m

--------

METAL ION PROMOTED ADDITION OF ALCOHOLS TO PHENYLDICYANDIAMIDES

Thesis Subm itted fo r D. P h il Degree

The University o f Burdwan, November, 1976.

Akoijam Mani'har Singh, m. s c .

............................

Sanasam Satyabhama Devi

emistry THE UNIVERSITY OF BURDWAN

GOLAPBAG, BURDWAN

Dated>........................

Certified that the works described in the

accompanying thesis ‘ Metal Ion Promoted Addition

ef Alcohols to Pheoyld icy andi amid e have boon

carried out entirely by the candidate himself

under my direct' guidance and supervision.

Certified further that the candidate hes

fulfilled all the conditions necessary for the

D.Phil degree examination of the University of

Burdwan.

Professor of Chemistry The University of Burdwan

Th© author Is grateful to his teacher and supervisor

Prof.R. L. Butt a for his valuable criticism and advice

extended during the entire course of this work*

* The author wishes to express his indebtedness to

Mr. Th. Nilaraani Singh, Secretary and Principal Imphal

College, Imph&l for granting study leave which has enabled

him to undertake the work described herein.

Thanks are due to Prof.S.K*Siddhanta, Head of the

Department of Chemistry for his good wishes and encourage­

ment .

Author’ s heartfelt thanks are due to Kumar P.N.Koy

Trust, for a Science Faculty Fellowship, during the tenure

of which this work was completed. Invaluable assistance

rendered by Miss Anjana Bhattacharya on many occasions had

gone a long way to complete the assignments.

(Akoijam Manihar Singh)

Inorganic Chemistry Laboratory The University of Burdwan Burdwan 713 101.

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Section

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Section

I kite

i

I i Review * Reaction of tne nitrile group 1

II i Plan of the present work, 46

III : Methods and Materials. 49

IV 8 Copper(II) promoted addition of 61

alcohols to phenyldicyandiamide and *

other substituted dicyandiamldes.

V i Nickel(II) promoted addition of 100

alcohols to substituted 4icyandiamide,

VI * Palladium(II) promoted additions of 111

alcohols to phenyldicyandiamide and

p-chlorophenyldicyandiamide.

VII 5 Cobalt(II) promoted addition of 121

methanol to phenyldicyandiamide and

p-chlorophenyldlcyandiamide.

VIII t Preparation of p-toluenesulphonyl- 133

dicyandiamide J Copper(II) and

Pallauium(II) promoted, addition of

alcohols to p-toluenesulphonyl-

dicy an diamide.

IX t Chromium(III) complex of l-amidino- 148

0-methylurea.

ftpr.3n Published Papers

Foreword

The thesis is divided into nine sections# It opens with

a general review of the reactions of the nitrile group with

special reference to the metal ion promoted addition Of alcohols

to dieyandiamide* The introductory section is then followed

by the studies carried out in our laboratory on substituted

dicyandiamldes* The salient features of the contents of the

different sections are given below J

Section I *The reactions of nitrile group’ gives a short

resume of the various types of reactions known to d&te for

organic cyanides (G^N )* ^comprehensive treatment of the metal

ion promoted alcoholysls of nitriles has been made. Tais

includes (a) addition of alcohols to cyanopyridine end transi­

tion metal complexes of O-alkyl-2-carboximidate end (b) addi-

tion of alcohols to dicyandiamide and transition metal complexes

of 1-amidino-O-alkylureas* The review covers relevant litera­

ture upto the end of 1976*

Section II presents the plan of the present work. Substituted

dicyandiamldes namely phenyl-, p-chlorophen/1-* o-cnlorophenyl-*

N '-p-chiorophenyl-N‘-methyl- and p-toluenesulphonyld5cyandiamiae

have been selected in order to examine the metal ion promoted*

addition of alcohols end to study the coordination complexes

formed as outcome of such reactions. It seemea worthwhile to

undertake these studies In the context of the reactions already

known for the mother compound - the unsubstituted dicyandiamide.

* I I -

Section I I I 1Methods and Materials1 includes the methods of

preparation of the above mentioned substituted dicyandiamldes

with the exception of p~toluenesulphonyldicyend!amiae ‘which

forms th® subject matter of a separate section. Outline of

the different physical measurements* analyses and Zi&sel's

method for estimation of elkoxyl group are described herein.*

Section IV describes copper(II) ion promoted addition of

alcohols to the substituted dicyandiamldes* The reactions

resulted In the formation of two series of complexes

(I) / “Cu(l-PhAAOT)_7X2 (l- m *0H a 1- p henyl ami d ino~ 0- alkyl urea

X » univalent anion)* These complexes are red-violet {

18*8 kK)f bi-univalent electrolytes and paramagnetic with a

squar e pianar L CuN^_7 chromophore * (II) £~0u(l-PhA AUn)Xg_/

(X * Cl, i BO^, MOg)• These are blue to green and absorb

around 15*2 kK for X * c i f at 14.4 kK for X * £ 30^ and 14*6

for X * HO3 • The sulfa to complexes are obtained only in

methanol while the only nitrate complex has been obtained in

ethanol medium. The sulphato complex is considered to contain

bridging sulphate group while the nitrate complex has both

coordinate and ionic nitrate. The sulphato and nitreto

compounds are altogether new types of complexes and have no

parallel yet in th® family of 1-amidino-0-alkyLurea complexes

or biguanlde complexes.

N 1-p-chlorophenyl-N1-methyldicyandiamide does not

respond to the metal ion promoted addition of alconol.

ill -

Section presents the nickel (I I) chloride promoted addition

of alcohols to substituted dieyandiamides# Grange yellow colo­

ured complexes of the types / NI(l~Ph£MUB)( l-PhAMU)_/Cl.KpO

( I-PhAMUH a 1-phenyl amid ino-O-methy lurea) and Z Ni( l-Ph A

Clo.Ho0 (1-PhAEKJH a 1-phenylamidino-O-ethylurea) ere descri- 2 &

bed# These are diamagnetic, absorb around 22„7, kK and hence

possess square planer /. ^ ^ 4—/ chromophore• Ho nickel(IT)

complexes could be had from alcohols higher then ethanol**

These complexes register solvent dependent spectra.

Section VI shows that palladium(II) reacts with the substi­

tuted dieyandiamides in different alcohols to provide only

diehloro-mono(ligend) complexes. They are diamagnetic and

show Pd-Cl stretch around 340 and 350 em“^. No bis(ligand)

complexes could be prepared, although such compounds are

known for 1-amidino-0-alkylureas. It is shown for the first

time that pelladium(II) can initiate alcohol addition to

dieyandiamide and substituted dioyandiamides# *

Section VII describes for the first time that cobalt(IX)

ion also can initiate methanol addition reaction to ‘phenyl-

dicyandiamide, ultimately giving tris(ligand) cobalt(XII)

complexes# With p-chlorophenyldieyandiamide however a mixed

chelate p-chlorophenyldieyandiamide bis(l-p-chlorophenyl~* “

amidino-O-methylurea) cobaltClII) is obtained. The compound

shows the hi* „ transition and is diamagnetic#Ig lg

- iv -

Section VIII describes the preparation of” p- toluene sulphonyl -

dieyandiamide• Reaction of p-toluenesulphonyldicyendiamide

with cupric chloride in presence of methanol/ethanol gives a

highly Insoluble violet compound* The analyses of the violet t

compound fit quite well with two different types of formula ;

Z-Cu(LH2)_7cuO, O.SHgO and Cu / “CuL^O.fiH 0 (LH « a molecule

of 1-p-toluenesulphonylamidino-O-methyl/ethylurea; * The violet

compound gives an unusual metal * ligand empirical r&fcio as

Xsl. Reaction of p-toluenesulphonyldieyandi amide with lithi-

umchloropalladite in methanol gives a cream coloured complex

Z_ P(1(I,H2)0HC1_7H20 which is highly insoluble in organic solvents.

*

Section IX describes the preparation and properties of rose-

red coloured /. Crd^AMU),^/ (1-AM1JH « 1-amidino-O-methylurea) •

The compound conforms to an anhydrobase and can be neutralised

with acid's to give respective salts* The electronic spectrum

of the nitrate salt gives bands at 20.4 kK ( ^

and 27.3 kK ( 4 A_ ^ 4T1 (F) ) .

i

SECTION - I

REACTIONS 0? THE. HITOHJJiaflilE

I . -A short r.eawpe-g.C-thfi-Tarloaa r_e&a^ign^_pj~

th« nttrU.g erpttp*

I I . Metsi Ion promoted alaoholysls of nltrlles.

A. Addition of alcohols to cvanopyrldlne.

B. Addition of alaohol* to dlevendlamlde.

I . ^_3hor.t. rflaamfl-OJ_-thfL.gj|glpaa.. r.efifl.tl.oa.e, -o£-the

n itr ile . grgaE-

Introduction t

The ability of nltriles or organic cyanides to undergo

various reactions with neucleophilic and electrophiiic reagents

Is due to its electronic structure1. Because of reduced elec­

tron density at the carbon atom of the - C = N group nltriles

react very readily with neucleophilic reagents. The reactions

of nltriles with neucleophilic reagents are enhanced in the

presence of acidic and alkaline compounds, this being due to

an Increase in the electrophilic activity at the nitrile

carbon atom.I Hydrogen halides are quite important as acid

catalysts In the reactions of the cyano group.. Pinner reac-

tion (preparation of imidate salts), Hoesch reaction

(preparation of ketlmine salts), Gatterraann reaction ,e *

Stephen reaction (aldimine salts) and several acirt cataly­

sed reaotions are carried out in the presence of hydropen

halides.

A brief resume of various types of reactions of nltriles

is presented below :

Reactions of Nltriles •

1. Hvdrolvsls : Nltriles, in general, are hydrolysed in

presence of strong acids, bases or hydrogen peroxide.

- 2 -

Recently hydrolysis of nltriles has also been carried out

in presence of metal ions* The reaction with hydrogen sul­

phide, hydrogen selenide may also be considered as a form

of hydrolysis, In the sense that they form amides with

nltriles.

(a) Acid hvdrolvsls : To cite an example, mandelonitrile is

readily converted to mandelamide or mandelic acid by aqueous

hydrochloric acid •♦

C6H£CH(0H)CN + H20 + HC1 -» C6H£CH(0H;C0NH2.HC1

CgH£CH(OH)CONHg.HCl + HgO -*• CgHgCHCOHJCOOH + NHjCl.

(b) Base hvdrolvsls : Me Elvain and Goese . was able to

hydrolyse nicotinonitrile to nicotinic acid by heating an

alkaline solution (70S alcohol) of nicotinonitrile for <3 hrs.

(o) Metal Ion Promoted tedrply_ala * Recent literature

reports that nltriles could also be hydrolysed by refluxing

them with nickel catalyst in water. 3-cyanopyridine is hyaro-o

lysed to nicotinamide' or nicotinic acid.

(d) Mgtal. chelate promoted hardroly si a : 2-cyanopyridine

was found to be hydrolysed to picolinamide when refluxed

with an aqueous solution of metal chelates like

/ Ni(en)3_7ci2 . 2H20 ; cu(en)gj7ci2. 2HgO etc. ( en = ethyle-

nediamine)9 .

N i(II)/C u (II)+ HgO --------- f 1 f ) | + Metal chelate

(e ) sogysrslsn.. 2Z.-nX$Til$2-.i9. apj-flea xX!to.J&Ja$£sa..£axpxi&s

Nitriles, in general, are converted to amides when treated

with 3% alkaline hydrogen peroxide* o<-napthonitrlle which«

resistssaponification with acids may be converted to the

corresponding amide using somewhat concentrated hydrogen

peroxide1 (6#).

C10H?CN + 2H202 -- » C ^ C O N H g + HgO + Og.

(f) Reaction with, hydrofean-sulPhisla * Nltriles rea'it with

hydrogen sulphide under pressure in anhydrous solvents to

form thioamides11*

RCN + HgS -> HCS.RHg

(R = methyl, propyl, benzyl, /3 -napthyl etc.)

(g) Reaction with hydrogen, sel.enldo : Dechend12 prepared

selenobenzaraide by conducting a current of hydrogen selenide

- 4 -

into a weakly ammoniacal alcoholic solution of benzonitrile.

C6K5CN ♦ HgSe -- * C€H6CSeNiig

2. Alcoholvsls of nltriles : Pinner2 first studied alcoho­

ly sis o f nitriles in presence of hydrobromic or hydrochloric

acid under anhydrous condition. Recent study shows that alco-

holysis of nitriles can also be effected in presence of a

base or metal salts.

2(a) Acid alcoholvsls ; Pinner synthesis consists of con-

densing a nitrile and an alcohol under anhydrous condition

in presence of HC1 or HBr* to give an imidate.

