,A-

A. ROSENTHAL,D. & TAYLOR, T. I., J. Am. chem. Soc., 79(1957), 2684.

5. PEETERS, o. M. & DE RANTER, C. J., J. chem. Soc.Perkin II, (1974), 1832.

6. PEETERS,O. M. & DE RANTER,C. J., J. chem. Soc. Perkin. II, (1976), 1062.

7. VOGEL,A. I., A text book of quantitative inorganic analysis(Longmans Green, London), 1955, 643.

8. BUNTON, C. A., NAYAK, B. & O'CONNOR, c., J. org.Chem., 33 (1968), 572.

9. BENDER, M. L., GINGER, R. D. & KEMP, K. C., J. Am.chem. Soc., 76 (1954), 3350; 80 (1958), 1044.

10. YAKOYAMA,F., J. pharm. Soc. Japan, 63 (1943), 5.11. HALE, C. R., HALE, M. N. & JONES,W. R., Analyt, Chem.,

21 (1949), 1549.12. LYNN, K. R., J. phys. Chem., 69 (1965), 687.13. BUNTON,C. A., FARBER,S. J. & MILBANK,A. J., J. chem.

Soc. Perkin II, 1972, 1869.14. LAIDLER, K. J., Chemical kinetics (McGraw-HilI, New

York), 1965, 53, 89.15. SMITH, S. G. & FELDT, R. J., J. org. Chem., 33 (1968),

1022.16. BRUICE,P. Y. & MAUTNER,R. G., J. Am. chem. Soc., 95

(1973)~ 1582.

Complexes of Ni(II) Propionate & Ni(I1) n-Butyratewith Pyridine N-oxides, Quinoline N-oxide & Tri-

phenylphosphine Oxide+

N. KUMAR*,P. L. KACHROO& R. KANTDepartment of Chemistry, University of Jammu, Jammu 180001

Received 3 October 1978; accepted 28 March 1979

Nickel(ll) propionate and n-butyrate react with pyridineN-oxide, 3-methylpyridine N-oxide, quinoline N-oxide and tri-phenylphosphine oxide to form stable, non-electrolytic, dimeric,1:1 addition complexes of the general formala [Ni (02CR)2.L]2'The infrared spectra reveal that the ligand (L) is unidentate,coordinating through oxygen atom, whilst the carboxylate anionsare bonded as bidentate bridging ligands, The complexes ex-hibit suhnormal magnetic moments recorded so far for Ni(II)alkanoate complexes, indicating considerable metal-metal inter-action.

AMASA et afl. reported that pyridine N-oxide andits 4-methyl derivative yielded dimeric carboxylate

bridged species with nickel (II) trifluoro- and trich-loroacetates. This is in contrast to the behaviourof nitrogen donors which invariably yield mono-meric, magnetically dilute complexes with carboxylicacid derivatives of nickel(II)2-4. In view of thispeculiar behaviour shown by aromatic amineN-oxides,we thought it worthwhile to prepare some complexesof aromatic amine N-oxides and triphenylphosphineoxide (TPO) with nickel(II) propionate and n-buty-rate to see if the nature of the carboxylate group hasanything to do with the stoichiometry, structure andmagnetic properties of the complexes. The resultsof the study are reported in this paper.

tPart II of the series studies on complex of metal (II)carboxylates with donor molecules.

I

I

NOTES

Nickel (II) propionate and n-butyrate were preparedby the method of Davis and Logan" as dark greenanhydrous compounds which gave satisfactoryelemental analyses. Pyridine N-oxide (Fluka) and 3-methylpyridine N-oxide (Fluka) were purified by disti-llation under reduced pressure. Triphenylphosphineoxide hemihydrate (Koch-Light) was heated at 110° for3 hr and recrystallised from dry acetone. QuinolineN-oxide was prepared in the laboratory by Ochiai'speracetic acid oxidation method", jn. p. 61-62°. Allother chemicals used were of AR grade, or otherwisewere purified by literature methods.

The complexes of nickel(II) propionate andn-butyrate with pyridine N-oxide, 3-methylpyridineN-oxide, quinoline N-oxide and triphenylphosphineoxide were prepared by mixing methanolic solutions ofthe carboxylates and the ligand in 1 : 1 molar ratioand in excess. The resultant solutions were concen-trated under reduced pressure, and dry ether addedto incipient precipitation. The solid adducts isolatedwere recrystallised from 1: 1 methanol-dry ethermixture containing a small amount of the parent ligand,washed a number of times with ether and vacuumdrived over P 20S. The stochiometry of the complexeswas independent of the amount of the ligand used.However, the yield of the complexes was maximum(57-70 %) when the reactants were used in equimolarratio.

