
518. Khan SA Siddiqui AA, Bhatt S, Asian J. Chem. 2002; 14: 1117
519. Quan Z, Chen S, Li Y, Cui X, Corros. Sci. 2002; 44 : 703
520. Vicini P, Geronikaki A, Incerti M, Busonera B, Poni G, Cabras CA, Colla PA
Bioorg Med Chem. 2003;11:4785–4789.
521. Kenderekar PS, Siddiqui RF, Patil PS, Bhusare SR, Pawar RP Indian J Pharm
Sci. 2003; May-June: 313.
522. Orazzhanova L, Yashkarova MG, Bimendina LA, Kudaibergenov SE, J. Appl.
Polym. Sci. 2003; 87 (5): 759–764
523. Kretzer RM, Ghiladi RA, Lebeau EL, Liang HC, Karlin KD, Inorg. Chem.
2003; 42:3016
524. Omae I, Coord .Chem Rev., 2004; 248: 995
525. S L Vasoya, D J Paghdar, P T Chovatia, H S Joshi, J. Sci. Islamic Republic
Iran. 2005; 16, 33-36.
59
526. Parekh J, Inamdhar P, Nair R, Baluja S, Chanda S, J. Serb. Chem. Soc. 2005;
70 (10): 1155.
527. Kuramshin AI, Kuramshina EA, Cherkasov RA, Russ. J. Org. Chem. 2005;41
(5): 649-655 .
528. Ronson TK, Adams H, Ward MD, Eur. J. Inorg Chem. 2005; 4533;
529. Ugras H I, I Basaran, T Kilic and U Cakir J. Heterocyclic Chem 2006; 43:
1679- 1684.
530. Mohamed G G, M M Omar and A M Hindy Turk. J. Chem. 2006; 30: 361-382
531. Omar and A M Hindy. Turk. J. Chem. 2006; 30: 461-468
532. Alagarsamy V, Duraraj S, Solomon VR Arkivoc. 2006; Xvi:285-291.
533. Bhuiyan MMH, Rahman KM, Hossain K, Rahim A, Hossain I, Naser MA
Acta Pharm. 2006;56(4):441-450.
534. Amirnasr M, Khalaji AD, Falvello LR, Solar T, Polyhedron. 2006; 25: 1967
535. Jarrahpour AA, Esmaeilbeig AR, Adabi A, Molbank, 2006; M457
536. Khalaji AD, Welter R, Inorganica Chemica Acta. 2006; 359: 4403
537. Pintilie O, Profire L, Sunel V, Popa M, PuRi, A. Mol. 2007; 12, 103-113.
538. Alagarsamy V, Vijyakumar S, Solomon VR, Biomed Pharmacother.
2007;61(5): 285- 291.
539. Khuhawar MY, Shah A, M. Mughal A, chinese journal of polymer science,
2007; 4: 399
540. Gennari M, Lanfranchi M, Cammi R, Pellinghelli MA, Marchio L, Inorg.
Chem. 2007; 46: 10143;
541. Bolz I, May C, Spange S, Arkivoc. 2007; 3: 60
542. Hadizadeh F and R Vosoogh J. Heterocyclic Chem. 2008; 45: 1-3.
543. Rajavel P, M S Senthil and C Anitha E-Journal Chem. 2008; 5(3): 620-626
60
544. S K Sonwane and S D Srivastava Proc. Nat. Acnd. Sci. India. 2008; 78A
(II):129-136
545. Elzahany E A, K H Hegab, S K H Khalil and N S Youssef. Aust. J. Basic
Appl. Sci. 2008; 2(2): 210- 220.
546. Wadher S J, M P Puranik, N A Karande and P G Yeole International Journal
of Pharm Tech Research. 2009; 1(1): 22-33.
547. Chhonker YS, Veenu B, Hasim SR, Kausik N, Kumar D, Kumar P. E-J Chem.
2009;6(S1):S342-S34 6.
548. Bawa S, Kumar S Indian J Chem. 2009;48B:142- 145
549. Vora JJ, Vasava SB, Parmar KC, Chauhan SK, Sharma SS J Chem.
2009;6(4):1205- 1210.
550. Atia AJK. Molecules. 2009;14:2431-2446.
551. Hossain MI, Bhuiyan MMH J. Sci. Res. 2009;1(2):317-325.
552. Srikar A, K. Channabasavaraj P, Dharmamoorty G, Valmiki N, Chinnappa C,
Venu Babu T, J. Pharm.Sci. & Res. 2009;1(2): 13
553. Morshedi M, Amirnasr M, Slawin AMZ, Woollins JD, Polyhedron.
2009;28:167.
554. Jitendra Kumar Gupta, Rakesh Kumar Yadav, Rupesh Dudhe, Pramod Kumar
Sharma, Inter. J. Pharm. Tech. Res. 2010; 2(2), 1493-1507.
555. Dabholkar VV, Ali Syed SAS, Rasayan J Chem. 2010;3(4):761-765.
556. Munj PP, Somani RR, Chavan AV Der Pharma Chemica. 2010;2(1):98-103.
557. Singh UK, Pandeya SN, Sethia SK, Pandey M, Singh A, Garg A, Kumar P. Int
J Pharm Sci Drug Res.2010;2(3):216-218.
558. Hunas HR, Ronad PK, Maddi V, Darbhamulla S, Kamdod M. Int J Drug
Desig Discov. 2010;1(1):107-113.
61
559. Singh UK, Pandeya SN, Jindal S, Pandey M, Srivastava B, Singh A. Der
Pharma Chemica. 2010;2(2):392-399.
560. Panneerselvam P, Ravi Sankar Reddy, Kumarasamy Murali and Natesh
Ramesh Kumar. Der Ph arma Chemica. 2010;2(1):28-37.
561. Devi KS, Ramaiah M, Roopa DL, Vaidya VP, E-J Chem. 2010;7(S1):S358-
S362.
562. Asiri AM, Khan SA, Molecules. 2010;15:6850-6858.
563. Salimon J, Salih N Int J Pharm Tech Res. 2010;2(1):205-208.
564. Xiao X, Jiang-tao W, Jie B, Journal of Chemical Engineering of Chinese
Universities04, 2010
565. Asamizu T, Nielsen JL, Nicholson BK, J. Organometal. Chem., 2010; 695: 96
566. Alang G, Kaur R, Kaur G, Singh A, Singla P Acta Pharmaceutica Sciencia.
2011;52:213-218.
567. Patel NB, Patel JC. Arabian J Chem. 2011;4(4):403-411.
568. Jubie S, Sikdar P, Antony S, Kalirajan R, Gowramma B, Gomathy S, Elango
K. Pak J Pharm Sci. 2011;24(2):109-112.
569. Panneerselvam P, Karikalan M Int J Pharm Bio Sci. 2011;2(1):267-272.
570. Yadav PS, Devprakash, Senthilkumar GP. Int J Pharm Sci Drug Res.
2011;3(1):01- 07.
571. Prabhu PP, Pande S, Shastry CS. Int J Chem Tech Res. 2011;3(1):185-191.
572. Ghadage RV, Shirot PJ , Bangladesh J Pharmacol. 2011;6:92-99.
573. Ghadage RV, Shirote PJ, Int J Pharm Res Dev. 2011;3(7):157-164.
574. Wei Q, Xiong J, Jiang H, Zhang C, Ye W, Int. journal of Food Microbiology.
2011; 150: 164
575. Mohammad MQ, Journal of Barash Researchers, 2011; 37(48)
62
576. Suresh Kumar K, Ganguly S, VijaiPandi P, Veerasamy R, John B. Int J Drug
Desig Discov. 2012;3(1);702-712.
577. Suraj B.Ade, M.N. Deshpande and D.G kolhatkar journal of chemicals
pharmaceutical research 2012, 4(2), 1033-1035
578. Ozlem, ozen karakug, HasalaettinDeligoz , J.IRAN CHEM SOC 2012,9:93-
100
579. L.Mitu, M.Ilis, N.Raman, M.Imran and S.Ravichandran , E.journal of
chemistry , vol 9,2012, 365-372.
580. M. Al-Neaimi mohammed ,periodica polytechnica chemical engineering 56/2,
2012, 83- 90
581. M.B. Fugu, N.P.Ndahi , B.B.Paul and A.N.Mustapha ,journal of chemical and
pharmaceutical research 2013,5(4),22-28.
582. RishuKatwal, HarpreetKaur and Brijkishore Kapur, Sci.
Reves.Chem.Commun; 3(1) : 201, 1-15.
583. Dinesh kumar , silky chadda, jyothi Sharma and Praveen suratin, Bio inorg
chem. 2013, 981764.
584. Amit kumar Sharma , sulekh Chandra , spectrochimica Acta part A; molecular
and Bio molecular spectroscopy , vol 103, 2013, 96-100.
585. Ersin In Kaya,Salih Gunnaz,Namik Ozdemir,osman payan,Muharrem
Dincer,Bekir Cetin Kaya,Spectro Chemica Acta Part A:Molecular and
Biomoleuclar SpectroScopy,Volume 103,2013,255-263.
586. Sulekh Chandra,Ruchi,Spectro Chemica Acta part A,molecular and
Biomolecular spectroscopy,Volume 103,2013,338-348.
587. Subbaiyan Sathiyaraj and Chinnasany Jayabalakirshnan J.Chil.Chem.Soc Vol
58 no.1 concepcion 2013.
588. A.P Mishra,Neha Sharama,Rajendra K.Jain,open journal of syntheris theory
and Applications.2013,vol.2,56-62.
63
II.1. Infrared Spectroscopy:
Infrared (IR) spectroscopy is one of the most common spectroscopic
techniques used by organic and inorganic chemists. Simply, it is the absorption
measurement of different IR frequencies by a sample positioned in the path of an IR
beam. The main goal of IR spectroscopic analysis is to determine the chemical
functional groups in the sample. Different functional groups absorb characteristic
frequencies of IR radiation. Using various sampling accessories, IR spectrometers can
accept a wide range of sample types such as gases, liquids, and solids. Thus, IR
spectroscopy is an important and popular tool for structural elucidation and compound
identification.
Infrared radiation spans a section of the electromagnetic spectrum having
wave numbers from roughly 13,000 to 10 cm–1 or wavelengths from 0.78 to 1000 µm.
It is bound by the red end of the visible region at high frequencies and the microwave
region at low frequencies. IR absorption positions are generally presented as either
wave numbers or wavelengths (l). Wave number defines the number of waves per unit
length. Thus, wave numbers are directly proportional to frequency, as well as the
energy of the IR absorption. The wave number unit (cm–1, reciprocal centimeter) is
more commonly used in modern IR instruments that are linear in the cm–1 scale. In the
contrast, wavelengths are inversely proportional to frequencies and their associated
energy. At present, the recommended unit of wavelength is µm (micrometers), but µ
(micron) is used in some older literature. Wave numbers and wavelengths can be
interconverted using the following equation:
64
IR absorption information is generally presented in the form of a spectrum
with wavelength or wave number as the x-axis and absorption intensity or percent
transmittance as the y-axis.
The transmittance spectra provide better contrast between intensities of strong
and weak bands because transmittance ranges from 0 to 100% T whereas absorbance
ranges from infinity to zero. The analyst should be aware that the same sample will
give quite different profiles for the IR spectrum, which is linear in wave number, and
the IR plot, which is linear in wavelength. It will appear as if some IR bands have
been contracted or expanded. The IR region is commonly divided into three smaller
areas: near IR, mid IR, and far IR.
Wave number 13,000–4,000 cm–1 4,000–200 cm–1 200–10 cm–1 Wavelength
0.78–2.5 µm 2.5–50 µm 50–1,000µm.
This chapter focuses on the most frequently used mid IR region, between 4000
and 400 cm–1 (2.5 to 25 µm). The far IR requires the use of specialized optical
materials and sources. It is used for analysis of organic, inorganic, and organometallic
compounds involving heavy atoms (mass number over 19). It provides useful
information to structural studies such as conformation and lattice dynamics of
samples. Near IR spectroscopy needs minimal or no sample preparation. It offers
high-speed quantitative analysis without consumption or destruction of the sample. Its
instruments can often be combined with UV-visible spectrometer and coupled with
fiber optic devices for remote analysis. Near IR spectroscopy has gained increased
interest, especially in process control applications.
Infrared spectroscopy exploits the fact that molecules have specific
frequencies at which they rotate or vibrate corresponding to discrete energy levels
(vibrational modes). These resonant frequencies are determined by the shape of the
65
molecular potential energy surfaces, the masses of the atoms and, by the associated
vibronic coupling. In order for a vibrational mode in a molecule to be IR active, it
must be associated with changes in the permanent dipole. In particular, in the Born–
Oppenheimer and harmonic approximations, i.e. when the molecular Hamiltonian
corresponding to the electronic ground state can be approximated by a harmonic
oscillator in the neighbourhood of the equilibrium molecular geometry the resonant
frequencies are determined by the normal modes corresponding to the molecular
electronic ground state potential energy surface. Nevertheless, the resonant
frequencies can be in a first approach related to the strength of the bond, and the mass
of the atoms at either end of it. Thus, the frequency of the vibrations can be associated
with a particular bond type. Simple diatomic molecules have only one bond, which
may stretch. More complex molecules have many bonds, and vibrations can be
conjugated, leading to infrared absorptions at characteristic frequencies that may be
related to chemical groups. For example, the atoms in a CH a group, commonly found
in organic compounds can vibrate in six different ways: symmetrical and
asymmetrical stretching, scissoring, rocking, wagging and twisting:
Fig–II.1: Schematic diagram of infrared spectroscopy
The infrared spectrum of a sample is collected by passing a beam of infrared
light through the sample. Examination of the transmitted light reveals how much
energy was absorbed at each wavelength. This can be done with a monochromatic
66
beam, which changes in wavelength over time, or by using a Fourier transform
instrument to measure all wavelengths at once. From this, a transmittance or
absorbance spectrum can be produced, showing at which IR wavelengths the sample
absorbs. Analysis of these absorption characteristics reveals details about the
molecular structure of the sample.
This technique works almost exclusively on samples with covalent bonds.
Simple spectra are obtained from samples with few IR active bonds and high levels of
purity. More complex molecular structures lead to more absorption bands and more
complex spectra. The technique has been used for the characterization of very
complex mixtures.
Isotope effect:
The different isotopes in a particular species may give fine detail in infrared
spectroscopy. For example, the O–O stretching frequency (in reciprocal centimeters)
of oxyhemocyanin is experimentally determined to be 832 and 788 cm–1 for
ν (16O–16O) and ν (180–18O) respectively.
By considering the O–O as a spring, the wave number of absorbance, ν can be
calculated:
µπυ
k
21
=
Where k is the spring constant for the bond, and is the reduced mass of the A–
B system:
BA
BA
mm
mm
+=µ
(mi is the mass of atom i).
Where v is the wave number [wave number = frequency/(speed of light)]
67
Applications:
Infrared spectroscopy is widely used in both research and industry as a simple
and reliable technique for measurement, quality control and dynamic measurement. It
is of especial use in forensic analysis in both criminal and civil cases, enabling
identification of polymer degradation for example. It is perhaps the most widely used
method of applied spectroscopy.
By measuring at a specific frequency over time, changes in the character or
quantity of a particular bond can be measured. This is especially useful in measuring
the degree of polymerization in polymer manufacture. Infrared spectroscopy has been
highly successful for applications in both organic and inorganic chemistry. Infrared
spectroscopy has also been successfully utilized in the field of semiconductor
microelectronics [12]: for example, infrared spectroscopy can be applied to semi-
conductors like silicon, gallium arsenide, gallium nitride, zinc selenide, amorphous
silicon, silicon nitride, etc.
II.2 NMR (Nuclear Magnetic Resonance Spectroscopy):
Nuclear magnetic resonance spectroscopy, most commonly known as NMR
spectroscopy, is the name given to a technique which exploits the magnetic properties
of certain nuclei. This phenomenon and its origins are detailed in a separate section on
nuclear magnetic resonance. The most important applications for the organic chemist
are proton NMR and carbon–13 NMR spectroscopy. In principle, NMR is applicable
to any nucleus possessing spin. The impact of NMR spectroscopy on the natural
sciences has been substantial. It can, among other things, be used to study mixtures of
analytes, to understand dynamic effects such as change in temperature and reaction
mechanisms, and is an invaluable tool in understanding protein and nucleic acid
68
structure and function. It can be applied to a wide variety of samples, both in the
solution and the solid state.
Basic NMR techniques:
When placed in a magnetic field, NMR active nuclei (such as 1H or 13C)
absorb at a frequency characteristic of the isotope. The resonant frequency, energy of
the absorption and the intensity of the signal are proportional to the strength of the
magnetic field. For example, in a 21 T magnetic field, protons resonate at 900 MHz. It
is common to refer to a 21 T magnet as a 900 MHz magnet, although different nuclei
resonate at a different frequency at this field strength. In the Earth’s magnetic field the
same nuclei resonate at audio frequencies. This effect is used in Earth’s field NMR
spectrometers and other instruments. Because these instruments are portable and
inexpensive, they are often used for teaching and field work.
Chemical shift:
Depending on the local chemical environment, different protons in a molecule
resonate at slightly different frequencies. Since both this frequency shift and the
fundamental resonant frequency are directly proportional to the strength of the
magnetic field, the shift is converted into a field–independent dimensionless value
known as the chemical shift. The chemical shift is reported as a relative measure from
some reference resonance frequency. (For the nuclei 1H, 13C, and 29Si, TMS
(tetramethylsilane) is commonly used as a reference.) This difference between the
frequency of the signal and the frequency of the reference is divided by frequency of
the reference signal to give the chemical shift. The frequency shifts are extremely
small in comparison to the fundamental NMR frequency. A typical frequency shift
might be 100 Hz, compared to a fundamental NMR frequency of 100 MHz, so the
chemical shift is generally expressed in parts per million (ppm)[9].
69
By understanding different chemical environments, the chemical shift can be
used to obtain some structural information about the molecule in a sample.
Fig.II.2 : A simple block diagram of an NMR spectrometer
J–Coupling:
Some of the most useful information for structure determination in a one–
dimensional NMR spectrum comes from J–coupling or scalar coupling (a special case
of spin–spin coupling) between NMR active nuclei. This coupling arises from the
interaction of different spin states through the chemical bonds of a molecule and
results in the splitting of NMR signals. These splitting patterns can be complex or
simple and, likewise, can be straightforwardly interpretable or deceptive. This
coupling provides detailed insight into the connectivity of atoms in a molecule.
Coupling to n equivalent (spin ½) nuclei splits the signal into a n+1 multiplet with
intensity ratios following Pascal’s triangle as described on the right. Coupling to
additional spins will lead to further splitting of each component of the multiplet e.g.
coupling to two different spin ½ nuclei with significantly different coupling constants
will lead to a doublet of doublets (abbreviation: dd). Note that coupling between
nuclei that are chemically equivalent (that is, have the same chemical shift) has no
70
effect of the NMR spectra and couplings between nuclei that are distant (usually more
than 3 bonds apart for protons in flexible molecules) are usually too small to cause
observable splittings. Long–range couplings over more than three bonds can often be
observed in cyclic and aromatic compounds, leading to more complex splitting
patterns.
Coupling to any spin ½ nuclei such as phosphorus–31 or fluorine–19 works in
this fashion (although the magnitudes of the coupling constants may be very
different). But the splitting patterns differ from those described above for nuclei with
spin greater than ½ because the spin quantum number has more than two possible
values. For instance, coupling to deuterium (a spin 1 nucleus) splits the signal into a
1:1:1 triplet because the spin 1 has three spin states. Similarly, a spin 3/2 nucleus
splits a signal into a 1:1:1:1 quartet and so on. Coupling combined with the chemical
shift (and the integration for protons) tells us not only about the chemical environment
of the nuclei, but also the number of neighbouring NMR active nuclei within the
molecule. In more complex spectra with multiple peaks at similar chemical shifts or in
spectra of nuclei other than hydrogen, coupling is often the only way to distinguish
different nuclei.
Application of NMR:
Today NMR has become a sophisticated and powerful analytical technology
that has found a variety of applications in many disciplines of scientific research
medicine and various industries modern NMR spectroscopy has been emphasizing the
application in biomolecular system and play an important role in structural biology
with developments in both methodology and instrumentation in the past two decades
NMR has become one of the most powerful and versatile spectroscopic technique for
the analysis of biomacromolecules ,and their compl4exes up to 100KDa together with
71
X-ray crystallography ,NMR spectroscopy is one of the two leading technologies for
the structural determinations of biomacromolecules at atomic resolution in addition
NMR provide unique and important molecular motional and interaction profile
containing pivotal information on protein function the information is also critical drug
development some of the applications of NMR spectroscopy are listed below.
NMR spectroscopy has contributed enormously to chemical knowledge.
A wide range of techniques has been used with a range of magnetic fields including
high-field super conducting magnets. NMR frequencies from 60 to 800 MHz for
medical magnetic resonance imaging (MRI). One of the major sources of chemical
information is the measurement of chemical shifts in high-resolution spectroscopy.
The chemical shifts are a very sensitive probe of the chemical environment of the
resonating nuclei.
II.3 Ultraviolet and Visible Spectrophotometer:
Introduction:
Ultraviolet-visible spectroscopy or ultraviolet-visible spectrophotometry
(UV-Vis or UV/Vis) involves the spectroscopy of photons in the UV-visible region. It
uses light in the visible and adjacent (near ultraviolet (UV) and near infrared (IR))
ranges. The absorption in the visible ranges directly affects the color of the chemicals
involved. In this region of the electromagnetic spectrum, molecules undergo
electronic transitions. This technique is complementary to fluorescence spectroscopy,
in that fluorescence deals with transitions from the excited state to the ground state,
while absorption measures transitions from the ground state to the excited state [10].
The instrument used in ultraviolet-visible spectroscopy is called a UV-vis
spectrophotometer. It measures the intensity of light passing through a sample (I), and
compares it to the intensity of light before it passes through the sample (I0). The ratio
72
I /10 is called the transmittance, and is usually expressed as a percentage (%T). The
absorbance, A, is based on the transmittance:
A = -log (%T/100%)
The basic parts of a spectrophotometer are a light source, a holder for the
sample, a diffraction grating or monochromator to separate the different wavelengths
of light, and a detector. The radiation source is often a Tungsten filament
(300-2500 nm), a deuterium arc lamp which is continuous over the ultraviolet region
(190-400 nm), and more recently light emitting diodes (LED) and Xenon Arc Lamps
[6] for the visible wavelengths. The detector is typically a photodiode or a CCD.
Photodiodes are used with monochromators, which filter the light so that only light of
a single wavelength reaches the detector. Diffraction gratings are used with CCDs,
which collects light of different wavelengths on different pixels.
Fig.II.3: Schematic Diagram of a single-beam UV/vis spectrophotometer
A spectrophotometer can be either single beam or double beam. In a single
beam instrument, all of the light passes through the sample cell. I0 must be measured
by removing the sample. This was the earliest design, but is still in common use in
both teaching and industrial labs. In a double-beam instrument, the light is split into
two beams before it reaches the sample. One beam is used as the reference; the other
73
beam passes through the sample. Some double-beam instruments have two detectors
(photodiodes), and the sample and reference beam are measured at the same time. In
other instruments, the two beams pass through abeam chopper, which blocks one
beam at a time. The detector alternates between measuring the sample beam and the
reference beam.
Applications:
UV/Vis spectroscopy is routinely used in the quantitative determination of
solutions of transition metal ions and highly conjugated organic compounds.
Solutions of transition metal ions can be coloured (i.e., absorb visible light) because
d-electrons within the metal atoms can be excited from one electronic state to another.
The colour of metal ion solutions is strongly affected by the presence of other species,
such as certain anions or ligands. For instance, the colour of a dilute solution of
copper sulphate is a very light blue; adding ammonia intensifies the colour and
changes the wavelength of maximum absorption (λmax).
Organic compounds, especially those with a high degree of conjugation, also
absorb light in the UV or visible regions of the electromagnetic spectrum. Solvent
polarity and pH can effect the absorption spectrum of an organic compound. Tyrosine,
for example, increases in absorption maxima and molar extinction coefficient when
pH increases from 6 to 13 or when solvent polarity decreases.
While charge transfer complexes also give rise to colours the colours are often
too intense to be used for quantitative measurement. The Beer-Lambert law states that
the absorbance of a solution is directly proportional to the concentration of the
absorbing species in the solution and the path length. Thus, for a fixed path length,
UV/VIS spectroscopy can be used to determine the concentration of the absorber in a
solution.
74
II.4 Electron Spin Resonance Spectrometry:
Before delving deeper into the physical and chemical aspects of ESR, it is
necessary that the operating principles of an ESR spectrometer be under stood[5], Just
as in other spectroscopic methods, ESR requires a source of radiant energy, a means
of routing this energy, a region for accommodating the sample, and an energy
detector; in addition it also requires a magnetic field to split the Zeeman energy levels
of the unpaired electrons in the sample, Figure II.4 presents a simple block diagram of
an ESR spectrometer. In describing its operation it is helpful to employ optical
analogies because many of the components are mechanically different, but serve
functions similar to counterparts used in more conventional forms of spectroscopy.
hυ = geµβH (1)
According to the resonance equation (1), ESR signals can be observed by
varying either the frequency u or the field H. From the practical standpoint of
engineering it is far simpler to vary the magnetic field and to maintain a constant
frequency of excitation during an ESR experiment. The required energy lies in the
microwave region of the electromagnetic spectrum, midway between infrared and
radio frequencies, monochromatic microwave radiation is available from electron
tubes called “klystrons”; the frequency output of a klystron may be altered over a
narrow band by adjustment of a grid voltage while coarser adjustments are possible
through physically changing the spacing of its internal electrodes. If another
frequency outside this range is desired, a tube with different physical dimensions must
be substituted. Due to the critical dependence of the frequency on the electrode
separation the klystron must be cooled (by immersion in a thermo stated mineral oil
bath or by conduction through a flange) in order to minimize the frequency drift
associated with thermal expansion during operation. The most widely used ESR
75
frequency is centered around 9.5 GHz, in the so–called “x–band” of microwave
radiation; other common ESR frequencies are 25 GHZ, (K–Band) and 35 HGZ, (Ka–or
Q–band). The letter designations are holdovers from the military secrecy which
surrounded the development of radar technology during World War – II.
Fig.II.4. Block diagram of ESR spectrometer
Factors Affecting the Magnitude of the g Values:
The value of g for an unpaired electron in a gaseous atom or ion, for which
Russell–Saunders coupling is applicable, is given by the expression
( ))1(2
)1()1((11
+
+−++++=
JJ
LLSSJJg (3)
For a free electron (S= ½, L=0, J = ½), the value of g = 2.0 is easily calculated
from equation (10–3). The actual value for a free electron is 2.0023 where the
contribution 0.0023 is due to a relativistic correction. For the halogen atoms in the gas
phase, g values predicted by equation 3 have been found to agree exactly with
experimental values. All halogen atoms have the same ground state term (2
32P , L = 1,
S = ½, J = ½) substitution of these values into equation (10–3) yields g = 34 , identical
with the experimental value. No such agreement is found, however, when the
unpaired electron is placed in a chemical environment, either in a free radical, or in a
transition metal ion complex crystal lattice. In such a chemical environment the
76
orbital motion of the electron is strongly perturbed and the orbital degeneracy, if it
existed before application of the chemical environment, is partly removed or
“quenched.” Jahn – Teller distortions also serve to remove orbital degeneracy. On the
other hand, a certain amount of orbital degeneracy tends to be sustained as the result
of spin – orbit coupling i.e., complete removal of the orbital degeneracy is prevented
by spin–orbit coupling but higher fold degeneracies are often decreased by this effect.
Qualitatively, this “sustaining effect” implies that if an electron has orbital angular
momentum, this is maintained by coupling to the spin angular momentum, and if it
has a spin angular momentum this tends to generate orbital angular momentum.
Consequently, because of the quenching and sustaining competition, the orbital
degeneracy is partly but not completely removed and a net orbital magnetic moment
results, giving rise to a g value different from the value magnetic moment results,
giving rise to a g value different from the value 2.0023 expected if the orbital
degeneracy were completely removed.
In most free radicals, the small orbital contribution results because either the
molecule has low symmetry (or) else if the gross symmetry of the molecule allows
degenerate energy levels, the degeneracy is destroyed by Jahn–Teller distortion.
Moreover, spin–orbit coupling in free radicals is very small. As a result, the g values
are nearly equal to the free electron value of 2.0023. The small deviations
(±0.05, or smaller) often observed for most radicals are accounted for by a mixing of
low–lying excited states with the ground state. Thus, g values for free radicals are of
limited use. Only when there are significant deviations from the free–electron value,
can some information be gained about the nature of the excited states. With transition
metal ions, however, the situation is much more complicated and interesting. The
properties of the transition metals are determined to a large extent by the relative
77
magnitudes of the crystal field and spin–orbit coupling. As we saw in the preceding
section, these two interactions have opposite effects on the orbital degeneracy.
We can distinguish three cases: The effect of spin–orbit coupling is much
larger than that of the crystal field. The rare–earth ions fall in this class because the
f–electrons are well shielded from the crystal field effects so that LS coupling is not
disturbed and J is a good quantum number. Thus the rare–earth ions are very much
like free ions, magnetic moments calculated by equation (3) give very good
agreement with experimental values.
The effect of the crystal field is strong enough to break the coupling between
L and S, hence J is no longer a good quantum number. The splitting of the mL levels
is large (i.e., the orbital degeneracy is quenched) and the EPR transitions are
described by the selection rule ∆ms= ± l. The first row transition metals fall into this
category. The magnetic moments cannot be calculated by equation (10–3), but
correspond more nearly to the “spin–only” value. As noted above the orbital
degeneracy is not removed completely because of the effect of spin–orbit coupling.
Consequently a net orbital magnetic moment results, giving rise to a g value different
from the free electron value expected if the orbital degeneracy were completely
removed, but closer to 2.0023 than predicted by equation (10–3). Ions which have an
orbitally non degenerate ground state such as Fe3+(6S) and Mn2+ (6S) give g values
nearly equal to the free–electron value, since there is practically no orbital angular
momentum. The small deviation from the free electron value is due to slight spin orbit
coupling.
In the strong field case, the effect of the crystal field is very large so that LS
coupling is broken down completely. This corresponds to covalent bonding and is
applicable to the complexes of the 4d and 5d transition metals and to the strong–field
78
complexes of the 4d and 5d transition metals and to the strong–field complexes of the
3d transition metals, such as cyanides. In many of these cases a molecular orbital
description gives better results than the crystal field approximation.
We shall now consider briefly two specific examples to illustrate what factors
determine the magnitude of the g values. For octahedral nickel (II) complexes,
calculations [7] which include mixing of the 3A2g ground state with the 3T2g excited
state, give the following equation for the g value :
g = 2–8λ/10Dq (4)
Where, λ is the spin-orbit coupling constant. In hexaquonickel (II), it is found
experimentally that g = 2.25 hence 8λ/10Dq must equal –0.25. From the electronic
spectrum one can calculate 10Dq=8500cm–1 producing λ.=–270cm–1. In the complex,
λ is reduced considerably from the free ion value of –324 cm–1 . In a molecular orbital
description the extent to which λ is lowered from the free–ion value is a measure of
the extent of mixing of metal and ligand orbitals. This example illustrates how both
spin orbit coupling and Dq can affect the magnitude of the g value.
II.5 Theoretical Aspects of Conductivity Measurements:
Conductance measurements are very much useful in knowing the nature of the
electrolyte in solution. The ionic species in solution carry more conductance value
than that of the non–electrolyte. There are also a number of direct applications of
conductance measurements to chemical problems. The usefulness of conductance
arises from its dependence on the ionic concentration and from its special sensitivity
to the concentration of H+ and OH– ions.
Conductivity measurements are extended to know the nature of the
coordination compounds. The majority of coordination compounds suggested are
79
good electrolytes. Conductivity studies are used to show that the expected number of
ions are present. These studies brought out the manner in which the charge on the
coordination sphere depends on the number of coordinated ions.
In order to determine whether the coordination compound is ionic or
non–ionic, conductance measurements play an important role. Cell constant, specific
conductance and molar conductance values will decide the nature of the metal
complex present in the electrolyte.
Conductivity Bridge:
The present solid complexes are easily soluble in dimethylformamide (DMF).