*

RCN + R'OH -*■ HC1 -> RC(NH)0R«.HC1

(b) 3aae alcoholvsls : Nef13 , converted nltriles to imi-

dates in methanol in presence of a catalytic amount of sodium

ethoxide13.

RONaRCN + R'OH --- » RC(NH)OR1

(c) Metal lon.jromoted a lc o h o ly ^ > The first such report

is credited to Dutta ijid Ray14. Dicyandlamide*reacts with

alcohols when refluxed in presence of metal ions :

r

,uAcPNH_C( NH)NHCN + ROH —-*-*•/. Cu(NH„-C(NH)NHC(SH)OR_/A0o

refluxed * ' d

h2s

V

NH2-C(NH)NHC(NH)0H

(R * methyl, ethyl, butyl, propyl etc. and Ac = acetate).

The products are 1-amidino-O-alkylareas.

(d) 3e&.ctlpna. of. nJ.-trlle.a with nercaptans i In presence of

mineral acids mercaptans react with nltriles In the sa:..e way

15as do alcohols to form iminoethers .

RjCH ♦ HSRg ♦ HC1 -> R^C(NH)SR^.HCl

(e) Formation o.f. 9-3t^r3 .from. nltriles i Apart from the above

iminoether formation reactions nltriles are known to .for.t

esters, when they are treated simultaneously with alcohol and

water in presence of a mineral acid16.

. R.CN ♦ HgO + HORg + HC1 --» R-jCOORg + NH^Cl.

3. Reactions, of nltriles with aclda » The reactions of

nitriles with different acids may be summarlsea as follows :

(a) Reaction with faydrQMnJMLl.flfta * The reactions of hydro­

gen halides with nitriles have been known for -long but the

reaction products were not identified for a long time. Many

17workers have given a formula RCN.2HX and many others

- 5 -

•

assign a formula 2RCI; nHI18. Lazaris and coworkers19 recently

reported that depending on the reaction conditions the same

nitriles may produce both the above mentioned products. For

example bromoacetonitrile may give the following reactions1^.

- 60° to - 5°BrCH0CN + HC1 / * BrCHgCH . 2HC1

2 \ JN— ------- > 2BrCH0CN • 2HC1

0 and above

<b) B.aastlon ttlfcfa^alpharla. ft.old : Cobb and Walton20 studied*

the reaction between hydrocyanic acid and sulphuric acid and

isolated a compound of the emperical formula liG-,.iio30 (aCm

probable iminoformyl sulfato HC(NH)S0^H, was mentioned, with

no supporting evidence). The product with water gives formic

acid and ammonium bisulfate.

HCN,HoS0 + w p -* HCOOH ♦ NH.HSO..2 4 2 4 4

(c) Reaction with nitric acid : Aromatic nltriles are

21generally nitrated with concentrated nitric acid .

HN0o

V 6 CH2CN — ^ N02C6H4CH2CN + H2°

(d) Relation with p^spfrorio asld : Nitriles react slowlyoo

with phosphoric acid to give product of the type‘s HCN.H^PQ^.

(o) Reaction with Organic acids : On being heated with cur-

boxylic acids in the presence of hydrogen chloride nltriles

- 6 -

- 7 -

°2give amides1" .

RCN + R»COOH + HC1 --^ RCONHg + C1C0R» .

Acid hydrides react with nitriles to give tertiary amides" :

RCN ■»* 0(C0R*>2 -->RC0N(C0R*)2

i

(4) Aminolyslfl of r.itriles * Nitriles when condensed with

ammonia or an amine leads to the formation of an anidine.

(a) Reaction with..organic..aginsjs : Nitriles usually do not

form amidines with free amines but do so in the presence of

2athe hydrochloride of the amine •

HOI ♦ C6HgNH2 + HC1 -MiC(NCeH5)NHC6H5 + Tr^Cl.

(b) Reaction with alkali aalda : Nitriles r=jact with pota-

25ssium amide in liquid ammonia to form ami dines

RCN KNH2 -» RC(NH) NHK.

(c) yorwatlon of. g4_an.tdinfl£ = The nitrile group in cyanide

and Its derivative undergo aminolysis. Dimethylgu&nidine is26

obtained by heating dieyandi amide and dimethyl amine at 18 3''

h2^c(nh)nhcn + 2:in(ch3) 2 — » 2H2nc<nh)n(ch3 )2 .

At a lover temperature and in the presence of cupric salts

27dimothylbiguanide is however obtained

Cu2+H2KC(SH)NHCN + 2HN(CH3)2 --- ?■ H2?I-C(NH)NH.C(fc’B)N(CRj}^

02

(<J) Formation of atnldoxlmas i The reaction of nitriles withQQ

hydroxyl amine produces arnidoxirne ,

4 RCN + HgNOH -> RC(N0H)NH2

(e) Reaction with hvdr.-sine : Nitriles react with hydrazinepQ

forming a hydrazidine .

RCN + HgN. NHg — »aC(NH)MH.NH2

P. Reaction of nltriles tfitn halogens : The reaction of

3 3nitriles with halogen normally give halogenated product •

CH3CN 4- 3r0 — > C ^ N B r ^

But In the case of hydrocyanic acid, nydrogea in the

hydrocyanic acid is replaced by halogens to fora cyanogen

halide31.

HCN ♦ Cl2 -» Cl.CN > HC1

Cyanogen halides are quite useful starting materials

for the preparation of cyanamide and substituted cyanaraides.

€. Reaction of Orlgnard r.eaj^n>_wltfr.. nlfcxi3..a • Nitriles

react with Grignard compounds, normally to forra iaino’compo-

32unds which on hydrolysis gives ketones .

7. Gattermann1 s synthesl s : Gattermann (1897) discovered

that in presence of aluminium chloride and hydrochloric acia,

hydrocyanic acid react with certain aromatic compounds to

form what he thought to be a simple aldimine4 (RGB = NH).

33Later Hinkel and coworkers' showed that in the presence of

A1C13 , methyleneformamide hydrochloride is first formed,

which in turn reacts with the aromatic compound# On hydroly­

sis of the above product aldehyde of the aromatic compound

is produced. Thus the reaction with benzene may be represen­

ted as follows 5

2HCN + HC1 + A1C13 ^ A1C13 .NH:CH.N:CHC1

C6H€ + A1C13 .NH:CH.N:CHC1 * CgHgCEiNCHxNHHCl + U C 13

3H20\ t

C*HcCHO ♦ NH-OCOH + NH.C1.6 c 4 4

5 Houben Hoesch synthesis

Is basically an extension of the Gattermann synthesis. In

many cases hydroxy compounds react with nitriles in presence

of hydrogen chloride to form lmlnoethers, in many otner c^ses

the CN - group adds on to a nuclear carbon atom forming a

34ketimlne .

- 10 -

The ketlnine may be readily hydrolysed to the corresponding

ketone.

OH

9. Polymerisation, of nltrUea s In many Instances nitriles

polymerise to form a trimoleeular cynurlc ring compoina^.

i ' i3 RCN -- » RC.N:CR.N:CR:N

The above type of polymerisation takes place only when no CH

or CHg group is attached to the CN group, as in the cyanogen

halides, benzonitrile, tribromo-, and trichloro- acetonitrile'"’ .

(a) Polymerisation, of aliphatic nitriles t Saturated rdlpha-

tic nltriles are quite stable but may be polymerised by tho

action of metallic sodium .

, 2GH3CN + 2’ia -> HaCHgCN + CH4 + NaCN

CHgCN + NaCH^CN — » CHgGCNI^) JCNaCN

CHgCCtlHg) JCNaCN + H20 — > CH3C(KH2):CN.CN + Natti.

(b) Polymerisation of aromatic nltriles * Polymerisation

of aromatic nltriles normally results In the formation of

1, 3 , 5 , triazine ring, ?o t example, benzonitrile is

HNtC.C^HCl

OH

- 11 -

polymerised in boiling benzene solution in the presence of

metallic sodium, forming l-sodio-2, 2, 4 , 6~ tet rap ft .snyl-1,2-

dihydro-1,3 ,6-triazlne37.

4ft6HgCN + 2Na -» C6H6C.N:C(C6HE).N:C(C6Hc)n- fa 4- .'aCN

38Recent literature*"' shows that trimerization of aromatic

nitriles or trichloroacetonitrile to 1,3,6-triazinos could

also be effected by the use of the combined catalyst PCl^-HCl.

10. Reduction,of. nitriles t (Stephen’ s synthesis) - Nitriles

may be reduced with anhydrous stannous chloride to innines,

which on hydrolysis give aldehydes5 *

RCN + SnCl^ + 3HC1 -* RCHiNH.HCl + SnCl^

. RCHxNH.HCl + HgO -» RCHO + NH4C1

The method is applicable to aliphatic and aromatic nitri-

les, the yield being nearly quantitative in some cases*

1 1 . Metal ion promoted, alQQ,hply_3is of. n itr ile

As noted above nitriles are susceptible to various <inds

of reactions. Since our primary concern is to extend met&l iont

promoted alcohol addition reactions to substituted dicyanaia-

mides, in the following pages is given an upto date ani elabo­

rate coverage of alcoholvsls of nitriles in the presence of

- 12 -

metal ions* Expectedlv metal long plav a vital role in such t

reactions, the stability of the resulting metal chelates being

the motivating factor behind such reactions* Thus a discussion,

of the properties and behaviour of the metal complexes inevi­

tably comes in.

The alcoholysis of nitriles in presence*of a metal ion

was first observed by tfutta and Ray14 in respect of dieyandi a-

mide. These reactions led to the syntheses of a new serfes of*

ligands namely 1-ami djno-0-alkylureas which are as powerful 0 7 30

as biguanides * • These studies prompted Barnard '* to

study metal ion promoted alcoholysis of 2-cyanopyridine.

A. Addition of. aleonol- .to. eyanopyriding =

4 0Barnard (1969) extended the study of metal ion promo­

ted alcohol addition reactions to 2-cyanopvridine. He reported

that copper(II), nickel(IT), cobalt(II) and iron(II) promote

addition of alcohol to 2-cyanopyridine providing the following

types of complexes :

1 . Z^OtePy^uClgJ7 2 • Z“"(EtPy)CuCl2J ?

3« 1 (3uPy)CuCl2_7 4. L UePy)2(H20)2CuJ7ci2

6 . / ( MePy) 2( H 20 ) BrNijBr 6 . Z“ (MePy)CoCl2-7 H2J

7. ZTMePy)2Cu^7(Cl04 ) 2 8 . Z‘’ (HePy)3NiJ7(aio4 ; 2

9. L (MePy)2CoClgJ7 10. L (MePy)6i?e J7(C104 )2ii20

11. Z““(MePy)3CoJ7(ci04 )2.

- 13 -/

= 0-methylpyridine-2-carboximidate

3tPy = 0-ethylpyridine-2-carbox!mi date

BuPy = 0-n-butylpyridine-2-carboximidate.

The formula of the complex /_ ( MePy)CuClg_7 suggests that the

ligand in the complex has been formed by the ruction of metha­

nol with•2-cyanopyridine, which is evident by tn? abs^ ce of

(C a N) absorption ne; r 223E cm" 1 in the Infrared spectra and

appearence of a new band at 1380 cm” 1 (Table 2) which may be

assing9d to 0 - 0 - C stretch.The formation of a new 13 eana

( I ) was supported by the preparation of the same compound

directly from O-.methylpyridine-2-carboximidate; The complex

was found to be non-electrolyte in nltromethane tnd Its elec­

tronic spectrum (Table l) in the saine solvent is consistent

with a square planar structure ( I I ) .

Cl--C u -- NH

Cl

(I) (II)

The infrared sturtv of the complex L (A ely)r,u(CIO^)

shows coordinating perculorate ion (Table 2 ). The complex

was found to be a 1:2 electrolyte In nltromethane. The sollu

and soloution electronic spectra studies (Table 1) reveal thcit

in solution there is a relative shift In band position

- 14

Table 1. > Solid and solution electronic spectral data of

. MePy-complexes.

Complex^olid-st ate

W kK

Sol ution

max “Solvent

C { M©Py)CuCl2J 7 27.6vs, 14.36s,

13.0sh.

26.86, l^ .f

13 .8 , 13.1

NM

ZTMePy)2(H20) "u_7cig 16.46s,br. 16.2, 13.2

lO.Osh.

NM

ZTM8Py>2C ^ J (^ 104 )2 16.95s,br 16.9 . NM

Zl.MePy > 2 (h2° )BrHi_73r 17.1m, 16.8w,

12.2w, 8 . 66m,br.

17.7, 16.8,

13.2, 1 0 .8 ,9 .7

1)A?

Z(MePjr)3Ni_7(CX0/1)2 18.66m, 12. 6sn,

11.4m.

26.6, 18.6,

12,8 , 11. 6 .