Nickel was determined gravimetrically as bis '(dimethylglyoximato )nickel(II). The magnetic mea-surements were carried out by the Gouy methodusing Hg[Co(NCS)4] as a calibrant". Diamagneticcorrections for the metal and ligand atoms werecalculated from standard source". Electronic spectraof the complexes were recorded in acetone over therange 8000-28,500 em= on a Beckman DK-2Aspectrophotometer. Solid state spectra of the quino-line N-oxide complexes were also scanned on CarlZeiss DMR-21 spectrophotometer. The IR spectrawere taken on Perkin-Elmer 337 and 621 double beamgrating spectrophotometers. Viscous liquids or thenujol emulsion of the solid complexes were pressedbetween sodium chloride or polyethylene plates.All manipulations were carried out under anhydrousconditions.

The analytical data (Table I) show I : 1 stoichio-metry for the complexes. The complexes are greenin colour except for the quinoline N-oxide complexeswhich are yellow green. The complexes are moder-ately soluble in most polar solvents like methanol,ethanol and acetone etc., but are sparingly soluble orinsoluble in non-polar solvents. This precludestheir cryoscopic molecular weight determinationin most cases. The molecular weight of the onlysufficiently soluble complex nickel(JI) n-butryate-pyridine N-oxide was found to be 628 in nitrobenzenewhich is nearly twice that of its monomeric molecularformula weight of 328. The molar conductance valuesof their 10-3 M solutions in methanol and in nitro-benzene are quite low (Table 2) suggesting that thecomplexes are predominantly covalent in character.

The complexes exhibit magnetic moments in therange 2.35-2.63 B. M. which is not only less than thevalue of 3.15-3.35 B. M. observed in magnetically nor-mal, octahedral nickel(II) carboxylate complexes+',but is also lower than the spin only value of 2.83

265

rINDIAN J. CHEM. VOL. 18A, SEPTEMBER 1979

TABLE 1 - CHARACTERISATIONDATA OF THE ADDITIONCOMPLEXESOF NICKEL(n) ALKANOATES

.Complex Formula

IIIIIIIVVVIVIIVIII

[Ni (O.CC.H.). (C.HsNOI.[Ni (O.CC2HSh (3-CHsC.H.NO)12[Ni (02CC.HS)2 (C,H7NO)I.[Ni (02CC.HS)2 (C6H5)sP01.[Ni (O.CC.H.-n). (CsH5NO)1.[Ni (O.CCsH.-n), (3-CHsCsH.NO)1.[Ni (O.CC.H.-n)z (C9HNO)1.[Ni (O.CC3H7-n). (C6H5). POI.

Calc (%) Found (%)

C H Ni C H Ni

44.04 5.00 19.59 44.35 4.50 i9.4445.90 5.42 18.71 45.35 5.00 18.445117 4.86 16.79 51.50 4.55 16.5759.66 5.18 12.16 59.25 5.05 12.08.47.60 5.80 17.92 46.95 6.20 17.6649.16 6.15 17.18 48.95 6.30 17.0154.01 5.56 15.54 54.25 6.00 -15.70·61.09 5.68 11.50 61.20 ,6.05 11.44

TABLE2 - CONDUCTANCE AND MAGNETIC MOMENTS OPADDmON COMPLEXESOF NICKEL (II) ALKANOATES

Complex A mhos em! fLeUmol= (B.M.)

I 18.96 2.36II 20.41 2.39

III 25.08 2.35IV 26.52 2.51V 20.81 2.48

VI 27.28VII 26.93 2.44

VIII 28.25 2.63

B. M. for nickelffl)". This indicates that there isconsiderable metal-metal interaction in these nickel(II)alkanoate complexes, and that the c0I?-plexesmay have a binuclear structure. A companson ofthe magnetic moment values of the present complexeswith those of the dimeric nickel(II) trifluoro - andtrichloroacetate complexes of pyridine N-oxide andits 4-methyl derivative (3.10-3.20 B. M.) rep?rtedearlier- shows that much stronger- metal-metal mter-action occurs in the present nickel(II) alkanoatecomplexes, and that it can be ascribed to the appreci-ably basic nature of the propionate and n-butyrateanions(pKa : 4.87 and 4.82) as compared to the weaklybasic trihaloacetate anions (pKa: 0.66 and 0.23respectively). Relatively higher magnetic momentsfor TPO complexes is considered to arise from greatersteric requirements or poorer re-acceptorability of theTPOligand. .. .