Therefore, solid complexes are dissolved in DMF to perform conductivity
experiments.
Known amounts of solid chelates are transferred to different 25 ml standard
flask and dissolved in DMF. The contents are made up to the mark with DMF and
transferred to a 100 ml beaker to measure the conductance of the solution. Specific
and molar conductance values are calculated using the following equations.
Specific Conductance (k) = cell constant x conductance
= (l/a) x conductance
= 1.192 x conductance
Molar conductance (µ) = k x 100 / c
Where, 1 = distance between two electrodes
A = area of two electrodes
C = concentration of conducting materials.
80
II.6. Thermogravimetric analysis (TGA):
When the sample was analyses, various chemical changes (e.g. thermal
decomposition, oxidation etc.) and several physical processes (solvent and water
desorption, evaporation, sublimation etc.) may take place, with a consequent change
in the weight of the sample. The examination of these processes is the task of
thermogravimetric analysis method (TGA method).
The schematic diagram for a continuous thermobalance is shown in Fig.II.5.
The sample is placed in a crucible, fixed on an upward – or downward–pointing
extension of the balance arm. The sample is heated in a programmed electric furnace,
which also houses a thermocouple. With the aid of this thermocouple and
millvoltmeter, the weight of the sample can be recorded continuously as a function of
temperature.
Balances are either and null–point or the deflection types of instruments. The
former incorporates a suitable sensing element that detects any deviation of the
balance beam and provides the application of a restoring force, proportional to the
change in weight to return the beam to its original null point. This restoring force is
then recorded either directly or through a transducer. Deflection instruments based on
a conventional analytical balance involve the conversion of deviations into a record of
the weight change. The recording system should be able to record both temperature
and weight continuously and to make a periodic record of the time. A continuous
record of weight and temperature ensures that no features of the thermograms are
overlooked.
81
Fig.II.5. Schematic diagram of a thermobalance
1. Crucible holding the sample 2. Porcelain rod, 3. Electric furnace 4. Thermocouple 5. Millivoltmeter 6. Arm of balance
Plateaus on the decomposition curve, indicative of constant weight, represent
stable phases over the particular temperature interval. An inflection may imply the
formation of an intermediate compound, or the adsorption of a volatile product on
(or in) the new solid phase. Successive plateaus correspond to the anhydrous salt,
calcium carbonate, and calcium oxide.
In interpreting thermogravimetric curves, one must always be cognizant that
the decomposition temperature is a function of method, apparatus and procedure.
The widest applications of the thermogravimetric analysis has been in the
investigation of analytical procedures
a) In investigating suitable weighing forms for many elements.
b) In testing materials that are actual or potential analytical standards and
c) In the direct application of the technique to analytical determinations.
The results furnished by TGA curves were used primarily for the
determination of the thermal stability of analytical precipitates. To the study of the
thermal stability of a wide range of inorganic compounds.
82
The scope of TGA and DTA thermoanalytical methods:
The thermal curves may be used to detect physical and chemical changes and
to evaluate qualitatively reactions occurring with or without a change in weight,
exothermic and endothermic processes etc., Much useful information and be drawn
from the results; however, it should be emphasized that final conclusions must not be
drawn from the results of thermal investigations alone. Thermal methods are suitable
for the determination of the character and even the extent of the decomposition, and
they present therefore a basis for other supplementary measurements, or they support
the results of other methods of instrumental analysis.
The methods most often used afford the following information. The TG curve
permits us to establish:
a) The temperature below which the compound investigated has a constant
weight, and at which it begins to decompose.
b) How far the decomposition reaction can proceed. The observed and
stoichiometric decrease in weight of the substance makes possible the
calculation of the stoichiometry of the decomposition and the amount of the
contaminants present can be estimated.
c) Whether an intermediate product is formed during decomposition and if so, at
what temperature, occasionally the temperature range where this intermediate
has constant weight, or can be isolated, may also be determined (d). The
temperature at the completion of the reaction.
It should be noted that in the TGA method the weight of the residual sample is
always measured. Either the volatile substances (gases) must be identified or their
nature must be deduced from the composition of the residual substance.
83
This method may yield information on the bond strengths in some substances,
e.g. how strongly water or some volatile ligands (e.g. NHS, CeHSN etc.) are bound in
a complex. Depending on this factor, water on the ligands will be liberated at different
temperatures.
The DTA curve yields important results from a qualitative point of view. The
signs of the enthalpy changes, the modes of the transformations, and their
characteristic temperatures can be established from the curve. The DTA curve also
indicates changes which do not appear on the TGA curve, because they are not
accompanied by a change in weight.
II.7. Powder X–Ray Diffraction:
X–ray diffraction has recently become an increasingly important technique for
qualitative and quantitative analysis. Crystal structure by X–ray diffraction is the only
convenient physical procedure available to the chemist for the complete analysis of
molecular structure and determination of electron distribution in the molecule. X–ray
diffraction methods are generally used for investigating the internal structures. The
method also provides all bond lengths and angles in the molecule which helps in the
determination of nature of bond.
Powder method was devised independently by P. Debye and P. Scherrer
(1916) and A.W. Hill (1917). X–ray powder diffraction (XRD) is a rapid analytical
technique primarily used for phase identification of a crystalline material and can
provide information on unit cell dimensions. The analyzed material is finely ground,
homogenized, and average bulk composition is determined. This method employs
powdered samples in which the crystals are oriented in all directions so that some of
the crystals will be properly oriented for observable reflections. A narrow beam of
monochromatic X–rays is allowed on the finely powdered specimen. The diffracted
84
rays are then passed on to a strip of film which almost completes surrounds the
specimen. The random orientation of crystals produces diffraction rings or caves
rather than spots. The method is commonly employed for identification purposes by
comparing the observed spacing of the axes produced on the film. Extensive files of
spicing from powder photographs are available for comparison. For a cubic crystal the
identification of lines in the powder photograph is relatively simple. Also the indexing
of lines in hexagonal, rhombohedral, tetrahedral etc. is not very complicated.
However, in crystals of lower symmetry a large number of lines are observed which
can not be accurately identified.
Fig.II.6. X Ray Diffraction Phenomena
The angle between the beam axis and the ring is called the scattering angle
and in X–ray crystallography always denoted as 2θ (In scattering of visible light the
convention is usually to call it θ). Powder diffraction data are usually presented as a
diffractogram in which the diffracted intensity I is shown as function either of the
scattering angle 2θ or as a function of the scattering vector q. The latter variable has
the advantage that the diffractogram no longer depends on the value of the
wavelength λ.
Bragg’s Law : nλ = 2d sin θ
85
This law relates the wavelength of electromagnetic radiation to the diffraction
angle and the lattice spacing in a crystalline sample. These diffracted X–rays are then
detected, processed and counted. By scanning the sample through a range of 2θangles,
all possible diffraction directions of the lattice should be attained due to the random
orientation of the powdered material. Conversion of the diffraction peaks to
d–spacings allows identification of the mineral because each mineral has a set of
unique d–spacings. Typically, this is achieved by comparison of d–spacings with
standard reference patterns.
II.8 MAGNETIC PROPERTIES (VSM)
Magnetic behavior of ligand and its Metal Complexes
The characterization of the magnetic properties of transition metal complexes
acquires greater significance, besides their spectroscopic properties.
Magnetic moments are generally useful in determining the number of unpaired
electrons to provide information about the population and relative energies of ‘d’
levels in a complex and allow the distraction to be made between octahedral and
tetrahedral complexes. Magnetic susceptibility of a sample can be determined by
several experimental approaches.
Magnetic susceptibility data was recorded on an EG and G-155 magnetometer.
The powdered and dissolved samples of the compounds were introduced in capsules
in a glove box and kept under an inert atmosphere before being placed into the
magnetometer. The calibration was made at 298o K using a palladium reference
supplied by quantum design. The independence of the susceptibility value with
regard to the applied field was checked at room temperature. Applied research
vibrating sample magnetometer VSM-155 operating at field strengths ranging from
86
0.3 to 0.8 T. The VSM is calibrated against the saturated moment of 99.999% ultra
pure nickel.
Finally ground powder of the sample, typically weighing 50mg is housed in a
sample holder and placed in a uniform homogeneous magnetic field. Where the
sample is made to undergo sinusoidal motion. The out put data are corrected for the
diamagnetism of the sample holder and for the underlying diamagnetism of the
constituent atoms of the ligands using Pascal’s constants. The moment recorded at
different field strengths is used to evaluate µ eff in Bohr magnetons using .
(µ eff ) = 2.84 strength field magnetic sampleWeight
T weight molecular moment Magnetic
×
××
From the magnetic moment values which are determined experimentally, it
is very easy to decide paramagnetic and diamagnetic nature of the metal complexes.
With the help of magnetic measurements it is easy to predict the appropriate
structure of the metal complex since the magnetic measurements decide the number
of unpaired electrons in the d-shall of the transition metal.
87
References:
1. Russell S.Drago, “Physical methods in inorganic chemistry” Reinhold & Co
Ltd, New York, 1965.
2. Wendlandt, W.W. and Smith, J.P., “The thermal properties of transition Metal
Ammine Complexes, Elsevier, Amsterdam, 1967.
3. R.R.Hill and D.A.E.Rendell, “The Interpretation of Infrared Spectra”,
Heyden&SonLtd. New York, 1975.
4. A.D.Cross and R.A.Jones, “An Introduction to Practical Infrared
Spectroscopy” Butterworth, London, 1969.
5. J.H.Van der Mass, “Basic Infrared Spectroscopy”, 2nd Edn, Heyden & Son,
London, 1972.
6. Duval, C., “Inorganic Thermo gravimetric analysis, Elsevier, Amsterdam,
1963.
7. M.Arram and Gh.D. Mateescu, Infrared Spectroscopy, Applications in organic
Chemistry, Wiley–Interscience, New York, 1972.
8. William Kemp, “NMR in chemistry”, Macmillan Education Ltd, London,
1986.
9. K.Burger, “Coordination chemistry: Experimental methods” Butterworth &
Co. Ltd, London, 1973.
10. R.E.Robertson, “Determination of organic structures by physical methods”,
Vol. 2, eds. F.C.Nachod and W.D.Phillips, Academic, New York, 1962.
11. L.J.Bellamy, “The infrared spectra of complex molecules”, Wiley, New York,
1954.
12. R.S.Khandpur, “Hand book of analytical instruments” Tata McGraw–Hill,
New Delhi, 2004.
13. R.A.Day et al., Quantitative Analysis, Prentice Hall, America
14. C.J.Ballhausen, “Introduction to Ligand field theory” McGraw–Hill, New
York, 1962.
15. Wendlandt, W.W., “Thermal methods of Analysis”, Interscience, New York,
1964.
16. H.T.S.Britton, “Conductometric Analysis”, Von Nostrand, Princeton, N.J.,
1934.
88
Scope of the Study:
The literature survey reveals that, there are very few reports on the synthesis
of schiff bases as well as the preparation of corresponding metal complexes based on
pramipexole and different aldehydes and ketones. Therefore the author has proposed
to take up the work based on the synthesis of new schiff bases as well as the
preparation of metal complexes of industrial, medicinal, biological importance and
their characterization using different analytical techniques.
Pramipexole is one of the most important compounds of amines. Pramipexole
has several important applications in many fields of greater interest mainly medicine,
pharmaceutical, biological, cosmetics, anti cancer, anti tuberculosis, anti tumor,
antiviral, and antibiotic activities, as well as ability to bind to proteins, DNA, and
RNA, has directed numerous synthetic studies and new applications of these azole
heterocycles.,etc. Pramipexole is a dopamineagonist of the non-ergoline class
indicated for treating Parkinson's disease (PD) and restless legs syndrome (RLS). It is
also sometimes used off-label as a treatment for cluster headache and to counteract
problems with sexual dysfunction experienced by some users of selective serotoninre
uptake inhibitor (SSRI) antidepressants. Pramipexole has shown robust effects on
pilot studies in a placebo-controlled proof of concept study in bipolar disorder. It is
also being investigated for the treatment of clinical depression and fibromyalgia.
Employing pramipexole as a common amine, the author in the present
investigation prepared altogether new schiffbases and its metal complexes from
various substituted aldehydes and ketones.
89
The Synthesized Schiff bases are
I) 2-Hydroxy Acetophenone + Pramipexole (OHAPP)
II) 4-Hydroxy Acetophenone+ Pramipexole (PHAPP)
III) Salicilaldehyde + Pramipexole (OHBP)
IV) O- Vanillin + Pramipexole (OVP)
V) Vaniline + Pramipexole (VP)
VI) 2,4-Dihydroxy Acetophenone + Pramipexole (RAPP)
The structures of the prepared Schiff bases were confirmed by elemental and
spectral analysis. Several metal complexes of industrial importance were also
prepared by using the above prepared new Schiff base ligands. Their structural were
also proposed using several analytical techniques like IR, NMR, ESR, TGA-DTA,
XRD, VSM and UV spectrophotometry.The thermal stabilities and conductivity
measurements were studied by thermal analysis and conductometry. The anti bacterial
activities of the above ligand and the complexes were also screened.
Materials used in the present work:
Analytical reagent grade chemicals were used in the present research work.
Where ever analytical grade chemicals were not available, laboratory grade chemicals
were purified and used in the present study. The inorganic salt solutions were
prepared by dissolving the suitable amounts of metal salt in requisite quantity of
distilled water. Few drops of suitable acids are added to avoid hydrolysis before
dilution. The molecular formula and quality of inorganic and organic chemicals used
and analytical data of the ligands are presented in Table.III.1 to III.2.
90
TABLE .III.1 Metal Salts used in the Preparation of Complexes
Metal Salt Formula Quality(Make)
Copper chloride dehydrate CuCl2 2H2O AR- Loba
Ruthenium tri chloride (pure) RuCl3 3H2O Loba
Cobalt chloride hexa hydrate CoCl2 6H2O Loba
Nickel chloride hexa hydrate NiCl2 6H2O Loba
Manganese chloride tetra hydrate MnCl2 4H2O Loba
Lanthanum chloride hepta hydrate LaCl3 7 H2O AR (Loba)
Yttrium chloride hexa hydrate YCl2 6H2O AR (Loba)
Palladium chloride pure PdCl2 AR( SD Fine )
Sodium Acetate CH3COONa .3H2O A R(Merk)
Sodium hydroxide NaOH AR (Qualigens)
TABLE III.2 List of organic compounds used in the present study
Organic Compound M.W Formula Quality(Make)
Pramipexole 211.324 C10H17N3S Aldrich
2- Hydroxy Acetophenone 136.15 C8H8O2 AR-SRL
4- Hydroxy Acetophenone 136.15 C8H8O2 AR-SRL
2-Hydroxy Benzaldehyde 122.12 C7H6O2 AR-SRL
O-vanillin 152.15 C8H9O3 Aldrich
Vanillin 152.15 C8H9O3 Aldrich
2,4-DihydroxyAcetophenone 152.15 C8H8O3 AR-SRL
N,N-Dimethylformamide 73.09 C3H7NO Ranboxy
Methanol 32.04 CH4O AR-Loba
Acetone 58.08 C3H6O SD Fine
Rectified spirit 46.07 C2H6O Loba
91
SYNTHESIS OF LIGANDS:
1. Pramipexole and O-Hydroxry Acetophenone Schiff Base (OHAPP):
Equimolar concentrations (0.01 moles) of pramipexole and
2-hydroxy acetophenone were dissolved in 50 ml of methanol in 250 ml round bottom
refluxing flask and stirred well with a magnetic stirrer. Then few drops of con.HCl
were added to mixture of O-hydroxy acetophenone pramipexole (OHAP-P) ligand.
Then the mixture were stirred well and refluxed for two hours on water bath. On
cooling the above mixture white colour (OHAPP) crystal products were obtained. The
compound was recrystallised from methanol. Yield of the compound is 74% and
melting point of the newly synthesized azomethine (OHAPP) is 255-256 oc.
92
2. Pramipexole and P-Hydroxry Acetophenone Schiff Base (PHAPP):
Equimolar concentrations (0.01 moles) of pramipexole and
4-hydroxy acetophenone were dissolved in 50 ml of methanol in 250 ml round bottom
refluxing flask and stirred well with a magnetic stirrer. Then few drops of con.HCl
were added to mixture of P-hydroxy Acetophenone pramipexole (PHAPP) ligand.
Then the mixture were stirred well and refluxed for two hours on water bath. On
cooling the above mixture Dark cream colour (PHAPP) crystal products were
obtained. The compound was washed with hot water. Dried and recrystallised from
methanol. Yield of the compound is 73% and melting point of the newly synthesized
azomethine ( PHAPP) is 185-186 oc.
O
S
NH2N
HN
N
N
S
P-Hydroxy AcetophenonePramipexole
PHAPP
OH OH
+
93
3. Pramipexole and O-Hydroxry Benzaldehyde Schiff Base (OHBP):
Equimolar concentrations (0.01 moles) of pramipexole and O-hydroxy
benzaldehyde were dissolved in 50 ml of methanol in 250 ml round bottom refluxing
flask and stirred well with a magnetic stirrer. Then few drops of con.HCl were added
to mixture of O-hydroxy benzaldehyde pramipexole (OHB-P) ligand. Then the
mixture were stirred well and refluxed for two hours on water bath. On cooling the
above mixture cream colour (OHBP) crystal products were obtained. The compound
was washed with hot water .Dried and recrystallised from methanol. Yield and
melting point of the newly synthesized azomethine (OHBP) is 73% and 160-162 oc.
94
4. Pramipexole and O-Vanillin Schiff Base (OVP):
Equimolar concentrations (0.01 moles) of pramipexole and O-Vanillin were
dissolved in 50 ml of methanol in 250 ml round bottom refluxing flask and stirred
well with a magnetic stirrer. Then few drops of con.HCl were added to mixture of
O-Vanillin pramipexole (OV-P) ligand. Then the mixture were stirred well and
refluxed for two hours on water bath. On cooling the above mixture light yellow
colour (OVP) crystal products were obtained. The compound was washed with hot
water .Dried and recrystallised from methanol. Yield and melting point of the newly
synthesized azomethine (OVP) is 74% and 242-244 oc.
95
5. Pramipexole and Vanillin Schiff Base (VP):
Equimolar concentrations (0.01 moles) of pramipexole and Vanillin were
dissolved in 50 ml of methanol in 250 ml round bottom refluxing flask and stirred
well with a magnetic stirrer. Then few drops of Con.HCl were added to mixture of
Vanillin pramipexole (V-P) ligand. Then the mixture were stirred well and refluxed
for two hours on water bath. On cooling the above mixture light yellow colour (VP)
crystal products were obtained. The compound was washed with hot water. Dried and
recrystallised from methanol. Yield and melting point of the newly synthesized
azomethine (VP) is 72% and 260- 262 oc.
96
6. Pramipexole and 2,4-Dihydroxry acetophenone Schiff Base (RAPP):
Equimolar concentrations (0.01 moles) of pramipexole and
2,4-Dihydroxy acetophenone were dissolved in 50 ml of methanol in 250 ml round
bottom refluxing flask and stirred well with a magnetic stirrer. Then few drops of
con.HCl were added to mixture of Resacetophenone pramipexole (RAPP) ligand.
Then the mixture were stirred well and refluxed for two hours on water bath. On
cooling the above mixture light brown colour (RAPP) crystal products were obtained.
The compound was washed with hot water. Dried and recrystallised from methanol.
Yield and melting point of the newly synthesized azomethine (RAPP) is 76% and
210-212 oc.
O
OH S
N
H2N
HN N
N
S
HO
2,4-Hydroxy Acetophenone Pramipexole
RAPP
OH
OH
(Resacetophenone)
+
97
Chart III.3
98
Preparation of metal complexes:
1. Preparation of Cu(II) and Ru(III) metal Complexes of OHAPP, PHAPP,
OHBP, OVP and VP ligands:
2:1 ratio of Schiff base ( OHAPP, PHAPP, OHBP, OVP , VP ) and metal salt
(Cu, Ru) (0.01 moles) were dissolved separately in 50 ml methanol and little amount
of water in 250 ml clean round bottom flask and refluxed the mixture for 6-7 hours on
a water bath in presence of sodium acetate. Then the reaction mixtures were
separately poured in excess of cold water. On cooling parrot green ( OHAPP-Cu) and
dark brown(OHAPP-Ru), dark green(PHAPP-Cu) and darkbrown (PHAPP-Ru),
lightgreen (OHBP-Cu) and darkbrown (OHBP-Ru), dark green (OVP-Cu) and dark
brown (OVP-Ru), dark green (VP-Cu) and dark brown (VP-Ru) coloured metal
complexes were obtained with good yield for OHAPP, PHAPP, OHBP, OVP and VP
ligands respectively. These products were washed several times with hot water and
cold methanol to free them from unreacted metal salts ligand and finally with ether
and dried in a vacuum desiccators for one day.
99
2. Prepartion of Cu, Ru, Co, Ni, Mn, Pd, La and Y metal Complexes of RAPP
ligand:
2:1 ratio of RAPP Schiff base and metal salt (Cu/ Ru/Co/Ni/Mn/Pd/La/Y)
(0.01 moles) were dissolved separately in 50 ml methanol and little amount of water
in 250 ml clean round bottom refluxing flask and refluxed the mixture for half an hour
on a water bath. Then 5ml sodium acetate solution was added and refluxion was
continued for 6-7 hours. On cooling dark green (RAPP-Cu), dark brown (RAPP-Ru),
dark blue (RAPP-Co), parrot green (RAPP-Ni), brown (RAPP-Mn), brown
(RAPP-Pd), light brown (RAPP-La) and light orange (RAPP-Y) colored metal
complexes formed respectively. It was separated by filtration and washed several
times with hot water and methanol then it was dried in vacuum desiccators.
100
IR SPECTRAL STUDIES:
Infrared spectroscopy is one of the main valuable analytical techniques
currently available to chemists, which is based on the interaction of electromagnetic
radiation with the matter .By utilizing this spectroscopy; the presence of important
functional groups in the compound can be identified. Infrared spectra were recorded
with a Perkin–Elmer IR 598 Spectrometer (4000–200cm–1) using KBr pellets. It was
observed that the IR spectra of all the metal complexes gave a considerable number of
peaks, each corresponding to a particular vibrational transition.
CHARACTERISATION OF OHAPP LIGAND AND ITS COMPLEXES:
IR Analysis of the Ligand:
The IR spectra of [OHAPP] ligand was presented in the Table.IV.1 and the
typical IR spectra is shown in Fig.IV.1., as concern the 2-hydroxy Acetophenone
pramipexole are main regions of the IR are of main interest.
First, the strong sharp characteristic band exhibited at 1642 cm-1 in the IR
spectrum of the ligand has been assigned to the (C=N) Stretching vibration of the
azomethine group a single sharp band at 3298 cm-1, 3309 cm-1 was assigned to the
stretching vibrations of the OH and NH bonds. The band at 2969 cm-1, 2722 cm-1
associated with the υ (C-H) and (C–Haldehyde) stretching vibrations. The N-H bending
vibration of secondary amine appeared in the a 1626cm-1 , for aromatic rings ,the most
characteristic aromatic ring (C=C) stretching bonds are observed at 1593 cm-1,1435
cm-1 ,The characteristic absorption band is appear in between the region of 1358-793
cm–1, (C-C, C–O, C–N).
101
I.R. Characterization of Metal Complexes:
The infrared sprectra of Cu (II), and Ru(III) complexes are presented were
compared with the [OHAPP] Lignad. The IR spectra of Cu(II) and Ru(III) metal
complexes are shown in Table.IV.1., and the typical I.R. sprectra of complexes were
presented in Fig.IV.2. and Fig.IV.3.
A strong band exhibited at 1642cm-1 in the IR spectrum of the ligand has been
assigned to the (C=N) Stretching vibration of the azomethine group. On complexation
this band is shifted to 1620 and 1635 cm-1 for Cu (II) and Ru(III) complexes
respectively [1,3] . This shift to lower wave numbers supports the participation of the
azomethine group of this ligand in binding to the metal ion.
The coordination of azomethine nitrogen to the metal atom would be expected
to reduce the electron density in the azomethine group and thus cause for a reduction
in C=N stretching frequency. Bands appeared at 3298 cm-1 and 1358 cm-1 due to the
stretching [4] and bending vibrations of phenolic OH group [5]. These bands are
disappeared in spectra of complexes indicating the deprotanation of phenolic OH
group. This is further confirmed by the appearance of new bands in the region
450-460 cm-1 and 625-680cm-1, which are assigned to the stretching frequencies of
M-N and M-O of the metal ligand bands [6-9] respectively for Cu (II) and Ru (III),
complexes. A weak band observed around 2958cm-1 in both ligands and complexes
could be assigned to the C-H stretching frequency [11]. A broad band exhibited at
3415 and 3425cm-1 for Cu (II) and Ru (III) complexes respectively. Which can be
assigned to the N-H and OH stretching vibration of the coordinated water molecules
[12, 13] These results indicate the formation of complex.
102
These results indicate that the ligand coordinate with the metal ion through the
azomethine nitrogen and the oxygen of the deprotonated hydroxyl group [14, 15].
Table IV.1. The important IR bands of the OHAPP ligand and their metal
complexes
Compound OH
Water
OH
Phenolic C=N N-H M-O M-N
OHAPP – 3298 1642 3309 – –
OHAPP-Cu 3415 – 1620 3312 625 450
OHAPP-Ru 3425 – 1635 3369 680 460
103
CHARACTERISATION OF PHAPP LIGAND AND ITS COMPLEXES:
I.R. Analysis of the Ligand:
The IR spectra of [PHAPP] ligand was presented in the Table.IV.2 and the
typical IR spectra is shown in Fig.IV.4., as concern the 4-hydroxy Acetophenone
pramipexole are main regions of the IR are of main interest.
First, the strong sharp characteristic band exhibited at 1634 cm-1 in the IR
spectrum of the ligand has been assigned to the (C=N) Stretching vibration of the
azomethine group a single sharp band at 3412 cm-1 , 3303 cm-1 was assigned to the
stretching vibrations of the OH and NH bonds respectively.The band at 2969 cm-1,
2799 cm-1 associated with the υ (C-H) and (C–Haldehyde) stretching vibrations. The
N-H bending vibration of secondary amine appeared in the a 1604cm-1 , for aromatic
rings ,the most characteristic aromatic ring (C=C) stretching bonds are observed at
1572 cm-1,1511 cm-1 ,The characteristic absorption band is appear in between the
region of 1276-711 cm–1, (C-C, C–O, C–N).
I.R. Characterization of Metal Complexes:
The infrared sprectra of Cu (II), and Ru(III) complexes are presented were
compared with the [PHAPP] Lignad. The IR spectra of Cu(II) and Ru(III) metal
complexes are shown in Table.IV.2., and the typical I.R. sprectra of complexes were
presented in Fig.IV.5. and Fig.IV.6.
A strong band exhibited at 1634 cm-1 in the IR spectrum of the ligand has been
assigned to the (C=N) Stretching vibration of the azomethine group. On complexation
this band is shifted to 1630 and 1625 cm-1 for Cu (II),and Ru(III) complexes
respectively [1,3] . This shift to lower wave numbers supports the participation of the
azomethine group of this ligand in binding to the metal ion.
104
The coordination of azomethine nitrogen to the metal atom would be expected
to reduce the electron density in the azomethine group and thus cause for a reduction
in C=N stretching frequency. Bands appeared at 3412 and 1440 cm-1 due to the
stretching [4] and bending vibrations of phenolic OH group [5]. These bands are
disappeared in spectra of complexes indicating the deprotanation of phenolic OH
group. This is further confirmed by the appearance of new bands in the region
460-455cm-1 and 640-680cm-1, which are assigned to the stretching frequencies of
M-N and M-O of the metal ligand bands [6-9] respectively for Cu (II), and Ru(III),
complexes. A weak band observed around 2848cm-1 in both ligands and complexes
could be assigned to the C-H stretching frequency [11]. A broad band exhibited at
3490 and 3510cm-1 for Cu (II),and Ru(III) complexes respectively. Which can be
assigned to the N-H and OH stretching vibration of the coordinated water molecules
[12,13]. These results indicate the formation of complex.
These results indicate that the ligand coordinate with the metal ion through the
azomethine nitrogen and the oxygen of the deprotonated hydroxyl group [14,15].
Table.IV.2. The important IR bands of the PHAPP ligand and their metal
complexes
Compound OH
Water
OH
Phenolic C=N N-H M-O M-N
PHAPP – 3412 1634 3303 – –
PHAPP-Cu 3490 – 1630 3215 640 460
PHAPP-Ru 3510 – 1625 3210 680 455
105
CHARACTERISATION OF OHBP LIGAND AND ITS COMPLEXES:
I.R. Analysis of the Ligand:
The IR spectra of [OHBP] ligand was presented in the Table.IV.3 and the
typical IR spectra is shown in Fig.IV.7., As concern the O-hydroxy benzaldehyde
pramipexole are main regions of the IR are of main interest.
First, the strong sharp characteristic band band exhibited at 1640 cm-1 in the
IR spectrum of the ligand has been assigned to the (C=N) Stretching vibration of the
azomethine group a single sharp band at 3285 cm-1 3320 cm-1 was assigned to the
stretching vibrations of the OH and NH bonds respectively . The band at 2958 cm-1,
2788 cm-1 associated with the υ (C-H) and (C–Haldehyde) stretching vibrations. The
N-H bending vibration of secondary amine appeared in the a 1626cm-1 , for aromatic
rings ,the most charecterstic aromatic ring (C=C) stretching bonds are observed at
1582 cm-1,1462cm-1 ,The characteristic absorption band is appear in between the
region of 1358-980 cm–1, (C-C, C–O, C–N).
I.R. Characterization of Metal Complexes:
The infrared sprectra of Cu (II), and Ru(III) complexes are presented were
compared with the [OHBP] Lignad. The IR spectra of Cu(II) and Ru(III) metal
complexes are shown in Table.IV.3., and the typical I.R. sprectra of complexes were
presented in Fig.IV.8. and Fig.IV.9.
A strong band exhibited at 1640cm-1 in the IR spectrum of the ligand has been
assigned to the (C=N) Stretching vibration of the azomethine group. On complexation
this band is shifted to 1621 and 1630 cm-1 for Cu (II),and Ru (III) complexes
respectively [1,3] . This shift to lower wave numbers supports the participation of the
azomethine group of this ligand in binding to the metal ion.
106
The coordination of azomethine nitrogen to the metal atom would be expected
to reduce the electron density in the azomethine group and thus cause for a reduction
in C=N stretching frequency. Bands appeared at 3285 and 1440 cm-1 due to the
stretching [4] and bending vibrations of phenolic OH group [5]. These bands are
disappeared in spectra of complexes indicating the deprotanation of phenolic OH
group. This is further confirmed by the appearance of new bands in the region
480-490 cm-1 and 744-772 cm-1, which are assigned to the stretching frequencies of
M-N and M-O of the metal ligand bands [6-9] respectively for Cu (II), and Ru(III),
complexes. A weak band observed around 2969 cm-1 in both ligands and complexes
could be assigned to the C-H stretching frequency [11]. A broad band exhibited at
3440 and 3459cm-1 for Cu (II) and Ru(III) complexes respectively. Which can be
assigned to the OH stretching vibration of the coordinated water molecules [12,13] of
both complexes. The same way A broad band exhibited at 3347 and 3328cm-1 for
Cu(II),and Ru(III) complexes respectively. Which can be assigned to the NH
stretching vibrations.
These results indicate that the ligand coordinate with the metal ion through the
azomethine nitrogen and the oxygen of the deprotonated hydroxyl group [14, 15].
Table .IV.3. The important IR bands of the OHBP ligand and their metal
complexes
Compound OH
Water
OH
Phenolic C=N N-H M-O M-N
OHBP – 3285 1640 3320 – –
OHBP-Cu 3440 – 1621 3347 744 480
OHBP-Ru 3459 – 1630 3328 772 490
107
CHARACTERISATION OF OVP LIGAND AND ITS COMPLEXES:
I.R. Analysis of the Ligand:
The IR spectra of [OVP] ligand was presented in the Table.IV.4 and the
typical IR spectra is shown in Fig.IV.10., As concern the 2-hydroxy 3-methoxy
benzaldehyde pramipexole are main regions of the IR are of main interest.