HA

ZrMePy)3CoJ7(ci04 )2 21.76s, 18.66sn,

10.6m.

26.6 , 21.6

18 .6 , 10. e.

ZlMePyJgCoOl^J7 20.6sh, 19.26,

I0.4vw, 7.2w.

20.86,* IS .9,

9 .9 .

JeQH

ZlMePy) 3?e_/ (Cl C>4 ) gHgO 26.1s, 19.6vs,

18.0 vs.

26 .1 , 19.9, •

18.7.

NM

NM = nitromethame, DM? = NN-dimethylformamide,

s = strong, vs= very strong, m = medium, br = broad,

sh = shoul'der, w = weak, vw = very weak.

16

Table 2 . Magnetic moments and selected principal IR bands

of the MePy-complexes.

Complexeff. -......Infrared spectraCccT1)

(E.M.)^(C*H> ^(C-O-C) Other bands

C (MePy)CuClgJ7 - 1649vs 1376 s

ZTMe?y)2(H20)cu_7ai2 - l€60vs 1376m 3380br,(Ho0)

/TM«Py)2Cq_7 (C104 )2

4

- 1C51VS 1376m 1120,1041s,

926m, 620s (Perchlorate)

ZT-fePy) (HgO)BrNi_7Br 3.10 1660vs 138 Ovs 340Qw,br( ’i90 )

ZTMePy)3N lJrCG104 )2 3.04 1661vs 1382vs 1086vs,930vw,

621(Perchlorate)

ZTMePy)3Co_7 (C104 )2 4.87 1660vs 1382vs I085vs*933vw

€21 s(Perchlorate)

^M «Py)2CoCl g j - 1649vs 1378vs

ZTMePy) 3 ?e_7 (C104 ) 0 0.80 164 Ovs 1400v s 1086v?,932vv,

623 s( i;er chlo­rate)3360,i;(H<_.0) .

towards lower frequency side. ?his is considered t^ be due to

a change in the environment of copper atom from tetragonally

distorted octahedral (in solid state) to planar (in solution).

The perchlorate in this complex is considered to be another

example of ’ semi-coordination'41 .

- 16 -

Th.-* infrared spectrum of the pink coloured complex

/ (MePy^tfi^AClO^)^ reveals ionic perchlorate group (Table 2 ),

and the magnetic moment value (3.04 3.M .) confirm the essentia­

lly octahedral nature of the cation. The 3olid state spectrum

and magnetic moment of complex £ “( MePy)gHgOBrNiJZlr chara­

cteristic of nickel(IT) in a tetra^onally distorted octahedral

geometry, An alternative structure l_ (MePy)2NI3r^_7H,?0 can not

he ruled out but attempts to dehydrate the cosnlex resulted

in decomposition, so the former structure se^rrs to be more

probable. The compound is undoubtedly the unknown product of

a oWalton In his study of 2-cyanopyridine complexes.

The complex Z~(MePy)3Go_7(C104 )2 was shown to be a tris-

chelated cation by its conductivity In nitromethane, the sl-'ai-

larity of the solution and solid state spectrum nr the perchlo­

rate group (Table l ) . The complex / (MePy^CoCl^V was fom-i

to be insoluble in nitromethane and dimethylformaalde. The

spectrum and conductivity in methanol indicate that reaction

with the solvent occurs. The solid state spectrum (Table 1)

was reported to be consistent with a tetragonally distorted

octahedral structure.

In order to test the amination of nitrile group in

chelates, Watanabe and coworkers (1971) ' , reacted methanol

solution of bis( 2-cyanopyridine) copper(II) chloride and a. lines

at 0°C. Instead of the expected complexes of the aminateu

products they obtained two types of complexes (Mefy)(amine)

\

1? -

CuCl0 (A) and (MePyJ^CuClg (3) (MePy = O-raethylpyridine-2-

carboximidate) depending on the amine used. When ammonia, meth-

yl amine 5 dimethyl amine, ethylamine or benzyl amine was used for

the reaction, the chelates of type (A) were obtained* On the

other hand, when trimethylamine, diethylamine or triethyl&-.1 no

was used, the chelato3 of type (B) were obtained* Steric hin­

drance of the bulky amines prevented their entry into tr.e

complex zone in the second case.

•The complexes were coloured from green to blue, 'lectr'Viic

absorption spectra were reported around 12.9 - 1E.0 kK and

no geometry was assigned to the complexes. The infra-red bands

at 13R1 - 1398 cm*”1 in the complexes were assigned to

anti symmetrical stretch with no cited reference.

B. Addition, of, alcohol, to, jUcv and 1 ami.de.

The ligand 1-amldlno-j-al.kylure * The addition of alcohols

to dieyandi amide in presence of copper(II) acetate was observed

in the year 1969 by Dutta and Ray14* In their attempt to syn­

thesise the biguanide derivative of methylanthranilat?, dicyan-

diamidej metnylanthranilate and copper(II) acetate were refluxed

in ethanol medium. Ethanol was chosen as the solvent, since

methy 1 anthranllate was not miscible with water. After* some

time the solution turned deep violet, suggesting apparent!/

the formation of the eopper(n) derivative of the corresponding

biguanide. The sulphate of the coloured complex was r rscf pit. ted

i

th© addition of an aqueous solution of aaunoniura sulphate.

The analyses of the sulphate salt were at variance with those

expected for an anthranilbiguanj.de complex, but suggested a

compound resulting from the combination of dieyandiamide and

ethanol. The experiment was then repeated in the absence of

aethvlanthranilate and formation of the sane compound showed

that methylanthranilate was not a partner in the reaction

that occurred. The strong resemblance of the products cop.ierC

bisCguanylurea) led the authors to believe that the derivative

wore ethyl substituted guanylureas. Just as aicyandiamide

takes up a molecule of water to form guanylurea in presence

of hydrogen ion, similarly a molecule of ethanol ad-is itself

to that of dieyandiamide followed by a rearrangement to the

^ 14alkyl substituted guanylureas •

HJJ-C-NH-C^N + ROH -- > Z HoN-C-NH-C-OR_yNH reiiaxea m m

Dieyandiamide 1-Amidino-O-alkylurea

/ I 2 5HgN-C-NH-C-NHR

NH 0

Guanylurea or

j» 1- Ami d lno-3-alkylurea.

The reaction between alcohol and dieyandiamide in pre­

sence of copper(II) acetate has been found to proceed smoothly

with methyl-, ethyl-, iso-propyl-, n-butyl-, isoamyl-,

n-hexyl-f phenylmethyl- and methoxyethyl alcohol, as well as

glycol yielding the corresponding copper(II) guanylurea comp­

lexes. The complex copper(II) guanylureas were converted into

their sulphate by treatment with ammonium sulphate and fro;,

the latter copper(II) ion was removed by sulphuretted hydrogen

when the sulphate of the substituted guanylureas was obta-

proeedurp without citing the Indian works and concludes that

the product obtained therefrom were 1-amidino-O-alkylureas

which they isolated as hydrochloride. To understand the real

structure 1-amidino-3-alkylureas were directly synthesise^

by the reaction of guanidine hydrochloride with an isocyanate

in the presence of sodium and acetone yielding the 1-amidi: o-

3-alkylurea as the free base i

In contrast to Outta and Ray's observation l-a:r;idino-3~

alkylureas do not form metal chelates. Hence it was concl uded

that the co/npound obtained by them from the reaction o; alco­

hols and dieyandiamide, were indeed 1-amidino-0-alkyl iraa and

oonclusion was supported by an Infrared study ( i/atta .ini

ined14,44 ’4g

In a later year Kawano and Odo46 published a similar

HgN-C-'IHg-HCl + R-H=C=0

"iH

Syamal)49 . The methyl and ethyl derivatives display very

-1 - -1 strong sharp band around 1200 cm and 1400 cm , which are

- 20 -

AQcharacteristics of C-OR stretching vibration • The ligands

and the complexes had no sharp bands around 1700 cm ^

characteristic of guanylurea, Zstimation of methoxy group

of the methyl derivative also gave a satisfactory positive

result49 .

I-An1_dlno-0-alkylureas and. r5 lfe-t.ed IX zzrA * '•

Dicyandiamide has an active nitrile group. In pret'snc'?

of water and acid it takes up a molecule of water and roes

over to guanylurea (or ami dinourea; while in present of

• ammonia and amines we get the formidable ligands called bl^ua-

n id e ^ . In presence of alcohols transition aetal ions like

copper(IT) and nickel(II) promote the addition of alcohols to

dicyandiamide giving 1-amidino-O-alkylureas1^ *A The 1-

ami dino-O-alkylureas are closely related to biuret, guanylurea

and biguanide.

H„N-C-NH-C=N H_N-C-NH-C-NH- H„N-C-NH-C-NK22 II ~ 2 II II 2 ^ II II

NH 0 0 NH 0

Dicyandiamide Biuret Guanylurea

HgN-C-NH-C-NHg

NH NH NH NH.

Biguanide l-Ami dino-0-alkyl urea.

Biuret may be considered to be deri ved fro:o the reaction«

of two molecules of urea, guanylurea from one molecule of

urea and one molecule of guanidine and in a similar fashion

21

1-ami dino-O-alkylurea from the condensation of one molecule

of guanidine and one molecule of 0-alkylurea.

Of these four closely related bodies, biuret forms anio­

nic complexes with metals. The constitution of the well known

violet copper biuret complex, due to I»ey and Wemer£1, i?

given below. On the other hand the remaining three ligands,

2-H0Pf - G - NH - C - 0"

2 II II0 N

N /Cu

X VN 0

0 - C - N H - C - N H ,

namely guanidines, biguanldes and 1-amidino-O-alkylureas form

well defined cationic complexes with transition metals. Complex

compounds of guanylurea and its phenylderivatlve (the phenyl

group being away from the carbonyl group) with copper(II/,

cobaltdll), palladium II) and zinc(II) have long bo«jii ins­

cribed*^-57. Kundu and Ray®8159 observed that l-amidino-3-

phenylurea which has the phenyl substituent adjacent to the

-CO- group, does not form metal complexes. The loss of chelat­

ing ability was attributed to the decrease in t: * basic!tv

of the nitrogen bearing aryl group. The same observation wasyt Q •

true when a methyl * , butyl or hexyl group w vb In the same

position. On the other hand, when the phenyl group is attached

to nitrogen away from carbonyl group the resulting guanylurea

- 22 -

shows complex forming ability. Bo the loss of chelating ability

of the substituted guanvlureas (substituent adjacent to carbo­

nyl group) is not due to the basicity of these compounds but

rather to the steric factors operating between the metul aton

and nitrogen atoms with which it complexes.

Biguanide3 have been found to give rise to numerous

complexes with bivalent, trivalent and tetravalent Metals of

the transition series and they function as very powerful biden­

tate chelating ligands. Complex compounds of biguanide with

copper(H), nickel(II) and cobalt(II) have long been described.

Systematic studies of the preparation and properties of vari­

ous biguanide complexes of copper(II), silver(III), goid(III),

n ick eK II), cobalt(II/III) 9 chromium(III), rhodium(III),

iridium(ITI/IV), rutfeenlun(III), iron(III), manganese(~TI / I 7 ; ,

rhenium(V)* venadium(T7) , platinum(II), platlnum(IV), palla­

d i a I I/IV) , zlnc(II) and osmiuin(VI) by Ray and his students'39

have unearthed many interesting facts about the chemistrv of

these fascinating coordinating ligands.

Like biguanide, l-amidino-3-alkylureas serve as biden-

tate ligands satisfying botn the primary and secondary valences

with the formation of inner metallic complexes. A comparison

of the dissociation constants of the ligands (Table 3) ana

instability constants (Table 4) of their copper(II) hnd

nickel(H) complexes with those of bigu&nides shows that,

23 -

Table 3 . Dissociation constants of prouonated ii?'»nds.

Ligan&s kal * a 2Kef.

Guanylurea €.30 X 1 0 " 9 1 . 5 8 X 10-2 61

1-Amidino-O-methylurea 3.90 X 1 0 - 1 1 1 . 3 4 X 10"3 €1

1-Amidino-O-ethylurea 0.79 X 1 0 " 1 1 0 . 6 3 X 10“ 3 e i

1-Ami d1 no-0-1 sobutylurea 1.69 X 1 0 “ 1 0 1 . 2 6 X 13" 3 e i

1-Amidlno-O-isoamylurea 6.02 X 1 0 - 1 ! 1.26•

X 10"3 €1

1-Amidino-O-n-hexylurea 6.02 X 1 0 - 11 0 . 5 f X 10"3 61

Biguanide 3.02 X 1 0 - 12 1 . 6 0 X 10-3 ♦ e%

-Methylbiguanide 3.63 X 1 0 -12 1 . 0 0 X 10"3 6 2

N'-Ethylbiguanide 3.39 X 1 0 -12 0 . R 3 X 10" 3 (2

fiaJC\-*J L H *Jka _ and ica_ = — ~ 55—

1 L lh2+_ / 2 C lh3 2+_ /

t,H = one moleeula of ligand

i. OfLH2 and LH^ are the ions of the mono arid di acid

salts respectively*

(

complex forming capacities of 1-amidino-O-alkyl areas are very*

close to those of blguanldes,substituted bigaanides and are

far stronger than that of ruanylurea.