The complexes show m their electronic spectrathree main absorption bands, around 9,000, 15,000and 25,000 cm-I. These bands can be assigned to3T2U+--3A2U' 3Tl~(F)_-:- 3A2g an~ 3T1U(P)_- 3A2g

transitions respectively, m conformity WIth the tran-sitions known in octahedral nickel(II) complexes'".Invariably a shoulder is also oberved on the loweror higher energy side of the mid ba,:d V2' ~he sho.ulderis believed to originate from the spin-forbidden smglettransition to the lEu (D) level gaining intensity throughconfigurational interaction or spin-orbit co~pli~g.The diffuse transmittance spectra of the qumohneN-oxide complexes reveal little difference from thosetaken in acetone solution. This suggests that thecomplexes do not undergo any significant change ondissolution in acetone and have octahedral stereo-chemistry both in solution and solid state.

The negative shifts of upto 50 em"? in theN -OjP=O

266

(

stretching bands of the complexes of PyNO, 3-Me-PyNO and TPO with nickel(II) alkanoates ~ndicatethat the ligands in these complexes are nnidentateand coordinate through their respective N~OjP=Ooxygen atoms. vN-O for the bridging amine oxidecomplexes of copper(II) halides", on the other hand,is known to shift to lower energy by> 60 em'? therebysuggesting the retention of dimeric ca~boxyl~tebridged structure as opposed to a structure u~volvmgbridging N-oxides or TPO. The N-O bending andC-H out-of-plane deformation modes a~so showslight shifts confirming thereby that the ligands areactually coordinated to nickel(II) in these complexes.The quinoline N-oxide complex~s, however, showdiverse behaviour in that vN-O m these complexeseither occurs at the same frequency, 1232 cm-I, as inthe free ligand or is slightly shifted to higher energy.This behaviour is typical of QNO-transition metalcomplexes and has been: primarily attributed toenhanced dn-pm back bonding capability of the QNOligand having exte~ded n-el~c.tron conjuga~ed system".Larger and invanably POSItIveaN-O shifts confirmthat QNO is coordinated to nickeJ(II).

The Vas COO and VB COO appear as sharp andintense bands at 1627-1615 and 1429-1412 ern"!respectively. The separation of these frequenciesworks upto 194-206 cnr? and is necessarily higherthan those generally observed in mon?meri.c nickel(II)alkanoate complexes having chelating carboxylateligands>". A "closesimilarity of these L.v(COO) valueswith those of copper (II) alkanoate complexes'<containing bidentate bridging carboxylate ligandsfurther suggests that the carboxyl stretching frequen-cies are not significantly altered wit~ chang~ of themetal (II) ion from copper(II) to mckel(II) m thesedimeric species. .

The authors express their thanks to Prof. R. K.Dewan Head of the Department of Chemistry,Univer;ity of Jammu, Jammu and Prof. 0..P. ~ig,Head Chemistry Department, Panjab University,Chandigarh for providing research facilities. Thanksare also due to the UGC, New Delhi for the awardof a junior Research scholarship to one of them(R.K.).

References1. AMASA,S., BROWN, D. H. & SHARP, D. W. A., J. chem,

Soc. (A), (1969), 2892.2. LEVER,A. B. P. & OGDEN, D., J. chem. Soc. (A), (1967),

2041.

3. MARCOTRIGIANO, G., PELLACANI,G. C. & PRETJ, C.,Z. anorg. allg: Chem., 408 (1974), 313; Chem. Abstr., 81(1974), 180454e.

4. CATTERICK, J. & THORNTON, P., J. chem. SOC. Dalton f

Trans., (1975), 233 ..5. DAVIS, T. L. & LOGAN, ·A. V., J. Am. chem. Soc., 62

(1940), 1276.6. OCRIAI, E. & SAI ZAI-REN, J. phatm. Soc. Japan., 65

n945), 73.7. FiGGIS, B. N. & NYHOLM, R. S., J. chem. Soc., (1958),

4190.8. FIGGlS, B. N. & LEWIS, J., cited in Modern coordination

chemistry edited by J. Lewis and R. G. Wilkins (Inter-science, New York), 1960, 403.

9. FIGGIS,B. N. & LEWIS,J., Progr. inorg. Chem., 6 (1964), 37.10. LEVER, A. B. P., Inorganic electronic spectroscopy, (Eles-

vier, New York), 1968.11. J(ARAYANNIS,N. M., PYTLEWSKI,L. L. & MIKULSKI, C. M.

Coord. Chem. Rev., 11 (1973), 93.12. HIBDON, D. H. & NELSON, J. H., Inorg . chim. Acta, 7

(1973), 629.

Reaction of Aryltellurium(IV) Chloride with BidentateChelating Ligandst

M. V. GARAD,(Mrs.) SARADAGOPINATHAN& C. GOPINATHAN*National Chemical Laboratory, Poona 411008

Received 28 November 1978; revised and accepted 21 February1979

New chelated arylteliurium(lV) compounds have been pre-pared from phenyltellurium trichloride, diphenyltellurium dichlo-ride, 4-phenoxyphenylterllurium trichloride and phenoxtellurine-10, 10-dichloride. The chelating ligands used are salicylaldehyde,8-hydroxyquinoline, dibenzoylmethane, benzoylphenyl hydroxyl-amine, 2-hydroxybentophenone and 2-hydroxy-4-methoxybento-phenone. The compounds are monometric in benzene. The IRand NMR spectra of some of them have been studied.