First, the strong sharp characteristic band band exhibited at 1649 cm-1 in the
IR spectrum of the ligand has been assigned to the (C=N) Stretching vibration of the
azomethine group a single sharp band at 3285 cm-1 3348 cm-1 was assigned to the
stretching vibrations of the OH and NH bonds respectively . The band at 2964 cm-1,
2820 cm-1 associated with the υ (C–H) and (C–Haldehyde) stretching vibrations. The
N-H bending vibration of secondary amine appeared in the a 1632cm-1, for aromatic
rings ,the most charecterstic aromatic ring (C=C) stretching bonds are observed at
1589 cm-1, 1435cm-1, The characteristic absorption band is appear in between the
region of 1353-1046 cm–1, (C–C, C–O, C–N).
I.R. Characterization of Metal Complexes:
The infrared sprectra of Cu (II), and Ru(III) complexes are presented were
compared with the [OVP] Lignad. The IR spectra of Cu(II) and Ru(III) metal
complexes are shown in Table.IV.4., and the typical I.R. sprectra of complexes were
presented in Fig.IV.11. and Fig.IV.12.
A strong band exhibited at 1649cm-1 in the IR spectrum of the ligand has been
assigned to the (C=N) Stretching vibration of the azomethine group. On complexation
this band is shifted to 1630 and 1625 cm-1 for Cu (II),and Ru (III) complexes
respectively [1,3] . This shift to lower wave numbers supports the participation of the
azomethine group of this ligand in binding to the metal ion.
108
The coordination of azomethine nitrogen to the metal atom would be expected
to reduce the electron density in the azomethine group and thus cause for a reduction
in C=N stretching frequency. Bands appeared at 3420 and 1435 cm-1 due to the
stretching [4] and bending vibrations of phenolic OH group [5]. These bands are
disappeared in spectra of complexes indicating the deprotanation of phenolic OH.
This is further confirmed by the appearance of new bands in the region 475-490 cm-1
and 609-690 cm-1, which are assigned to the stretching frequencies of M-N and M-O
of the metal ligand bands [6-9] respectively for Cu (II), and Ru(III), complexes.
A weak band observed around 2958 cm-1 in both ligands and complexes could be
assigned to the C-H stretching frequency [11]. A broad band exhibited at 3420 and
3435cm-1 for Cu (II),and Ru(III) complexes respectively. Which can be assigned to
the OH /NH stretching vibrations of the coordinated water molecules [12,13] of both
complexes.
These results indicate that the ligand coordinate with the metal ion through the
azomethine nitrogen and the oxygen of the deprotonated hydroxyl group [14,15].
Table .IV.4. The important IR bands of the OVP ligand and their metal
complexes
Compound OH
Water
OH
Phenolic C=N N-H M-O M-N
OVP ---- 3285 1649 3348 - -
OVP-Cu 3420 - 1630 3303 609 475
OVP-Ru 3435 - 1625 3315 690 490
109
CHARACTERISATION OF VP LIGAND AND ITS COMPLEXES:
I.R. Analysis of the Ligand:
The IR spectra of [VP] ligand was presented in the Table.IV.5 and the typical
IR spectra is shown in Fig.IV.13., As concern the 4-hydroxy 3-methoxy benzaldhyde
pramipexole are main regions of the IR are of main interest.
First, the strong sharp characteristic band band exhibited at 1645 cm-1 in the
IR spectrum of the ligand has been assigned to the (C=N) Stretching vibration of the
azomethine group a single sharp band at 3240 cm-1 3342 cm-1 was assigned to the
stretching vibrations of the OH and NH bonds respectively . The band at 2958 cm-1
,2515 cm-1 associated with the υ (C-H) and (C–Haldehyde) stretching vibrations. The
N-H bending vibration of secondary amine appeared in the a 1589 cm-1 , for aromatic
rings the most charecterstic aromatic ring (C=C) stretching bonds are observed at
1506 cm-1,1473cm-1 ,The characteristic absorption band is appear in between the
region of 1298-1024 cm–1, (C-C, C–O, C–N).
I.R. Characterization of Metal Complexes:
The infrared sprectra of Cu (II), and Ru(III) complexes are presented were
compared with the [VP] Lignad. The IR spectra of Cu(II) and Ru(III) metal
complexes are shown in Table.IV.5., and the typical I.R. sprectra of complexes were
presented in Fig.IV.14. and Fig.IV.15.
A strong band exhibited at 1645cm-1 in the IR spectrum of the ligand has been
assigned to the (C=N) Stretching vibration of the azomethine group. On complexation
this band is shifted to 1625 and 1638 cm-1 for Cu (II),and Ru (III) complexes
respectively [1,3] . This shift to lower wave numbers supports the participation of the
azomethine group of this ligand in binding to the metal ion.
110
The coordination of azomethine nitrogen to the metal atom would be expected
to reduce the electron density in the azomethine group and thus cause for a reduction
in C=N stretching frequency. Bands appeared at 3240 and 1430 cm-1 due to the
stretching [4] and bending vibrations of phenolic OH group [5]. These bands are
disappeared in spectra of complexes indicating the deprotanation of phenolic OH
group. This is further confirmed by the appearance of new bands in the region
480-500 cm-1 and 720-778 cm-1, which are assigned to the stretching frequencies of
M-N and M-O of the metal ligand bands [6-9] respectively for Cu (II), and Ru(III),
complexes. A weak band observed around 2947 cm-1 in both ligands and complexes
could be assigned to the C-H stretching frequency [11]. A broad band exhibited at
3420 and 3460cm-1 for Cu (II),and Ru(III) complexes respectively. Which can be
assigned to the OH stretching vibration of the coordinated water molecules [12,13] of
both complexes. The same way A broad band exhibited at 3325 and 3320 cm-1 for
Cu (II),and Ru(III) complexes respectively. Which can be assigned to the NH
stretching vibrations.
These results indicate that the ligand coordinate with the metal ion through the
azomethine nitrogen and the oxygen of the deprotonated hydroxyl group [14,15].
Table .IV.5. The important IR bands of the VP ligand and their metal complexes
Compound OH
Water
OH
Phenolic C=N N-H M-O M-N
VP – 3240 1645 3342 – –
VP-Cu 3420 – 1625 3325 720 480
VP-Ru 3460 – 1638 3320 778 500
111
Elemental Analysis IV.6 (Two pages)
112
Elemental Analysis IV.6 (Two pages)
113
Fig .IV.1: IR Spectra of OHAPP Ligand
Fig.IV.2 : IR Spectra of Cu(OHAPP))complexes
114
Fig.IV.3: IR Spectra Ru(OHAPP) complexes
Fig.IV.4: IR Spectra of PHAPP Ligand
115
Fig.IV.5. IR Spectra of Cu(PHAPP) complex
Fig.IV.6. IR Spectra of Ru(PHAPP) complex
116
Fig.IV.7. IR spectra of OHBP Ligand
Fig.IV.8. IR Spectra of Cu(OHBP) complexes
117
Fig.IV.9. IR Spectra of Ru(OHBP) complexes
Fig.IV.10. IR Spectra of OVP Ligand
118
Fig.IV.11. IR Spectra of Cu( OVP) complex
Fig.IV.12. IR Spectra of Ru(OVP) complex
119
Fig.IV.13. IR Spectra of VP Ligand
Fig.IV.14. IR Spectra of Cu(VP) complexes
120
Fig.IV.15. IR Spectra of Ru( VP) complexes
121
1 H-NMR SPECTRAL STUDIES:
1H Nuclear Magnetic Resonance (NMR) spectroscopy is an analytical
technique based on the magnetic properties of nuclei. By using this spectroscopy, the
nature of protons and the number protons present in a particular environment can be
deterermined. In this principle, chemical shifts, internal reference standard
tetramethylsilance (TMS) is needed. TMS is chosen for several reasons i.e. it contains
12 equivalent protons and four equivalent carbons and also it is chemically inert,
soluble in most organic compounds, and sufficiently volatile to be easily removed
from the sample after the spectrum has been recorded.
In the present study, 1H NMR spectra were recorded on an av-400 MHz NMR
spectrometer in HCU, Hyd in DMSO-d6 solvent at room temperature.
1H-NMR ANALYSIS OF OHAPP AND ITS METAL COMPLEXES:
The NMR spectra are given in Fig.IV.16 to IV.18 and the important chemical
shift vaules of the ligand and metal complexes are summarized Table.IV.7.
The typical NMR Spectra of [OHAPP] ligand was presented in the Fig.IV.16.,
a singlet observed at 2.50 ppm for 1H NMR spectrum of the OHAPP ligand is
assigned to the methyl protons attached to azomethine (C=N) group [16,17]. The
signals appeared at 1.67 and 1.27 ppm is attributed to the methelene protons of the
cyclohexane ring. Another multiplets observed at 6.30-7.66ppm for 1H NMR
spectrum of the = C-H proton of the phenyl ring. A singlet is observed in the region
7.20 [18,19] due to the aromatic –OH proton.The another singlet appeared at 12.70
ppm due to N-H proton of ligand.
122
In the 1H NMR spectrum of the OHAPP– Cu complex as shown Fig.IV.17,
a signal appeared due to methyl protons attached to azomethine group has been
shifted to 2.59. ppm compared to 2.50 ppm in the case of ligand [21]. This downfield
shift indicates the deshielding of azomethine proton on coordination through nitrogen
atom of azomethine group [27]. The signal observed at 1.98 ppm due to the methelene
protons of cyclohexane ring for the (Cu) complex. A signal is dis appeared at 7.2 ppm
to phenolic hydroxyl proton is absent in the NMR spectrum of (Cu) complex
indicating the deprotonation of hydroxyl group and the involvement of that oxygen in
coordination [28]. The multiplet observed in the region 6.6-6.9 ppm due to aromatic
two C-H protons of phenyl ring for (Cu) complex may be due to the drifting of ring of
electrons towards the metal ion. Another multiplet absorverd in the region of
7.9-8.2 ppm indicate two C-H protons of phenyl ring. A new signal is observed as a
singlet at 4.80 ppm in the case of Cu(II) complex indicating the presence of water
molecules coordinated to the metal atom a signal observed at 12.70 ppm in ligand due
to N-H proton is shifted to 7.79 ppm for Cu complex [104,105].
In the 1H NMR spectrum of the OHAPP– Ru complex as shown Fig.IV.18.,
a signal appeared due to methyl protons attached to azomethine group at 1.81 ppm.
The signal observed at 1.148 ppm due to the methelene protons of cyclohexane ring
for the (Ru) complex. A signal is dis appeared at 7.2 ppm to phenolic hydroxyl proton
is absent in the NMR spectrum of (Ru) complex indicating the deprotonation of
hydroxyl group and the involvement of that oxygen in coordination [28]. The
multiplet observed in the region 7.5 ppm due to aromatic two C-H protons of phenyl
ring for (Ru) complex. A new signal is observed as a singlet at 4.699. ppm in the case
of Ru(III) complex indicating the presence of water molecules coordinated to the
123
metal atom a signal observed at 12.70 ppm in ligand due to N-H proton is shifted to
8.356 ppm for Ru complex [104,105].
Table: IV.7. 1H NMR spectral data of the OHAPP ligand and its metal complexes in
CDCl3 in ppm
Compound H3C-
C=N Ar-H CH2 Ar-OH N-H H2O-OH
OHAPP 2.50 6.30-7.66 1.67-1.27 7.20 12.70 –
OHAPP-Cu 2.59 6.6-6.9 1.98 – 7.79 4.80
OHAPP-Ru 1.81 7.5 1.148 – 8.356 4.669
124
1H-NMR ANALYSIS OF PHAPP AND ITS METAL COMPLEXES:
The NMR spectra are given in Fig.IV.19 to IV.21 and the important chemical
shift vaules of the ligand and metal complexes are summarized Table.IV.8.
The typical NMR Spectra of [PHAPP] ligand was presented in the Fig.IV.19.,
a singlet observed at 2.580 ppm for 1H NMR spectrum of the PHAPP ligand is
assigned to the methyl protons attached to azomethine (C=N) group [16,17]. The
singlet appeared at 1.80 ppm is attributed to the methelene protons of the cyclohexane
ring. Another doublet observed at 6.905-7.931 ppm for 1H NMR spectrum of the C-H
proton of the phenyl ring. A singlet is observed in the region 6.359 [18,19] due to the
aromatic O-H protons of phenolic hydroxyl group . The doublet appeared at
7.909-7.931 ppm due to two C-H proton of the phenyl ring.The another singlet
appeared at 7.20 ppm due to N-H proton of ligand.
In the 1H NMR spectrum of the PHAPP – Cu complex as shown Fig.IV.20.,
a signal appeared due to methyl protons attached to azomethine group has been
shifted to 2.586 ppm compared to 2.580 ppm in the case of ligand [21]. This
downfield shift indicates the deshielding of azomethine proton on coordination
through nitrogen atom of azomethine group [27]. The signal observed at 1.719 ppm
due to the methelene protons of cyclohexane ring for the (Cu) complex. A signal is
appeared due to para at 6.20 ppm due to OH proton on para position of phenolic
group. The multiplet observed in the region 6.6-8.2 ppm due to aromatic two C-H
protons of phenyl ring for (Cu) complex may be due to the drifting of ring of electrons
towards the metal ion. Another multiplet observed in the region of 7.9-8.2 ppm
indicate two C-H protons of phenyl ring. A new signal is observed as a singlet at
4.67 ppm in the case of Cu(II) complex indicating the presence of water molecules
125
coordinated to the metal atom.A signal observed at 7.20 ppm in ligand due to N-H
proton is shifted to 7.28 ppm for Cu complex [104,105].
In the 1H NMR spectrum of the PHAPP-Ru complex as shown Fig.IV.21,
a signal appeared due to methyl protons attached to azomethine group has been
shifted to 2.60 ppm compared to 2.580 ppm in the case of ligand [21]. This downfield
shift indicates the deshielding of azomethine proton on coordination through nitrogen
atom of azomethine group [27]. The signal observed at 1.719 ppm due to the
methelene protons of cyclohexane ring for the (Ru) complex. A signal is appeared due
to para at 6.37 ppm due to OH proton on Para position of phenolic group. The
multiplet observed in the region 6.6-8.24 ppm due to aromatic two C-H protons of
phenyl ring for (Ru) complex may be due to the drifting of ring of electrons towards
the metal ion. Another multiplet observed in the region of 7.93-8.24 ppm indicate two
C-H protons of phenyl ring. A new signal is observed as a singlet at 5.01ppm in the
case of Ru(III) complex indicating the presence of water molecules coordinated to the
metal atom A signal observed at 7.20 ppm in ligand due to N-H proton is shifted to
7.25 ppm for Ru complex [104,105].
Table:IV.8. 1H NMR spectral data of the PHAPP ligand and its metal complexes in
CDCl3 in ppm
Compound H3C-C=N Ar-H CH2 Ar-OH N-H H2O-OH
PHAPP 2.580 6.905-7.931 1.80 6.359 7.20 –
PHAPP-Cu 2.586 6.6-8.2 1.719 6.20 7.28 4.67
PHAPP-Ru 2.60 6.6-8.24 1.719 6.37 7.25 5.01
126
1H-NMR ANALYSIS OF OHBP AND ITS METAL COMPLEXES:
The NMR spectra are given in Fig.IV.22 to IV.24 and the important chemical
shift vaules of the ligand and metal complexes are summarized Table.IV.9.
The typical NMR Spectra of [OHBP] ligand was presented in the Fig.IV.22.,
A singlet observed at 6.30 ppm for 1H NMR spectrum of the OHBP ligand is assigned
to the protons attached to azomethine (C=N) group [16,17]. The singlet appeared at
2.50-1.70 ppm is attributed to the methelene protons of the cyclohexane ring. Another
singlet observed at 5.71 ppm for 1H NMR spectrum of the C-H proton of the phenyl
ring. A multiplet is observed in the region 6.37-7.65 [18,19] due to the aromatic C-H
protons of phenyl ring. A singlet appeared at 7.2 ppm is attributed to the C-H proton
attached to the phenyl ring in the ligand [20]. The doublet appeared at 7.63-7.65 ppm
due to two C-H proton attached to the phenyl ring.The singlet appeared at 8.53 ppm
due to N-H proton of ligand.
In the 1H NMR spectrum of the OHBP –Cu complex as shown Fig.IV.23., a
signal appeared due to protons attached to azomethine group has been shifted to 6.66
ppm compared to 6.30 ppm in the case of ligand [21].This down field shift indicates
the deshielding of azomethine proton on coordination through nitrogen atom of
azomethine group [27]. The signal observed at 1.71 ppm due to the methelene protons
in the cyclohexane ring ligand is shifted to 2.82 -2.92 ppm for the (Cu) complex.The
signal disappeared at 5.71 ppm due to phenolic hydroxyl proton is absent in the NMR
spectrum of (Cu) complex indicating the deprotonation of hydroxyl group and the
involvement of that oxygen in coordination [28]. A new signal observed at 4.717 ppm
in complex due to O-H proton of water molecule present in the complex. The
multiplet observed in the region 6.90-7.32 ppm due to aromatic protons for (Cu)
127
complex. A signal observed at 8.53 ppm in ligand due to N-H proton is shifted to
9.26 ppm for Cu complex [104,105].
In the 1H NMR spectrum of the OHBP-Ru complex as shown Fig.IV.24.,
a signal appeared due to protons attached to azomethine group has been shifted from
6.30 to 7.50 ppm. This down field shift indicates the deshielding of azomethine proton
on coordination through nitrogen atom of azomethine group [27]. The signal observed
at 1.14-2.85 ppm due to the cyclo hexane protons of the Ru complex. The signal
disappeared at 5.71 ppm due to phenolic hydroxyl proton is absent in the NMR
spectrum of Ru complex indicating the deprotonation of hydroxyl group and the
involvement of that oxygen in co-ordination[22]. A new signal is observed as a signal
at 4.699 ppm in the case of Ru (III) complex indicating the presence of water
molecules coordinated to the metal atom [29,30]. The multiplet observed in the region
6.41-7.00 ppm due to aromatic protons for Ru complex [24-26]. A signal observed at
8.35 ppm due to N-H proton for Ru complex.
Table:IV.9. 1H NMR spectral data of the OHBP ligand and its metal complexes in
CDCl3 in ppm
Compound H-C=N Ar-H CH2 Ar-OH N-H H2O-OH
OHBP 6.30 6.37-7.65 2.50-1.70 5.71 8.53 ------
OHBP-Cu 6.60 6.90-7.32 2.82-2.92 ----- 9.26 4.717
OHBP-Ru 7.50 6.41-7.00 1.14-2.85 ----- 8.35 4.699
128
1H-NMR ANALYSIS OF OVP AND ITS METAL COMPLEXES:
The NMR spectra are given in Fig.IV.25 to IV.27 and the important chemical
shift vaules of the ligand and metal complexes are summarized Table.IV.10.
The typical NMR Spectra of [OVP] ligand was presented in the Fig.IV.25.,
A singlet observed at 6.90 ppm for 1H NMR spectrum of the OVP ligand is assigned
to the proton attached to azomethine (C=N) group [16,17]. The another signal
appeared at 1.557 ppm is attributed to the methelene protons of the cyclohexane ring.
A singlet is observed in the region 7.10 ppm due to the aromatic –OH protons of
phenolic hydroxy group The multiplet observed at 6.90-7.22 ppm for 1H NMR
spectrum of the = C-H proton of the phenyl ring. A singlet is observed in the region
3.936 ppm [18,19] due to the aromatic –OCH3 protons of phenolic methoxy
group.The another singlet appeared at 9.932 ppm due to N-H proton of ligand.
In the 1H NMR spectrum of the OVP– Cu complex as shown Fig.IV.26, a
signal appeared due to protons attached to azomethine group at 7.10 ppm. This field
shift indicates the deshielding of azomethine proton on coordination through nitrogen
atom of azomethine group [27]. The signal observed at 1.9-2.3 ppm due to the
methelene protons of cyclohexane ring for the (Cu) complex. . The multiplet observed
in the region 6.60-6.90 ppm due to aromatic two C-H protons of phenyl ring for (Cu)
complex may be due to the drifting of ring of electrons towards the metal ion. Another
multiplet absorverd in the region of 7.9-8.2ppm indicate two C-H protons of phenyl
ring. A new signal is observed as a singlet at 4.70. ppm in the case of Cu(II) complex
indicating the presence of water molecules coordinated to the metal atom A signal
observed at 9.932 ppm in ligand due to N-H proton is shifted to 8.50 ppm for
Cu complex [104,105].
129
In the 1H NMR spectrum of the OVP– Ru complex as shown Fig.IV.27., a
signal appeared due to protons attached to azomethine group has been shifted to
7.20 ppm compared to 6.90 ppm in the case of ligand [21]. This downfield shift
indicates the deshielding of azomethine proton on coordination through nitrogen atom
of azomethine group [27]. The signal observed at 1.6-2.57 ppm due to the methelene
protons of cyclohexane ring for the (Ru) complex. The multiplet observed in the
region 6.30-7.66 ppm due to aromatic two C-H protons of phenyl ring for (Ru)
complex may be due to the drifting of ring of electrons towards the metal ion. Another
multiplet absorverd in the region of 7.64-7.66 ppm indicate two C-H protons of
phenyl ring. A new signal is observed as a singlet at 4.90 ppm in the case of Ru(III)
complex indicating the presence of water molecules coordinated to the metal atom a
signal observed at 9.932 ppm in ligand due to N-H proton is shifted to 12.07 ppm for
Ru complex [104,105].
Table:IV.10. 1H NMR spectral data of the OVP ligand and its metal complexes in
CDCl3 in ppm
Compound H–C=N Ar-H CH2 Ar-OH N-H H2O-OH
OVP 6.90 6.90-7.22 1.557 7.10 9.932 ------
OVP-Cu 7.10 6.60-8.20 1.9-2.3 ----- 8.50 4.70
OVP-Ru 7.20 6.30-7.66 1.6-2.57 ----- 12.07 4.90
130
1H-NMR ANALYSIS OF VP AND ITS METAL COMPLEXES:
The NMR spectra are given in Fig.IV.28 to IV.30 and the important chemical
shift vaules of the ligand and metal complexes are summarized Table.IV.11.
The typical NMR Spectra of [VP] ligand was presented in the Fig.IV.28.,
A singlet observed at 6.2 ppm for 1H NMR spectrum of the VP ligand is assigned to
the proton attached to azomethine (C=N) group [16,17]. The singlet appeared at 1.595
ppm is attributed to the methelene protons of the cyclohexane ring. Another doublet
observed at 7.04-7.44 ppm for 1H NMR spectrum of the C-H proton of the phenyl
ring. A singlet is observed in the region 3.978 [18,19] due to the aromatic –OCH3
protons of phenolic methoxy group . The doublet appeared at 7.426-7.443 ppm due to
two C-H proton of the phenyl ring The another singlet appeared at 9.8 ppm due to
N-H proton of ligand.
In the 1H NMR spectrum of the VP – Cu complex as shown Fig.IV.29.,
a signal appeared due to protons attached to azomethine group has been shifted to
6.5 ppm compared to 6.2 ppm in the case of ligand [21]. This down field shift
indicates the deshielding of azomethine proton on coordination through nitrogen atom
of azomethine group [27]. The singlet observed at 1.595 ppm due to the methelene
protons in the cyclohexane ring ligand is shifted to 1.65 ppm for the (Cu) complex.
A signal is appeared due to para at 7.28 ppm due to OH proton on para position of
phenolic group. The multiplet observed in the region 6.37-6.41 ppm due to aromatic
protons for the ligand showed a shift to 6.39-7.66 ppm for (Cu) complex may be due
to the drifting of ring of electrons towards the metal ion. A new signal is observed as a
singlet at 5.05 ppm in the case of Cu (II) complex indicating the presence of water
molecules coordinated to the metal atom a signal observed at 9.8 ppm in ligand due to
N-H proton is shifted to 10.1 ppm for Cu complex [104, 105].
131
In the 1H NMR spectrum of the VP – Ru complex as shown Fig.IV.30.,
a signal appeared due to protons attached to azomethine group at 6.7 ppm. This
downfield shift indicates the deshielding of azomethine proton on coordination
through nitrogen atom of azomethine group [27]. The signal observed at 1.58 ppm
due to the methelene protons of cyclohexane ring for the (Ru) complex. A signal is
appeared due to para at 7.20 ppm due to OH proton on Para position of phenolic
group. The multiplet observed in the region 6.50-7.50 ppm due to aromatic C-H
protons of phenyl ring for (Ru) complex may be due to the drifting of ring of electrons
towards the metal ion. A new signal is observed as a singlet at 4.60 ppm in the case of
Ru(III) complex indicating the presence of water molecules coordinated to the metal
atom. A signal observed at 9.8 ppm due to N-H proton for Ru complex [104,105].
Table:IV.11. 1H NMR spectral data of the VP ligand and its metal complexes in
CDCl3 in ppm
Compound H-C=N Ar-H CH2 Ar-OH N-H H2O-OH
VP 6.2 7.04-7.44 1.595 5.71 9.8 –
VP-Cu 6.5 6.39-7.66 1.65 7.28 10.1 5.05
VP-Ru 6.7 6.50-7.50 1.58 7.2 9.8 4.60
132
Fig.IV.16. NMR Spectra of OHAPP Ligand
Fig.IV.17.NMR Spectra of Cu(OHAPP) complex
133
Fig.IV.18.NMR Spectra of Ru( OHAPP) complex
Fig.IV.19:NMR Spectra of PHAPP Ligand
134
Fig.IV.20: NMR Spectra of Cu(PHAPP) complex
Fig.IV.21: NMR Spectra of Ru( PHAPP) complex
135
Fig.IV.22: NMR Spectra of OHBP Ligand
Fig.IV.23 : NMR Spectra of Cu(OHBP) complex
136
Fig.IV.24 : NMR Spectra of Ru(OHBP) complex
Fig.IV.25. NMR Spectra of OVP ligand
137
Fig.IV.26: NMR Spectra of Cu(OVP) complex
Fig.IV.27: NMR Spectra of Ru(OVP) complex
138
Fig.IV.28: NMR Spectra of VP Ligand
Fig.IV.29 : NMR Spectra of Cu(VP) complex
139
Fig.IV.30 : NMR Spectra of Ru(VP) complex
140
UV-Spectral Studies:
In UV-Visible electromagnetic radiation, the transitions are associated with
the electronic energy levels of the compound under the investigation. The electronic
spectra were recorded on a thermo Spectronic Heylos α spectrophotometer. The
description of this instrument is presented in chapter-II.It was noted that the transition
metal ions occur in variety of structural environment identified through UV-Visible
spectroscopy.
Analysis of OHAPP ligand and its metal complexes:
The electronic spectra of the aqueous solutions of Cu, and Ru individual ions
are compared with the corresponding ligand nature. The data is given in
Table.V.1 and Fig.V.1 to V.3. The data indicates that the energy of the d-d transitions
in the complexes is slightly less when compared to the corresponding aqua ions either
[56-59] because of slight covalent interaction of the 3d vacant orbitals with ligands,
leading to some delocalization with consequent reduction in inter electronic repulsion,
[59] or by increased nuclear shielding of the orbitals due to slight covalent ligand-
metal electron drift.
The transition for the ligand occurred at 294 nm. But on complexation with the
different metal ions like Cu and Ru new bands appeared at 320 nm, and 329 nm,
respectively corresponding to the transitional charge transfer from the ligand to the
different metal ions [60, 61]. Bands occurred in the region of 320-330 nm for two
complexes are assigned to charge transfer transition (L→M). Based on the results
octahedral structure is proposed for Cu, and Ru complexes [70-73].
141
Table:V.1. Electronic Spectral data of OHAPP ligand and its metal complexes
Compound λmax of compound
OHAPP 294
OHAPP-Cu 320
OHAPP-Ru 329
Analysis of PHAPP ligand and its metal complexes:
The electronic spectra of the aqueous solutions of Cu, and Ru individual ions
are compared with the corresponding ligand nature. The data is given in Table.V.2
and Fig.V.4 to V.6. The data indicates that the energy of the d-d transitions in the
complexes is slightly less when compared to the corresponding aqua ions either
[56-59] because of slight covalent interaction of the 3d vacant orbitals with ligands,
leading to some delocalization with consequent reduction in inter electronic repulsion,
[59] or by increased nuclear shielding of the orbitals due to slight covalent ligand-
metal electron drift.
The transition for the ligand occurred at 289 nm. But on complexation with the
different metal ions like Cu and Ru new bands appeared at 316 nm, and 334 nm,
respectively corresponding to the transitional charge transfer from the ligand to the
different metal ions [60, 61]. Bands occurred in the region of 316-334 nm for two
complexes are assigned to charge transfer transition (L→M). Based on the results
octahedral structure is proposed for Cu, and Ru complexes [70-73],
Table:V.2. Electronic Spectral data of PHAPP ligand and its metal complexes
Compound λmax of compound
PHAPP 289
PHAPP-Cu 316
PHAPP-Ru 334
142
Analysis of OHBP ligand and its metal complexes:
The electronic spectra of the aqueous solutions of Cu, and Ru individual ions
are compared with the corresponding ligand nature. The data is given in Table.V.3.,
and Fig.V.7 to V.9. The data indicates that the energy of the d-d transitions in the
complexes is slightly less when compared to the corresponding aqua ions either
[56-59] because of slight covalent interaction of the 3d vacant orbitals with ligands,
leading to some delocalization with consequent reduction in inter electronic repulsion,
[59] or by increased nuclear shielding of the orbitals due to slight covalent ligand-
metal electron drift.
The transition for the ligand occurred at 285 nm. But on complexation with the
different metal ions like Cu and Ru new bands appeared at 326 nm, and 337 nm,
respectively corresponding to the transitional charge transfer from the ligand to the
different metal ions [60, 61]. Bands occurred in the region of 326-337 nm for two
complexes are assigned to charge transfer transition (L→M). Based on the results
octahedral structure is proposed for Cu, and Ru complexes [70-73],
Table:V.3. Electronic Spectral data of OHBP ligand and its metal complexes
Compound λmax of compound
OHBP 285
OHBP-Cu 326
OHBP-Ru 337
Analysis of OVP ligand and its metal complexes:
The electronic spectra of the aqueous solutions of Cu, and Ru individual ions
are compared with the corresponding ligand nature. The data is given in Table.V.4.,
and Fig.V.10 to V.12. The data indicates that the energy of the d-d transitions in the
complexes is slightly less when compared to the corresponding aqua ions either
143
[56-59] because of slight covalent interaction of the 3d vacant orbitals with ligands,
leading to some delocalization with consequent reduction in inter electronic repulsion,
[59] or by increased nuclear shielding of the orbitals due to slight covalent ligand-
metal electron drift.
The transition for the ligand occurred at 280 nm. But on complexation with the
different metal ions like Cu and Ru new bands appeared at 329 nm, and 345 nm,
respectively corresponding to the transitional charge transfer from the ligand to the
different metal ions [60, 61]. Bands occurred in the region of 329-345 nm for two
complexes are assigned to charge transfer transition (L→M). Based on the results
octahedral structure is proposed for Cu, and Ru complexes [70-73].
Table:V.4. Electronic Spectral data of OVP ligand and its metal complexes
Compound λmax of compound
OVP 280
OVP-Cu 329
OVP-Ru 345
Analysis of VP ligand and its metal complexes:
The electronic spectra of the aqueous solutions of Cu, and Ru individual ions
are compared with the corresponding ligand nature. The data is given in Table V.5.,
and Fig.V.13 to V.15. The data indicates that the energy of the d-d transitions in the
complexes is slightly less when compared to the corresponding aqua ions either
[56-59] because of slight covalent interaction of the 3d vacant orbitals with ligands,
leading to some delocalization with consequent reduction in inter electronic repulsion,
[59] or by increased nuclear shielding of the orbitals due to slight covalent ligand-
metal electron drift.
144
The transition for the ligand occurred at 245 nm. But on complexation with the
different metal ions like Cu and Ru new bands appeared at 321 nm, and 341nm,
respectively corresponding to the transitional charge transfer from the ligand to the
different metal ions [60, 61]. Bands occurred in the region of 321-341 nm for two
complexes are assigned to charge transfer transition (L→M). Based on the results
octahedral structure is proposed for Cu, and Ru complexes [70-73].