- 24 -

Table 4 . Instability constants of copper(II) and nickel(II)

complexes of guanylurea, 1-Amidino-O-alkylurea ana

Biguanide8 .

Copper( II > Nickcl(II) hef*complexes complexes

G u a n y lu r e a 6 .10 x 10"8 - 6 1

1 - A m id in o -0- m e t h y lu r e a 1.0 2 x 10-16 6 .5 0 x I O " 11 6 1

1 -A m i d i n o -O -e t h y l u r e a 4 .9 7 x 10"18 1 .6 6 x i o - 12 • 1

B ig u a n id e 4 .9 0 x 10-1* 3 .2 0 x io-4 63

IT f -M e t h y lb i 'g u a n i de 7 .0 8 x r r i8 1 .6 6 x 10 -12 63

N ' - E t h y l b i g u a n i d e 1.0 2 x 10-17 1 .6 6 x 10 "12 63

Tlig-giakaJL gomplexaa. gf l*aFMlafe9rrtfcylMr.flag * .

gpypgrilJQ- gjpnpl«aa J

The ligands, 1-amidino-O-alkylurea, react with copper(II)

64ion to give the following types of complexes •

(1) /~Cu( 1-ami dino-O-alkyl urea

(II) . / Cu( 1-amidino-O-alkylureaih ^ _ “

alkyl = methyl, ethyl, isopropyl, n-butyl, isobut/1 ,

Isoamyl, n-hexyi , n-butyl or etnoxyethyl.

x « ch3coo, o .6sc4 , ci, ^r, I , scn, ng^> cr>3 ,

vl°4 . K02 , is 206 , C204 or H?04 .

- 25 -

(III) /fcu( 1-ami dino-O- alkyl urea) Cl .

alkyl = methyl or ethyl.

The rose coloured bis(ligand) copper(II) acetate

was obtained by refluxlng copper(II) acetate, dicyandiamide

in the 1*3 ratio in excess of alcohol for 3-4 hrs. The

other bis(ligand) copper(II) salts (type I) were obtained by

the addition of an aqueous solution of alkali metal salt of

the corresponding anion to that of the complex acetate^. The

complex copper (IX) bis( 1- ami dino-O- alkylurea-H)bas e (type II)

were prepared by the addition of alkali to an aqueous or alco­

holic solution of the complex copper acetate or cnloride. On

treatment with ammonium salts they are- proton&ted with the

liberation of ammonia and salts of the complexes t*re formed.

Their magnetic moment values 1.62 - 1.84 3 .M are cha ;<.ct ?ristic

of Inner level complexes possessing square planar structure.

Unlike the brown red bis(benz imidazole) copper(II) complex

the pink 1-amidino-O-alkylurea complexes and their salts have

no near infrared absorption characteristic of tetrahedral

geometry. The molar extinction coefficient of the visible

absorption bands are well within the range 1-100 observed for

d —> d transitions and the spectra are consistent with a

67planar geometry for the complexes

The molar conductance of bis(ligand) coprer(II) salts

in aqueous solution provides values for biunivalent electro­

lytes. Electronic spectra of a large number of bis(l’igand)

- 26 -

copper(II) complexes in several solvents such as water, etha­

nol, ethyl^neglyeol and dim ethyl sulfoxide indicate the fol i.01%-

in? order of tetragonality .

Dimethyl sulfoxide^ Sthanol Sthyleneglycol^> vater.

The result points to ths weak donor ability of dimethylsul­

foxide compared to ethanol and water: these observations are

in keeping with the respective positions of these ligands 5 :

the spectrochemical series * ‘ .

The unusual pink colouration of the bis(ligand) coppor(ll)

2 -nitrata salts arises from the strong ligsnd field in .the Cuj<4

chromophore^. The calculated values of the bonding parameters

indicate th&t strong cr bond3 are present in the copper(H)

1-amidino-O-alkylurea complexes. The strength of <j- bonds is

comparable to that of the cr bonds in copper(II) /6 -naj.tha-

67locvanlne and copper(II) tetraphenylporphlnes .

Many chelate structures have been suggested for the dcprc-

tonated and protonated complexes 3 . ?rom the rose red

colour of the complex, their chemical properties, molecular

orbital calculation and electron spin resonance spectra of

the bls(1-amidino-O-methylurea) copper(II) nitrate it has

been concluded that structure (III) and (IV) are the most

favoured ones for deprotonated and protonated 1-amidino-O-

67alkvlurea complexes respectively .

- 27

V - J - m - c - or

IIN NH

Cu/ 2

(III)

Cu/ g

(IV)

The above suggested structures are consistent with the crystal

structures found for the substituted biguanide complexes 1-

(2-aminoethyl)-biguanidecyanoguanidine copoer(II) sulphat?

monohydrate and ethylene bis(biguanide) nickel(Ii) cnloride

aqueous solution of their corresponding bisCli^and) complex

chloride till the solution turned from red-viole*’ to deep

blue (pH 3.8 to 4 *0). The blue crystals were obtained by

concentrating the solution and allowing to stand. The blue

crystals when in contact with water (pH ^>6) Suffers trans­

formation to the corresponding bis(ligand) complex. A series

of solutions containing copper(II) chloride and 1-amiiino-

O-alkylurea hydrochloride in molar ratio 1:4 were studiei

at different pH values61 . On Increasing the pH of the system

the green colour of the initial solution turned ieep blue

and the formation of the blue mono(ligand) complex was com­

pleted at pH 4 . 0 . On further Increase of pH the blue solution

70monohydrate .

The dichloro-mono(1-amidino-O-alkylurea) c^p^erC71)

complex was prepared by the addition of 3;.:-rlCl to an

- 28 -

gradually changed to red-violet the formation of which went

to completion at pH 6 .8 . The formation of mono(ligand) comp­

lex was also established by the spectrophotomstric study

(Job's method) between equimolecular solutions of cupric

chloride and the ligand hydrochloride61.

The blue oono(ligand) copper(II) complex has magnetic

moment 1.7 - 1.8 B.M.and exhibits an absorption band around

13.38 - 13®1 kK in aqueous solution whereas the rose-red

bis(ligand) copper(II) complexes give a band around 18.£ &KC1.4°

Dutta and Syamal interpreted the absorption spectra 5r»

terms of distorted octahedral structure in solution for the

mano(ligand) complexes. Nevertheless not much work hes b^en

done, on the structure of these fascinating compounds to have

a definite conclusion and calls for further exploitation in

this area.

Mixed chelates : Apart from the above described three t/pes

of copper(II) 1-ami dino-O-alky lurea complexes, Dutta and lie

reported the formation of copper(II) mixed chelate of 1-

amidino-O-alkylurea and ?-2 '-dlpyridyl and o-ph«nantnroline

in solution, attempts to isolate the mixed chelates in solid

state have not been successful so far. Extensive srectral

neasurements and molar ratio variation between tne com:lex

and heterocylic ligands at more than one wave length Indicator-

the formation of 1*1 chelate of the type J Z Cu(dipy) ( AA fHj/ aq

- 29 -

• _ _2+ or L Cu(o-phen) ( AAUH)_/ aq. (dipy = 2-2!-dipyrid^l, o-phen=

orthophenanthroline, AMJH * 1-amidino-O-alkylurea). The

shift of original band of bis(l-amidino-O-methylurea) copper(II;

acetate from 20 kK in dimethyl sulfoxide to 14.7 - 1£.6 kK in

aqueous medium in presence of heterocyclic lieands points to

the square planar structure being strained to a distortedCQ

octahearal structure . A comparision with the spectra of the

71corresponding biguanide mixed chelates in aqueous solution

indicates some what greater distortion in the structure ofCO

1-amidino-O-alkylurea mixed chelates •

Mgkel(II) coBPlgxes :

The nickel(II) completes of 1-amidino-O-alkylurea are

72of the following type 3 .

(I) L Nl( 1-amidino-O-alkylur ea-H)

(IT) /~Ni( 1-ami dino-0-alkylurea)J>y x0 .nH20.

alkyl = methyl, ethyl, isopropyl, n-butyl, isoamyl or n-nexyl.

X = Cl, Br, I , 0.5S04 , SOI, CIO^, N03 or O .S C ^ .

(Ill) L Ni(1-amidlno-0-n-hexylurea)g_/(OH)

Dutta and R&y7 ~ prepared the complex bases (tvpo I)

from the nickel sulphate and the corresponding l-aniiino-0-

alkylurea sulphate by the action of excess of sodium hydro-

xide. The bis(ligsnd) nickel(II) chloride salts (type IIJ*

were prepared by triturating the complex bases with dilate

hydrochloric acid, while other salts were obtained by double

30

decomposition between the complex chloride and appropriate

alkali metal salt in aqueous alcoholic solution. The .

bis(ligand) nickel(II) complexes were also prepared by re-

fluxing nickel(II) salts and dicyandiamide in alcohol for50 *73

12 hours or longer * . So nickel(II) catalysed the addi­

tion of alcohols to dicyandiamide, although it was less

efficient than copper(II).

All the complexes are orange yellow in colour. The

molar conductance of the bis(ligand) nickel(II) chloride in

aqueous solution are in fair agreement with those for a bi­

univalent electrolyte4 4 * ^ ’72. The complexes are all diamag­

netic, indicating a strong tetragonal distortion from the

octahedral geometry#

Reflectance spectra study of all the species show a

broad band (maximum 21.5 kK and 19.0 kK). The absence of any

other discernible band between 4000 and 30,000 cm ^ indicate

that the three possible transitions in nickel(H) atom in

square planar environment are not widely spaced in energy

(Fig. 1 ). Spectrum of neutral complex ^"Hi(1-amidino-0-

n-butylurea-H)shows a shift of the band maximum to a

higher energy (24.4 kK) and a more fully resolv&d shoulder

to the low energy side in the case of cationic complexas.

The width and structure of the band suggest that the three

possible transitions are all contained therein. The shift

ring in the band position when the z-perturbations are

- 31 -

added are readily explained, if the d- orbital energy levels

73for this complex are taken tcbe as shown in figure 1 .

eg

2g

/

\

x2-y2

xy

z2

xz, yz

Fig. 1. Suggested ordering of d-orbitals.

The solution s p e c t r a studv (Table 6) Indicatesthat for

cationic complexes there is a steady increase in energy of

the d 2 orbital with increasing basicity of the solvent z

2 2 2and consequently a steady decrease in the z~ --* (x~-y~)

transition energy. The spectrum of the neutral complex

C Ni(l-amidino-O-n-butylurea-HigJ7 vhich is soluble only in

the most basic solvents was found to display little change

in band positions in different solvents. This may be due to%

steric hindrance between the bulky n-butyl group and solvent

73molecules, preventing a close axial approach ' . from tne

close spectral similarities of cationic and neutral complexes

(Table 6)* it is reasonable to consider the bonding system

within the square plane is the same in both complex types.

I- 32 -

Table 6 . Solution spectral data of the cationic and nautrai

complexes in various solvents.

Complex Solvents 3and positions (in kK) Ref

/Ni(l-amidino-O-n-propylureaJg^/Brp Methanol 22.0%

19.4 73

Water 23.3 19.4 73

Dimethyl- formamide

23.3 19.3 73

Pyridine 24.4 19.2 73

Piperidine 23.6 19.2 73

/Ni( l-amidino-O-n-butvlurea-H)^/ Dimethyl-formamide

23.6 19.4 73

Acetone 23.5 19.4 73

Pyri dine 23.3 19.4 73

Piperidine 23.3 19.4 73

The general invariance in the solid spectra with differing

alkyl group8 as substituents implies that the alkyl group is

73bonded to one of the non coordinating atoms of the ligand

The complex nickel bases of 1-araldino-O-methy1urea and 1-

amidino-O-ethylurea liberate a -nmonia on warming with aqueous

solution of ammonium salts and produce the corresponding

bis(ligand)complex salts. The suggested structure for tne

cationic and neutral nickel(II) 1-amidino-0-alkylurea com­

plexes are (V) and (VI) respectively. The structures are

- 33 -

in good agreement with the proposed structure (II I and IV)

of copper(II) 1-amidino-O-alkylurea complexes/40 ’67.

h2n

HC - NH - C - ORII II

'N NH

N - C - N H - C - O R

! Ji ii •N NH

Ni2+

Ni2+/o

(V)

HpN - C2 II

"N

NH - C - ORIINH

Ni2+/o

(VI)

Unlike copper(II) 1-amidino-O-alkylurea complexes

nickel(II) complexes are formed in a single step4^. Compari-

sion of the instability constants of the complexes with

those of biguanide shows slightly lower stability (Table 4) ’ ' .