MORGAN and coworkers=" carried out extensivestudies on the condensation of tellurium tetra-

chloride with acetylacetone and concluded thatin the trichloro-derivative formed, tellurium is directlyattached to C-5 of ligand. Similar reactionswere observed with several mono-and di-ketones also",Other chelated derivatives reported include thecarboxylates", acetates" and dithiocarbamatesv".Clark et al. described some hexa coordinated telluriumcompounds". In this note we describe the preparationand characterization of. chelates of aryltelluriurnchloride with bidentate chelating ligands, The dataare recorded in Table 1.

Reactions were carried out under anhydrous condi-tions and nitrogen atmosphere, since organotellurium(IV) chelates are hygroscopic in nature. Separation ofsolids from solutions was done as far as possible on acentrifuge. .

Tellurium tetrachloride", tetraphenyltin-", diphenyl-tellurium(IV) dichloride'>, phenyltellurium(IV) trichlo-ride!', 4-phenoxyphenyltellurium(IV) trichloride'?and phenoxtellurine-l0,1O-dichloride12 were preparedby the literature methods and their purity checked.

Preparation of tris~salicylaldehydophenyltellurium-

tNCI Communication No 2353

I

f

NOTES

(IV) - The sodio-derivative of salicylaldehyde.[from salicylaldehyde (4.88 g; 0.04 mol), sodium(0.92 g; 0.04mol.), methanol (20 mlj] wassuspended in benzene (50 ml) and reacted withphenyltellurium (IV) trichloride (3.11 g; 0.01 mol)dissolved in benzene (50 ml). After refluxingfor 2 hr the reaction mixture was cooled and centri-fuged to separate the solids. The clear benzenesolution was decanted and the solids extrac-ted once again with benzene. The combined benzeneextract was concentrated under reduced pressure at40-50° till crystals of the product began separating out.The flask was cooled and the crystals obtained washedwith hexane and dried in vacuum. The yellow solidobtained weighed; yield 4.3 g, (75 %) [Found :Te,22.84; C, 56.97; H, 3.68 C27H2006Terequires: Te,22.48; C, 57.07; H, 3.53 %]. Tris-salicyaldehydo-phenyleUurium(IV) is a yellow hygroscopic solid,melting at 156°, soluble in benzene and slightly solublein carbon tetrachloride and chloroform and insol-uble in hexane.

Other aryltellurium (IV) chelates listed in Table 1were prepared similarly.

Tellurium tetrachloride when reacted with salicyl-aldehyde in an inert solvent gave HCI and productsof indefinite composition. Aryltellurium(IV) chloridesdid not react with salicylaldehyde under similarconditions. However, when the sodio-derivative ofthe ligand was made to react with aryltelluriumchlorides, the replacement of the chlorine atomsproceeded smoothly leading to the formation of achelated aryltellurium(IV) derivative. Phenyltel-lurium trichloride, diphenyltellurium dichloride,4-phenoxyphenyltellurium trichloride and phenoxte-llurine-l0, 10-dichloride reacted with sodio-deriva-tives of the various ligands in benzene giving thechlorine-free products in 60-75 % (Table 1). However,2-hydroxy-4-methoxybenzophenone when reactedwith trichlorotellurium compounds gave productscontaining chlorine. The new compounds are yellowto red hygroscopic solids, which decompose onheating, some above their melting points. All of themare soluble in benzene and sparingly soluble in carbontetrachloride and chloroform. The low volatilityof these compounds precluded mass spectral analysis.However their monomeric nature is revealed bymolecular weight determinations in benzene using asemi-micro ebulliometer.

The infrared spectrum Vmax in em'? of bis-salicy-laldehydodiphenyltellurium shows two carbonylabsorption peaks at 1640and 1740. Hence at least oneof the carbonyl group is coordinated to tellurium.The hydrogen-bonded hydroxyl band at 3125 in thefree ligand is totally absent in the compound. Theevidence for coordination is also seen in the spectrumof bis-8-hydroxyquinolinodiphenyltellurium. TheC=N and C-C absorptions at 1587 in the spectrumof the free ligand, splits into two (1613 and 1575) inthe metal complex, due to C=N coordination. ThevOH, present in the spectrum of 8-hydroxyquinoline,is absent in the tellurium complexes. Theb and dueto phenyl CoO group, when oxygen is bonded toa metal appears as a sharp peak at 1120 inthis complex. Other compounds also show similarevidences for coordination.

The PMR spectrum (chemical shift in a, ppm)

267