Table:V.5. Electronic Spectral data of VP ligand and its metal complexes
Compound λmax of compound
VP 245
VP-Cu 321
VP-Ru 341
145
Fig.V.1 : UV spectra of OHAPP ligand
Fig.V.2 : UV spectra of Cu( OHAPP ) complex
146
Fig.V.3 : UV spectra of Ru( OHAPP ) complex
Fig.V.4 : UV spectra of PHAPP ligand
147
Fig.V.5 : UV spectra of Cu (PHAPP ) complex
Fig.V.6 : UV spectra of Ru (PHAPP ) complex
148
Fig.V.7 : UV Spectra of OHBP Ligand
Fig.V.8 : UV Spectra of Cu (OHBP ) complex
149
Fig.V.9 : UV Spectra of Ru (OHBP ) complex
Fig.V.10 : UV spectra of OVP Ligand
150
Fig.V.11 : UV Spectra of Cu(OVP) complex
Fig.V.12 : UV Spectra of Ru(OVP) complex
151
Fig.V.13 : UV Spectra of VP Ligand
Fig.V.14 : UV Spectra of Cu(VP ) complex
152
Fig.V.15 : UV Spectra of Ru(VP ) complex
153
Conductivity Measurements of OHAPP, PHAPP, OHBP, OVP and VP metal
complexes:
The molar conductance of complexes in DMF (~10-3 M) was determined at
27+2oC using systronic 303 reading conductivity bridge Cu(II) and Ru (III)
complexes of azomethine compound formed due to the condensation of 2-Hydroxy
Acetophenone, 4-Hydroxy acetophenone, 2-hydroxybenzaldehyde, O-Vaniline, and
Vaniline with Pramipexole ligands is prepared. The complexes of OHAPP, PHAPP,
OHBP, OVP and VP ligand are highly soluble in dimethyl formamide (DMF).
Therefore these metal chelates are dissolved in DMF to perform conductivity
measurements. A known amount of solid complex was transferred into 25 ml standard
flask and dissolved in DMF. The contents were made up to the mark with DMF. The
complex solution is transferred into a clean and dry 100 ml beaker. The molar
conductance values of these metal complexes which are residual are given in
Table.V.6. These values suggest non-electrolytic nature [92, 93] of the present
complexes.
Table:V.6. Molar conductivity of Cu and Ru complexes
Metal complexes Molar conductance(ohm-1 cm
2mol
-1)
OHAPP-Cu 18
OHAPP-Ru 21
PHAPP-Cu 20
PHAPP-Ru 23
OHBP-Cu 19
OHBP-Ru 20
OVP-Cu 18
OVP-Ru 21
VP-Cu 21
VP-Ru 20
154
ESR Spectral analysis of Cu (OHAPP) maetal complex:
The ESR spectrum of Orthohydroxy Acetophenone copper complex was
recorded by using JEOL, JES–FA200 ESR Spectrometer, HCU Hyderabad.
ESR spectra of Cu metal complexes give useful information regarding the
stereochemistry and nature of metal–ligand bonding. The ESR spectra of the complex
in polycrystalline state exhibit only one broad signal, which was attributed to dipolar
broadening and enhanced spin–lattice relaxation [35]. ESR spectra obtained for
copper complex in DMF at liquid nitrogen temperature and representative ESR
spectrum of Cu (II) ion complex are presented in Fig.VI.1., and as shown in
Table.VI.1. In this low temperature spectrum, four peaks of small intensity have been
identified which are considered to originate from (g||, g┴, A|| and A┴) were determined
from the intense peaks of the spectrum [45]. Kivelson & Neiman [58] have reported
that g|| value is less than 2.3 for covalent character and it is greater than 2.3 for ionic
character of the metal–ligand bond in complex. Applying this criterion, the covalent
bond character can be predicted to exist between the metal and the ligand for complex
[35].
The trend g|| > g ave> g ┴ > 2.0023 observed for the complex suggests that the
unpaired electron was localized in dx2 – y2 orbital [16, 46] of the copper (II) complex.
The lowest g value (>2.06) also consistent with a dx2 – y2 ground state. The g|| / A||
quotient ranges was 107.166 cm–1, evidence in support of the octahedral geometry
without any distortion.
The axial symmetry parameter G values was calculated by using Kneuuh’s
method by using the expression, G = g||–2/ g┴–2 and related to the exchange
interactions between copper – copper centers. According to Hathway [83], if the
155
G value was greater than four, the exchange interaction was negligible indicating the
monomeric nature of complex. For the coper complex the G=4.539 indicates the
formation of monomeric complexes [42]
The ESR parameters g||, g┴, A||*, and A ┴* of the complex and the energies of
d–d transitions were used to evaluate the orbital reduction parameters (K||, K┴). The
molecular orbital coefficients or the bonding parameters α2 (in plane σ–bonding) and
β2 (in plane π–bonding) were calculated [36]. If the α2 = 0.5, it indicates a complete
covalent bonding, while the value of α2=1.0 suggests a complete ionic bonding. The
observed α2 value for the present chelate 0.45 indicates that the complex was
exhibiting some covalent character.
The dipolar interaction term (P) which takes into account the dipole–dipole
interaction of the electron moment with the nuclear moment [45]. The Fermi constant
interaction term (K) indicates the interaction between the electronic and the nuclear
spins [80] given by the expression K=A0/(P–∆g0), where (∆g0= ge–g0), it represents
the amount of unpaired electron density at the nucleus and K was the independent
property of the central ion [45].
The observed K|| < K┴. indicates the presence of significant in plane
π–bonding [36]. Giordano and Bereman suggested the identification of bonding
groups from the values of dipolar term P, reduction of P values from the free ion
value (0.045 cm–1) might be attributed to the strong covalent bonding [47]. The lower
P and α2 values for Cu [OHAPP] complex suggest the presence of strong in–plane
π bonding in agreement with higher ligand field. The shape of ESR lines, ESR data
together with the electronic spectral data suggest octahedral geometry for Cu(II)
complex [48].
156
Table:VI.1.Spin Hamiltonian and orbital reduction parameters of
Cu(II) complex in DMF solution
Parameters Cu (OHAPP)2
g|| 2.0566
g┴ 2.0749
gave 2.0694
G 4.539
A||* 0.0193
A┴* 0.0154
A*ave 0.0499
K|| 0.3220
K┴ 0.1976
P* 0.045
α2 0.45 * Values are given as cm–1 units.
ESR Spectral analysis of Ru (OHAPP) metal complex:
The ESR spectrum of Ruthenium complex was recorded by using JEOL,
JES–FA200 ESR Spectrometer, HCU, Hyderabad.
ESR spectra of Ru metal complexes give useful information regarding the
stereochemistry and nature of metal–ligand bonding. The ESR spectra of the complex
in polycrystalline state exhibit only one broad signal, which was attributed to dipolar
broadening and enhanced spin–lattice relaxation [35]. ESR spectra obtained for
ruthenium complex in DMF at liquid nitrogen temperature and representative ESR
spectrum of Ru (III) ion complex are presented in Fig.VI.2. and as shown in
Table.VI.2. In this low temperature spectrum, four peaks of small intensity have been
identified which are considered to originate from (g||, g┴, A|| and A┴) were determined
from the intense peaks of the spectrum [45]. Kivelson & Neiman [58] have reported
that g|| value is less than 2.3 for covalent character and it is greater than 2.3 for ionic
character of the metal–ligand bond in complex. Applying this criterion, the covalent
157
bond character can be predicted to exist between the metal and the ligand for complex
[35].
The trend g|| > g ave> g ┴ > 2.0023 observed for the complex suggests that the
unpaired electron was localized in dx2 – y2 orbital [16, 46] of the Rutenium (III)
complex. The lowest g value (>2.08) also consistent with a dx2 – y2 ground state. The
g|| / A|| quotient ranges was 107.36 cm–1, evidence in support of the octahedral
geometry without any distortion.
The axial symmetry parameter G values was calculated by using Kneuuh’s
method by using the expression, G = g||–2/ g┴–2 and related to the exchange
interactions between Ru – Ru centers. According to Hathway [83], if the G value was
greater than four, the exchange interaction was negligible indicating the monomeric
nature of complex. For the Ru(III) complex the G=4.144 indicates the formation of
monomeric complexes [42].
The ESR parameters g||, g┴, A||*, and A ┴* of the complex and the energies of
d–d transitions were used to evaluate the orbital reduction parameters (K||, K┴). The
molecular orbital coefficients or the bonding parameters α2 (in plane σ–bonding) and
β2 (in plane π–bonding) were calculated [36]. If the α2 = 0.5, it indicates a complete
covalent bonding, while the value of α2=1.0 suggests a complete ionic bonding. The
observed α2 value for the present chelate 0.120 indicates that the complex was
exhibiting some covalent character.
The dipolar interaction term (P) which takes into account the dipole–dipole
interaction of the electron moment with the nuclear moment [45]. The Fermi constant
interaction term (K) indicates the interaction between the electronic and the nuclear
spins [80] given by the expression K=A0/(P–∆g0), where (∆g0= ge–g0), it represents
158
the amount of unpaired electron density at the nucleus and K was the independent
property of the central ion [45].
The observed K|| < K┴. indicates the presence of significant in plane
π–bonding [36]. Giordano and Bereman suggested the identification of bonding
groups from the values of dipolar term P, reduction of P values from the free ion
value (0.036 cm–1) might be attributed to the strong covalent bonding [47]. The lower
P and α2 values for Ru [OHAPP] complex suggest the presence of strong in–plane
π bonding in agreement with higher ligand field. The shape of ESR lines, ESR data
together with the electronic spectral data suggest octahedral geometry for Ru(III)
complex [48].
Table:VI.2.Spin Hamiltonian and orbital reduction parameters of
Ru(III) complex in DMF solution
Parameters Ru (OHAPP)2
g|| 2.1796
g┴ 2.044
gave 2.090
G 4.144
A||* 0.0203
A┴* 0.0095
A*ave 0.0131
K|| 0.1068
K┴ 0.1772
P* 0.0126
α2 0.120 * Values are given as cm–1 units.
159
ESR Spectral analysis of Cu (OHBP) metal complex:
The ESR spectrum of copper complex was recorded by using JEOL,
JES–FA200 ESR Spectrometer, HCU, Hyderabad.
ESR spectra of Cu metal complexes give useful information regarding the
stereochemistry and nature of metal–ligand bonding. The ESR spectra of the complex
in polycrystalline state exhibit only one broad signal, which was attributed to dipolar
broadening and enhanced spin–lattice relaxation [35]. ESR spectra obtained for
copper complex in DMF at liquid nitrogen temperature and representative ESR
spectrum of Cu (II) ion complex are presented in Fig.VI.3., and as shown in
Table.VI.3. In this low temperature spectrum, four peaks of small intensity have been
identified which are considered to originate from (g||, g┴, A|| and A┴) were determined
from the intense peaks of the spectrum [45]. Kivelson & Neiman [58] have reported
that g|| value is less than 2.3 for covalent character and it is greater than 2.3 for ionic
character of the metal–ligand bond in complex. Applying this criterion, the covalent
bond character can be predicted to exist between the metal and the ligand for complex
[35].
The trend g|| > g ave> g ┴ > 2.0023 observed for the complex suggests that the
unpaired electron was localized in dx2 – y2 orbital [16, 46] of the copper (II) complex.
The lowest g value (>2.04) also consistent with a dx2 – y2 ground state. The g|| / A||
quotient ranges was 111.58 cm–1, evidence in support of the octahedral geometry
without any distortion.
The axial symmetry parameter G values was calculated by using Kneuuh’s
method by using the expression, G = g||–2/ g┴–2 and related to the exchange
interactions between copper – copper centers. According to Hathway [83], if the
G value was greater than four, the exchange interaction was negligible indicating the
160
monomeric nature of complex. For the coper complex the G=7.654 indicates the
formation of monomeric complexes [42].
The ESR parameters g||, g┴, A||*, and A ┴* of the complex and the energies of
d–d transitions were used to evaluate the orbital reduction parameters (K||, K┴). The
molecular orbital coefficients or the bonding parameters α2 (in plane σ–bonding) and
β2 (in plane π–bonding) were calculated [36]. If the α2 = 0.5, it indicates a complete
covalent bonding, while the value of α2=1.0 suggests a complete ionic bonding. The
observed α2 value for the present chelate 0.643 indicates that the complex was
exhibiting some covalent character.
The dipolar interaction term (P) which takes into account the dipole–dipole
interaction of the electron moment with the nuclear moment [45]. The Fermi constant
interaction term (K) indicates the interaction between the electronic and the nuclear
spins [80] given by the expression K=A0/(P–∆g0), where (∆g0= ge–g0), it represents
the amount of unpaired electron density at the nucleus and K was the independent
property of the central ion [45].
The observed K|| < K┴. indicates the presence of significant in plane
π–bonding [36]. Giordano and Bereman suggested the identification of bonding
groups from the values of dipolar term P, reduction of P values from the free ion
value (0.036 cm–1) might be attributed to the strong covalent bonding [47]. The lower
P and α2 values for Cu [OHBP] complex suggest the presence of strong in–plane
π bonding in agreement with higher ligand field. The shape of ESR lines, ESR data
together with the electronic spectral data suggest octahedral geometry for Cu(II)
complex [48].
161
Table:VI.3. Spin Hamiltonian and orbital reduction parameters of
Cu(II) complex in DMF solution
Parameters Cu (OHBP)2
g|| 2.0445
g┴ 2.006
gave 2.0182
G 7.6540
A||* 0.0190
A┴* 0.0140
A*ave 0.0161
K|| 0.4060
K┴ 1.5143
P* 0.05864
α2 0.643 * Values are given as cm–1 units.
ESR Spectral analysis of Ru(OHBP) metal complex:
The ESR spectrum of ruthenium complex was recorded by using JEOL,
JES–FA200 ESR Spectrometer, HCU, Hyderabad.
ESR spectra of Ru metal complexes give useful information regarding the
stereochemistry and nature of metal–ligand bonding. The ESR spectra of the complex
in polycrystalline state exhibit only one broad signal, which was attributed to dipolar
broadening and enhanced spin–lattice relaxation [35]. ESR spectra obtained for
ruthenium complex in DMF at liquid nitrogen temperature and representative ESR
spectrum of Ru(III) ion complex are presented in Fig.VI.4., and as shown in
Table.VI.4. In this low temperature spectrum, four peaks of small intensity have been
identified which are considered to originate from (g||, g┴, A|| and A┴) were determined
from the intense peaks of the spectrum [45]. Kivelson & Neiman [58] have reported
that g|| value is less than 2.3 for covalent character and it is greater than 2.3 for ionic
162
character of the metal–ligand bond in complex. Applying this criterion, the covalent
bond character can be predicted to exist between the metal and the ligand for complex
[35].
The trend g|| > g ave> g ┴ > 2.0023 observed for the complex suggests that the
unpaired electron was localized in dx2 – y2 orbital [16, 46] of the Ru(III) complex.
The lowest g value (>2.04) also consistent with a dx2 – y2 ground state. The g|| / A||
quotient ranges was 111.58 cm–1, evidence in support of the octahedral geometry
without any distortion.
The axial symmetry parameter G values was calculated by using Kneuuh’s
method by using the expression, G = g||–2/ g┴–2 and related to the exchange
interactions between Ru – Ru centers. According to Hathway [83], if the G value was
greater than four, the exchange interaction was negligible indicating the monomeric
nature of complex. For the Ru(III) complex the G=7.301 indicates the formation of
monomeric complexes [42].
The ESR parameters g||, g┴, A||*, and A ┴* of the complex and the energies of
d–d transitions were used to evaluate the orbital reduction parameters (K||, K┴). The
molecular orbital coefficients or the bonding parameters α2 (in plane σ–bonding) and
β2 (in plane π–bonding) were calculated [36]. If the α2 = 0.5, it indicates a complete
covalent bonding, while the value of α2=1.0 suggests a complete ionic bonding. The
observed α2 value for the present chelate 0.596 indicates that the complex was
exhibiting some covalent character.
The dipolar interaction term (P) which takes into account the dipole–dipole
interaction of the electron moment with the nuclear moment [45]. The Fermi constant
interaction term (K) indicates the interaction between the electronic and the nuclear
spins [80] given by the expression K=A0/(P–∆g0), where (∆g0= ge–g0), it represents
163
the amount of unpaired electron density at the nucleus and K was the independent
property of the central ion [45].
The observed K|| < K┴. indicates the presence of significant in plane
π–bonding [36]. Giordano and Bereman suggested the identification of bonding
groups from the values of dipolar term P, reduction of P values from the free ion
value (0.036 cm–1) might be attributed to the strong covalent bonding [47]. The lower
P and α2 values for Ru [OHBPP] complex suggest the presence of strong in–plane
π bonding in agreement with higher ligand field. The shape of ESR lines, ESR data
together with the electronic spectral data suggest octahedral geometry for Ru(III)
complex [48].
Table:VI.4. Spin Hamiltonian and orbital reduction parameters of
Ru(III) complex in DMF solution
Parameters Ru (OHBP)2
g|| 2.0451
g┴ 2.0060
gave 2.0190
G 7.301
A||* 0.0190
A┴* 0.0140
A*ave 0.0161
K|| 0.4044
K┴ 1.4721
P* 0.058
α2 0.596 * Values are given as cm–1 units.
164
Fig.VI.1 : ESR Spectra of Cu(OHAPP) complex
Fig.VI.2 : ESR Spectra of Ru(OHAPP) complex
165
Fig.VI.3 : ESR Spectra of Cu(OHBP) complex
Fig.VI.4 : ESR Spectra of Ru(OHBP) complex
166
Powder X-RD Studies:
The powder X-ray diffraction data obtained for metal complexes with
difractograms using DROL-2 powder diffractometer. Radiation filled by metal foil.
Powder XRD study of OHAPP –Cu complex:
The powder X-ray diffraction data obtained for complexes with difractograms
using DROL-2 powder diffractometer. Radiation filled by metal foil. The
diffractogram (10-diffractions) reflects Fig.VI.5 between 10-25 (2θ) values for
OHAPP-Cu complex values for Cu complex. Where θ is Bragg’s angle all the main
peaks are indicted and calculated values of Miller indices (h k l) along with observed
d-specified and reveled intensities are specified in the Fig:VI.5. All the peaks have
been indexed 2θ values compared in graph. Comparison values revels that there is
good agreement between values of 2θ and d-values. The powder x-ray diffraction data
showed identical features [91] with very poor crystalinity. The patterns are qualitative
and dispersive in intensity for Cu complex. The XRD patterns are used to explain
qualitatively the degree of crystalinity. X-ray Diffraction data of OHAPP-Cu complex
are presented in Table.VI.5 .
Table:VI.5. X-ray Diffraction data of OHAPP-Cu complex
S.No. d expt d Calc 2θ expt Calc h k l
1 5.5615 5.5614 15.92 15.82 3 2 1
2 5.5276 5.5275 16.02 16.00 4 3 1
3 5.4862 5.4855 16.14 16.11 4 2 0
4 5.4784 5.4723 16.16 16.12 5 2 1
5 5.4726 5.4723 16.18 16.12 5 3 2
6 5.3733 5.3722 16.48 16.21 5 4 1
7 4.9725 4.9722 17.82 17.33 6 3 2
8 4.6908 4.6902 18.90 18.43 6 2 1
9 4.4431 4.4412 19.96 19.52 7 3 2
10 3.9958 3.9912 21.94 21.44 8 3 1
167
Powder XRD study of OHAPP –Ru complex:
The powder X-ray diffraction data obtained for complexes with difractograms
using DROL-2 powder diffractometer. Radiation filled by metal foil. The
diffractogram (10-diffractions) reflects Fig.VI.6 between 15-35 (2θ) values for
OHAPP-Ru complex values for Ru complex. Where θ is Bragg’s angle all the main
peaks are indicted and calculated values of Miller indices (h k l) along with observed
d-specified and reveled intensities are specified in the Fig.VI.6. All the peaks have
been indexed 2θ values compared in graph. Comparison values revels that there is
good agreement between values of 2θ and d-values. The powder x-ray diffraction data
showed identical features [91] with very poor crystalinity. The patterns are qualitative
and dispersive in intensity for Ru complex. The XRD patterns are used to explain
qualitatively the degree of crystalinity. X-ray Diffraction data of OHAPP-Ru complex
are presented in Table VI.6.
Table:VI.6.X-ray Diffraction data of OHAPP-Ru complex
S.No. d expt d Calc 2θ expt Calc h k l
1 4.5427 4.5417 19.52 19.42 5 3 1
2 4.2030 4.2010 21.14 21.11 5 3 0
3 3.8520 3.8510 23.10 23.09 6 2 1
4 3.666 3.656 24.26 24.12 6 3 1
5 3.5897 3.5877 24.78 24.23 6 7 2
6 3.5863 3.5823 24.80 24.55 6 9 1
7 3.4747 3.4727 25.60 25.58 7 1 2
8 3.3354 3.3314 26.70 26.66 7 4 0
9 3.1217 3.1117 28.56 28.45 7 6 8
10 2.9287 2.9147 32.15 32.12 7 9 1
168
Powder XRD study of PHAPP –Cu complex:
The powder X-ray diffraction data obtained for complexes with difractograms
using DROL-2 powder diffractometer. Radiation filled by metal foil. The
diffractogram (11-diffractions) reflects Fig.VI.7 between 10-25 (2θ) values for
PHAPP-Cu complex values for Cu complex. Where θ is Bragg’s angle all the main
peaks are indicted and calculated values of Miller indices (h k l) along with observed
d-specified and reveled intensities are specified in the Fig: VI.7. All the peaks have
been indexed 2θ values compared in graph. Comparison values revels that there is
good agreement between values of 2θ and d-values. The powder x-ray diffraction data
showed identical features [91] with very poor crystalinity. The patterns are qualitative
and dispersive in intensity for Cu complex. The XRD patterns are used to explain
qualitatively the degree of crystalinity. X-ray Diffraction data of PHAPP-Cu complex
are presented in Table VI.7.
Table:VI.7. X-ray Diffraction data of PHAPP-Cu complex
S.No. d expt d Calc 2θ expt Calc h k l
1. 5.5817 5.5807 15.86 15.16 4 4 1
2. 5.5395 5.5385 15.98 15.88 5 5 1
3. 5.5375 5.5365 16.00 16.00 5 3 1
4. 5.4648 5.4628 16.02 16.01 5 7 2
5. 5.058 5.048 16.08 16.04 5 9 1
6. 5.500 5.496 16.10 16.02 6 0 1
7. 5.4862 5.4852 16.14 16.12 6 3 2
8. 5.0858 5.0848 17.42 17.40 6 4 5
9. 4.1984 4.1974 21.14 21.11 6 8 1
10. 4.0324 4.0314 22.02 22.00 6 7 9
11. 3.7225 3.7112 23.88 23.83 7 1 0
169
Powder XRD study of OHBP –Cu complex:
The powder X-ray diffraction data obtained for complexes with difractograms
using DROL-2 powder diffractometer. Radiation filled by metal foil. The
diffractogram (07-diffractions) reflects Fig.VI.8 between 35-80 (2θ) values for
OHBP-Ru complex values for Cu complex. Where θ is Bragg’s angle all the main
peaks are indicted and calculated values of Miller indices (h k l) along with observed
d-specified and reveled intensities are specified in the Fig:VI.8. All the peaks have
been indexed 2θ values compared in graph. Comparison values revels that there is
good agreement between values of 2θ and d-values. The powder x-ray diffraction data
showed identical features [91] with very poor crystalinity. The patterns are qualitative
and dispersive in intensity for Cu complex. The XRD patterns are used to explain
qualitatively the degree of crystalinity. X-ray Diffraction data of OHBP-Cu complex
are presented in Table VI.8.
Table:VI.8.X-ray Diffraction data of OHBP-Cu complex
S.No. d expt d Calc 2θ expt Calc h k l
1. 1.8748 1.8448 48.50 48.45 8 1 0
2. 1.2620 1.2520 75.20 75.14 8 2 0
3. 1.2606 1.2596 75.30 75.22 8 1 3
4. 1.2597 1.2587 75.36 75.33 8 4 2
5. 1.2577 1.2567 75.50 75.48 8 2 6
6. 1.2574 1.2564 75.52 75.32 8 9 3
7. 1.2369 1.2359 77.00 76.98 9 2 1
170
Powder XRD study of OHBP –Ru complex:
The powder X-ray diffraction data obtained for complexes with difractograms
using DROL-2 powder diffractometer. Radiation filled by metal foil. The
diffractogram (08-diffractions) reflects Fig.VI.9 between 30-60 (2θ) values for
OHBP-Ru complex values for Ru complex. Where θ is Bragg’s angle all the main
peaks are indicted and calculated values of Miller indices (h k l) along with observed
d-specified and reveled intensities are specified in the Fig:VI.9. All the peaks have
been indexed 2θ values compared in graph. Comparison values revels that there is
good agreement between values of 2θ and d-values. The powder x-ray diffraction data
showed identical features [91] with very poor crystalinity. The patterns are qualitative
and dispersive in intensity for Ru complex. The XRD patterns are used to explain
qualitatively the degree of crystalinity. X-ray Diffraction data of OHBP-Ru complex
are presented in Table.VI.9.
Table:VI.9.X-ray Diffraction data of OHBP-Ru complex
S.No. d expt d Calc 2θ expt Calc h k l
1. 2.8319 2.8259 31.56 31.36 7 3 2
2. 2.8267 2.8257 31.62 31.42 7 6 2
3. 2.8246 2.8236 31.64 31.54 7 9 1
4. 2.8179 2.8169 31.72 31.62 8 0 1
5. 1.9930 1.9910 45.46 45.36 8 2 6
6. 1.1894 1.1874 45.44 45.34 8 4 3
7. 1.9878 1.9868 45.58 45.48 8 7 9
8. 1.6190 1.6180 56.80 56.70 9 2 4
171
Powder XRD study of OVP –Cu complex:
The powder X-ray diffraction data obtained for complexes with difractograms
using DROL-2 powder diffractometer. Radiation filled by metal foil. The
diffractogram (15-diffractions) reflects Fig.VI.10 between 10-50 (2θ) values for
OVPP-Cu complex values for Cu complex. Where θ is Bragg’s angle all the main
peaks are indicted and calculated values of Miller indices (h k l) along with observed
d-specified and reveled intensities are specified in the Fig: VI.10. All the peaks have
been indexed 2θ values compared in graph. Comparison values revels that there is
good agreement between values of 2θ and d-values. The powder x-ray diffraction data
showed identical features [91] with very poor crystalinity. The patterns are qualitative
and dispersive in intensity for Cu complex. The XRD patterns are used to explain
qualitatively the degree of crystalinity. X-ray Diffraction data of OVP-Cu complex
are presented in Table: VI.10.
Table:VI.10. X-ray Diffraction data of OVP-Cu complex
S.No. d expt d Calc 2θ expt Calc h k l
1. 5.5535 5.5455 15.94 15.84 3 2 1
2. 5.5335 5.5225 16.00 15.98 4 2 1
3. 5.5058 5.5057 16.08 16.06 5 3 2
4. 5.4862 5.4859 16.14 16.11 6 2 1
5. 5.4590 5.4587 16.22 16.19 6 3 0
6. 4.0729 4.0719 21.80 21.79 7 4 3
7. 4.0473 4.0464 21.94 21.89 8 4 1
8. 4.0356 4.0346 22.00 21.98 9 4 3
9. 2.7421 2.7419 32.62 32.52 9 2 1
10. 2.6293 2.6284 34.06 34.04 9 4 7
11. 2.5425 2.5414 35.26 35.16 9 8 5
12. 2.5412 2.5411 35.28 35.18 9 8 6
13. 2.3699 2.3688 37.92 37.82 9 9 0
14. 2.0276 2.0256 44.64 44.44 9 6 9
15. 2.0268 2.0266 44.66 44.56 9 7 9
172
Powder XRD study of OVP –Ru complex:
The powder X-ray diffraction data obtained for complexes with difractograms
using DROL-2 powder diffractometer. Radiation filled by metal foil. The
diffractogram (15-diffractions) reflects Fig.VI.11 between 20-50 (2θ) values for
OVP-Ru complex values for Ru complex. Where θ is Bragg’s angle all the main
peaks are indicted and calculated values of Miller indices (h k l) along with observed
d-specified and reveled intensities are specified in the Fig: VI.11. All the peaks have
been indexed 2θ values compared in graph. Comparison values revels that there is
good agreement between values of 2θ and d-values. The powder x-ray diffraction data
showed identical features [91] with very poor crystalinity. The patterns are qualitative
and dispersive in intensity for Ru complex. The XRD patterns are used to explain
qualitatively the degree of crystalinity. X-ray Diffraction data of OVP-Ru complex
are presented in Table VI.11.
Table:VI.11. X-ray Diffraction data of OVP-Ru complex
S.No. d expt d Calc 2θ expt Calc h k l
1. 5.5235 5.5455 15.94 15.84 3 2 1
2. 5.5235 5.5225 16.00 15.98 4 2 1
3. 5.5858 5.5057 16.08 16.06 5 3 2
4. 5.5862 5.4859 16.14 16.11 6 2 1
5. 5.4590 5.4587 16.22 16.19 6 3 0
6. 4.0829 4.0719 21.80 21.79 7 4 1
7. 4.0773 4.0464 21.94 21.89 7 4 3
8. 4.0556 4.0346 22.00 21.98 7 5 2
9. 2.8421 2.7419 32.62 32.52 7 6 3
10. 2.6393 2.6284 34.06 34.04 7 9 1
11. 2.5525 2.5414 36.26 35.16 8 2 1
12. 2.5512 2.5411 36.28 35.18 8 4 2
13. 2.3799 2.3688 38.92 37.82 8 7 6
14. 2.1276 2.1256 45.64 44.44 8 9 1
15. 2.1028 2.0966 45.66 44.56 9 0 1
173
Powder XRD study of VP –Cu complex:
The powder X-ray diffraction data obtained for complexes with difractograms
using DROL-2 powder diffractometer. Radiation filled by metal foil. The
diffractogram (10-diffractions) reflects Fig.VI.12 between 10-70 (2θ) values for
VP-Cu complex values for Cu complex. Where θ is Bragg’s angle all the main peaks
are indicted and calculated values of Miller indices (h k l) along with observed
d-specified and reveled intensities are specified in the Fig: VI.12. All the peaks have
been indexed 2θ values compared in graph. Comparison values revels that there is
good agreement between values of 2θ and d-values. The powder x-ray diffraction data
showed identical features [91] with very poor crystalinity. The patterns are qualitative
and dispersive in intensity for Cu complex. The XRD patterns are used to explain
qualitatively the degree of crystalinity. X-ray Diffraction data of VP-Cu complex are
presented in Table VI.12.
Table: VI.12. X-ray Diffraction data of VP-Cu complex
S. No. d expt d Calc 2θ expt Calc h k l
1. 5.5475 5.5275 15.96 15.86 3 2 1
2. 5.5276 5.5176 16.02 15.92 4 1 0
3. 5.4590 5.4480 16.22 16.12 4 3 1
4. 5.4862 5.4722 16.14 16.04 5 3 2
5. 5.4726 5.4686 16.18 16.08 6 4 1
6. 2.7372 2.7232 32.68 32.58 7 5 2
7. 2.7338 2.7228 32.72 32.62 7 9 1
8. 1.3675 1.3555 68.54 68.42 8 0 1
9. 1.3668 1.3658 68.58 68.47 8 1 2
10. 1.3636 1.3626 68.76 68.56 8 4 9
174
Powder XRD study of VP –Ru complex:
The powder X-ray diffraction data obtained for complexes with difractograms
using DROL-2 powder diffractometer. Radiation filled by metal foil. The
diffractogram (12-diffractions) reflects Fig.VI.13 between 20-50 (2θ) values for
VP-Ru complex values for Ru complex. Where θ is Bragg’s angle all the main peaks
are indicted and calculated values of Miller indices (h k l) along with observed
d-specified and reveled intensities are specified in the Fig: VI.13. All the peaks have
been indexed 2θ values compared in graph. Comparison values revels that there is
good agreement between values of 2θ and d-values. The powder x-ray diffraction data
showed identical features [91] with very poor crystalinity. The patterns are qualitative
and dispersive in intensity for Ru complex. The XRD patterns are used to explain
qualitatively the degree of crystalinity. X-ray Diffraction data of VP-Ru complex are
presented in Table VI.13.