- 34 -

CQbalt(II/III) complexes.

(a) CobaltCII) complexes i Cobalt(II) salts form complexes74

of the following type with 1-amidino-O-alkylurea*

l_ Go( 1-araidino-O-alkylurea-H) iS

alkyl 3 methyl, ethyl, isopropyl, n-butyl ,i s<?-butyl

or isoarayl.

Cobalt(Il) salts react with 1-amidino-O-alkyluraas in

presence of ammonia to precipitate a bis(1-arcidino-0-alkyi-

7A 7 curea-H) cobalt(II) complex base . Biguanlde 0 however forms

a bis(ligand) complex salt# The difference in the behaviour

of these two closely related ligands may be traced to a

61weaker base strength of 1-aaidino-O-alkylureas . The magnetic

moment values 2 .3 - 2 .6 B.M#and the absence of any spectral

band in the tetrahedral cobalt(II) region (13.3 - 16.4 kK)76”7^

and also in the octahedral cobalt(II) region around 18.2 <K7

appear to indicate a square planar structure. In prossnco of

donor solvents rapid oxidation occurs and the usual cobalt'III)

six coordinated absorption bands around 30 kK and 20 kK &re^

74 R 1 found to appear *

(b) Cobalt(III) complexes : The known complexes are of the

82following types *

✓

( I ) /"”Co( 1-ami dino-0-alkyl urea)3_ /X 3 .nH 2

(II) ^fCo(1-amidino-0-alkyl urea-H)3_/nHg0

- 36 -

alkyl = methyl, ethyl, n-butyl, iso-butyl, iso-amyl

or hexyl.

X = Cl or 0 .6S0..4

The complexes tris(ligand) cobalt(III) base were prepared

by oxidising cobalt(II) complex with HgOg and their salts were

82obtained by neutralising with appropriate acids . The complex

bases and its salts are rose to rose-red in colour. The conduc-

tance values of the chloride salts in aqueous solution agree

2 -1with triunivalent electrolyte (346.7 - 391.2 mh6s cm mole ) •

Th© complexes are all diamagnetic and their electronic spectra

show two absorption bands around 28 and 21 kK, suggesting an«

82octahedral stereochemistry~ •

(c) Cobalt(HI) mixed ligand complexes J The mixed ligand

complexes'of eobalt(III) are of the following types !

(I) /'Co(AAUH)2L2_7x3 .nH20

X = Cl, I , Br, CIO , 0 .6 S 0 ., 0.6S 0 , 0.6C 0 or

0 .3 3 / C o U Q , , ) ^ .

(II ) / “ Co(AAU)(AAUH)L2_7X2 .nH20

X = 0.680 or SCN.4

( i n ) / ‘co(aau)2x,2_7x

X = SCN or OH.

(IV) /~Co(AA0H)2B2_7NO2.nH2O

L = pyridine,/3 -picoline, acetonitrile

B = N02 or CM

*AAtJH = A molecule of 1-amidino-O-alkylurea.

- 36 -

The diamine bis(1-araldino-O-alkylurea) cobalt(III)

complexes (type I and II) were prepared by oxidising (either

by air or HgO^) the unstable yellow coloured bis( 1-ami di no-

O-alkylurea-H) cobalt(II) complexes in presence of ammonia

83under different experimental conditions . Similar complexes

were also prepared by replacing ammonia with pyridine,Q

fb -pi coline and acetonitrile . When the unstable bis(l-

amidino-O-methylurea-H) cobalt(II) complex was dissolved in

strong aqueous solution of ammoniumthiocyanate complex diam ­

ine bis(1-amidino-O-methylurea-H) cobalt(III) (type III) was

obtained, instead of expected a diisothiocyanato bis(l-

amidino-O-methylurea) cobalt(III) complex . The dlnitro

bis(1-amidino-O-alkylurea) cobalt(III) nitrite complexes

(type IV )f the first example in the metal biguanide ana 1-

amidino-O-alkylurea family were prepared by two differentqc

methods giving trans and cis dlnitro derivatives0 . Conduc­

tance studies of these two specimens in methanol shows that

cis series recorded much lower conductance in contrast to

the trans series which shows normal 1:1 electrolyte. Low*

values in the cis series have been explained to be due to

86 87strong ion pair formation ’

The nature of the above complexes was ascertained

through elemental analysis, extensive measurements of equi-

85valent weight and conductance in aqueous solution . 31 ec-

tronlc spectra of all the types of diammine bis( 1-aiaidino-

O-alkylurea) cobalt(III) complexes, show two absorption

- 37 -

bands around 30 kK and 20 kK. The dinitro b i3(ligand) nitrite

salt also shows two absorption bands around 30 kK and 21 kK

and record a very high molar absorptivity of charge transfer

type. The infrared study indicates that the nitrite group ispe

linked to cobalt(III) through the nitrogen The spectral*

nature and absorptivity are parallel to the other alnitropo

cobalt(III) six aoorainated systems' .

(d) I I I a t o d Skal&t.g. SPKPiL&L&S : The mixed chelate

complexes of cobalt(III) are of the following types8^ ’^

(i) L Co( 1-ami dino-O-alkylurea) 2(A/l)_/Xo.nci20

(jl) L Co(l-amidino-0-mothylurea)p

( 1-amidino-0-ethylurea) . nh^O

(iTl) / Co( 1-amidino-O-alkylurea)(bigiianide)^^^.^^

A.A = dipvridyl, o-phenanthroline, glycine,

ethylenediamine, biguanide.

X = Cl, I or 0.6S04 .

The mixed chelates of the above types were prepared

by the fiction of appropriate bidentate ligand on the transgo

diammine bis(1-araldino-O-alkylurea) cobalt(III) ’" , except_3+

for /^Co(l-amidino-O-alkylurea)(biguanide)^/ complexes,

which were prepared by the reaction of 1-amidino-O-alkylurea

with diammine bis(higuanide) cobalt(III) base” .

The complexes have all been adequetly characterised

through elemental analysis, conductance measurements and

\\

- 38

equivalent weight determinations"0 ’^1 . The absorption spectra

show two ligand field bands typical of cobalt(III) complexes

over the wavelength range 31 kK and 18 kK. A comparative

quantitative study of corresponding bands gives the following

ligand field order, which is in keeping with the position of

9? 93these ligands in the spectrochemical series' :

o-phenanthrolino dipyridine 1-amidino-O-alkylurea

^ ethyl enediamine glycine.

The complex biguanide bis(1-amidino-O-methylurea.)

cobalt(ITI) and 1-amidino-O-alkylurea bis(biguanide) cobalt(III>

complexes have been resolved through fractionation of the

d-camphore-l'O-sulphon&te salt. In all the cases only the

90 91pure levo isomer could be isolated" ,v .

Fail&diumdl) complexes.

The complexes of palladium(II) with l-amidino-0-

94alkylurea are of the following types:

(I) Pd( 1-amidino-O-alkylurea-H)

( I I ) Pd(1-amidino-O-alkylurea)2-7^2#nH2°

alkyl = methyl, ethyl, isooutyl, n-butyl,

Isoamyl or ethoxyethyl.

X * Cl, 1I03 , SCN or 0.6S04 .

39

The complexes palladium( II) bis( 1-ami di no-0-&r<cylurea-i;)

base (type 1) , excepting methyl derivative were prepared as

water insoluble products by digesting a solution of sodiuru

chloropalladite and 1-ami dino-O-alkylurea in presence of

sodium hydroxide94. The bis(ligand) complex sulphate (type II)

was prepared by the addition of a solution of sodium chloro­

palladite to 1-amidino-O-alkylurea sulphate in neutral or

faintly amnionical medium. Chloride salt was prepared by the

action of barium chloride on the complex sulphate or by neutra­

lising the complex base with hydrochloric acid and the other

bis(ligand) complex salts were obtained by double decomposi­

tion between the complex chloride and the appropriate alkali

metal salt. The complex palladium(II) bis( 1-ami dino-O-alkylurea;

palladothiocyanate was obtained by treatment with dilute aci i

of the respective thiocyanate complex salt.

The complexes are all diamagnetic, characteristic of a

planar structure. Equivalent conductance of the bis(lieana)

complex chloride salts provides the values for bi-univalent

2 -1x94electrolyte (170-225 mhos cm mole )

Oro-vanadlumdV) cpnunlflxfla »

Vanadium(IV) complexes of 1-ami dino-O-alkylurea may

be represented as

ZVO( 1-ami dino-O-alkyl urea-H)^../

alkyl * methyl9 ethyl, butyl, ethoxyethyl or

butoxyethyl.

Complexes of the above type were prepared by reacting vanadyl♦95

sulphate and 1-amidino-O-alkylurea in alkali medium Their

magnetic moment values, 1.67 - 1.69 B.M.indicate a quadri­

valent vanadium. The complexes resemble the vanadium(IV)

complexes of biguanide and substituted biguanides in colour,

properties and magnetic moments.

Pater.gngflj *

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- 44

68. R.L.Dutta and D.De, J.Indian Chem.Soc., 1969,46f63.«

69. R.Drago, 'Physical Methods in Inorganic Chemistry’

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1960, 37, 673.

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- 46 -

86 . B.Bosnich, M.L.Tobe and G.A.Webb., Inorg.Chem.,

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1963, 40, 863.

SECTION - II

Plan of. the Present J-QTk.

The inaugural report of Dutta end R&y^on the addition

of alcohols to dicyandiamide in the presence of cupric salts

has generated a good deal of interest in such reactions.

Thus metal ion promoted addition of water or of alcohol to a

2multiple -C=N- bond in 2-cyanopyridine and -CH=N- bond in

schiff bases have attracted attention. It was considered

worthwhile to study further the alcohol addition reactions♦

of substituted dicyandiamides in the presence of various

transition metal ions. The following substituted dicyandia-

mides were chosen for the present study :

1. — NH — C — NHC = N

Phenyldicyand!amide.

P-chlorophenyldicyandiamide.

0-chlorophenyldicyandiami de.

N'-p-chlorophenyl-N’-methyldicyandiamid

- 47 -

P-toluenesulphorxyldicv and! amide.

So far only unsubstituted dicyandiamide has been explo­

red by Dutta and Ray and only two transition metal ions

namely copper(II) and nickel(II) have been observed to promote

alcohol addition reactions. In this dissertation the above-

listed substituted dicyandiamldes were investigated with a

view to obtaining informations on the following points :

I . Whether alcohol addition can be initiated in substitu­

ted dicyandiamldes and to what extent these reactions are

dominated by steric and inductive factors.

II . Whether alcohol addition reactions can be stimulatedt

by metal ions other than copper(II) and nickel(II).

I I I . Whether newer types of metal complexes can be synthe­

sised during such alcohol addition reactions.

■

IV. To what extent the ligand field strengths of the

substituted 1-phenylamidino-O-alkylureas vary from those of

the 1-amidino-O-alkylureas.

V. Whether the free 1-phenylamidino-O-alkylurea ligands

are stable enough for isolation in the solid crystalline

state.

. ~

Reference *

1. R.L*i)utta and P.Ray, J.Indian Chem *Soc.,

1969, 36, 499.

2 . P*F.B.Barnard, J.Chem.Soo.CA)f 1969, 2141*

3. C.M.Harris and E.D#Mokenzie, Nature,

1962, 196, 670*

- 48 -

Methods and Materials.

SSCTION - I I I

In this section the methods of preparation of the

following substituted dicyandiamldes are given :

1 . Phenyldicyandiamide

2 . P-chlorophenyldicyandiamide

3* O-chlorophenyldicyandiamide

4• N'-p-chlorophenyl-N *-methyldicyandiamide*

The compounds were characterised through elemental analysis

and infrared spectra.•

The synthesis and characterisation of p-toluenesulphonyl-

dicyandiamide and dieyandiamidine p-toluenesulphonate form

the subject matter of a separate section.

The compounds 1,2 and 4 were prepared by following

essentially the methois of Curd and Rose1, Some slight

changes were made so that we preferred to record the synthe­

ses In details.

1. Phenvldicvandlamide : Aniline (23g) was ’diazotised at

5°C In 2.6 N-HC1 (2£0 ml) with NaNOg (17 .6 g in 100 ml

distilled water) in a flask provided with a mechanical

stirrer, and the mixture was added to a solution of dicyan­

diamide (23 g) in water (700 ml) at 20°C.Then an excess of

10 N-NaOH was added to maintain a strong alkaline reaction

- 60 -

and after half an hour, the golden yellow solution was acidi­

fied with acetic acid. The precipitated triazine was filtered

off, washed with cold water and was partly dried by suction

on the filter. This partly dried triazine was aadeu during

16 - 20 mins.to a mixture of acetone (200 ml) and concentra­

ted HC1 (28 ral) stirred at 28 - 30°C. After one hour, when

no more nitrogen was evolved, water (600 ml) was added ani

the crude precipitate of phenyldicyandiamide was collected

and dissolved in boiling N-NaOH solution (260 ml). The solu­

tion was decolourised by treatment with charcoal. Th& product

was precipitated frooi cold filtrate with dil.HCl. The crys­

talline solid gave colourless needles from methanol; yield

20 g.

2 . P-chlorophenvldicyandiamlde : The suspension obtained

by cooling a solution of p-chloroaniline (26.6 g) in hot

6 N-HC1 (100 ml) was dlazotised at 3-6°C by adding NaNOg

(14 g in 40 ml water). The diazotised solution was added

to dicyandiamide (18.4 g) dissolved in water (660 ml) at

20°C. Anhydrous sodium carbonate was added during one hour

to maintain an alkaline reaction and the suspension was*

then filtered off. The washed and pressed triazene was addei

during 15 - 20 mins.to a stirrei mixture of acetone (100 ml)

end 10 N-HC1 (22.4 ml) at 33-36°C. After 30 mins.water

(900 ml) was added and the crystalline precipitate collected,

washed with water and dried. The crude p-chlorophenyldicyan-

diamide was purified as described for phenyldicyandiamide

- e l ­

and finally r©crystallised from ethanol. It formed colourless

needles; yield 19 g.

3. 0-ghlProphenyId 1 cvandlAml do * O-chloroaniline (25.6 ?)

was diazotised at 3-5°C by adding NaNOg (14 g) in wtfter

(40 ml), and the solution was added to dicyandiamide (IP .4 g)

dissolved In water (560 ml) at 20°C. Excess of 10 N-NaOH

was added to maintain a strong alkaline reaction, and after

30 mins.'the solution was acidified with acetic acid. The

precipitated triazine was filtered off. The washed and pressed

triazine was added during 16 - 20 mins* to a stirred mixture

of acetone (100 ml) and 10 N-H01 (22.4 ml) at 32-3*°0.- After

30 mins.water (900 ml) was added and the crystalline preci-•«

pitate collected, washed and dried. The crude o-cnlorophenyl-

dicyandiamide was purified as described above for the phenyl

derivative and was finally recrystall5sed from ethanol. It

formed colourless needles; yield 10 g.

4 . JL'-P-chloroPhenyl—:»-methyldlcyandlarqjjte : Methyl sulphate

(12.6 ml) In methanol (12.6 ml) was added during 20 mins.to

p-chlorophenyldloyandlamide (9 .8 g) dissolved in methanol

(2E ml) and 10 N-NaOH (IS ml) stirred at If - 20°r.. After

one hour water (126 ml) was added and the precipitate collec­

ted and dried. The crude product was extracted with hot

benzene (60 ml) and reprecipitated by adding lip:ht petroleum

(boiling range 60-80°C) (25 ml). The product was recrvr*ta-

llised from water. It formed colourless needles* yield 2 g.

Characterisation data of the substituted dicyandi&mi-

des are siven in Table - 1.

Table - 1 . Characterisation data of substituted dicyan-

diamides.

9. Analysis___

Compound Formula NitroeenCi) r .(°c )Calcd. Found Lit.1 Found

Phenyldicyandia-

mide.W 4

35.0 36.2 197 196.6

P-chlorophenyl-

dicyandiamideW 4C1

28.8 28.9 . 203 203.0

O-chlorophenyl-

dicyandiamideW 4 C1 28.8 29.0 - 160.0

•

N’-p-chlorophenyl-

N1- methyldicyan-

diamide.

W 4 C126.9 27.1 167 166.5

Table - 2. Infrared data of substituted dicyandiamides.

Compound Bands ( cm’ 1)

1. Dicvandiamide 3333s, 3135s, 2222vs, 2174s,

1639 s, 1567wbr, 1499w, 12£4n,

1093hr, 930m, 747w.

Contd

Tabla-g.CContd.)

Compound Banc.s (cm-1)

2. Phenyldicyandiamide 3247m, 3126v, 2174vs, 1629s.

1666m, 1493m, 1449ra, 138£w,

1299m, 1206m, 908m, 746m,

719vbr, 69CV.

3. P-chloro phenyl dicyandia­

mide.

3420s, 3320m, 3 2 l0w , .il?0w,

2170vs, 1626wbr, 1600w,

1660wbr, 1420m, 1390m, 1300vw,

1210m, 1100m, 1016v, 826vs,

726m.

4 . 0-chlorophenyldicyan-

di ami de.

3340sbr, 32l0m, 2170vs, 1660m,

1620m, 1680s, 1636sbr, 1470v,

1440a, 1386w, 1286s, 1210w>

1080w , 1060w, l025w, 920w,

726vs, 690w.

6. TP-p-chlorophenyl-N*-

methyldicyandiamide.

3279wsh, 3125w, 2174vs,

16398, 1638sbr, 1408v, 1206vw,

1087wsh, 1020s, 917m, 833s,

799w, 730sh, 719vv, 690w.

br 3 broad? m = medium; s = strong; sh = shouldor;

v = weak; vs = very strong; vw = very weak.

64

Table-3. Probable assigment of some of the main infrared

bands in cm"1.

Compound ^ (C = N )2 ’3 ^(N-H)4 ,5 •

Dicyandiamide 2222vs 3333 s

166 7w

1639 s

Phenyld icyandi ami de 2174v s 3247m

1666m

1629 s

P-chlorophenyldicyan-

diamide.

2170vs 3320m

1660wbr

1626wbr

O-chlorophenyldicyan­

diamide.

2170vs 3340sbr

1636sbr

1620m

N'-p-chlorophenyl-N1-

methyldicyandiamide•

2174v s

4

3279wsh

1638wbr.

1639 s

It is interesting to note that phenyldicyandiamide

and p-chlorophenyldicyandiamide could be recovered unchan­

ged in almost quantitative yield after refluxing in

methanol or ethanol (Table -4 . /

Table - 4 . Characterisation data of phenyldicyandiamide and p-chloro phenyl dicyandiaaid 9

after reflux ing in alcohols.

Compound SolventRefluxingtimeChr.)

Recovery

wPound Lit. Pound Calcd.

Phenyldicyandiamide Methanol 40 96 196.0 197 36.3 35.0

Ethanol 60 96 196.5 197 35.1 35.0

P-chlorophenyldicyandiamide Methanol 40 95 202.5 203 28.9 28.8

Ethanol 60 96 202.0 203 28.9 28.8

56

Since the main objective is the study of alcoribl addition

reactions of the above substituted dicyandiamldes it is nece­

ssary to mention here the method of estimation of alkoxy group

in the resulting alcohol addition product.

7Estimation of alkoxvigroup : The determination is based

upon a procedure first suggested by Zeisel (1885)• A known

weight of the compound is decomposed by heating with constant

boiling hydriodic acid whereby the methoxylgroup is converted

to methyl iodide.

R0CH3 ♦ HI -- » ROH + CH3I

*The methyl iodide is absorbed in an acetic acid sodium

acetate solution containing bromine; under these conditions

iodine monobromide is first formed, which is further oxidised

to iodic acid.

CHgl + Brg -- * CH-jBr + IBr

ISr + 23r„ ♦ 3H^0 -* HIC.. + 5HBr.c c <3

The iodic acid is diluted with water and treated with

concentrated sodium acetate solution, and the 'excess of bromine

destroyed with formic acid.

Br2 + HCOOH -» 2HBr ♦ COg

The solution is then acidified with sulphuric acid,

potassium iodide solution is added ana the liberated ioaine

is titrated with standard thiosulphate solution.

It is clear that a very favourable conversion factor

results since six times the original quantity of iodine is

liberated it

-0CH3 = CH3I se HI03= 31 g 6Na2S203

Similarly ethoxylgroup could also be determined * by the

same method.

Calculation :

V- x N. x M x 100 % of alkoxyl = --- 1-------

W x 6 x 1000

= volume (ml) of thiosulphate solution.

N1 » normality of thiosulphate solution.

M = molecular weight of alkoxyl group*.

W » weight (g) of the sample.

Ziesel estimations take quite a bit of the time of a *resecr“»h

worker and are quite costly too. Because of these reasons vi

could not carry out as many Ziesel estimations as we would

have really liked to do.

Physical aeaaugMflnts •

1 ) Spectra t The infrared s p e c t r a were run on potassium

bromide phase at Oentral Drug Research Institute, Lucknow.

- 58 -

Solution spectra were recorded in a Rilger Uvispek Spectro­

photometer. Solid state electronic spectra of some selected

compounds were run by Wright State University, Dayton, Ohio,

U .S.A .

2) Magnetic susceptibility « The magnetic susceptibilities

of the compounds wore measured with the help of a Gouy

Balence at room temperature using copper sulphate pentahy-

drate as a standard. Diamagnetic corrections were taken from

Pascalfs constants.

I

3) Conductance : Conductances were determined at 26°C with

the help of a Phillips Conductivity Bridge.

Analysis * Estimations of metal, nitrogen, anions and

alkoxyl(methoxyl or ethoxy!) group were carried out by the

author. Alkoxyl group was estimated by adopting Zeisel serai-

micro technique and nitrogen was estimated by se£r.imicro

Combustion technique (Duma's method). Dehydration was studied

in an oven at 110°C.

Estimation of copper : Estimation of copper via decomposi­

tion of the complexes by normal decomposition method (KN03

and HgSO^) gives unreliable and varying results, possibly

due to incomplete decomposition. Copper was estimates by

fusing t^e complex with potassium bisulphate, then extract­

ing with a mixture of HNO^ and K2S04 and finally performing

the usual iodometric method.

•

.<?£..fll.sfcal 1 Nickel complexes ware first ignited

to NiO and extracted with HC1 and HgS04 and finally nickel

wag estimated as bis(dimethylgloximato) nickel ( I I ) »

B_s.tlma.tion. of cobalt s Cobalt complexes were ignited in

a silica crucible, treated first with concentrated HC1 and

then with two to three drops of concentrated H^SO anaCt

finally weighed as CoS04#♦

Estimation of palladium : Palladium was estimated as meta­

llic palladium by igniting the complexes in a silica crucible.

- 69 -

60 -

fifllergpflag 3

1. F.H.Curd and P.L.Rose, J.Chem.Soc., 1946, 729.

2. R . A. Penneman and L.H.Jones, J.Chem.Phys.,

1966, 24, 293? 1968, 28, 169.

3. R.M. Silverstein and G.C.Bassler, ’Spectrometric Iaenti

fication of Organic Compounds1, John Wiley .a Sons. Inc

New York, 1964, p .67.

4 . R.L.Dutta and A. Syamal, J.Indian Chem.Soc.,

1967, 44, 669.

6. P. P. B.Barnard, J.Chem.Soc.(A), 1969, 2140.

6. J.R.Dyer, ’Application of Absorption Spectroscopy of

Organic Compounds*, Prentice Hall, Inc ., 196f, p .38.

7. A.I.Vogel, ’ Elementary Practical Organic Chemistry’

Part-Ill * Longmans, 1958, p .771.

A.Steyermark, ’Quantitative Organic Microanalysis’ ,

Academic Press, Inc ., 1961, p .422.

SECTION IV :

gapp.«F.(IJLjBrgiaaAflg-»d-4A.U.on. of. alcohols, to Phsnvlalcv-

ap air-Jqig. flpj othg.

Copper,1U J ) . sPM lexaa . of I-Ph9m3An^.4Jtng.rP-.ftlJsyl'-ir. fcSi

1-p- chioroPhenvlaialdlno-O-metnyluraa. l-O-chloroph-rrrl-

amldino-O-BBtftvlurea and l-amldlno.-O-alfrrlureas.

Dieyandi amide (I) has an active nitrile (C =sN) group.

In presence of water and acid it takes up a molecule of water

and goes over to guanylurea (II) (also called dieyandi ami dine)

while In presence of ammonia and amines we get the formidable

coordinating ligands called biguanides ( I I I ) 1 . In presence of

alcohols .transition metal ions li'*e copper (II) and nick el (II)♦ to

promote the addition of alcohol s^iicyandi amide giving 1-amidino*

0-alkylureas (IV) which again are powerful coordinating

ligands2 .