Table:VI.13. X-ray Diffraction data of VP-Ru complex
S. No. d expt d Calc 2θ expt Calc h k l
1. 3.3846 3.3816 26.30 26.20 7 0 1
2. 3.3801 3.3791 26.34 26.24 7 2 3
3. 3.3749 3.3729 26.38 26.18 7 7 1
4. 3.2421 3.2391 27.48 27.47 7 3 4
5. 2.8210 2.8200 31.68 31.66 7 7 9
6. 2.8158 2.8148 31.74 31.72 8 2 1
7. 2.8127 2.8117 31.78 31.71 8 4 2
8. 2.8107 2.8097 31.80 31.78 8 7 3
9. 2.8056 2.8046 31.86 31.77 8 9 0
10. 1.9870 1.9790 45.60 45.53 9 0 1
11. 1.9847 1.9787 45.66 45.52 9 4 2
12. 1.6253 1.6153 56.56 56.52 9 7 9
175
Fig. VI.5. Powder XRD of Cu( OHAPP) complex
Fig. VI.6 : Powder XRD of Ru( OHAPP) complex
176
Fig.VI.7 : Powder XRD of Cu( PHAPP) complex
Fig.VI.8 : Powder XRD of Cu(OHBP) complex
177
Fig.VI.9 : Powder XRD of Ru(OHBP) complex
Fig.VI.10 : Powder XRD of Cu(OVP) complex
178
Fig.VI.11 : Powder XRD of Ru(OVP) complex
Fig.VI.12 : Powder XRD of Cu(VP) complex
179
Fig.VI.13 : Powder XRD of Ru(VP) complex
180
Thermal Studies –TGA/ DTA:
Majority of the compounds and complexes suffer physical and chemical
changes when subjected to heat under defined experimental conditions. These
changes are characteristic of the substance examined, and can be used for its
qualitative and quantitative analysis. For analysis of this kind, the phenomena
accompanying the thermal analysis are changes in temperature and weight of the
compound.
Though several methods are adopted in thermo analytical analysis, then no
gravimetric analysis (TGA) and differential thermal analysis (DTA) are the most
suitable methods used in coordination chemistry. The data obtained as continuously
recorded curves which may be considered as thermal spectra. These thermo grams
characterize a system, single or multicomponent, in terms of temperature dependence
of its thermodynamic properties. Thermo gravimetric analysis involves changes in
weight of a system under investigation as the temperature is increased at a
predetermined rate. Differential thermal analysis consists of measuring the changes in
heat content, as a function of the difference in temperature between the sample under
investigation and a thermally inert reference compound; In this manner enthalpy
changes, such a melting and chemical changes are detected from the endo and
exo- thermal bands and peaks that appear in the thermo grams, the corresponding
weight changes are detected by thermo gravimetric analysis.
The thermal studies of these complexes are carried out to know the stability of
the complexes on thermal decomposition, as well as to know the different final
products that are obtained in thermal decomposition having novel catalytic Properties
[72,73]. Thermogravimetric analyses of the metal complexes were carried out by
181
using the METTLER TOLEDO STAR System in thermal analysis center IICT
Hyderabad. All possible precautions wer taken to optimize conditions, so as to carry
out all the Thermogravimetric analysis experiments under the same conditions.
Thermal Analysis of OHAPP Metal Complexes:
TG techniques were employed to follow the thermal behavior of complexes.
According to the results obtained, the complexes are not volatile and their
decomposition occurs in more than one step. The typical thermograms of complexes
were shown in the Fig VII.1 and VII.2. Thermo gravimetric studies on the complexes
confirmed their proposed molecular formula. The thermal decomposition of metal
complexes has been followed up to 1000°. The decomposition behavior of the
complexes was observed in nitrogen atmosphere. The experimental mass losses were
in good agreement with the calculated mass loss values which were summarized in
the Table VII.1.
The Copper complex of OHAPP shows three main decomposition stages, and
the first stage with small endothermic dehydration step in the range of 120°C to
170°C was due to loss of two water molecules coordinated to the metal [75-77]. The
Second step involves two sub steps which involves decomposition of the ligand
moiety, Exothermic decomposition of the ligand moiety takes place around
180–350°C, [78-81] to give the stable intermediate M (OHAPPP)2 and this was stable
up to 450°C, which on further undergoes exothermic decomposition in the above
500°C in the third stage forming Copper Oxide (CuO) as final residual product.
The Ruthenium complex of OHAPP shows three main decomposition stages,
and the first stage with small endothermic dehydration step in the range of 140°C to
170°C was due to loss of two water molecules coordinated to the metal [75-77]. The
Second step involves two sub steps which involves decomposition of the ligand
182
moiety, Exothermic decomposition of the ligand moiety takes place around
280–360°C, [78-81] to give the stable intermediate M (OHAPPP)2 and this was stable
up to 440°C, which on further undergoes exothermic decomposition in the above
450°C in the third stage forming Ruthenium Oxide (RuO) as final residual product.
Table: VII.1. Thermo analytical data of metal complexes
Complex
X=H2O
Temperature
range in °C Probable assignment
Mass loss
(%)
Total mass
loss (%)
CuL2X2 L=C28H23N3SO
120-170 Loss of 2H2O molecules 14.03 59.52 180-350 Decomposition of L 34.50
Above-450 Formation of CuO 10.99
RuL2X2 L=C28H23N3SO
140-170 Loss of 2H2O molecules 13.13 66.86 280-360 Decomposition of L 40.82
Above-450 Formation of RuO 12.91
183
Thermal Analysis of PHAPP Metal Complexes:
TG techniques were employed to follow the thermal behavior of complexes.
According to the results obtained, the complexes are not volatile and their
decomposition occurs in more than one step. The typical thermograms of complexes
were shown in the Fig VII.3 and VII.4. Thermo gravimetric studies on the complexes
confirmed their proposed molecular formula. The thermal decomposition of metal
complexes has been followed up to 1000°. The decomposition behavior of the
complexes was observed in nitrogen atmosphere. The experimental mass losses were
in good agreement with the calculated mass loss values which were summarized in
the Table VII.2.
The Copper complex of PHAPP shows three main decomposition stages, and
the first stage with small endothermic dehydration step in the range of 100°C to
160°C was due to loss of two water molecules coordinated to the metal [75-77]. The
Second step involves two sub steps which involves decomposition of the ligand
moiety, Exothermic decomposition of the ligand moiety takes place around
180–200°C, [78-81] to give the stable intermediate M (PHAPP)2 and this was stable
up to 440°C, which on further undergoes exothermic decomposition in the region
440-840°C in the third stage forming Copper Oxide (CuO) as final residual product.
The Ruthenium complex of PHAPP shows three main decomposition stages,
and the first stage with small endothermic dehydration step in the range of 100°C to
110°C was due to loss of two water molecules coordinated to the metal [75-77]. The
Second step involves two sub steps which involves decomposition of the ligand
moiety, Exothermic decomposition of the ligand moiety takes place around
184
310–530°C, [78-81] to give the stable intermediate M (PHAPP)2 and this was stable
up to 770°C, which on further undergoes exothermic decomposition in the above
region of 770°C in the third stage forming Ruthenium Oxide (RuO) as final residual
product.
Table:VII.2. Thermo analytical data of metal complexes
Complex
X=H2O
Temperature
range in °C Probable assignment
Mass loss
(%)
Total mass
loss (%)
CuL2X2 L=C28H23N3SO
100-160 Loss of 2H2O molecules 3.67 78.94 180-200 Decomposition of L 65.42
440-840 Formation of CuO 9.85
RuL2X2 L=C28H23N3SO
100-110 Loss of 2H2O molecules 5.68 60.32 310-530 Decomposition of L 40.73
Above-770 Formation of RuO 13.91
185
Thermal Analysis of OHBP Metal Complexes
TG techniques were employed to follow the thermal behavior of complexes.
According to the results obtained, the complexes are not volatile and their
decomposition occurs in more than one step. The typical thermograms of complexes
were shown in the Fig VII.5 and VII.6. Thermo gravimetric studies on the complexes
confirmed their proposed molecular formula. The thermal decomposition of metal
complexes has been followed up to 1000°. The decomposition behavior of the
complexes was observed in nitrogen atmosphere. The experimental mass losses were
in good agreement with the calculated mass loss values which were summarized in
the Table VII.3.
The Copper complex of OHBP shows three main decomposition stages, and
the first stage with small endothermic dehydration step in the range of 120°C to
140°C was due to loss of two water molecules coordinated to the metal [75-77]. The
Second step involves two sub steps which involves decomposition of the ligand
moiety, Exothermic decomposition of the ligand moiety takes place around
380–440°C, [78-81] to give the stable intermediate M (OHBP)2 and this was stable up
to 600°C, which on further undergoes exothermic decomposition in the above 600°C
in the third stage forming Copper Oxide (CuO) as final residual product.
The Ruthenium complex of OHBP shows three main decomposition stages,
and the first stage with small endothermic dehydration step in the range of 220°C to
260°C was due to loss of two water molecules coordinated to the metal [75-77]. The
Second step involves two sub steps which involves decomposition of the ligand
moiety, Exothermic decomposition of the ligand moiety takes place around
270–440°C, [78-81] to give the stable intermediate M (OHBP)2 and this was stable up
186
to 650°C, which on further undergoes exothermic decomposition in the above 650°C
in the third stage forming Ruthenium Oxide (RuO) as final residual product.
Table:VII.3. Thermo analytical data of metal complexes
Complex
X=H2O
Temperature
range in °C Probable assignment
Mass loss
(%)
Total mass
loss (%)
CuL2X2 L=C17H21N3SO
120-140 Loss of 2H2O molecules 15.64 90.94 380-440 Decomposition of L 64.53
Above-600 Formation of CuO 10.77
RuL2X2 L=C17H21N3SO
220-260 Loss of 2H2O molecules 11.33 71.09 270-440 Decomposition of L 52.81
Above-650 Formation of RuO 7.55
187
Thermal Analysis of OVP Metal Complexes:
TG techniques were employed to follow the thermal behavior of complexes.
According to the results obtained, the complexes are not volatile and their
decomposition occurs in more than one step. The typical thermograms of complexes
were shown in the Fig VII.7 and VII.8. Thermo gravimetric studies on the complexes
confirmed their proposed molecular formula. The thermal decomposition of metal
complexes has been followed up to 1000°. The decomposition behavior of the
complexes was observed in nitrogen atmosphere. The experimental mass losses were
in good agreement with the calculated mass loss values which were summarized in
the Table VII.4.
The Copper complex of OVP shows three main decomposition stages, and the
first stage with small endothermic dehydration step in the range of 160°C to 180°C
was due to loss of two water molecules coordinated to the metal [75-77]. The Second
step involves two sub steps which involves decomposition of the ligand moiety,
Exothermic decomposition of the ligand moiety takes place around 210–380°C,
[78-81] to give the stable intermediate M (OVP)2 and this was stable up to 700°C,
which on further undergoes exothermic decomposition in the above 710 in the third
stage forming Copper Oxide (CuO) as final residual product.
The Ruthenium complex of OVP shows three main decomposition stages, and
the first stage with small endothermic dehydration step in the range of 120°C to
160°C was due to loss of two water molecules coordinated to the metal [75-77]. The
Second step involves two sub steps which involves decomposition of the ligand
moiety, Exothermic decomposition of the ligand moiety takes place around
188
180–360°C, [78-81] to give the stable intermediate M (OVP)2 and this was stable up
to 520°C, which on further undergoes exothermic decomposition in the above 520°C
in the third stage forming Ruthenium Oxide (RuO) as final residual product.
Table:VII.4. Thermo analytical data of metal complexes
Complex
X=H2O
Temperature
range in °C Probable assignment
Mass loss
(%)
Total mass
loss (%)
CuL2X2 L=C18H23N3SO2
160-180 Loss of 2H2O molecules 9.53 84.87 210-380 Decomposition of L 67.46
Above-710 Formation of CuO 7.88
RuL2X2 L=C18H23N3SO2
120-160 Loss of 2H2O molecules 12.89 79.64 180-360 Decomposition of L 58.53
Above-520 Formation of RuO 8.22
189
Thermal Analysis of VP Metal Complexes:
TG techniques were employed to follow the thermal behavior of complexes.
According to the results obtained, the complexes are not volatile and their
decomposition occurs in more than one step. The typical thermograms of complexes
were shown in the Fig VII.9 and VII.10. Thermo gravimetric studies on the
complexes confirmed their proposed molecular formulae. The thermal decomposition
of metal complexes has been followed up to 1000°. The decomposition behavior of
the complexes was observed in nitrogen atmosphere. The experimental mass losses
were in good agreement with the calculated mass loss values which were summarized
in the Table VII.5.
The Copper complex of VP shows three main decomposition stages, and the
first stage with small endothermic dehydration step in the range of 90°C to 190°C was
due to loss of two water molecules coordinated to the metal [75-77]. The Second step
involves two sub steps which involves decomposition of the ligand moiety, Exo-
thermic decomposition of the ligand moiety takes place around 220–290°C, [78-81] to
give the stable intermediate M (VP)2 and this was stable up to 550°C, which on
further undergoes exothermic decomposition in the above 550°C in the third stage
forming Copper Oxide (CuO) as final residual product.
The Ruthenium complex of VP shows three main decomposition stages, and
the first stage with small endothermic dehydration step in the range of 230°C to
240°C was due to loss of two water molecules coordinated to the metal [75-77]. The
Second step involves two sub steps which involves decomposition of the ligand
moiety, Exothermic decomposition of the ligand moiety takes place around
190
290–460°C, [78-81] to give the stable intermediate M (VP)2 and this was stable up to
630°C, which on further undergoes exothermic decomposition in the above 660°C in
the third stage forming Ruthenium Oxide (RuO) as final residual product.
Table:VII.5. Thermo analytical data of metal complexes
Complex
X=H2O
Temperature
range in °C Probable assignment
Mass loss
(%)
Total mass
loss (%)
CuL2X2 L=C18H23N3SO2
90-190 Loss of 2H2O molecules 11.14 84.07 200-290 Decomposition of L 66.11
Above-550 Formation of CuO 7.22
RuL2X2 L=C18H23N3SO2
230-240 Loss of 2H2O molecules 6.78 65.13 290-460 Decomposition of L 52.11
Above-660 Formation of RuO 6.24
191
Fig.VII.1: TG/ DTA of Cu (OHAPP) complex
Fig.VII.2 : TG/ DTA of Ru (OHAPP) complex
192
Fig.VII.3 : TG/ DTA of Cu (PHAPP) complex
Fig.VII.4 : TG/ DTA of Ru (PHAPP) complex
193
Fig.VII.5: TG/ DTA of Cu (OHBP) complex
Fig.VII.6: TG/ DTA of Ru (OHBP) complex
194
Fig.VII.7: TG/ DTA of Cu (OVP) complex
Fig.VII.8: TG/ DTA of Ru (OVP) complex
195
Fig.VII.9: TG/ DTA of Cu (VP) complex
Fig.VII.10: TG/ DTA of Ru (VP) complex
196
Vibrational spin magneto meter (VSM)
Magnetic behaviour of ligand and its metal complexes:
The magnetic properties along with spectroscopic properties acquire greater
significance in the characterization of transition metal complexes.
Magnetic moments are generally useful in determining the number of unpaired
electrons to provide information about the population and relative energies of ‘d’
levels in a complex and allow the distraction to be made between octahedral and
tetrahedral [87,88] complexes. Magnetic susceptibility of a sample can be determined
by several experimental approaches.
Magnetic susceptibility data was recorded on an EG and G-155 magneto
meter. The powdered samples of the compounds were introduced in capsules in a
glove box and kept under an inert atmosphere before being placed into the magneto
meter. The calibration was made at 2980 K using a palladium reference supplied by
quantum design. The independence of the susceptibility value with regard to the
applied field was checked at room temperature. Applied research vibrating sample
magneto meter VSM-155 operating at field strengths ranging from 0.3 to 0.8 T. The
VSM is calibrated against the saturated moment of 99.999 % ultra pure Nickel.
Finally ground powder of the sample, typically weighing 50 mg is housed in a
sample holder and placed in a uniform homogeneous magnetic field. Where the
sample is made to undergo sinusoidal motion. The output data are corrected for the
diamagnetism of the sample holder and for the underlying diamagnetism of the
constituent atoms of the ligands using Pascal’s constants. The moment recorded at
different field strengths to evaluate µeff in Bohr magnetons using [82].
197
µeff = 2.84 strength field magnetic sampleWeight
T weight molecular moment Magnetic
×
××
Magnetic Susceptibility Measurements of Copper and Ruthenium complexes:
The magnetic susceptibility values are given in Table.VII.6. The Copper
complexs at room temperature were observed to be consistent between the range
2.4-4.8 B.M. [85]. This magnetic momentum value indicates the presence of unpaired
electrons as expected for Cu (II) complexs. The magnetic moment value also revealed
that the complexs is monomeric in nature and metal-metal interaction along the axial
positions is absent. It was observed that there was considerable orbital contribution
and effective magnetic moments for an octahedral complexs at room temperature
around the range 5.0-5.2 B.M for high spin octahedral complexes [89, 90], the
magnetic moment was observed 4.8 B.M for Cu (II) complex. Thermal analysis
showed that the Copper complex involved thelose of two water molecules at about
100-190 0C. This suggests that two water molecules coordinated with the central
metal ion, which is further confirmed by their characteristic IR spectrum.
The magnetic susceptibility values are given in Table.VII.6. The Ruthenium
complexes or know for both high and low spin state. The high spin complexes are
expected to show magnetic moments very close to the spin only vaules range
5.21-5.81B.M., and independent of temperature, irrespective of whether the ligand
arrangement is of tetrahedral symmetry respectively. Thermal analysis shows that the
Ruthenium complexs lose two water molecules at about 100-2600C which suggest the
presence of two water molecules coordinating with the central metal ion. This is
further confirmed by their characteristic IR spectrum.
198
Table VII.6 Magnetic moments of Copper and Ruthenium complexes
Complex Cupper in (B.M) Ruthenum in (B.M)
(OHAPP)2 2.40 5.41
(PHAPP)2 4.60 5.81
(OHBP)2 4.20 5.62
(OVP)2 4.40 5.58
(VP)2 4.80 5.21
199
Spectro Chemical Studies of RAPP metal Complexes
2,4-dihydoxy acetophenone and pramipexole was selected for carrying out
the present investigation far various studies such as spectro chemical behavior of
ligand in different analytical methods and its complexing ability toward bio inorganic
metal far ananlysis, like elucedation of structures of complexes biological studies and
DNA activites, this formation of metal complexes with pramipexole is much stable.
This the reason for seclecting RAPP as a comman complexing ligand were
summarized below.
1. Prepartion of RAPP was very easy and the percentage yield of ligand and
metal complexes were very good.
2. Its solubility of ligand and complexes in highly stable.So its useful for spectro
chemical studies.
3. The important point form seclting the RAPP ligand was that it was two
hydroxyl groups. In this structure a of which one will be at ortho position there
by faciliting the formation of complex species there by metal chelation is
highly stable color, high purites and it exhibit clear spectra’s there by easy to
analyzing different dimensional studies.
Keeping the above advantages in view the author in present investigation
employed RAPP as metal complexing agent to carryout various investigations.The
present work was devoted to study the spectrochemical behavior of the RAPP, which
include IR, NMR, UV, Powder XRD, Conductivity measurement , TGA-DTA
biological activity and also DNA Binding.
200
IR Spectral Studies:
Infrared spectroscopy is one of the main valuable analytical techniques
currently available to chemists, which is based on the interaction of electromagnetic
radiation with the matter .By utilizing this spectroscopy, the presence of important
functional groups in the compound can be identified. Infrared spectra were recorded
with a Perkin–Elmer IR 598 Spectrometer (4000–200cm–1) using KBr pellets. It was
observed that the IR spectra of all the metal complexes gave a considerable number of
peaks, each corresponding to a particular vibrational transition.
Charaterisation of RAPP lignad and its Complexes
I.R. Analysis of the Ligand
The typical I.R spectrum of [RAPP] ligand was presented in the Fig.VIII.1,
and observation vaules as shown in Table.VIII.1. As concern the 2,4-Dihydroxy
acetophenone pramipexole are main regions of the IR are of main interest.
Nitrogen bond order between a single bond (υ = 1250-1350 cm-1) and a double
bond (υ = 1600–1690 cm-1). Chart et al., characterized by a strong delocalization of
electrons ,In addition to the usual aromatic hydroxyl groups or phenolic groups
provide information as regards the strength of O-H bonds appeared at (3500-3227)
and (1410-1300) cm-1 due to the stretching [4] and bending vibrations of phenolic OH
[5] respectively
First, the strong sharp characteristic band band exhibited at 1632 cm-1 in the
IR spectrum of the ligand has been assigned to the (C=N) Stretching vibration of the
azomethine group A single sharp band at 3290 cm-1 was assigned to the stretching
vibrations of the OH and NH bonds . The band at 2964 cm-1,2722 cm-1 associated
with the υ (C-H) and (C–Haldehyde) stretching vibrations. The N-H bending vibration of
201
secondary amine appeared in the a 1604 cm-1 , for aromatic rings ,the most
charecterstic aromatic ring (C=C) stretching bonds are observed at 1517 cm-1,
1435 cm-1,The characteristic absorption band is appear in between the region of
1374-793 cm–1, (C-C, C–O, C–N).
I.R. Characterization of Metal Complexes:
The infrared sprectra of Cu (II), Ru(III),Co(II),Ni(II), Mn (II), La(III), Y(III)
and Pd(II) complexes were compared with the [RAPP] Lignad. The typical I.R.
sprectra of complexes were presented in Fig.VIII.2. to Fig.VIII.8., and IR spectra of
complexes were shown in the Table.VIII.1.
A strong band exhibited at 1632cm-1 in the IR spectrum of the ligand has been
assigned to the (C=N) Stretching vibration of the azomethine group. On complexation
this band is shifted to 1627cm-1, 1621 cm-1, 1590cm-1 , 1627cm-1,1627 cm-1,1625 cm-1
1627 cm-1and 1621 cm-1 for Cu (II), Ru(III),Co(II),Ni(II), Mn (II), La(III), Y(III) and
Pd(II) complexes respectively [1,3] . This shift to lower wave numbers supports the
participation of the azomethine group of this ligand in binding to the metal ion.
The coordination of azomethine nitrogen to the metal atom would be expected
to reduce the electron density in the azomethine group and thus cause for a reduction
in C=N stretching frequency. Bands appeared at 3290 and 1330 cm-1 due to the
stretching [4] and bending vibrations of phenolic OH [5] respectively. These bands
are disappeared in spectra of complexes indicating the deprotanation of phenolic OH.
This is further confirmed by the appearance of new bands in the region 421-495cm-1
and 608-712cm-1, which are assigned to the stretching frequencies of M-N and M-O
of the metal ligand bands [6-9] respectively for Cu (II), Ru(III),Co(II),Ni(II), Mn (II),
La(III), Y(III) and Pd(II) complexes. The IR spectrum of the ligand has shown a band
in the region 1528-1435 cm-1 due to the aromatic ring C=C stretching vibrations.
202
A weak band observed around 2900 cm-1 in both ligands and complexes could be
assigned to the C-H stretching frequency [11]. A broad band exhibited at 3412, 3435,
3530, 3397, 3430 cm-1,3402 cm-1,3424 cm-1 and 3421 cm-1 for Cu (II), Ru(III), Co(II),
Ni(II), Mn (II), La(III), Y(III) and Pd(II)) complexes respectively. Which can be
assigned to the N-H and /OH stretching vibration of the coordinated water molecules
[12,13]. These results indicate the formation of complex.
These results indicate that the ligand coordinate with the metal ion through the
azomethine nitrogen and the oxygen of the deprotonated hydroxyl group [14,15].
Table:VIII.1. The important IR bands of the RAPP ligand and their metal
complexes
Compound OH
Water
OH
Phenolic C=N N-H M-O M-N
RAPP – 3290 1632 3303 – –
RAPP-Cu 3412 – 1627 3309 608 482
RAPP-Ru 3435 – 1621 3309 712 495
RAPP-Co 3530 – 1590 3308 644 421
RAPP-Ni 3397 – 1627 3297 668 486
RAPP-Mn 3430 – 1627 3301 635 451
RAPP-La 3402 – 1625 3305 673 490
RAPP-Y 3424 – 1627 3307 695 486
RAPP-Pd 3420 – 1621 3300 712 476
203
Fig.VIII.1 : IR Spectra of RAPP Ligand
Fig.VIII.2 : IR Spectra of Cu(RAPP) Complexes
204
Fig.VIII.3 : IR Spectra of Ru( RAPP) complexes
Fig.VIII.4 : IR Spectra of Co( RAPP) complexes
205
Fig.VIII.5 : IR Spectra of Ni( RAPP) complexes
Fig.VIII.6 : IR Spectra of Mn(RAPP) complexes
206
Fig.VIII.7 : IR Spectra of La(RAPP) complexes
Fig.VIII.8 : IR Spectra of Y(RAPP) complexes
207
Fig.VIII.9 : IR Spectra of Pd(RAPP) complexes
208
1 H-NMR Spectral Studies:
1H Nuclear magnetic resonance (NMR) spectroscopy is an analytical
technique based on the magnetic properties of nuclei. By using this spectroscopy, the
nature of protons and the number protons present in a particular environment can be
deterermined. In this principle, chemical shifts, internal reference standard
tetramethylsilance (TMS) is needed. TMS is chosen for several reasons i.e. it contains
12 equivalent protons and four equivalent carbons and also it is chemically inert,
soluble in most organic compounds, and sufficiently volatile to be easily removed
from the sample after the spectrum has been recorded.
In the present study, 1H NMR spectra were recorded on an av-400 MHz NMR
spectrometer in HCU, Hyd in DMSO-d6 solvent at room temperature.
Interpretation of NMR spectra of RAPP ligand and its metal complexes:
Fig VIII.10 to VIII.18., shows the NMR spectra of the RAPP ligand and its
Cu, (II), Ru(III), Co (II), Ni(II), Mn(II), La(III) Y(III) and Pd( II) complexes.
Table. VIII.2.,contains the important chemical shift values along with their
assignments. A singlet observed at 2.71 ppm for 1H NMR spectrum of the RAPP
ligand is assigned to the methyl protons attached to azomethine (C=N) group [16,17].
The singlet appeared at 1.70 ppm is attributed to the methelene protons of the
cyclohexane ring. Another doublet observed at 5.71-5.72 ppm for 1H NMR spectrum
of the O and P- hydroxyl proton of the phenyl ring. A multiplet is observed in the
region 6.37-7.65 [18,19] due to the aromatic C-H protons of phenyl ring. A singlet
appeared at 7.2 ppm is attributed to the C-H proton attached to the phenyl ring in the
ligand [20]. ]. The doublet appeared at 7.63-7.65 ppm due to two C-H proton attached
to the phenyl ring The singlet appeared at 12.69 ppm due to N-H proton of ligand.
209
In the 1H NMR spectrum of the RAPP –Cu complex, a signal appeared due to
methyl protons attached to azomethine group has been shifted to 2.573 ppm compared
to 2.71 ppm in the case of ligand [21].This down field shift indicates the deshielding
of azomethine proton on coordination through nitrogen atom of azomethine group
[27]. The signal observed at 1.73 ppm due to the methelene protons in the
cyclohexane ring ligand is shifted to 1.26-1.73 ppm for the (Cu) complex. A singlet
observed at 7.27 ppm due to the para hydroxy proton shifted for the Cu complex. The
signal disappeared at 5.71-5.72 ppm due to phenolic hydroxyl proton is absent in the
NMR spectrum of (Cu) complex indicating the deprotonation of hydroxyl group and
the involvement of that oxygen in coordination [28]. The multiplet observed in the
region 6.37-7.65 ppm due to aromatic protons for the ligand showed a shift to
6.64-6.62 ppm for (Cu) complex may be due to the drifting of ring of electrons
towards the metal ion. A signal observed at 12.69 ppm in ligand due to N-H proton is
shifted to 12.7 ppm for Cu complex [104,105]. A signal observed at
13.18-13.37 ppm in complex due to O-H proton of water molecule present in the
complex.
In the 1H NMR spectrum of the RAPP-Ru complex, a signal appeared due to
methyl protons attached to azomethine group has been shifted to 2.4 ppm in the case
of ligand [21]. This down field shift indicates the deshielding of azomethine proton on
coordination through nitrogen atom of azomethine group[27]. The signal observed at
1.81 ppm due to the cyclo hexane protons of the Ru complex. The signal disappeared
at 5.71-5.72 ppm due to phenolic hydroxyl proton is absent in the NMR spectrum of
Ru complex indicating the deprotonation of hydroxyl group and the involvement of
that oxygen in co-ordination [22]. A new signal is observed as a signal at 4.8-4.9 ppm
in the case of Ru (III) complex indicating the presence of water molecules
210
coordinated to the metal atom [29,30]. The multiplet observed in the region 6.37-7.59
ppm due to aromatic protons for the ligand showed a shift to 6.41 -7.59 ppm for Ru
complex [24-26] may be due to the drifting of ring of electrons towards the metal ion.
A signal observed at 8.35 ppm due to N-H proton for Ru complex.
In the 1H NMR spectrum of the RAPP – Co complex, a signal appeared due to
methyl protons attached to azomethine group has been shifted to 2.7 ppm compared to
2.71 ppm in the case of ligand [21]. This downfield shift indicates the deshielding of
azomethine proton on coordination through nitrogen atom of azomethine group [27].
The signal observed at 1.65 ppm due to the methelene protons of cyclohexane ring for
the (Co) complex. A signal is appeared due to para at 7.45 ppm due to OH proton on
Para position of phenolic group. The signal disappeared at 5.71-5.72 ppm due to
phenolic hydroxyl proton is absent in the NMR spectrum of (Co) complex indicating
the deprotonation of hydroxyl group and the involvement of that oxygen in
coordination [28]. The multiplet observed in the region 6.37-7.65 ppm due to
aromatic protons for the ligand showed a shift to 6.45-7.65 ppm for (Co) complex
may be due to the drifting of ring of electrons towards the metal ion. A new signal is
observed as a singlet at 5.05ppm in the case of Co (II) complex indicating the
presence of water molecules coordinated to the metal atom A signal observed at 12.69
ppm in ligand due to N-H proton is shifted to 12.95 ppm for Co complex [104,105].
In the 1H NMR spectrum of the RAPP –Ni complex, a signal appeared due to
methyl protons attached to azomethine group has been shifted to 2.579 ppm compared
to 2.71 ppm in the case of ligand [21].This down field shift indicates the deshielding
of azomethine proton on coordination through nitrogen atom of azomethine
group[27]. The signal observed at 1.64 ppm due to the methelene protons of
cyclohexane in the Ni complex. The signal dis appeared at 5.71-5.72 ppm due to
211
phenolic hydroxyl proton is absent in the NMR spectrum of Ni complex indicating the
deprotonation of hydroxyl group and the involvement of that oxygen in coordination
[28]. A new signal is observed as a singlet at 4.5 ppm in the case of Ni (II) complex
indicating the presence of water molecules coordinated to the metal atom. The
multiplet observed in the region 6.35-7.65 ppm due to aromatic protons for the ligand
showed a shift to 6.39-7.66 ppm for Cu complex [19] may be due to the drifting of
ring of electrons towards the metal ion. A signal observed at 12.7 ppm due to N-H
proton for Ni complex.
In the 1H NMR spectrum of the RAPP –Mn complex, a signal appeared due to
methyl protons attached to azomethine group has been shifted to 2.18 ppm compared
to 2.71 ppm in the case of ligand [21].This upfield shift indicates the shielding of
azomethine proton on coordination through nitrogen atom of azomethine group [27].
The signal observed at 1.71 ppm due to the methelene protons in the cyclohexane ring
ligand is shifted to 1.64 ppm for the (Mn) complex. A signal is appeared due to para
at 7.33ppm due to OH proton on para position of phenolic group. The signal
disappeared at 5.71-5.72 ppm due to phenolic hydroxyl proton is absent in the NMR
spectrum of (Mn) complex indicating the deprotonation of hydroxyl group and the
involvement of that oxygen in coordination [28]. The multiplet observed in the region
6.37-7.65 ppm due to aromatic protons for the ligand showed a shift to 6.73-7.38 ppm
for (Mn) complex may be due to the drifting of ring of electrons towards the metal
ion. A new signal is observed as a singlet at 5.05 ppm in the case of Mn (II) complex
indicating the presence of water molecules coordinated to the metal atom.A signal
observed at 12.69 ppm in ligand due to N-H proton is shifted to 12.70 ppm for Mn
complex [104,105].