H-N — C — NH — C = N H«N — C — NH — C — NH«2 II * 1 1 .11

NH NH 0

(I) (II)

H0N — C — NH — C — NH- H^N — C — NH C OHR II 2 Z II IINH NH NH NH

(II I ) (IV)

We have been studying for sometime alcohol addition

reactions to phenyl-, p-chlorophenyl-, o-chlorophenyldicycn^ia-

mides in the presence of transition metal salts. V7hile explor­

ing these aspects we have obtained some hitherto unknown

metal complexes. The Isolates complexes are of the types :

s

- 62 -

Z~Cu(l-PhAAUH)?_7x2 , /"cud-PhAiimDClgV, L Cu( 1-PhAMUH)SO£J

and £ ~ Cu(l-PhAE0H)NOg_7tTO3 (1-PhAAUH = 1-phenylamldino-O-

alkyl urea, l-?hAMUH = 1-phenylamidino-O-methvlurea, 1-PhASiJH=

1-phenylamidino-O-ethvl urea, X = Cl" or NO3" ) . The complexes

of /~Cu(l-PhAHT7H)S04J7 and /~Cu(l-PhABOHJSOgJ^HOg have no

parallel even in the family of metal blguanide complexes.4

affflrtingpjbA 5

Phenyl dicyandiamide (1*6 g) was dissolved in A.R. methanol

(40 ml) by little warming and to this was added cupric chlo-

ride dihydrate (0.86 g). The mixture was refluxed on a steam

bath until the light blue colour changes to violet (6 hrs)

and was left in a refrigerator overnight when the vi61et com­

plex bls( 1-phenyl amidino-0-methyl urea) copper(II) chloride

crystallised out. The compound was re^rystaliised from methanol

and dried in air.

M s( 1-Phenvlamldlno- ^-methylurea) coPP.er.( I I ) . .nltaAtJ? *

This was prepared analogously, by refluxing phenol die*/ andi a-

mide (1 .6 * ) , cupric nitrate trihyarate (1 .2 g) in A.tt. metha­

nol (4£ ml). The crystals were purified from methanol and

dried in air.

fll*hloro-mono( l-ptienvlamidlnp-p_-gi2tnyl.ur.ea) s

Phenyldicyandiamide (0 .8 g) was dissolved in A.R. methanol

(26 ml) and to this was added cupric chloride dihydrate (0.85g).

63 -

The mixture was refluxed on a steam bath (46 mins) when blue

crystals separated out* The crystals were washed with a little

methanol and dried in air.

5lllphft.tormpnp.( lrPheny 1 amjdIno-0-me thyl_ur&*) codt er (11) s

Phenyldicyanaiamide (0 .8 g) was dissolved in methanol (2f cOJ

by little warming. Cupric sulphate pentahydrate (1 .2 g) was

powdered and dissolved In hot methanol (40 ml). The solutions

were mixed and refluxed on a steam bath (2 hrs). The bluisn

preen crystals formed were filtered off, washed with methanol

repeatedly and finally dried in air.

gip.(l-£hamrl»nildlnp-0-s.thylurea) ooc-jgrCII) nitrate • i Jhis

was prepared like its methyl analogue by refluxing cupric

nitrate trlhydrate and phenyldicyandiamide in 1x2 ratio in

ethanol. The violet crystals were purified from ethanol and

dried In* air.

P1 chioro-mono(1-PhenyI ami dlno - J-ethvl ur aa) coprorCtl; :

This compound was obtained as for the lichioro-mono ( 1-phenyl-

amidino-O-methylurea) copper(II) by refluxing cupric chloride

dihydrate and p h e n y l dieyandiamide in 1 j1 ratio in ethyl

alcohol. The compound was purified by washing with ethanol

and was finally dried in air.

Mtrato-monoCl-phanvla:nldino-O-ethvlurea) ,g.oi?rer(Ti;. Mtr.^tjp :

Phenyldicy and!anide (1 .6 g) was dissolved in ethanol (4* ml)

and to this solution was added cupric nitrate trihydr; te( 2.4 g).

♦

The mixture was refluxed on a steam bath for &Z mins. and

was cooled in ice bath, (fiflfluxlnfi. I<?r, a. iPPKer. PsrXPl ?f

standing the solution overnight, .changesthe. ,nono.(ligand)

complex to the bls(llgand) complex). The green crystals

were filtered, washed with ethanol and dried in air.

Diehloro-monod-Dhanvlanildlno-O-lsopropvlurea) c o n e r d l ) :

This compound was obtained as described for dichloro-mono-

( 1-phenylamidino-O-methylurea) copper(II), by frefluxing

cupric chloride dihydrate and phenyldicyandiaraide in 1:1

ratio in isopropyl alcohol. The compound was purified 'by

repeated washing with isopropyl alcohol and was dried in air.

Dlchlorp-aono( 1-Phenylaal.dlno-Q-lgpbutylurqa) gopp.eri W ■

This compound was obtained as described for the previous

isopropyl compound, by using isobutyl alcohol in place of

isopropyl alcohol. The compound was purified by wasidng with

isobutyl alcohol and dried In air.

M s ( l-p-chlorophenvlami dlno-O-jnatiivlurea) g,op_er.( J

This compound was prepared as for b is(1-phenylamidino-0-

methvlurea) copper(IT) chloride using p-chlorophenvldicyan-

diamide in place of phenyl dieyandi amide. A little longer

reflux (6 hrs) was employed. The compound was recrystallised

from methanol and dried in air.

- 64 -

*

Plsd-P-chloroPhenylamldlno-O-aethylurQa) coPtor(II) nltr-uts :

This complex was obtained as described for the above compo­

und, by using cupric nitrate trihydrate in place of cupric

chloride. The compound was purifiea from methanol and driod

in air.

Dlchloro-mono( l-p-chlorophenylamidlno-j-mathyl-ur'sa) aosport II ;

This compound was prepared as for di chi oro-mono(l-phenyl a^i-

dino-O-methylurea) copper(II) by refluxing cupric cnloriie

dihydrate with p-chlorophenyldicyandiamide in 1:1 ratio in

methanol. The compound was purified by washing with methanol

and dried in air.

S’ilPhato-mono( l-p-chlorophanylamldlno-0-mathylvrg&) qor-.r.er.U I >

P-chlorophenyldicyandiamide (0 .97 g) was dissolved in methanol

( a 0 ml) by little warming. Copper sulphate pentahydrate (1 .2 g)

was dissolved separately in hot methanol (30 ml). The two

solutions were then mixed and refluxed on a steam bath (2 hrs>.

The green crystals were filtered and washed with methanol

repeatedly.

SulT?hat o-mono (1-o-chi croPhenyl d 1 ami d in o- j- m e t hy 1>ir ea J

copper ( I I ) • This compound was prepared like the previous

one by using o-chlorophenyldicyandianide in place of r-ehloro-

phenyldlcy andi amide. The green compound was washed with metha­

nol and dried in air.

- 65 -

66 -

This compound was prepared as for dichloro-mono( 1-phenyla.»i iino-

O-methylurea) copper(II), by refluxing cupric chloride dihy­

drate with o-chlorophenyldieyandiamide in 1*1 ratio in methanol*

The compound was washed with methanol and dried in air.

01 chioro-mono( 1-amidlno-J-.alKylurea) TOPrer.q.T) '■ (alkyl =

methyl, ethyl and n-butyl). These compounds were preparoa by

refl'ixlng cupric chloride dihydrate in 1*1 ratio in appropriate

alcohols as described for the 1-phenylami dlno-0-alkyl irea

complexes earlier in this section.

*

smphatOTmono(l-»ml31no-0-methyl'.get0..jP£rjgLri> •• This

compound was prepared as for ?ulphato-mono( 1-phenyl an 135 io-

0-methylurea) copper(II) using dicyandiamide in place of

phenyld'icyandiamide. The bluish green compound was washed

with methanol and dired in air.

Table 1. Characterisation data of copper(II) complexes of 1-phenyl ami dlno-O-alkylurea.

Compound Colour Copper(^) Nitrogen(^) Anicn(/t) Alkoxyl( o) Water(^)

C Cu( 1-PhAMOH ) C lgH gb Violet 11.8(11.8)* 20.7(20i9) 13.2(13.2) 11.1(11.2) 4 .0 (3 .4 )♦

C Cu(l-Ph»MOH)g_7(N03 )2H20 Violet 10.9(10.8) 23.8(23.8) - 10.2(10.3) 3 .6 (3 .6 )

Z-Cu(X-PhAMUH) Clg_7 Blue 19.2(19.4) 17.4(17.1) 21.6(21.7) 9 .3 (9 .5 ) -

Cu( l-PhAMTJH) S0„_7 Ho0 Blulsh-green

17.2(17.2) 15.2(16.5) 25.6(25.9) 8 .2 (8 .4 ) 4 .6 (4 .9 )

fr.\i( l-PhAEOH)g_7 (N03 )2H20 Violet 10.3(10.3) 22 .6 (22.6) - 14.5(1/1.6) 3 .1(2 .9)

Z~Cu( 1-PhABTO) Clg_7 Blue 18.6(13.6) 16 .2( 16.4) 20.7(20.8) - -

Z“cu( i-PhA5;aH)N03_7N03 Light-green

16.1(16.1) 21 .1( 21.3) - 11.2(11.4) -

Z~Cu( l-PhAP^JH) r .l g j Green 18.1(17.9) 16.9(15.7) 20.2(20.0) - -

Z~Cu( 1-PhAB TJH) Cl£_/ Light-green

17.3(17.4) 14.9(15.2) 19.4(19.3) — —

* Calc’ll at ed values are in parentheses.

l-PhMrJH = 1-phenylamidino-O-methylurea; 1-PhAKUH = 1-phenylamidino-J-ethylurea;

1-PhAP^UH = l-phenylasidino-O-ijopropylurea; l-PhAB^JH = 1-phenyl ami dino-O-i sobutylurea.

»

j. -

- 68

Table 2 . Characterisation data of copper(II) complexes of l-p-chlorophenyiarcictino-O-metbylurea and

1-o-chloroDhenylamidino-O-methylurea.

Compound Colour Copper(;2) N it r o g e n ( ,£ ) Anlon(,5>) M e t h o x y l (^ ) V a t e r ( %)

L Cu( l-p-dPh*>5IH)p_7cigHgO Violet 10.7(10.5)* 18.6(18.5) 11.6(11.7) 10.3(10.2) 3 .1 (3 .0)

C Cu( 1-p-ClPtaAMTO) 2_ 7 ( N03 ) 2H20 Violet 9 .4 (9 .6 ) 21.8(21.4) - - 3.1(2 .7)

I Cu(1-p-ClPhAMOH)Clg_7 Blue 17.3(17.5) 16.5(15.4) 19.3(19.6) 8 . 6( 8 . 5 ) -

Z " C u ( l -p -C l P h A M IiH )R 0 ._ 7 2 . 5fl„0 L l g h t -4 ^ b lu e

14.5(14.7) 13.1(13.0) 21.9(22.3) 7 .0(7 .2) 10.1(10.4)

/ “Cu(l-O-ClPhAMOH) Clg _7 Darkblue

17.2( 17.6) 16 .6( 16 .4) 19.3(19.6) - -

L C u (l -o -C lP h A M U H )S 0 A_ 7 2.5H20 n iu e 14.6(14.7) 12.8(13.0) 22 .J(22.3) 7 .1(7 .2) 10.3(1J.4)

* Calculated values are in Parentheses.

l-p-ClPhAM’JH = l-puraehlorophenylattidino-O-jiefchylurea ;

1-o-ClPhAMUH = l-orthocnlorophenylar'dolno- ->-raethyl urea.

69 -

Table 3 ♦ Characterisation data of copper(II) complexes of 1-amidino-O-alkylurea.

Compound Colour Copper($) NitrogenW Anion($) Alkoxyl{%) Water(/f)

C Cu( 1-AMUH) C X ^ J Blue 25.3(25.4)* 22.1(22.4) 28.1(28.3) 12.2 (12.4) -

Z"cu( 1-AEtJH) Cl g_7 Blue 24 . 2(24.0) 21 .0( 21.2) 26.7(26.9) 16.8(17.0) -

L Cu( 1-A’flJH) S04_72.eHg0 Bluish-green

19.9(19.8) 17.3(17.6) 29.8(30.0) 9 .8 0 .7 ) 13.6(14 J

Z~Cu(l-ABnUH) Clg_7 Blue 21.7(81.7) 18.9(19.1) 24.2(24.3) - -

♦ Calc’ilated values are in parentheses.