212
In the 1H NMR spectrum of the RAPP – La complex, a signal appeared due to
methyl protons attached to azomethine group has been shifted to 2.579 ppm compared
to 2.71 ppm in the case of ligand [21]. This upfield shift indicates the shielding of
azomethine proton on coordination through nitrogen atom of azomethine group [27].
The signal observed at 1.61 ppm due to the methelene protons in the cyclohexane ring
ligand is shifted to 1.67 ppm for the (La) complex. A signal is appeared due to para at
7.28 ppm due to OH proton on para position of phenolic group. The signal
disappeared at 5.71-5.72 ppm due to phenolic hydroxyl proton is absent in the NMR
spectrum of (La) complex indicating the deprotonation of hydroxyl group and the
involvement of that oxygen in coordination [28]. The multiplet observed in the region
6.37-7.65 ppm due to aromatic protons for the ligand showed a shift to 6.39-7.66 ppm
for (La) complex may be due to the drifting of ring of electrons towards the metal ion.
A new signal is observed as a singlet at 5.05 ppm in the case of La (III) complex
indicating the presence of water molecules coordinated to the metal atom. A signal
observed at 12.69 ppm in ligand due to N-H proton is shifted to 12.70 ppm for La
complex [104,105]
In the 1H NMR spectrum of the RAPP – Y complex, a signal appeared due to
methyl protons attached to azomethine group has been shifted to 2.579 ppm compared
to 2.71 ppm in the case of ligand [21]. This downfield shift indicates the deshielding
of azomethine proton on coordination through nitrogen atom of azomethine group
[27]. The signal observed at 1.65 ppm due to the methelene protons of cyclohexane
ring for the (Y) complex. A signal is appeared due to para at 7.28 ppm due to OH
proton on Para position of phenolic group. The signal disappeared at 5.71-5.72 ppm
due to phenolic hydroxyl proton is absent in the NMR spectrum of (Y) complex
indicating the deprotonation of hydroxyl group and the involvement of that oxygen in
213
coordination [28]. The multiplet observed in the region 6.37-7.65 ppm due to
aromatic protons for the ligand showed a shift to 6.39-7.66 ppm for (Y) complex may
be due to the drifting of ring of electrons towards the metal ion. A new signal is
observed as a singlet at 5.00 ppm in the case of Y(II) complex indicating the presence
of water molecules coordinated to the metal atom. A signal observed at 12.69 ppm in
ligand due to N-H proton is shifted to 12.70 ppm for Y complex [104,105].
In the 1H NMR spectrum of the RAPP – Pd complex, a signal appeared due to
methyl protons attached to azomethine group has been shifted to 2.87 ppm compared
to 2.71 ppm in the case of ligand [21]. This downfield shift indicates the deshielding
of azomethine proton on coordination through nitrogen atom of azomethine group
[27]. The signal observed at 1.65 ppm due to the methelene protons of cyclohexane
ring for the (Pd) complex. A signal is appeared due to para at 7.28 ppm due to OH
proton on Para position of phenolic group. The signal disappeared at 5.71-5.72 ppm
due to phenolic hydroxyl proton is absent in the NMR spectrum of (Pd) complex
indicating the deprotonation of hydroxyl group and the involvement of that oxygen in
coordination [28]. The multiplet observed in the region 6.37-7.65 ppm due to
aromatic protons for the ligand showed a shift to 6.55-7.93 ppm for (Pd) complex may
be due to the drifting of ring of electrons towards the metal ion. A new signal is
observed as a singlet at 5.3. ppm in the case of Pd(III) complex indicating the
presence of water molecules coordinated to the metal atom A signal observed at 12.69
ppm in ligand due to N-H proton is shifted to 12.9 ppm for Pd complex [104,105].
214
Table:VIII.2. 1H NMR spectral data of the RAPP ligand and its metal complexes
in CDCl3 in ppm
Compound H3C-C=N Ar-H CH2 Ar-
OH N-H
H2O-
OH
RAPP 2.71 6.37-7.65 1.70 7.20 12.69 ------
RAPP-Cu 2.573 6.64-6.62 1.73 7.27 12.7 4.7
RAPP-Ru 2.4 6.41-7.59 1.81 7.2 8.35 4.8-.4.9
RAPP-Co 2.7 6.45-7.65 1.65 7.45 12.95 5.05
RAPP-Ni 2.579 6.39-7.66 1.64 7.2 12.7 4.5
RAPP-Mn 2.18 6.73-7.38 1.64 7.33 12.70 5.05
RAPP-La 2.579 6.39-7.66 1.67 7.28 12.70 5.05
RAPP-Y 2.579 6.39-7.66 1.65 7.28 12.70 5.00
RAPP-Pd 2.87 6.55-7.93 1.65 7.28 12.9 5.3
215
Fig.VIII.10 : NMR Spectra of RAPP Ligand
Fig.VIII.11 : NMR Spectra of Cu( RAPP) complex
216
Fig.VIII.12 : NMR Spectra of Ru( RAPP) complex
Fig.VIII.13 : NMR Spectra of Co( RAPP) complexes
217
Fig.VIII.14 : NMR Spectra of Ni(RAPP) complexes
Fig.VIII. 15 : NMR Spectra of Mn(RAPP) complexes
218
Fig.VIII. 16 : NMR Spectra of La(RAPP) complexes
Fig.VIII. 17 : NMR Spectra of Y(RAPP) complexes
219
Fig.VIII.18 : NMR Spectra of Pd(RAPP) complexes
220
UV-Spectral Studies:
In UV-Visible electromagnetic radiation, the transitions are associated with
the electronic energy levels of the compound under the investigation. the electronic
spectra were recorded on a thermo Spectronic Heylos α spectrophotometer the
description of this instrument is presented in chapter-II., it was noted that the
transition metal ions occurs in variety of structural environment identified through
UV-Visible spectroscopy.
Analysis of RAPP ligand and its metal complexes:
The electronic spectra of the aqueous solutions of Cu, Ru, Co, Ni, Mn, La, Y
and Pd individual ions are compared with the corresponding ligand nature. The data is
given in Table.VIII.3., and Fig (VIII.19 to VIII.27). The data indicates that the energy
of the d-d transitions in the complexes is slightly less when compared to the
corresponding aqua ions either [56-59] because of slight covalent interaction of the 3d
vacant orbitals with ligands, leading to some delocalization with consequent reduction
in inter electronic repulsion, [59] or by increased nuclear shielding of the orbitals due
to slight covalent ligand-metal electron drift.
The transition for the ligand occurred at 292 nm. But on complexation with the
different metal ions like Cu,Ru,Co,Ni,Mn,La,Y and Pd new bands appeared at 316nm,
330 nm, 313 nm, 320 nm, 323 nm, 315nm ,310 nm and 308 nm, respectively
corresponding to the transitional charge transfer from the ligand to the different metal
ions [60, 61]. Bands occurred in the region of 305-410 nm for all complexes are
assigned to charge transfer transition (L→M). Based on the results octahedral
structure is proposed for Cu, Ru, Co, Ni, Mn, La, Y and Pd complexes ,
221
Table:VIII.3. Electronic Spectral data of RAPP ligand and its metal complexes
Compound λmax of compound
RAPP 292
RAPP-Cu 316
RAPP-Ru 330
RAPP-Co 313
RAPP-Ni 320
RAPP-Mn 323
RAPP-La 315
RAPP-Y 310
RAPP-Pd 308
222
Fig.VIII.19 : UV Spectra RAPP Ligand
Fig.VIII.20 : UV spectra of Cu(RAPP) complex
223
Fig.VIII.21 : UV spectra of Ru(RAPP) complex
Fig.VIII.22 : UV spectra of Co(RAPP) complex
224
Fig.VIII.23 : UV spectra of Ni(RAPP) complex
Fig.VIII.24 : UV spectra of Mn(RAPP) complex
225
Fig.VIII.25 : UV spectra of La(RAPP) complex
Fig.VIII.26 : UV spectra of Y(RAPP) complex
226
Fig.VIII.27 : UV spectra of Pd(RAPP) complex
227
Conductivity Measurements of RAPP metal complexes:
The molar conductance of complexes in DMF (~10-3 M) was determined at
27+2oC using systronic 303 reading conductivity bridge Cu(II),Ru(III),Co(II),
Ni(II),Mn(II),La(III),Y(II) and Pd(II) complexes of azomethine compound formed
due to the condensation of 2,4- Dihydroxy AcetoPhenone and Pramipexole (RAPP)
ligand is prepared. The complexes of RAPPP ligand are highly soluble in dimethyl
formamide (DMF). Therefore these metal chelates are dissolved in DMF to perform
conductivity measurements. A known amount of solid complex was transferred into
25 ml standard flask and dissolved in DMF. The contents were made up to the mark
with DMF. The complex solution is transferred into a clean and dry 100 ml beaker.
The molar conductance values of these metal complexes which are residual are given
in Table VIII.4. These values suggest non-electrolytic nature [92, 93] of the present
complexes.
Table:VIII.4. Molar conductivity of Cu, Ru, Co, Ni, Mn, La, Y and Pd complexes
Metal complexes Molar conductance(ohm-1 cm
2mol
-1)
RAPP-Cu 17
RAPP-Ru 20
RAPP-Co 19
RAPP-Ni 16
RAPP-Mn 18
RAPP-La 21
RAPP-Y 22
RAPP-Pd 21
228
Powder X-RD Studies:
The powder X-ray diffraction data obtained for metal complexes with
difractograms using DROL-2 powder diffractometer. Radiation filled by metal foil.
Powder XRD study of RAPP –Cu complex:
The powder X-ray diffraction data obtained for metal complexes with
difractograms using DROL-2 powder diffractometer. Radiation filled by metal foil.
The diffractogram (06-diffractions) reflects Fig.VIII.28 between 10-20 (2θ) values
for RAPP-Cu complex values for Cu complex. Where θ is Bragg’s angle all the
main peaks are indicted and calculated values of Miller indices (h k l) along with
observed d-specified and reveled intensities are specified in the Fig:VIII.28. All the
peaks have been indexed 2θ values compared in graph. Comparison values revels that
there is good agreement between values of 2θ and d-values. The powder x-ray
diffraction data showed identical features [91] with very poor crystalinity. The
patterns are qualitative and dispersive in intensity for Cu complexe. The XRD
patterns are used to explain qualitatively the degree of crystalinity. X-ray Diffraction
data of RAPP-Cu complex are presented in Table.VIII.5 .
Table:VIII.5.X-ray Diffraction data of RAPP-Cu complex
S.No. d expt d Calc 2θ expt 2θ Calc h k l
1. 5.5535 5.5432 15.94 15.81 4 3 1
2. 5.4862 5.4777 16.14 16.12 4 1 0
3. 5.4532 5.4230 16.24 16.11 4 4 2
4. 4.9390 4.8390 17.94 17.82 4 3 0
5. 4.7619 4.6619 18.62 18.35 5 4 2
6. 4.4793 4.4612 19.80 19.75 5 5 1
229
Powder XRD study of RAPP –Ru complex:
The powder X-ray diffraction data obtained for metal complexes with
difractograms using DROL-2 powder diffractometer. Radiation filled by metal foil.
The diffractogram (07-diffractions) reflects Fig.VIII.29 between 30-50 (2θ) values for
RAPP-Ru complex values for Ru complex. Where θ is Bragg’s angle all the main
peaks are indicted and calculated values of Miller indices (h k l) along with observed
d-specified and reveled intensities are specified in the Fig:VIII.29.All the peaks have
been indexed 2θ values compared in graph. Comparison values revels that there is
good agreement between values of 2θ and d-values. The powder x-ray diffraction data
showed identical features [91] with very poor crystalinity. The patterns are qualitative
and dispersive in intensity for Cu complex. The XRD patterns are used to explain
qualitatively the degree of crystalinity. X-ray Diffraction data of RAPP-Ru complex
are presented in Table.VIII.6.
Table.VIII.6.X-ray Diffraction data of RAPP-Ru complex
S. No. d expt d Calc 2θ expt Calc h k l
1. 2.8158 2.8148 31.74 31.44 4 3 1
2. 2.8143 2.8133 31.76 31.66 5 2 0
3. 2.8127 2.8117 31.78 31.18 5 4 2
4. 2.8025 2.8005 31.90 31.60 6 3 0
5. 2.7989 2.749 31.94 31.44 6 4 2
6. 1.9878 1.978 45.58 45.28 6 5 1
7. 1.8682 1.8662 48.68 48.08 6 1 1
230
Powder XRD study of RAPP –Co complex:
The powder X-ray diffraction data obtained for metal complexes with
difractograms using DROL-2 powder diffractometer. Radiation filled by metal foil.
The diffractogram (09-diffractions) reflects Fig.VIII.30 between 10-35 (2θ) values for
RAPP-Co complex values for Co complex. Where θ is Bragg’s angle all the main
peaks are indicted and calculated values of Miller indices (h k l) along with observed
d-specified and reveled intensities are specified in the Fig: VIII.30. All the peaks have
been indexed 2θ values compared in graph. Comparison values revels that there is
good agreement between values of 2θ and d-values. The powder x-ray diffraction data
showed identical features [91] with very poor crystalinity. The patterns are qualitative
and dispersive in intensity for Co complex. The XRD patterns are used to explain
qualitatively the degree of crystalinity. X-ray Diffraction data of RAPP-Co complex
are presented in Table.VIII.7.
Table: VIII.7. X-ray Diffraction data of RAPP-Co complex
S.No. d expt d Calc 2θ expt Calc h k l
1. 5.6534 5.6432 15.66 15.55 6 4 2
2. 5.6451 5.6234 15.68 15.66 6 3 3
3. 5.6245 5.6123 15.74 15.46 7 4 2
4. 5.6102 5.6102 15.78 15.16 7 3 1
5. 2.8298 2.8119 31.58 31.22 8 4 2
6. 2.8210 2.8205 31.68 31.45 9 6 5
7. 2.8194 2.8176 31.70 31.58 9 6 5
8. 2.8179 2.8162 31.72 31.68 9 8 4
9. 2.8040 2.8012 31.88 31.66 9 9 5
231
Powder XRD study of RAPP –Ni complex
The powder X-ray diffraction data obtained for metal complexes with
difractograms using DROL-2 powder diffractometer. Radiation filled by metal foil.
The diffractogram (09-diffractions) reflects Fig.VIII.31 between 20-35 (2θ) values for
RAPP-Y complex values for Y complex. Where θ is Bragg’s angle all the main peaks
are indicted and calculated values of Miller indices (h k l) along with observed
d-specified and reveled intensities are specified in the Fig:VIII.31. All the peaks have
been indexed 2θ values compared in graph. Comparison values revels that there is
good agreement between values of 2θ and d-values. The powder x-ray diffraction data
showed identical features [91] with very poor crystalinity. The patterns are qualitative
and dispersive in intensity for Ni complex. The XRD patterns are used to explain
qualitatively the degree of crystalinity. X-ray Diffraction data of RAPP-Ni complex
are presented in Table.VIII.8 .
Table:VIII.8.X-ray Diffraction data of RAPP-Ni complex
S. No. d expt d Calc 2θ expt Calc h k l
1. 3.6811 3.6809 24.02 24.00 8 6 2
2. 3.6549 3.6533 24.16 24.10 8 7 1
3. 3.6362 3.6344 24.22 24.11 8 9 2
4. 3.6060 3.6035 24.34 24.02 9 0 1
5. 3.5872 3.5856 24.42 24.21 9 2 4
6. 3.5847 3.5834 24.64 24.44 9 4 7
7. 3.5367 3.5355 25.02 25.10 9 6 3
8. 3.5343 3.5323 25.10 25.09 9 7 0
9. 3.4780 3.4769 25.46 25.34 9 9 2
232
Powder XRD study of RAPP –Mncomplex:
The powder X-ray diffraction data obtained for metal complexes with
difractograms using DROL-2 powder diffractometer. Radiation filled by metal foil.
The diffractogram (07-diffractions) reflects Fig.VIII.32 between 10-50 (2θ) values for
RAPP-Mn complex values for Mn complex. Where θ is Bragg’s angle all the main
peaks are indicted and calculated values of Miller indices (h k l) along with observed
d-specified and reveled intensities are specified in the Fig:VIII.32. All the peaks have
been indexed 2θ values compared in graph. Comparison values revels that there is
good agreement between values of 2θ and d-values. The powder x-ray diffraction data
showed identical features [91] with very poor crystalinity. The patterns are qualitative
and dispersive in intensity for Mn complex. The XRD patterns are used to explain
qualitatively the degree of crystalinity. X-ray Diffraction data of RAPP-Mn complex
are presented in Table. VIII.9.
Table: VIII.9. X-ray Diffraction data of RAPP-Mn complex
S. No. d expt d Calc 2θ expt Calc h k l
1. 5.5276 5.5272 16.02 16.01 3 3 1
2. 5.5137 5.5132 16.06 16.00 4 2 0
3. 1.9953 1.9951 45.40 45.12 5 2 2
4. 1.8392 1.8383 49.50 49.45 6 3 1
5. 1.8385 1.8366 49.52 49.51 6 2 2
6. 1.8344 1.8322 49.64 49.55 6 5 1
7. 1.7982 1.7919 50.28 50.22 6 2 1
233
Powder XRD study of RAPP –La complex:
The powder X-ray diffraction data obtained for metal complexes with
difractograms using DROL-2 powder diffractometer. Radiation filled by metal foil.
The diffractogram (12-diffractions) reflects Fig.VIII.33 between 30-70 (2θ) values for
RAPP-La complex values for La complex. Where θ is Bragg’s angle all the main
peaks are indicted and calculated values of Miller indices (h k l) along with observed
d-specified and reveled intensities are specified in the Fig:VIII.33. All the peaks have
been indexed 2θ values compared in graph. Comparison values revels that there is
good agreement between values of 2θ and d-values. The powder x-ray diffraction data
showed identical features [91] with very poor crystalinity. The patterns are qualitative
and dispersive in intensity for La complex. The XRD patterns are used to explain
qualitatively the degree of crystalinity. X-ray Diffraction data of RAPP-La complex
are presented in Table. VIII.10 .
Table:VIII.10.X-ray Diffraction data of RAPP-La complex
S. No. d expt d Calc 2θ expt Calc h k l
1. 2.8871 2.8861 30.94 30.93 6 7 2
2. 2.8387 2.8377 31.48 31.47 6 4 3
3. 2.8267 2.8257 31.62 31.61 6 9 2
4. 2.8210 2.8010 31.68 31.67 7 0 2
5. 2.8158 2.8148 31.74 31.73 7 2 1
6. 2.8143 2.8123 31.76 31.74 7 4 6
7. 2.8127 2.8116 31.78 31.77 7 6 5
8. 2.4695 2.4694 36.34 36.22 7 8 2
9. 2.3414 2.3411 38.40 38.39 8 0 1
10 1.4115 1.4112 66,12 66,11 8 4 2
11 1.4111 1.4110 66.14 66.12 8 6 1
12 1.4107 1.4106 66.16 66.11 8 7 1
234
Powder XRD study of RAPP –Y complex:
The powder X-ray diffraction data obtained for complexes with difractograms
using DROL-2 powder diffractometer. Radiation filled by metal foil. The
diffractogram (09-diffractions) reflects Fig.VIII.34 between 20-30 (2θ) values for
RAPP-Y complex values for Y complex. Where θ is Bragg’s angle all the main peaks
are indicted and calculated values of Miller indices (h k l) along with observed d-
specified and reveled intensities are specified in the Fig:VIII.34. All the peaks have
been indexed 2θ values compared in graph. Comparison values revels that there is
good agreement between values of 2θ and d-values. The powder x-ray diffraction data
showed identical features [91] with very poor crystalinity. The patterns are qualitative
and dispersive in intensity for Y complex. The XRD patterns are used to explain
qualitatively the degree of crystalinity. X-ray Diffraction data of RAPP-Y complex
are presented in Table.VIII.11.
Table:VIII.11.X-ray Diffraction data of RAPP-Y complex
S. No. d expt d Calc 2θ expt Calc h k l
1. 3.6921 3.6911 24.08 24.04 5 1 2
2. 3.6649 3.6613 24.26 24.11 5 4 3
3. 3.6466 3.6444 24.38 24.33 5 7 2
4. 3.6090 3.6045 24.64 24.33 5 2 9
5. 3.5972 3.5956 24.72 24.22 5 9 4
6. 3.5947 3.5934 24.74 24.44 6 2 1
7. 3.5467 3.5455 25.08 25.07 6 7 2
8. 3.5443 3.5423 25.10 25.09 6 9 0
9. 3.4810 3.4809 25.56 25.44 7 2 1
235
Powder XRD study of RAPP –Pd complex:
The powder X-ray diffraction data obtained for metal complexes with
difractograms using DROL-2 powder diffractometer. Radiation filled by metal foil.
The diffractogram (09-diffractions) reflects Fig.VIII.35 between 30-45 (2θ) values for
RAPP-Pd complex values for Pd complex. Where θ is Bragg’s angle all the main
peaks are indicted and calculated values of Miller indices (h k l) along with observed
d-specified and reveled intensities are specified in the Fig:VIII.35. All the peaks have
been indexed 2θ values compared in graph. Comparison values revels that there is
good agreement between values of 2θ and d-values. The powder x-ray diffraction data
showed identical features [91] with very poor crystalinity. The patterns are qualitative
and dispersive in intensity for Pd complexe. The XRD patterns are used to explain
qualitatively the degree of crystalinity. X-ray Diffraction data of RAPP-Pd complex
are presented in Table. VIII.12.
Table:VIII.12.X-ray Diffraction data of RAPP-Pd complex
S.No. d expt d Calc 2θ expt Calc h k l
1. 2.8518 2.8516 31.60 31.59 6 7 2
2. 2.8519 2.8517 31.62 31.61 6 4 3
3. 2.8246 2.8245 31.64 31.62 7 2 1
4. 2.8230 2.8220 31.66 31.63 7 4 3
5. 2.8179 2.8176 31.72 31.66 7 6 7
6. 2.8127 2.8125 31.78 31.67 7 9 0
7. 2.2514 2.2512 40.00 39.09 8 0 1
8. 2.9927 2.9921 45.38 45.28 8 2 1
9. 3.1234 3.1231 46.18 46.11 8 4 5
236
Fig.VIII.28 : Powder XRD of Cu(RAPP) complex
Fig.VIII.29 : Powder XRD of Ru( RAPP) complex
237
Fig.VIII.30 : Powder XRD of Co( RAPP) complex
Fig.VIII.31 : Powder XRD of Ni( RAPP) complex
238
Fig.VIII.32 : Powder XRD of Mn( RAPP) complex
Fig.VIII.33 : Powder XRD of La( RAPP) complex
239
Fig.VIII.34 : Powder XRD of Y( RAPP) complex
Fig.VIII.35 : Powder XRD of Pd( RAPP) complex
240
Thermal Studies –TGA/ DTA:
Majority of the compounds and complexes suffer physical and chemical
changes when subjected to heat under defined experimental conditions. These
changes are characteristic of the substance examined, and can be used for its
qualitative and quantitative analysis. For analysis of this kind, the phenomena
accompanying the thermal analysis are changes in temperature and weight of the
compound.
Though several methods are adopted in thermo analytical analysis, then no
gravimetric analysis (TGA) and differential thermal analysis (DTA) are the most
suitable methods used in coordination chemistry. The data obtained as continuously
recorded curves which may be considered as thermal spectra. These thermo grams
characterize a system, single or multicomponent, in terms of temperature dependence
of its thermodynamic properties. Thermo gravimetric analysis involves changes in
weight of a system under investigation as the. temperature is increased at a
predetermined rate. Differential thermal analysis consists of measuring the changes in
heat content, as a function of the difference in temperature between the sample under
investigation and a thermally inert reference compound; In this manner enthalpy
changes, such a~- melting and chemical changes are detected from the endo and exo-
thermal bands and peaks that appear in the thermo grams, the corresponding weight
changes are detected by thermo gravimetric analysis.
The thermal studies of these complexes are carried out to know the stability of
the complexes on thermal decomposition, as well as to know the different final
products that are obtained in thermal decomposition having novel catalytic Properties
[72,73]. Thermogravimetric analyses of the metal complexes were carried out by
using the METTLER TOLEDO STAR System in thermal analysis center IICT
241
Hyderabad. All possible precautions wer taken to optimize conditions, so as to carry
out all the Thermogravimetric analysis experiments under the same conditions.
Thermal Analysis of RAPP Metal Complexes:
TG techniques were employed to follow the thermal behavior of complexes.
According to the results obtained, the complexes are not volatile and their
decomposition occurs in more than one step. The typical thermo grams of complexes
were shown in the Fig.VIII.36 to VIII.43. Thermo gravimetric studies on the
complexes confirmed their proposed molecular formulae. The thermal decomposition
of metal complexes has been followed up to 1000°. The decomposition behavior of
the complexes was observed in nitrogen atmosphere. The experimental mass losses
were in good agreement with the calculated mass loss values which were summarized
in the Table.VIII.13.
The Copper complex of RAPPP shows Fig.VIII.36. three main decomposition
stages, and the first stage with small endothermic dehydration step in the range of
140°C to 160°C was due to loss of two water molecules coordinated to the metal
[75-77]. The Second step involves two sub steps which involves decomposition of the
ligand moiety, Exothermic decomposition of the ligand moiety takes place around
200–380°C, [78-81] to give the stable intermediate M (RAPPP)2 and this was stable
up to 500°C, which on further undergoes exothermic decomposition in the region
500–850°C in the third stage forming Copper Oxide (CuO) as final residual product
as shown in the Table. VIII.13.
The thermogram of the Ruthenium complex shows Fig. VIII.37., First stage of
decomposition around 150°C to 170°C, which indicates the presence of coordinated
water molecules and this decomposition corresponds to small endothermic
dehydration of the complex and gives anhydrous complex [75-77]. The second
242
decomposition stage with one broad exothermic peak corresponds to the degradation
of ligand moiety in the region 180°C to 350°C forming M(RAPP)2 intermediate
[78-81]. This on subsequent stages undergoes exothermic decomposition to give the
corresponding RuO [82-83] as the final decomposition product at a high temperature
above 520°C as shown in the Table. VIII.13.
The thermogram of the Cobalt complex shows Fig. VIII.38.,First stage of
decomposition around 120°C to 160°C,which indicates the presence of coordinated
water molecules and this decomposition corresponds to small endothermic
dehydration of the complex and gives anhydrous complex [75-77]. The second
decomposition stage with one broad exothermic peak corresponds to the degradation
of ligand moiety in the region 270°C to 420°C forming M(RAPPP)2 intermediate
[78-81]. This on subsequent stages undergoes exothermic decomposition to give the
corresponding CoO [82-83] as the final decomposition product at a high temperature
above 720°C as shown in the Table. VIII.13.
The thermogram of the Nickel complex shows Fig. VIII.39., First stage of
decomposition around 140°C to 160°C, which indicates the presence of coordinated
water molecules and this decomposition corresponds to small endothermic
dehydration of the complex and gives anhydrous complex [71-75]. The second
decomposition stage with one broad exothermic peak corresponds to the degradation
of ligand moiety in the region 200°C to 650.56°C forming M(RAPP)2 intermediate
[78-81]. This on subsequent stages undergoes exothermic decomposition to give the
corresponding NiO [82-83] as the final decomposition product at a high temperature
in the region 490-730°C as shown in the Table. VIII.13.
The thermogram of the Manganese complex shows Fig. VIII.40., First stage of
decomposition around 160°C to 170°C, which indicates the presence of coordinated
243
water molecules and this decomposition corresponds to small endothermic
dehydration of the complex and gives anhydrous complex [75-77]. The second
decomposition stage with one broad exothermic peak corresponds to the degradation
of ligand moiety in the region 180°C to 350°C forming M(RAPPP)2 intermediate
[78-81]. This on subsequent stages undergoes exothermic decomposition to give the
corresponding MnO [82-83] as the final decomposition product at a high temperature
in the region 360-720°C as shown in the Table. VIII.13.
The thermogram of the Lanthanum complex as shows Fig.VIII.41., First stage
of decomposition around 110°C to 160°C, which indicates the presence of
coordinated water molecules and this decomposition corresponds to small
endothermic dehydration of the complex and gives anhydrous complex [75-77]. The
second decomposition stage with one broad exothermic peak corresponds to the
degradation of ligand moiety in the region 180°C to 200°C forming M(RAPPP)2
intermediate [78-81]. This on subsequent stages undergoes exothermic
decomposition to give the corresponding LaO [82-83] as the final decomposition
product at a high temperature in the above 620°C as shown in the Table. VIII.13.
The thermogram of the Yitrium complex as shown Fig.VIII.42., First stage of
decomposition around 90°C to 110°C, which indicates the presence of coordinated
water molecules and this decomposition corresponds to small endothermic
dehydration of the complex and gives anhydrous complex [75-77]. The second
decomposition stage with one broad exothermic peak corresponds to the degradation
of ligand moiety in the region 260°C to 400°C forming M(RAPPP)2 intermediate
[78-81]. This on subsequent stages undergoes exothermic decomposition to give the
corresponding YO [82-83] as the final decomposition product at a high temperature in
the region 590-860°C as shown in the Table. VIII.13.
244
The thermogram of the Palladium complex shows Fig.VIII.43.,First stage of
decomposition around 90°C to 150°C, which indicates the presence of coordinated
water molecules and this decomposition corresponds to small endothermic
dehydration of the complex and gives anhydrous complex [75-77]. The second
decomposition stage with one broad exothermic peak corresponds to the degradation
of ligand moiety in the region 220°C to 450°C forming M(RAPPP)2 intermediate
[78-81]. This on subsequent stages undergoes exothermic decomposition to give the
corresponding PdO [82-83] as the final decomposition product at a high temperature
above 360-480°C as shown in the Table. VIII.13.
245
Table. VIII.13.Thermo analytical data of metal complexes
Complex
X=H2O
Temperature
range in °C Probable assignment
Mass
loss (%)
Total mass
loss (%)
CuL2X2 L=C18H23N3SO 2
140-160 Loss of 2H2O molecules 12.95 63.44 200-380 Decomposition of L 42.89
500-850 Formation of CuO 7.6
RuL2X2 L=C28H23N3SO2
150-170 Loss of 2H2O molecules 10.56 78.11 180-350 Decomposition of L 57.16
Above-520 Formation of RuO 10.39
CoL2X2 L=C28H23N3SO2
120-160 Loss of 2H2O molecules 5.13 71.04 270-420 Decomposition of L 56.46
Above-720 Formation of CoO 9.45
NiL2X2 L=C28H23N3SO2
140-160 Loss of 2H2O molecules 13.1 87.52 170-460 Decomposition of L 68.96
490-730 Formation of NiO 5.46
MnL2X2 L=C28H23N3SO2
160-170 Loss of 2H2O molecules 14.20 78.81 180-350 Decomposition of L 57.21
360-720 Formation of LaO 7.40
LaL2X2 L=C28H23N3SO2
110-160 Loss of 2H2O molecules 4.95 83.61 180-200 Decomposition of L 67.67
Above-620 Formation of LaO 10.99
YL2X2 L=C28H23N3SO2
90-110 Loss of 2H2O molecules 8.66 54.55 260-400 Decomposition of L 40.09
590-860 Formation of YO 5.8
PdL2X2 L=C28H23N3SO2
90-150 Loss of 2H2O molecules 2.84 43.22 220-450 Decomposition of L 35.84
Above-480 Formation of PdO 4.54
246
Fig.VIII.36 : TGA/ DTA of Cu(RAPP) complex
Fig.VIII.37 : TGA/ DTA of Ru(RAPP) complex
247
Fig.VIII.38 : TGA/ DTA of Co(RAPP) complex
Fig.VIII.39 : TGA/ DTA of Ni(RAPP) complex
248
Fig.VIII.40 : TGA/ DTA of Mn(RAPP) complex
Fig.VIII.41 : TGA/ DTA of La(RAPP) complex
249
Fig.VIII.42.TGA/ DTA of Y (RAPP) complex
Fig.VIII.43.TGA/ DTA of Pd (RAPP) complex
250
Magnetic susceptibility measurements of Copper, Rethenium, Cobalt, Nickel,
Manganese, Lathanum, Yitrium and Palladium metal complexes:
The magnetic susceptibility values are given in Table.VIII.14.
The Copper complex at room temperature was observed the magnetic moment
is 4.82 B.M. [85] suggest octrahydral geometry. Thermal analysis showed that the
Copper complex involved the lose of two water molecules at about 140-1600C. This
suggests that two water molecules coordinated with the central metal ion, which is
further confirmed by their characteristic IR spectrum.
The magnetic properties of Ruthenium complex help to know the geometry of
them. The magnetic moment of the present Ruthenium complex is 5.61 B.M
[116,117] suggest tetrahydral geometry. Thermal analysis shows that the ruthenium
complex lose two water molecules at about 150-1700C which suggest the presence of
two water molecules not coordinating with the central metal ion, which is further
confirmed by their characteristic IR spectrum.
The magnetic properties Cobalt complex help to know the geometry of them.
The octahedral and tetrahedral complexes differ in their magnetic properties at room
temperature 3.42 B.M range is in favour of octahedral geometry. The magnetic
moment of the present Cobalt (II) complex value is 3.42 B.M [85] suggest a high spin
octahedral geometry. Thermal analysis shows that the Cobalt complex lose two water
molecules at about 120-1600C which suggest the presence of two water molecules
coordinating with the central metal ion. This is further confirmed by their
characteristic IR spectrum.
The magnetic properties of Nickel complex help to know the geometry of
them. The magnetic moment of the present Nickel (II) complex is 4.22 B.M [115]
251
suggest tetrahydral geometry. Thermal analysis shows that the Nickel complex lose
two water molecules at about 140-1600C which suggest the presence of two water
molecules not coordinating with the central metal ion, which is further confirmed by
their characteristic IR spectrum.
The magnetic properties of Manganese complexe help to know the geometry
of them. The magnetic moment of the present Manganese complex is 4.71 B.M
[113,114] suggest an octahedral geometry. Thermal analysis shows that the
Manganese complex lose two water molecules at about 160-1900C which suggest the
presence of two water molecules coordinating with the central metal ion, which is
further confirmed by their characteristic IR spectrum.
The magnetic properties of Lanthanum complex help to know the geometry of
them. The magnetic moment of the present Lanthanum complex is 5.42 B.M
[113,114] suggest an tetrahydral geometry. Thermal analysis shows that the
Manganese complex lose two water molecules at about 110-1600C which suggest the
presence of two water molecules not coordinating with the central metal ion, which is
further confirmed by their characteristic IR spectrum.
The magnetic properties of Yitrium complex help to know the geometry of
them. The magnetic moment of the present Yitrium complex is 5.22 B.M [113,114]
suggest an tetrahydral geometry. Thermal analysis shows that the Manganese
complex lose two water molecules at about 90-1100C which suggest the presence of
two water molecules not coordinating with the central metal ion, which is further
confirmed by their characteristic IR spectrum.
The magnetic properties of Palladium complex help to know the geometry of
them. The magnetic moment of the present Palladium complex is 5.02 B.M [115]
252
suggest an tetrahydral geometry. Thermal analysis shows that the Palladium complex
lose two water molecules at about 90-1500C which suggest the presence of two water
molecules not coordinating with the central metal ion, which is further confirmed by
their characteristic IR spectrum.
Table.VIII.14.Mangnetic moments of Metal chelate Complexes
S.No Complexes Magnetic moment (B.M)
1 Cu(RAPP)2 4.82
2 Ru(RAPP)2 5.61
3 Co(RAPP)2 3.42
4 Ni(RAPP)2 4.22
5 Mn(RAPP)2 4.71
6 La(RAPP)2 5.42
7 Y(RAPP)2 5.22
8 Pd(RAPP)2 5.02
253
References:
1. Froneous, S., Acta. Chem. Scand., 4, 72 (1950).
2. Rottistrov, M,N.,Kulik,G.V.,Skrynik, E.m., Corbons, T.V., Bredikhina, A.N.,
and Taranova,L.A., Fiziol.Aktiv.Veshchesta,5, 123 (1973).
3. A.H. Maki, and B.RMcGarvery. J. Chern. Phys., (1958) 29, 31&35.
4. Curtin, D.Y. and Hausser, J.N., Am. Chem.Soc.,83,3474 (1961).
5. Ozha, D.A., Singhavi, B.R., and Mehta, R.K., J. Indian Chem. Soc., 52, 1104
(1975).
6. Kogan, V.A., Dorokhova, N.I. and Osipov, O.A., Zh. Nerg. Khim., 16,179
(1971).
7. B.N.Singh, V.Saxena and S.S.Iyer. Indian J. Expt. BioI., (1965), 3, 110.
8. Dey, K. and Sen, S.K., J. Indian Chem.Soc., 52,261 (1975).
9. S.Yamada, J. Coord.Chem.Rev.,1, 415 (1966).
10. S.Yarnada, J. Coord. Chern. Rev., 1,415 (1966).
11. Jain, P.c. and Lingafelter,E.C., J.Am. Chern. Soc., 1967,89, 724.
12. J.E.Kovacic. J. Spectrochern. Acta, 23A, 183 (1967).
13. RC.Stade, A.A.G.Tornlinson and B.J.Hathaway J. Chern.Soc.(A), 61 (1968).
14. E.P.Dudek, E. Chaffe and G.Dudek, J. Inorg. Chern. 7, 1257 (1968).
15. Cottrell, T.L., The Strength of Chemical Bonds. 2nd Ed., Butterworhs, London
(1958).
16. Hathaway, B.J1, Dudley,RJ. and Nicholls,P., J. Chern. Soc., 1968, A, 1645.
17. Sacconi, L., J. Transitition metal chemistry, VolA. Marcel Dekker, New York,
1968, p.221.
18. M.J.Cleare and W.P.Griffith. J. Chern. Soc. (A), 372 (1969).
19. L.T.Taylor, F.L.Vrbach and D.H.Busch, J. Am. Chern. Soc. 91. 1072 (1969).
254
20. B.J. Hathaway and D.E.Billing. J. Coord. Chern. Rev., 1970,5,143.
21. Dudley, RJ. and Hathaway, BJ., J. Chern. Soc. 1970, A, 1725.
22. B.J.Hathaway and A.A.G.Tomilson. J. Coordination. Chern. Rev., 5 (1970) 1.
23. K. Nakamoto. J. "I.RSpectra of Inorganic and Coordination compounds".
Wiley. New York (1970).
24. W.Heiber and P.John. J. Chem.Ber., 103, 2161 (1970).
25. W.J.Geary J. Coord. Chern. Rev., 7(1971) 81.
26. A.P. Ginsberg Inorg. Chim Acta Rev.,(1971), 5, 45.
27. M.E. Lines J. Chern. Phys., (1971), 55, 2977.
28. Hathaway,B.J., Essay in Chemistry (Ed.Bradley,J.N. and Gillard,R.D).
Academic press, New York, 1971, p. 61.
29. B.J.Hathaway. J. Structure and Bonding, (1971) 49.
30. Boucher L J J. Inorg chern. Acta, 6 (1972) 29
31. Anne, J.P. & Metzger, J., Bull. Soc., Chim. Fr., (1972),3536.
32. G. Giordano and RD.Bereman. J. Am. Chern. Soc., 96 (1974) 1019.
33. Z.Jawarska, c.Jose and J.Urbanski. J. Spectrochim. Acta, 30a, 1161 (1974).
34. T.J.Mabry e K. R Markham, in the Flavonoids, eaited by J.B.Harborne, T.J.
Mabry and H.Mabry, p.78. Chapman and Hall, London (1975).
35. MJ.M. Campbell. Coord. Chern. Rev., 15 (1975) 81.
36. C. Preti and G.Tosi. J. Spectrochem. Acta., 31A., 1139 (1975).
37. M.J.M.Campbell and RGreskowiak. J. Chern. Soc., (1976) 396.
38. M.Wiebei-and E. Kauzinger, J.Organomet. Chern. 129,339 (1977).
39. L.Vancea and W.A.G.Graham. J. OrganomeLChem., 134, 21lJ (1977).
40. Crowford & Hatfield. J. Inorg. Chern, 16 (1977) 1336.
41. Barbucci, R,Bencini, A.and Gatteschi,D. J. Inorg. Chern., 1977, 16,2117.
255
42. RS.Drago. Physical methods in chemistry W.B.Saunders. Co., Philadelphia
(1977).
43. S.S. Gnanamanickam and D.A. Smith Phytopathology 70, 894 (1981).
44. Mishra L & Singh V K Indian J Chern B2A (1993). 446
45. Malhotra R Kumar S & Dhindsa K S. Indian J Chern, 32A (1993) 451
46. Levinson W & Jawetz E Medical Microbiology and immunology, 4th Edn
(Mc Graw Hill) 1996.
47. B.Chiswell, J.P.Crawford andE.J.O.Reylly. J.lnorg. Chirn. Acta, 40, 223
(1980).
48. Palmer, W.G., Valency, 2nd Ed. Cambridge University Press, p. 125 (1959).
49. M.N.Patel, S.H.Patel J.Macrornol. Sci. A 16 (1981)1420.
50. A. Bencini and D.Gatteschi Transition Met. Chern., (1982), 8, 1. .
51. B. Singh and RD.Singh. Ind. J. Chern., 21, 648 (1982).
52. N.Shah and D.Bhattacharya. Ind. J. Chern., 21, 574 (1982).
53. J.M.Bret, P.Castan, G.Cornrneges, and J.P.Laurent and D.Muller. J. Chern.
Soc., Chern. Cornrnun., 1273 (1983).
54. M.RWagnar and F.AWalker. J. Inorg. Chern., (1983),22,3021.
55. P.R.Shukla, V.KSingh, A.M.Jaiswal and N.Gopal. J. Ind. Chern. Soc., 60, 321
(1983).
56. Deford, D.D. and Hume, D.N., J. Am. Chem. Soc., 73, 5351 (1951).
57. B.Singh., B.P.Yadav and RC.Agarwal. Indian J. chern., 23A (1984) 441.
58. KL.Reddy, S.Srihari and P.Lingaiah. J.lndian Chern. Soc., 61 (1984), 801.
59. Thaker, B.T. and Bhattacharya, P.K., Proc. Int. Conf. Coord. Chem., R40,3
(1974).
60. N.Ohkaku and KNakarnato. J. Inorg. Chern., 24, 1018 (1985).
256
61. El.H.M.Diefallah, A.O.Baghlaf, M.S. EI-Meligy and E.A. Abu EI-Futooh.
Radiat.Phys. Chern., 27, 123 (1986).
62. G.M.Gasparini and G.Grossi J. Solv. Extr. Ion Exch., 4, 1233. (1986).
63. G.Wilkinson, RD.Gillard and J.A. McCleverty. Comprehensive coordination
chemistry (eds) Pergarnan, Oxford (1987).
64. C.Musikas J. Inorganica Chirn. Acta, 140, 197. (1987).
65. T.R.Goudar, G.S.Nadagouda and S.M.Sindagi. J.Indian Chem.Soc.,LXV,509
(1988).
66. J.A.Seviour, A.C.McGill, G.Dale and A.C.Craft, J. Chromatog., 432, 273
(1988).
67. J.C.Blais, N.Hebert and G.Bolbach, InU.Mass Spectrom. Ion Process.
88,29(1988)
68. A.T.Lebedev, Mass Spectrom. Rev. 10,91 (1991).
69. C.Musikas J. Sep. Sci. Technol., 23, 1211. (1988).
70. (Mrs) M.P.Degaonkar, C.Gopinathan and (Mrs) Sarada Gopinathan. Synth.
ReactJnorg. Met-rg. Chem., 19(6), 613-625 (1989).
71. W.Brzyska, Z.Rzaczyska and A.Kula. J. Montsh. Chern., 120,211 (1989).
72. I.Bertini,L.Banci, M.Piccioli and C.Luchinat. J.Coord. Chern. Rev.,
1990,100,67.
73. P.Karagiannidis, P.Akrivos, A.Terzis, and D.Mentzafos. Inorg. Chim. Acta,
181,263 (1991)
74. De Mendoza, J.M. Ontoria, M:C. Ortega and T. Torres Synthesis,(1992),398.
75. Dey K and Bandyopadhyay D Indian J Chern, 31A (1992) 34.
76. Z.Cimerman, N.Galesic and B.Bosner. J. Mol. Struct., 274, 131 (1992).
77. Thamizharasi, S. and Venkata Rami Reddy, A., J. Polymer, (1992), 33, 2421.
257
78. G.C.Basseter and R.M.Silverstein. Spectrophotometric Identification of
Organic Compounds 3rdEdn. Wiley, New York, p.111 (1992)
79. M. Doring, W.Ludwig, E.Vhlig, S.Wocadlo and V.Muller Z.anorg.alleg.
Chern., 611 (61 (1992).
80. M. Gaber, H.E. Mabrouk, Y.M. Shaibi and A.A. Ba-lssa.Thermochimica
Acta,207(1992) 239-224
81. N. Condamines and C. Musikas J. Solv. Extr. Ion Exch., 10,69. (1992).
82. 1.J.P.C0ostes, F. Dahan and A. Dupuis, Inorg.Chem., (2000),39,165.
83. G.De Munno, M.Julve, F.Liore J.Faus and A.Caneschi J. Chern. Soc., Dalton
Trans., 1994, 1175.
84. Kamalendu Dey' & Kartik Kumar Nandi Indian Journal of Chemistry Vol.
33A, October (1994), pp.908-913.
85. Kamalendu Dey' & Kartik Kumar Nandi Indian Journal of Chemistry Vol.
33A, October 1994, pp.908-913.
86. Tomas Torres atal., J. Chern. Soc. Dalton Trans. (1995) 2305-2310
87. Tomas Torres ataI., J. Chern. Soc. Dalton Trans.(1995) 2305-2310.
88. S.S.Mandal, P.C.Ghorai, S.Ray and H.KSaha. J.lndian Chem.Soc., 72, 807
(1995).
89. Reeves, R.L., The Chemistry of the Carbonyl Group (Ed. S. Patai),
Interscience, p. 567 (1966).
90. KKoh, J.D.Ranford, W.T.Robinson, J.O.Svensson, A.L.C.Tan and D.Wu. J.
Inorg. Chern., (1996), 35 , 6466.
91. Costa, J.,Delgado, R., Figuera, M.C., Henriques, R.T., Teixeira, M.C.,
J.Chem., Soc., Dalton Trans., (1997), 65.
258
92. S.G.Teoh, G.Y.Yeap, C.C.Loh, S.B.Teo, L.W.Fong and H.KFun.
J.Polyhedron, 16, 2213 (1997).
93. S.Thamizharasi, S.Balasubramanian and A.Venkatarami Reddy. Eur. Polym
J.VoI.34. No.3/4, pp. 503-507, (1998).
94. M.G.Bhowon, H.Li Kam Wah and R.Narain. Polyhedron, 18, 341 (1998).
95. M.A.Halcrow, L.M.L.Chia, X. Liu, E.J.L.Mc1nnes and J.E.Davies.atal, Chern.
Commun., (1998), 2465.
96. Lioyid Jones, G.C.Butts, G.P., J. Tetrahedron, 1998,54,901.
97. Mustafa Tastekin', Adnan Kenar and Orhan Atakol J. Synth. React Inorg.Met
Org.Chem., 28(10),1727-1741 (1998).
98. Xiao-Ming Chen',La-Sheng Long,.Shi-Ping Yang, Ye-Xiang Tong, Zong Wan
Mao, and Liang-Nian Ji. J.Chem.Soc., Dalton Trans., 1999,1999-2004
99. K.S.Siddiqi* and N.Nishat J. Synth.React.Inorg.Met-Org.Chem., 29(2), 297-
308 (1999).
100. A.Kumar, G.singh, R.N. Handa and S.N.Dubey'. Indian Journal of Chemistry
Vol. 38A, June (1999), pp.613-617.
101. Malcolm A. Halcrow*,Ian J.Scowen, Frank E.Mabbs, John E.Davies at.aI., J.
Chern.Soc., Dalton Trans., (1999),1753-1762.
102. Wafaa M. Hosny. J. Synth. React. Inorg.Met-Org.Chern ., 29(3), 361-375
(1999).
103. KB. Gudasi and T.R.Goudar Synth.React.Met-Org.Chern., 30(10), 1859
1869(2000).
104. Asrna I. EI-Said*, Amna S.A.Zidan, Aref A.M. Aly , Ornar F.Moharnrned and
Mahmoud S.EI-Meligy. Synth.React.Inorg.Met-Org.Chern., 30(7), 1373-
1392(2000).
259
105. Hong-yun Zhang* ,Yi-yun Chen Wen-xiu Sun ,Qing-an Wu And Hong-quan
Zhang Synth.React.Inorg.Met-Org.Chern., 30(4), 571-582 (2000)
106. Sudhir Ranjan and Sheo KDikshit* Synth.React.Inorg.Met-Org.Chern., 30 (6),
1039-1055 (2000)
107. Saied Mohamed EI-Sayed Khalil J. Synth.React.Inorg.Met-Org.Chem., 30(3),
543-555 (2000).
108. Ketan M. Patel, N.H.Patel, KN.Patel and M.N.Patel Synth.React.Inorg.Met
Org.Chern., 30(10), 1953-1963 (2000).
109. Cauntry Charlas, J., Frost, John. R., Haryak, John Rasano and Henri, L., J.
Colloided Interface Sci., 45(2), (1973).
110. Franco, E., Torres, E.L., Mendiola, M.A., and Sevilla, M.T. Polyhedron, 2000,
19, 441.
111. Singh., N.K, Srivastava, A., J. Trans. Met. Chern., 2000, 25,133.
112. Davar M.Boghae( and Maryarn Lashanizadegan J. Synth.React.Inorg. Met
Org.Chern., 30(7),1393-1404 (2000).
113. Costes, F. Dahan and A. Dupuis, Inorg. Chern., (2000), 39, 165.
114. S.A.Schuetz, V.W.Day, R.D.Somrner, A.L.Rheingold and I.A.Belot, Inorg.
Chern., (2001), 40, 5292.
115. Jean-Pierre Costes*, Jean-Pierre and Franck Nicodeme J. Chern. Soc.,Dalton
Trans., (2002), 2731-2736.
116. G.Hernakanthi, Balachandran Unni Nair, Aruna Dhathathreyan * Chemical
Physics Letters 341(2001)407-411.
117. Rajib Lal De *, Indrajit Banerjee and Keka Samanta (neeBera) Indian Journal
of Chemistry Vol. 40A, February 2001, pp. 144-148
260
118. Sulekh Chandra* , V.P.Tyagi, Gajendra Singh, Smriti Raizada. Journal of the
Indian Councile of Chemists.VoL18, No.2, 2001,pp.5-11
119. Roger, R. and Nicoles,G., Rev. Farm. (Buens Aires), 96, 5 (1954).
120. Mauricio Cavicchioli, P.P.Corbi, Petr Melnikov*, and Antonic C.Massabni. J.
Coord. Chern., 2002, Vol. 55(8), pp.951-959.
121. Jessica. M.Fauth, Philip.E.Fanwick. Jonathan J.wilker., European j.org.chem.,
vol.22., p.33-37, 14 Nov 2008.
122. G.Jayanthi, S.Muthuswamy, R. Paramasivam, VT Ramakrishnan,
N.K.Ramaswamy and P.Ramamurthy. j.,org.chern vol.62(17)., pp 5766-5770.,
Aug 22 1997.
123. A.senthilvelau, D.Thirumalai., J.Org.Chem., vol.60,p.851-860, 19 Jan 2004.
124. Hui wang, Jeony-Tak Ryu, Yoonsoo – Hau., vol.463.,p.3/285-13/295, Feb
2007.
125. Yujiezhao,Adebert Bacher., J.org.Che.vol.74(15), pp 5297-5303 (2009).
261
Antibacterial Activity:
Method Employed:
To prove the antibacterial activity of the ligand and metal complexes on
bacteria, paper disc diffusion procedure was employed.
Medium:
Nutrient agar medium was employed for the testing.
Peptone (5g) was dissolved in a liter of distilled water. Beef extract (5g) was
added to the peptone solution and agar (15g) was mixed. The contents were mixed
thoroughly and the pH was adjusted to 7.4–7.6. The solution was sterilized in the
autoclave for 10–15 minutes at 15 Ibs. per sq. inch pressure, to prove the same.
Testing Equipment:
Petri dishes, hot air oven, autoclave, sterilized pipettes, spreader, suitable
Whatman filter paper and incubator.
Organisms selected for testing : Escherichia coli,
Klebsiella,
Bacillus subtilis
Maintenance and Sterility:
All the required apparatus was sterilized before use and every reasonable
precaution was taken to avoid contamination throughout the operation.
Procedure of Testing:
The solutions of the synthesized compounds were prepared at different
concentrations viz 50ppm, 100ppm concentrations DMF solvent. Few sterilized filter
paper (Whatman) discs soaked in the solvent were used for preparing test solution.
262
These sterilized paper discs were soaked in the 5ml of the solution of known
concentration of the corresponding test samples, for 2–3 minutes. Sufficient time was
allowed for the solvent to evaporate from the paper discs. Sterilized nutrient agar
15–20ml was poured into Petri dishes under aseptic conditions. The bacterial culture
was poured over the solidified surface of the nutrient agar in Petri dishes and spread
evenly for uniform distribution with spreader. Paper discs soaked with the solution of
known concentration of the desired test samples were placed under aseptic conditions
at a distance in each Petri plates, containing known bacterial suspension. These
Petridishes were labeled with the compound number and the incubated for 24 hours at
25–30°C in incubator. After 24 hours of incubation each Petri plate was observed for
bacterial growth. Later the zone of inhibition of bacterial growth in each petri plate
was measured. The discs soaked with the respective solvents of test solution were
used as controls. The bacterial growth in the test Petri plates was compared with the
growth in the controls. Then zone of inhibition of bacterial growth in the Petri plates
under examination were measured.
The present investigation was an attempt to find out the antibacterial activity
of ligand and their metal complexes against Escherichia coli, Klebsiella and
Bacillus subtilis in the range 50–100 urn/ml. Choosing serial paper disc diffusion
method. The Antibacterial activity results were given in the Table.IX.1. the results of
the biological activity of the metal complexes indicated the following facts.
The high antimicrobial activities of all the newly synthesized metal complexes
surmounting that of ligands showed that complexation of the organic moiety to the
metal ions substancially enhanced their activities such increased activity of metal
chelates had been explained by Overtones concept and the Tweedy’s chelation theory.
263
On chelation the polarity of the metal ion reduced to a greater extent due to the
overlap of the ligand orbital and partial sharing of positive charge of metal ion with
donor groups. It was further noted that the delocalization of El–electrons over the
whole chelate ring enhanced the lipophillicity of the complexes. This increased
lipophillicity enhanced the penetration of the complexes into lipid membrane and
blocking the metal binding sites on enzymes of microorganism thus retards the normal
cell processes.
Table:IX.1. Antibacterial activities of ligands and their transition metal
complexes (Zone formation in mm)
Compound Escherichia coli Klebsiella Bacillus subtills
OHAPP 10 9 10
(OHAPP)2 Cu 12 12 13
(OHAPP)2 Ru 11 13 14
PHAPP 14 9 10
(PHAPP)2 Cu 13 12 13
(PHAPP)2 Ru 12 9 11
OHBP 11 14 12
(OHBP)2 Cu 7 10 13
(OHBP)2 Ru 9 10 11
OVP 15 15 14
(OVP)2Cu 11 13 11
(OVP)2Ru 13 14 14
VP 8 13 11
(VP)2Cu 11 9 12
(VP)2Ru 12 13 15
RAPP 10 11 10
(RAPP)2Cu 13 15 14
(RAPP)2Ru 12 14 14
(RAPP)2Co 15 13 12
(RAPP)2Mn 12 12 14
(RAPP)2Ni 10 12 11
(RAPP)2Pd 12 13 10
(RAPP)2La 11 14 12
(RAPP)2Y 10 11 12
264
DNA Binding Studies of Metal Complexes:
DNA activation would produce more quantities of the required protein, or
could induce DNA replication; depending on which site the drug is targeted. DNA
inhibition would restrict protein synthesis, or replication, and could induce cell death.
Though both these actions are possible, mostly DNA is targeted in an inhibitory
mode, to destroy cells for antitumor and antibiotic action. Drugs bind to DNA both
covalently as well as non–covalently.
Covalent binding in DNA is irreversible and invariably leads to complete
inhibition of DNA processes and subsequent cell death. Cis–platin (cis–
diamrninedichloroplatinum) is a famous covalent binder used as an anticancer drug,
and makes an intra/interstrand cross –link via the chloro groups with the nitrogens on
the DNA bases.
DNA–drug binding may be described in the following manner
Consider DNA–drug binding in an aqueous environment. DNA is polyanionic
in nature and the drug molecule is also often charged. The associated counterions lie
near the charged groups and are also partially solvated. When binding occurs, it
results in a displacement of solvent from the binding site on both the DNA and drug.
Also, since there would be partial compensation of charges as the DNA and drug are
oppositely charged, some counterions would be released into the bulk solvent and are
265
solvated fully. Also, the binding process would be associated with some structural
deformation/adaptation of the DNA as well as the drug molecule in order to
accommodate each other. All these events are associated with some energetic
gains/losses, the comprehensive estimation of which is a major challenge.
In order to investigate the DNA binding mode of the compounds generally the
following techniques were carried out.
1. UV–Visible spectrophotometry
2. Fluorescence method
3. Isothermal calorimetric titrations
4. Cyclic voltametry
5. Circular Dichroic spectral studies
6. Viscosity measurements
Among the above mentioned techniques, UV–Visible spectral studies were
carried out in the present research work.
UV – Visible spectroscopy–A best tool for studying interactions of complexes
with DNA:
Studies on DNA drug interactions are important in several purposes. If metal
complex act as DNA probe, its spectroscopic properties should change upon binding
with DNA. These variations in spectroscopic properties provide an excellent data
about DNA conformation and structure. Hypochromicity in absorption, appearance of
isosbestic points, red–shift in the absorption maxima, and luminescence increasing are
the special characteristic features of DNA interactions. In some cases, hyperchromic
shift also observed upon addition of successive addition of calf–thymus DNA to the
266
complexes. Therefore, change in absorbance upon addition of DNA has been
indicative of the binding of the complexes with DNA.
A. Present Studies:
In present study, DNA interactions were studies with newly synthesized
Cu, Ru complexes of OHAPP, PHAPP, OHBP, OVP and VP , Cu, Ru, Ni, Mn, Co,
Pd, La, Y complexes of RAPP using absorption spectrophotometric titrations and
results are presented below.
DNA binding Experimental studies of metal complexes:
The interactions of all the newly synthesised complexes were monitored by
UV–Visible spectral studies.
Disodium salt of calf thymus DNA was stored at 5°C. Solution of DNA in the
buffer 45 mM NaCl/5 mM Tris HC1 (pH, 7.1) in water gave a ratio 1:9 of UV
absorbance at 260 and 280 nm, A260/A280, indicating that the DNA was sufficiently
free from protein [28]. The concentration of DNA was measured by using its
coefficient at 260 nm (6600 Cm-1) after 1:100 dilutions.
Concentrated stock solutions of the complexes were prepared by dissolving in
DMSO and diluting suitably with the corresponding buffer to the required
concentrations for all the experiments.
The absorption spectra of complexes were compared in the absence and
presence of CT–DNA. In the presence of increasing amounts of DNA, the spectra of
complexes showed a strong decrease (hypochromicity) in intensity with shift in
absorption maxima towards higher (red–shift) wavelengths. The binding of
intercalative molecules to DNA has been well characterized by large hypochromism
and significant red–shift due to strong stacking interaction between the aromatic
267
chromophore of the ligand and DNA base pairs with the extent of hypochromism and
red shift commonly consistent with the strength of intercalative interaction.
To enable quantitative comparison of the DNA binding affinities the intrinsic
binding constants Kb of the complexes for binding with CT DNA were obtained by
using the equation.
[DNA]/(εa– εf) = [DNA] / (εb– εf) + 1 Kb (εb– εf)
Where [DNA] is the concentration of DNA in base–pairs, εa is the apparent
extinction coefficient obtained by calculating Aobs / [complex], εf corresponds to the
extinction coefficient of the complex in its free form and εb refers to the extinction
coefficient of the complex in the bound form. Each set of data, when fitted to the
above equation, gave a straight line with a slope of 1/ (εa– εf) and a y–intercept of
1/Kb (εb– εf) and Kb was determined from the ratio of the slope to intercept. The
intrinsic binding constants Kb, obtained for the complexes.
Absorption spectra were recorded 240–400 ranges. The ranges were selected
where maximum absorption change observed on addition of DNA. Electronic
absorption spectral data upon addition of CT–DNA and binding constants were given
in Table. IX.2., it was evident that these complexes bind with DNA with high
affinities and the estimated binding constants are in the range of 105–106 M–1. This
may due to the presence of pi–stacking of the pyridine ring present in the ligand
moiety and as shown in the Fig.IX.1 to IX.18., and as shown in Table:IX.2.
268
Table.IX.2. DNA binding constants of metal complexes
S.No Complex (X= H2O) λmax nm
∆λ nm H% Kb(M–1)
Free Bound
1 [Cu(OHAPP)2X2] 326 331 5 6.59 3.00 × l05
2 [Ru (OHAPP)2X2] 315 320 5 6.28 2.22 × l05
3 [Cu (PHAPP)2X2] 304 310 6 6.99 1.25 × l06
4 [Ru (PHAPP)2X2] 371 376 5 6.59 10.20 × l06
5 [Cu (OHBP)2X2] 334 340 6 6.66 2.24 × l05
6 [Ru (OHBP)2X2] 347 350 3 6.29 1.1 × l06
7 [Cu (OVP)2 X2] 331 337 6 6.65 3.33 × l06
8 [Ru (OVP)2 X2] 351 356 5 6.33 4.25× l06
9 [Cu (VP)2X2] 302 305 3 6.65 2.03 × l05
10 [Ru(VP)2 X2 ] 314 317 3 6.33 3.33× l05
11 [Cu (RAPP)2X2] 291 298 7 6.33 2.00 × l05
12 [Ru (RAPP)2X2] 272 278 6 6.03 2.50 × l05
13 [Co(RAPP)2X2] 286 290 4 6.36 2.50 × l05
14 [Ni (RAPP)2X2] 315 320 5 6.36 1.66 × l05
15 [Mn (RAPP)2X2] 306 310 4 6.39 1.42 × l05
16 [La(RAPP)2X2] 330 336 6 5.77 1.25 × l05
17 [Y (RAPP)2X2] 292 296 4 6.12 2.00 × l05
18 [Pd (RAPP)2X2] 301 305 4 5.99 2.03 × l05
269
240 260 280 300 320 340 360 380 400
0.1
0.2
0.3
0.4
0.5
0.6
Absorb
ance
Wavelength(nm)
A
B
C
D
E
Fig.IX.1. Binding interaction of Cu [OHAPP]
240 260 280 300 320 340 360 380 400
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
Ab
so
rba
nce
Wavelength(nm)
A
B
C
D
E
Fig.IX.2.DNA Binding interaction of Ru [OHAPP]
270
240 260 280 300 320 340 360 380 400
0.1
0.2
0.3
0.4
0.5
Ab
so
rba
nce
Wavelength(nm)
A
B
C
D
E
Fig.IX.3.DNA Binding interaction of Cu [PHAPP]
240 260 280 300 320 340 360 380 400
0.1
0.2
0.3
0.4
0.5
0.6
0.7
Absorb
ance
Wavelength(nm)
A
B
C
D
E
Fig.IX.4.DNA Binding interaction of Ru [PHAPP]
271
240 260 280 300 320 340 360 380 400
0.1
0.2
0.3
0.4
0.5
0.6
0.7
Ab
so
rba
nce
Wavelength(nm)
A
B
C
D
E
Fig.IX.5. DNA Binding interaction of Cu [OHBP]
240 260 280 300 320 340 360 380 400
0.1
0.2
0.3
0.4
0.5
0.6
Absorb
ance
Wavelength(nm)
A
B
C
D
E
Fig.IX.6.DNA Binding interaction of Ru [OHBP]
272
240 260 280 300 320 340 360 380 400
0.0
0.2
0.4
0.6
0.8
1.0
Ab
so
rba
nce
Wavelength(nm)
A
B
C
D
E
Fig.IX.7.DNA Binding interaction of Cu [OVP]
240 260 280 300 320 340 360 380 400
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
Absorb
ance
Wavelength(nm)
A
B
C
D
E
Fig.IX.8. DNA Binding interaction of Ru [OVP]
273
240 260 280 300 320 340 360 380 400
0.1
0.2
0.3
0.4
0.5
0.6
Absorb
ance
Wavelength(nm)
A
B
C
D
E
Fig.IX.9.DNA Binding interaction of Cu [VP]
240 260 280 300 320 340 360 380 400
0.1
0.2
0.3
0.4
0.5
0.6
0.7
Ab
so
rba
nce
Wavelength(nm)
B
C
D
E
F
Fig.IX.10.DNA Binding interaction of Ru [VP]
274
240 260 280 300 320 340 360 380 400 420
0.08
0.10
0.12
0.14
0.16
0.18
0.20
0.22
0.24
0.26
0.28
Absorb
ance
Wavelength (nm)
A
B
C
D
E
Fig.IX.11. DNA Binding interaction of Cu [RAPP]
240 260 280 300 320 340 360 380 400
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
Absorb
ance
Wavelength(nm)
A
B
C
D
E
Fig.IX.12. DNA Binding interaction of Ru [RAPP]
275
240 260 280 300 320 340 360 380 400
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
Absorb
ance
Wavelength(nm)
A
B
C
D
E
Fig.IX.13. DNA Binding interaction of Co [RAPP]
240 260 280 300 320 340 360 380 400
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
Ab
so
rba
nce
Wavelength(nm
A
B
C
D
E
Fig.IX.14. DNA Binding interaction of Ni [RAPP]
276
240 260 280 300 320 340 360 380 400
0.1
0.2
0.3
0.4
0.5
0.6
Ab
so
rba
nce
Wavelength(nm)
A
B
C
D
E
Fig.IX.15.DNA Binding interaction of Mn [RAPP]
240 260 280 300 320 340 360 380 400
0.1
0.2
0.3
0.4
0.5
0.6
Absorb
ance
Wavelength(nm)
A
B
C
D
E
Fig.IX.16.DNA Binding interaction of La [RAPP]
277
240 260 280 300 320 340 360 380 400
0.1
0.2
0.3
0.4
0.5
0.6
Absorb
ance
Wavelength(nm)
A
B
C
D
E
Fig.IX.17.DNA Binding interaction of Y [RAPP]
240 260 280 300 320 340 360 380 400
0.1
0.2
0.3
0.4
0.5
0.6
0.7
Absorb
ance
Wavelength(nm)
A
B
C
D
E
Fig.IX.18. DNA Binding interaction of Pd [RAPP]
278
References:
1. Cheatham, T. E., Ill, Kollman, P. A. (2000) Molecular dynamics simulation of
nucleic acids. Annu. Rev. Phys. Chem., 51,435–471.
2. Cheatham, T.E. Ill (2004) Simulation and modeling of nucleic acid structure,
dynamics and interactions. Curr Opin Struct Biol. 14, 360–367.
3. Norberg, J., Nilsson, L. (2002) Molecular dynamics applied to nucleic acids.
Ace. Chem. Res., 35, 465–472.
4. Jorgensen, W. L. (1989) Free Energy Calculations, A Breakthrough for
Modeling Organic Chemistryin Solution. Ace. Chem. Res., 22, 184–189.
5. van Gunsteren, W. F., Berendsen, H. J. C. (1990) Computer Simulation of
Molecular Dynamics: Methodology, Applications and Perspectives in
Chemistry Angew. Chem. Int. Ed. Engl., 29, 992–1023.
6. McCammon, J. A. (1991) Free Energy from Simulations. Curr. Opin. Struct.
Biol., 1,196–200.
7. Beveridge, D. L., DiCapua, F. M. (1989) Free energy via molecular
simulation: applications to chemical and biomolecular systems. Annu. Rev.
Biophys. Biophys. Chem., 18, 431–492.
8. Tidor, B., Irikura, K. K., Brooks, B. R., Karplus, M. (1983) Dynamics of DNA
oligomers. J. Biomol. Struct. Dyn., 1, 231–1238.
9. Nordlund, T. M, Andersson, S., Nilsson, L., Rigler, R., Graeslund, A.,
McLaughlin, L. W. (1989) Structure and dynamics of a fluorescent DNA
oligomer containing the EcoRI recognition sequence: fluorescence, molecular
dynamics, and NMR studies. Biochemistry, 28, 9095–10003.
10. Beveridge, D.L., McConnell, K.J. (2000) Nucleic acids: theory and computer
simulation, Y2K. Curr Opin Struct Bio I,, 10, 182–196.
279
11. Beveridge, D.L, Barreiro, G., Byun, K.S., Case, D.A., Cheatham, I.E. 3rd,
Dixit, S.B., Giudice, E., Lankas, F., Lavery, R., Maddocks, J.H., Osman, R.,
Seibert, E., Sklenar, H., Stoll, G., Thayer, K.M., Varnai, P., Young, M.A.
(2004) Molecular dynamics simulations of the 136 unique tetranucleotide
sequences of DNA oligonucleotides. I. Research design and results on d(CpG)
steps.Biophys J., 87, 3799–3813.
12. Beveridge, D.L., Dixit, S. B., Barreiro, G., Thayer, K.M. (2004) Molecular
dynamics simulations of DNA curvature and flexibility: helix phasing and
premelting.73, 380–403.
13. Olson, W. K., Zhurkin, V. B. (2000) Modeling DNA deformations. Curr Opin
Struct Biol., 10, 286–297.
14. Madhumalar, A., Bansal, M. (2003) Structural insights into the effect of
hydration and ions on A–tract DNA: a molecular dynamics study. Biophys. J.,
85, 1805–1816.
15. Thenmalarchelvi, R, Yathindra, N. (2005) New insights into DNA triplexes:
residual twist and radial difference as measures of base triplet non–
isomorphism and their implication to sequence–dependent non–uniform DNA
triplex. Nucleic Acids Res., 33, 43–55.
16. Spackova, N, Cubero, E, Sponer, J, Orozco, M (2004) Theoretical study of the
guanine to 6–thioguanine substitution in duplexes, triplexes, and tetraplexes. J
Am Chem Soc. 126, 14642–14650.
17. Fadrna, E, Spackova, N, Stefl, R, Koca, J, Cheatham, TE III, Sponer, J. (2004)
Molecular dynamics simulations of Guanine quadruplex loops: advances and
force field limitations. Biophys J., 87,227–242
280
18. Singh, S. B., Kollman, P. A. (1999) Calculating the absolute free energy of
association of netropsin and DNA. J. Am. Chem. Soc., 121, 3267–3271.
19. Spackova, N., Cheatham, I.E. 3rd, Ryjacek, F., Lankas, F., Van Meervelt, L.,
Hobza, P., Sponer, J. (2003) Molecular dynamics simulations and
thermodynamics analysis of DNA–drug complexes. Minor groove binding
between 4’,6–diamidino–2–phenylindole and DNA duplexes in solution. J.
Am. Chem. Soc., 125, 1759–1769.
20. Harris, S.A., Gavathiotis, E., Searle, M.S., Orozco, M., Laughton, C.A. (2001)
Cooperativity in drug–DNA recognition: a molecular dynamics study. J. Am.
Chem. Soc., 123, 12658–12663.
21. Lu, X. J., Shakked, Z., Olson, W. K. (2000) A–form conformational motifs in
ligand–bound DNA structures. J. Mol. Biol, 300, 819–840.
22. Olson, W. K., Gorin, A., Lu, X.J., Hock, L.M., Zhurkin, V. B. (1998) DNA
Sequence–dependent Deformability Deduced from Protein–DNA Crystal
Complexes Proc. Natl. Acad. Sci., USA 95,11163–11168.
23. Langley, D.R., Golik, J., Doyle, T. W.,Beveridge, D. L. (1994) The DNA–
Esperamicin Al Complex: A Model Based on Solvated Molecular Dynamics
Simulation. J. Am. Chem. Soc., 116,15–29.
24. Haq, I. (2002) Thermodynamics of drug–DNA interactions. Arch. Biochem.
Biophys., 403,1–15.
25. Breslauer, K. J., Remeta, D. P., Chou, W. Y., Ferrante, R., Curry, J.,
Zaunczkowski, D., Snyder, J. G., Marky, L. A. (1987) Enthalpy–entropy
compensations in drug–DNA binding studies. Proc. Natl. Acad. Sci. USA., 84,
8922–8926.
281
26. Chalikian, T. V., Breslauer, K. J. (1998) Thermodynamic analysis of
biomolecules: a volumetric approach. Curr. Opin. Struct. Biol, 8, 657–664.
27. Pilch, D.S., Poklar, N., Baird, E.E, Dervan, P.B., Breslauer, K.J. (1999) The
thermodynamics of polyamide–DNA recognition: hairpin polyamide binding
in the minor groove of duplex DNA. Biochemistry, 38, 2143–2151.
28. Chaires, J.B. (1996) Dissecting the free energy of drug binding to DNA.
Anticancer DrugDes., 11, 569–580.
29. Rentzeperis, D, Marky, L.A. (1995) Interaction of minor groove ligands to an
AAATT/AATTT site: correlation of thermodynamic characterization and
solution structure. Biochemistry, 34,2937–2945.
30. Haq, I, Ladbury, J.E., Chowdhry, B.Z., Jenkins, T.C., Chaires, J.B. (1997)
Specific binding of Hoechst 33258 to the d(CGCAAATTTGCG)2 duplex:
calorimetric and spectroscopic studies.,/. Mol. Biol., 271, 244–257.
31. Mazur, S., Tanious, F., Ding, D., Kumar, A., Boykin, D.W., Simpson, I. J.,
Neidle, S., Wilson, W.D. (2000) A thermodynamic and structural analysis of
DNA minor–groove complex formation. J. Mol. Biol, 300, 321–337.
32. Wang, L., Kumar, A., Boykin, D.W., Bailly, C., Wilson, W.D. (2002)
Comparative thermodynamics for monomer and dimer sequence–dependent
binding of a heterocyclic dication in the DNA minor groove. J. Mol. Biol.,
317, 361–374.
33. Pilch, D. S., Yu, C., Makhey, D., LaVoie, E. J., Srinivasan, A. R., Olson, W.
K., Sauers, R. R., Breslauer, K. J., Geacintov, N. E., Liu, L. F. (1997) Minor
groove–directed and intercalative ligand–DNA interactions in the poisoning of
human DNA topoisomerase I by protoberberine analogs. Biochemistry, 36,
12542–12553.
282
34. Mohan, S., Yathindra, N. (1994) A study of the interaction of DAPI with DNA
containing AT and non–AT sequences– molecular specificity of minor groove
binding drugs. J. Biomol. Struct. Dyn., 11, 849–867.
35. Sathyapriya, R., Vishveshwara, S. (2004) Interaction of DNA with clusters of
amino acids in proteins Nucleic Acids Res. 32, 4109–4118
36. Moravek, Z., Neidle, S., Schneider, B. (2002) Protein and drug interactions in
the minor groove of DNA Nucleic Acids Res., 30, 1182–1191.
37. Chaires, J.B. (1997) Energetics of drug–DNA interactions Biopoly., 44, 201–
215.
38. Cooper, A. (1999) Thermodynamic analysis of biomolecular interactions.
Curr. Opin. Chem. Biol, 3, 557–563.
39. Haq, I., Jenkins, T.C., Chowdhry, B.Z., Ren, J., Chaires, J.B. (2000) Parsing
free energies of drug–DNA interactions., Methods Enzymol, 323, 373–405.
40. Lane, A. N., Jenkins, T. C. (2000) Thermodynamics of nucleic acids and then–
interactions with ligands Q. Rev. Biophys., 33,255–306.
41. Vega, M.C., Garcia Saez, I., Aymami, J., Eritja, R., van der Marel, G. A., van
Boom, J. H., Rich, A., Coll, M. (1994) Three–dimensional crystal structure of
the A–tract DNA dodecamer d(CGCAAATTTGCG) complexed with the
minor–groove–binding drug Hoechst 33258. Eur. J. Biochem., 222, 721–726.
42. Sriram, M., van der Marel, G. A., Roelen, H. L., van Boom, J. H., Wang, A.
H. (1992) Conformation of B–DNA containing O6–ethyl–G–C base pairs
stabilized by minor groove binding drugs: molecular structure of
d(CGC[e6G]AATTCGCG complexed with Hoechst 33258 or Hoechst 33342.
EMBOJ.,11,225–232.
283
43. Clark, G. R., Squire, C. J., Gray, E. J., Leupin, W., Neidle, S. (1996) Designer
DNA–binding drugs: the crystal structure of a meta–hydroxy analogue of
Hoechst 33258 bound to d(CGCGAATTCGCG)2. Nucleic Acids Res., 24,
4882–4890.
44. Nunn, C. M., Neidle, S. (1995) Sequence–dependent drug binding to the
minor groove of DNA: crystal structure of the DNA dodecamer
d(CGCAAATTTGCG)2 complexed with propamidine. J. Med. Chem., 38,
2317–2325.
45. Edwards, K. J, Jenkins, T. C., Neidle, S. (1992) Crystal structure of a
pentamidine–oligonucleotide complex: implications for DNA–binding
properties. Biochemistry, 31, 7104–7109.
46. Nunn, C. M., Jenkins, T. C., Neidle, S. (1994) Crystal structure of gamma–
oxapentamidine complexed with d(CGCGAATTCGCG)2. The effects of drug
structural change on DNA minor–groove recognition. Eur. J. Biochem., 226,
953–961.
47. Brown, D. G., Sanderson, M. R., Skelly, J. V., Jenkins, T. C., Brown, T.,
Garman, E., Stuart, D. I., Neidle, S. (1990) Crystal structure of a berenil–
dodecanucleotide complex: the role of water in sequence–specific ligand
binding. EMBOJ., 9,1329–1334.
48. Brown, D. G., Sanderson, M. R., Carman, E., Neidle, S. (1992) Crystal
structure of a berenil–d(CGCAAATTTGCG) complex. An example of drug–
DNA recognition based on sequence–dependent structural features. J. Mol.
Bio/., 226,481.
49. Laughton, C. A., Tanious, F., Nunn, C. M., Boykin, D. W., Wilson, W. D.,
Neidle, S. (1996) A crystallographic and spectroscopic study of the complex
284
between d(CGCGAATTCGCG)2 and 2,5–bis(4–guanylphenyl)furan, an
analogue of berenil. Structural origins of enhanced DNA–binding affinity.
Biochemistry, 35, 5655–5661.
50. Guerri, A., Simpson, I. J., Neidle, S. (1998) Visualisation of extensive water
ribbons and networks in a DNA minor–groove drug complex. Nucleic Acids
Res., 26, 2873–2878.
51. Trent, J. O., Clark, G. R., Kumar, A, Wilson, W. D., Boykin, D. W., Hall, J.
E., Tidwell, R. R., Blagburn, B. L., Neidle, S. (1996) Targeting the minor
groove of DNA: crystal structures of two complexes between furan derivatives
of berenil and the DNA dodecamer d(CGCGAATTCGCG)2. J. Med. Chem.,
39,4554–4562.
52. Simpson, I. J., Lee, M., Kumar, A., Boykin, D. W., Neidle, S. (2000) DNA
minor groove interactions and the biological activity of 2,5–bis Bioorg. Med.
Chem. Lett., 10,2593–2597.
53. Tabernero, L., Verdaguer, N., Coll, M., Fita, I., van der Marel, G. A., van
Boom, J. H., Rich, A., Aymami, J. (1993) Molecular structure of the A–tract
DNA dodecamer d(CGCAAATTTGCG) complexed with the minor groove
binding drug netropsin. Biochemistry, 32, 8403–8410.
54. Sriram, M., van der Marel, G. A., Roelen, H. L. P. F, van Boom, J. H., Wang,
A.H.J. (1992) Structural consequences of a carcinogenic alkylation lesion on
DNA: effect of 06–ethylguanine on the molecular structure of the
d(CGC[e6G]AATTCGCG)–netropsin complex. Biochemistry, 31, 11823–
11834.
285
55. Goodsell, D. S., Ng, H.L., Kopka, M.L., Lown, J.W., Dickerson, R.E. (1995)
Structure of a dicationic monoimidazole lexitropsin bound to DNA.
Biochemistry, 34, 16654–16661.
56. Coll, M, Frederick, C. A, Wang, A. H. J., Rich, A. Proc. Nat. Acad. Sci. USA.
1987, A bifurcated hydrogen–bonded conformation in the d(A.T) base pairs of
the DNA dodecamer d(CGCAAATTTGCG) and its complex with distamycin.
84, 8385–8389.
57. Coll, M., Aymami, J., van der Marel, G. A., van Boom, J. H., Rich, A., Wang,
A.H.J. (1989) Molecular structure of the netropsin–d(CGCGATATCGCG)
complex: DNA conformation in an alternating AT segment. Biochemistry, 28,
310–320.
58. Larsen, T. A., Goodsell, D. S., Cascio, D., Grzeskowiak, K., Dickerson, R. E.
(1989) The structure of DAPI bound to DNA. J. Biomol. Struc. Dyn., 7, 477–
491.
59. Squire, C. J., Clark, G. R., Denny, W. A. (1997) Minor groove binding of a
bis–quaternary ammonium compound: the crystal structure of SN7167 bound
to d(CGCGAATTCGCG)2. Nucleic Acids Res., 25,4072–4078.
60. 80. 77. Berman, H. M., Westbrook, J., Feng, Z., Gilliland, G., Bhat, T. N.,
Weissig, H., Shindyalov, I. N., Bourne, P. E. (2000) The Protein Data Bank.
Nucleic Acids Res., 28,235–242.
61. Shaikh, S. A., Ahmed, S. R., Jayaram, B. (2004) A Molecular Thermodynamic
View of DNA–drug Interactions: A Case Study of 25 Minor–groove Binders.
Arch Biochem. Biophys., 429, 81 –99.
62. Pearlman, D.A., Case, D.A., Caldwell, J.W., Ross,W.S., Cheatham, T.E.III,
DeBolt,S., Ferguson,D., Seibel,G. and Kollman,P. (1995)AMBER,a package
286
of computer programs for applying molecular mechanics, normal mode
analysis, molecular dynamics and free energy calculations to simulate the
structural and energetic properties of molecules.
63. 83.Jorgensen, W. L., Chandrasekhar, J., Madura, J. P. (1983) Comparison of
Simple Potential Functions for Simulating Liquid Water. J. Chem. Phys., 79,
926
64. Schmidt, M. W., Baldridge, K. K., Boatz, J. A., Elbert, S. T., Gordon, M. S.,
Jensen, J. H., Koseki, S., Matsunaga, N., Nguyen, K. A., Su, S. J., Windus, T.
L., Dupuis, M., Montgomery, J. A. (1993) J. Comput. Chem., 14,1347–1363.
65. Bayly, C. I., Cieplak, P., Cornell, W. D., Kollman, P. A. (1993) A Well–
Behaved Electrostatic Potential Based Method Using Charge Restraints For
Determining Atom–Centered Charges: The RESP Model J. Phys. Chem., 97,
10269–10280.
66. Cornell, W. D., Cieplak, P., Bayly, C. F., Gould, I. R., Kenneth, M. M,
Ferguson, D. M., Spellmeyer, D. C., Fox, T., Caldwell, J. W., Kollman, P. A.
(1995) A Second Generation Force Field for the Simulation of Proteins,
Nucleic Acids and Organic Molecules. J. Am. Chem. Soc., 117, 5179–5197.
67. York, D. M., Yang, W., Lee, H., Darden, T., Pedersen, L. G. (1995) Toward
the accurate modelling of DNA: the importance of long–range electrostatics. J.
Am. Chem. Soc.? 117, 5001–5002.
68. Still, W. C., Tempczyk, A., Hawley, R. C., Hendrickson, T. J. (1990)
Semianalytical treatment of solvation for molecular mechanics and dynamics./
Am. Chem. Soc., 112, 6127–6129.
69. 86.Lee, K., Richards, F. M. (1971) The interpretation of protein structures:
Estimation of static accessibility. J. Mol. Biol., 55, 379–400.
287
70. Jayaram, B., Liu, Y., Beveridge, D. L. (1998) A Modification of the
Generalized Born Theory for Improved Estimates of Solvation Energies and
pKa Shifts. J. Chem. Phys., 109, 1465–1471.
71. Hawkins, G. D., Cramer, C. J., Truhlar, D.G. (1996) Parameterized Models of
Aqueous Free Energies of Solvation Based on Pairwise Descreening of Solute
Atomic Charges from a Dielectric Medium. J. Phys. Chem., 100, 19824–
19839.
72. Jayaram, B., Sprous, D., Beveridge, D. L. (1998) Solvation Free Energy of
Biomacromolecules: Parameters for a Modified Generalized Born Model
Consistent with the AMBER Force Field. J. Phys. Chem. B, 102, 9571–9576.
73. Dill, K. A. (1997) Additivity Principles in Biochemistry. J. Biol. Chem., 272,
701–704.
74. Jayaram, B., McConnell, K. J., Dixit, S. B., Beveridge, D. L. (1999) Free
Energy Analysis of Protein–DNA Binding: The EcoRJ Endonuclease – DNA
Complex. J. Comput. Phy., 151, 333–357.
75. K.P. Balasubramanyam, R. Karvembu, V.Chinnuswamy, and K. Natarajan
Ind. J. of Chem. Vol. 44A December 2005 pp. 2450 – 2454
76. Mishra L & Singh V K Indian J Chem B2A (1993). 446
77. Malhotra R. Kumar S & Dhindsa K. S. Indian J Chem, 32A (1993) 451
78. K.R. Venagopala Reddy, J. Keshavayya, J. Seetharamappa. Dyes and
pigments 59 (2003) 237 – 244.
79. Neidle, S., Thurston, D.E. (2005) Chemical approaches to the discovery and
development of cancer therapies Nat Rev Cancer, 5, 285–96.
80. Geierstanger, B.H., Wemmer, D.E. (1995) Complexes of the minor groove of
DNA. Annu, Rev. Biophys. Biomol. Struct., 24,463–493.
288
81. Chaires, J. B. (1998) Drug–DMA interactions. Curr. Opin. Struc. Biol., 8,
314–320.
82. Neidle, S. (2001) DNA minor–groove recognition by small molecules. Nat.
Prod Rep., 18,291–309.
83. Hurley, L. H. (2002) DNA and its associated processes as targets for cancer
therapy. Nature Reviews Cancer, 2,188.
84. Wemmer, D. E., Dervan, P. B. (1997) Targeting the minor groove of DNA.
Curr. Opin. Struc. Biol., 7, 355–61.
85. Jones, S, van Heyningen, P, Berman, H. M., Thornton, J. M. (1999) Protein–
DNA interactions: A structural analysis. J. Mol Biol., 287, 877–896.
86. Jen–Jacobson, L. (1997) Protein–DNA recognition complexes: conservation
of structure and binding energy in the transition state. Biopolymers, 44,153–
180.
87. Janin, J. (1999) Wet and dry interfaces: the role of solvent in protein–protein
and protein–DNA recognition. Structure FoldDes., 7, R277–279.
88. Turner, P. R., Denny, W. A. (2000) The genome as a drug target: sequence
specific minor groove binding ligands Curr. Drug Targ., 1, 1–14.
89. Goodsell, D. S. (2001) Sequence recognition of DNA by lexitropsins. Curr.
Med. Chem., 8, 509–516.
90. Reddy, B. S., Sondhi, S. M., Lown, J. W. (1999) Synthetic DNA minor
groove–binding drugs. Pharmacol. Ther., 84.
91. Dervan, P. B., Edelson, B. S. (2003) Recognition of the DNA minor groove by
pyrrole–imidazole polyamides. Curr. Opin. Struct. Biol., 13, 284–299.
289
92. Jayaram, B., Beveridge, D.L. (1996) Modeling DNA in aqueous solutions:
theoretical and computer simulation studies on the ion atmosphere of DNA.
Annu. Rev. Biophys. Biomol. Struct., 25, 367–394.
93. Auffmger, P., Westhof, E. (1998) Simulations of the molecular dynamics of
nucleic acids. Curr. Opin. Struct. Biol., 8, 227–236.
94. Wang, L., Srinivasan, A. R., Hingerty, B.E., Olson, W.K., Broyde, S.,
Accurate Representation of B–DNA Double Helical Structure with Implicit
Solvent and Counterions,” Biophys. J. 83, 382–406 (2002).
290
CONCLUSIONS:
The complexing ability of Schiff bases also termed as azomethines (>C=N)
was well established by several authors. This is due to the presence of lone pair of
electrons on the nitrogen atom and of the general electron donating character of the
double bond. The basic strength of the >C=N group alone is not sufficient to form
highly stable complexes. If a functional group with a replaceable hydrogen atom,
preferably a hydroxyl group, close to the >C=N group is present, more stable metal
complexes will be formed by chelation with five or six membered ring.
Literature survey revealed that there are numerous references for the existence
of Schiff bases, where they act as mono dentate, bidentate, tridentate and so on.
Survey also revealed that the azomethine compounds not only have very good
complexing ability towards metal ions but also have innumerable applications in
various fields namely pharmacy, medicine, agriculture, textiles, industries, catalysis
and polymer technology, photochemical reactions and toxins.
In view of the above important applications the author is tempted to prepare a
new Schiff base and its metal solid complexes with a hope that the new Schiff base or
its metal complexes may find a place in any one of the fields cited above. Schiff base
complexes of various metals have been investigated for their coordinating capability,
pharmaceutical and biological activities. These complexes are used as catalysts for
water photolysis or reduction of oxygen at a modified carbon cathode. Some
compounds have been used for catalytic hydrogenation of unsaturated hydrocarbons.
Schiff bases have also been used for analytical purposes in the determination of metal
ions, and some schiff base derivatives have been used in the extraction of metal
solvents. The applications of such complexes depend to a large extent on their
molecular structures.
291
The present work provides a new series of metal complexes of Cu(II), Ru(III),
Ni(II),Mn(II), Co(II),Pd(II), La(III) and Y(III) with schiff base ligands derived from
pramipexole and different aldehydes and ketones. These complexes were
charecterised by elemental analysis, IR, NMR, UV, ESR, TG-DTA, Powder
XRD,VSM and conductivity measurements to determine the mode of bonding and
geometry, biological activites of the metal complexes were also studied.
The author has prepared new schiff base metal complexes using pramipexole
and different aldehydes and ketones namely Cu(II) and Ru(III) complexes of OHAPP,
PHAPP, RAPP, OHBP, OVP and VP, further the author synthesized Cu, Ru, Ni, Mn,
Co, Pd, La nd Y complexes of RAPP( chapter-III).
When anew schiff base metal complex is reported, it is in partice to carry out
in detail studies of solid metal complexes. Solid State Chemistry in fact gives
important conclusions like geometry, metal-ligand bond strength, oxidation state,
electronic configuration, structure and stability of the complexes. Solid metal
complexes of trasitional metal ions have been prepared and characterised by
elemental analysis (chapter-IV). In order to ascertain the nature of bonding, oxidation
state, stability and structure, various studies like IR, NMR, TG-DTA, Powder XRD,
ESR, Conductometry and VSM. In addition, the author also investigated antibacterial
activites of the metals complexes bsecause using different bacteria it is more active
towards microbial activites compared to other schiff base metal complexes
(Chapter-IX ).
Infrared studies provided the way to understand the behaviour of the ligand
and nature of bonding with various metal ions by Analysing the IR graphs
(Chapter-IV). By this it is understood that the phenolic oxygen atom, nitrogen atom of
the azomethine functional group (>C=N) participate to form metal chelate ring.
292
Further it is seen that water is also coordinated in majority of the metal complexes
studied.
1H NMR spectroscopy proved the adjacent nature and the presence of a
number of protons in a particular environment for various ligands and their metal
complexes (Chapter-IV). The singlets observed in the NMR spectra of ligands due the
presence of H-C=N proton showed downfield shift in their respective complexes. It
indicates the shielding of azomethine proton on coordination through nitrogen atom of
the azomethine group.
The analysis of UV spectar and λmax of different ligands and their metal
complexes helped to identify he stable nature of the complexes owing to charge
transfer. This in turn indicated that the complexes were non electrolytic in nature
(Chapter-V).
Conductivity measurements really helped to understand the behaviour of the
ligand in complexes. The molar conductance values of all the solid complexes when
dissolved in DMF were found to be very low (Chapter-V). This indicates that the
overall charge on the complex species is practically zero.when this fact was further
elaborated ,it clearly help us to understand that the ligand should carry with it
-2 charge in order tcluo balance +2 charge of the central metal ion.Hence it was
established that the ligand acted as bidentate in 1:2 complexes.
ESR spectra of Cu and Ru complexes for OHAPP, OHBP and provides
bonding nature and geometry of the complexes. It was observed that the g║ value was
less than 2.30 for Cu(II) and Ru(III) complexes which in turn indicated covalent
character of the M-O and M-N bonds for metal complexes.It was noted that the
α 2 and P-values obtaind for the present complexes lay in between 0.029-0.032 cm-l
and it was indicative of the bonding of copper ions and Ru ion to oxygen and nitrogen
293
donor atoms. The shape of ESR lines, ESR data suggested an octahedral and
tetrahedral geometry for Cu and Ru complexes. (Chapter-VI).
The powder XRD diffractions for showed sharp peaks indicative if the
crystalline nature and the h k l parameters came handy to prove the stable values of
the complexes. (Chapter-VI).
In assigning final structure of metal complexes, thermal studies have helped
immensely. From the thermograms, the presences of number of water molecules in
and out side the coordination sphere were easily predicated. Fromation of 1:2
complexes by Cu(II), Ru(III),Ni(II),Mn(II),Co(II), Pd(II), La(III) and Y(III) have
been understood from weight loss of the ligand from the thermograms for all
azomethine metal complexes (Chapter –VII). From the thermal decomposition of the
complexes the following appromimate stability orders for various metal ions have
been established.
The author has been pursuing anti bacterial activity for the synthesized new
ligands and Cu(II), Ru(III), Ni(II), Mn(II), Co(II), Pd(II), La(III) and Y(III) . Then
Schiff base metal complexes highly active against (viz. Salmonella Typhi Escherichia
coli and Enterococcus faecalis) bacteria. Confirming that chelation of metal to the
ligand increasing the toxicity of the complexes. (Chapter-IX).
DNA Binding studies of all the metal complexes. Ligands do not show any
binding affinity with calf thymas DNA, but the affinity is greatly enhanced by the
incorporation of metal ions in respective ligands. Metal complexes show higher
binding affinity towards DNA. The binding constants of the complexes were found to
be in the order 105 to 106 cm–1(Chapter-IX).
294
Finally, the author basing his agreement on the above information concludes
that different Schiff bases of pramipexole with various aldehydes and ketones namely
O-hydroxy acetophenone, P-hydroxyacetophenone, O-hydroxy benzaldehyde,
O-Vanillin, vanillin and Resacetophenone acts as a very good complexing agent
towards many transition metal ions. By using above spectral studies it is concluded
that they behave bidentates during complexation. All the metal complexes carry no
charge and are thermally stable. As such no single technique is independent of
predicting final structures of the complexes. Hence the entire information available
from all the studies is clubbed together and appropriate structures of the complexes
under investigation can be formulated as follows.
295
STRUCTURES
OHAPP
OHAPP
PHAPP
PHAPP
296
OHBP
H3CO
O
HCN
Cu
OCH3
O
CHN
X
X
N
S NHX =
+2O
OH H
HH
OVP
OVP
Cu
O
NO
N
CH
HC
X
X
O
O
H
HH
H
X=
+2
N
S NH
OHBP
297
VP
VP
OH
O
CN
M
HO
O
CN
X
X
N
S NH
X =
+2
O
OH H
HH
H3C
CH3
M = Cu, Mn, Co
RAPP
OH
O
CN
M
HO
O
CN
X
X
N
S NH
X =
+n
M = Ni, Pb = +2M = Ru, La, Y = +3
H3C
CH3.2H2O
RAPP