1-AMUH = 1-amidino-O-methylurea ;

1-AgUH = l-a;aldino-0-ethylurea ;

1- A.3nUH = 1-ami dino-O-n-butyl ureal

70 -

Results and Plscusalpn.

a( UK.e-n.djgpp^rXJ.. spmrlsxes *

The reactions of two moles of phenyldieyandiamide or

p-chiorophenyldieyandiamide with one mole of appropriate

copper salts in methanol or ethanol results in the formation

of violet.bls(ligand) copper(IT) salts (Table 1 and 2). No

violet bis(llgand) copper(II) complex could be had from the

reactions of o-chlorophenyldicyandiamide in methanol or

ethanol•

Conductivity and Magnetic, moment * All the bis( ligand)

copper(IT) nitrate or chloride salts are as expected bi-

3 4univalent electrolytes in methanol * (Table 4 ) . The magnetic

m om ents are a lm o s t the 3 p in only values (around 1.8 T3.M)^

(Table 4 ) . The magnetic moment values and electronic spectra

indicate that the bis(ligand) copper(IT) complexes do not

have tetrahedral stereochemistry. For tetrahedral copper(II)

complexes a magnetic moment of Ca 2 .0 B.M alongwlth a low

6—8energy absorption band are expected

Ipfrared sppctra i Phenyldicyandiamide and p-chlorophenyl

dicyandiamide have a strong nitrile (C=N) band at 2174 and

2170 cm""1 respectively9-11. The infrared spectra of the

bis(ligand) copper(IT) complexes show the absence of the

nitrile band and also there is no C = 0 stretch around

Table 4 ♦ M a g n e tic moment and c o n d u c ta n c e d a t a o f c o p p e r ( I I ) c o m p le x e s .

CompoundOia.Corr.

x 106

"Xw.Corr.

x V/ e f f

B.M(°K)

103 x Cone.

(«)

A u In methanol2 -1

mhos cm mole

C Cu( l-PhAM!JH) 2_7C12H20 256 1400 1.84(300) 2 161

Z"C u ( 1-Ph A VPTH) g_7( N03 ) 2Hz0 248 1362 1.83(303)•2 170

/fCu(l-PhAMTH) r .X ^ J 141 1502 1.9 (300) 21

52104

C Cu( 1-PhAHCTU) S0d_7H 20 143 1366 1.83( 303) - -

C Cu( X-PhA 'TH) 2-7(n03 V 120 272 1287 1.77(303) 2 170

Z~Cu( 1-PhAEtIH) ClgJ 153 1283 1.77(303) 21

52103

C ?u(1-PhAEUH)(N03)_7N03 145 1372 1.82(300) 210.521

119136160116*120*

/"Cud-PhAP1™ ) 01^.7 166 1460 1.88(303) - -

C Cu( 1-p-ClPhAM'm) 2_7rl 2H20 290 14 76 1.88(300) 2 159

Z"Ou(l-p-ClPhAM!JH) Clg_7 159 1462 1.87(300) 21

51103•

Z“ cu( l-o-ciPhAwm) 01 g_7 159 1435

•

1.86(300) -

* Conductance in acetonitrile.

72

1740 cm indicating that the complexing ligands are

not substituted guanylureas (V ), Instead all the bis(ligand)

complexes have very strong C-O-C stretch around 1210 - 1214.

112 $16cm (Table 7) with a medium intensity shoulder around

1206 cm"1 to support the 1-phenyl ami dino-O-alkyl urea struc­

ture (V I). Uncomplexed phenyldicyandiaraide has a medium in­

tensity band at 1206 cm*1 which is oossibly due to C-N

stretch16.

,12-14

C.Kc — NH — C — NH — C — NHR . 6 5 ii ii

NH 0

(V)

c n — NH— C — NH— G = N GCH ,— NH— C— NH-C-OR6 6 j ROH 6 6 || ||

NH NIi Nh

(VI)

In this connection it Is pertinent to mention ‘that some of

A 17the previous workers Barnard'} Harris and Mckenzie and

1 QSuzuki, Nakahara and Watanabe have taken a band around

1380 cm"1 as dignostic of C-O-C stretch. We however wish to

observe that this band can not be taken as an assignment oV

C-O-C stretch because of the fact that characteristic infrared

bands o£ alkyl ethers (C-O-C) occurs around 1160-1060 c.tT1 ;

aralkyl ethers 1276 - 1200 cm"1 and vinyl ethers 1226-1200cm 1

as will be evident from the following Table 5.

73

Tabl.e. 5 . Infrared absorption regions of C-O-C in different

compounds.

IR Range

(in cm"1)axample Ref.

1150 - 1085s aliphatic ethers (C-O-C) ie

1276 - 1200s aralkyl ethers (C-O-C) 15

1225 - 1200s vinyl ethers ( =C-0-C) 15

1150 - 1060s acycylic ethers (CHp-0-CHo) 19

1270 - 1230s aryl and aralkyl ether (=C-0-C) 19

1150 - 1060s aliphatic ethers (CH^-O-CHg) 20

1205s h^- c-nh-c-o-ch3

NH NH

12

In fact the band indentified by the above thr*? groups of

pi -.03workers is due to the symmetrical CK^ deformation vibration

IS -1Suzuki and cowor^ers have assigned C-O-C bands at 1381-1398en*:

for the complexes (MePy)(amine) CuCl^ and (MePy)2CuCl2

(MePy = 0-methylpyridine-2-carboxiraidate)(VII). Strangely enoa^h

they have not cited any specific reference in support of their

assignment.

NH

(VII)

74 -

It is our presumption that they have drawn from Barnard’s

work4 . Barnard assigned 1375 - 1400 cm"1 bands for C-O-C

stretch of his (MePy) complexes (Page-16; Table 2) by compa-

rision of the methylbenzimidate. Chemical Abstract^4 of

their cited reference readsas "The spectra of the hydroxamic

compounds are interpreted by analogy with the amide spectra,out

with deuteriated acids an important difference with respect

to the amide spectra has been moted : a band in the region

1360 - 1430 cm” 1 analogous to the amide band, believed to be

due to mainly to the C-H stretching, does not move after

deuteriation”*

17Harris and Mckenzie have made their assignment of

o n

C-O-C vibration through Bellamy's text , but examination

of their reference shows that the assigned band around

1360 cm”1 was in fact due to the symmetrical CH^ deforma­

tion in C-0-CHQ group but not due to (C-O-C) stretch. ?iggin..

9* -1and Busch assigned band around 1344 - 1373 cm for a

symmetrical CH^ deformation vibration for the complexes

(PMI = 2-pyridinal methylimine), 1344 cm ^ i

Z~Co (PMI)3 _ 7 < * V 2 > 1373 C“" li ^~Cu(Pi'll)C12-7> 1373 Cn 5

/ “ ?e(pDMI) 22H20 ( P M = 2-6-pyrid indial bis-methvlim1.ne),

1356 cm"1 ; 1366 cm*1 ; Z“ ??e(BMI)3J 7I2

(BMI = biacetyl bis methylimine), 1388 cm"1 , / tfi(3MI)3_7l3 ,

i 21 1384 cd . According to Silversteln and "Bassler methyl

symmetrical vibration occurs near 1376 cm 1 . Many other texts,.

75 -

also assigned symmetrical CH~ deformation vibratioi around .22,23 01

1370 cm

4

So we are convinced that the identification made by

4 17Barnard , Harris and Mckenzie , Suzuki, Nakahara and

IQ -l

Watanabe of C-O-C vibration around 1380 cm" was in feet

erronomus and what actually they identified was the sym: etri-

cal CH^ deformation vibration of the methyl grour present

in their compounds.

The infrared spectrum and conductivity evidence

(Table 4 and 7) of /~Cu(1-PbAMOH)2_7(N03 > gH.O suggest that

the nitrate is ionic, having a very strong absorption hana 27 28

at 1374 cm"1 - * (Table 7).

Alkoxvl- estimation * The methoxyl and ethoxyl estimations.

(Table 1 and 2) show that the bls(l-PhAMUH) copper(il),

bis( 1-PhAEUH) copper(II) and bls(l-p-ClPhAMUH) copper(II)

contain two alkoxyl groups. It is evident that out of thea

three possible alcohol addition products (V ), (VI) or (VIII)

only the structure (VI) will respond to the alkoxyl esti­

mation. So the possibility of alcohol addition proauct to

be (V) or (VIII) is ruled out. Prior to this work Dutta

pand Syamal could only perform one methoxyl estimation of

the ligand 1-amidino-3-methylurea sulphate. No co.nplex wts

subjected to Ziesel estimation whatsoever.

C*Hc-- NH — C — NH — C — OH6 6 ii ||

NH N-R

(VIII)

♦

- 76 -

Table 6 . Infrared spectral data of copper(II) complexes

Compound Infrared bands, In era-1

L Cu(l-PhA.'TOH)2_/C l2K20

Zcu( 1-PhAMOH) g_7( NOg) gHgO

Z~Cu( 1-PhAMOH) Cl2_7

/Cu( 1-PhAMtJH) SO ._7Ho0

^Cu(1-PhASOH)(N0_)_7(N0_)

I Cu< l-PhAP1® ) Clg_7

3154s, 295SW, 1667vw, 1563a,

1488m, 1449m, 1408m, 1309m,

1214vs, 1124m, 1008vw, 764m,

694ra.

3175s, 1672VS, 1600m, 1676®,

1496m, 1374vs , 1296vv, 1210vs,

1124m, I046vw, 1008vw, 800vw*

3196s, 1696vs, 1603m, 1668s,

1493w , 1446m, 1374vw, 1325m,

126Ovw, 1190s, 1116m, 800m.

3176s, 1696vs, 160Qm, 1663m,

1449vw, 1385vw, H80mbr, 1096sbr,

1000s, 968m, 763m.

3186s, 3240v, 1666vs, 1600vw,

1600m, 1370sbr, 126Ovs, 1200vs,

1116m, 1010s, 78Ow, 696m, 600m,

3186s, 170lvs, 1600m, 1663s,

1488m, I449w, 1389w , 1193s,

1106m, 9l0w, 69Ovw*

ZCu(l-p-ClPhAtfJH) 0 1 ^ 7 3190w, 16f0vs, 1600m, 1480m,

140 Ow, 1320m, 1260m, 119 Om,

1160s, 1090m, 1010w, PlOm.

Contd

•4P

*

— 77 -

T a b l e 6 , ( C o n t i . ) •

Compound Infrared bands, in cm-1

/ C u ( l -p -C lP h A t< 0 H )S 0 4_ 7 2 .6 H 20 3l75sbr, 1667vs, 1638vw, 1408vw,

1333sh, 1200m, 1099nbr, 1010m,

962m, S93vbr.

Z C u (l -o -C lP h A M T J H ) C l g _ 7 3190m, 3100s, 16^:>vs, 1660s,

1480m, I460w, 1380w, 1330s,

1245w, 12O0m, 1160m, 1060m,

800w, 760s.

Z “ u ( 1 -o -C lP h A M?JH ) <504 J z . 6H s0

•

3126mbr, 1639 s, 1638vfcr, 1*71*/,

1206m, 1100m, 1031sh, lOOOw,

962w, 800sh, 726vbr.

s =* strong, m = medium, br = broad, w = woak

v =» vary, sh = shoulder#

Table ? . Assignment of infrared bands of copper(II)

complexes.

Compound ■ (c-o-c) Other bands (cm*"1)

C C u ( 1 -P h A KUH) C l g H g O 1214VS -

z “ c u ( i -P h A ;O H ) g _7 ( r o 3 ) 2h 2o 12l0vs 1374vs( Ionic nitrate)

Z ~ C u ( 1 -P h A MOH> C l g J 7 1190s -

Z “ c u ( l-P h A ;T O H )8 0 4 _ 7 H 2 0 1180mbr 1180mbr, 1396sbr,

IOOO3, 958m (bridging

sulphate). .

L C u ( l-P h A S TJH )N 0 3_7N’0 3 1200vs 1370sbr (Tonic nitrate)

1500m, 12€0vs, 101)s

(biaentate nitrace).

/ “ C u d -P h A P 1™ ) 01 1193s -

Z ~ C u (l -P -C lP h A M O H ) C l 2J 1190m -

Z 5 u ( 1 -p -C lP h A M tJH ) S 0 ^_7 2 H 20 1200m 1099mbr, 1010m, 962m

(bridging sulphate).

Z ~ c u ( l -o -c iP h a i 'P J H ) n i 5_ 7 1200m -

f C u ( 1 -o -O lP h A M tJH ) S04 _ 7 1205m Il00m,l000w, 962v

(bridging sulphate).

♦

- 79 -

Electronic spectra : The electronic spectra of bls(ligand)

copper(IT) selts show typical absorption bands around 18.8 kK

in acetonitrile or nitromethane (Table 8) which is good

enough for a square planar Z*~CuN4_7 chromophore. For .a

square planar geo m try three transitions * dxy --» ,

dxz * dyz — * dx 2-y2 and dz 2 --* ^x2-y2 ai*9 l iv e ly . In

most copper(II) chelates these transitions are covered in a

somewhat broad envelope. Other square planar L CuN4_7

chromophores appear in bis(biguanide) copper(II) (19,2 kK,

£ , 38.5 in water)29 bis(phenyl-biguanide) copper(II)

(18 .2 kK, £, 65.6 in water)29 ( ethylenedibiguanide) copper(IJ)

(19 .2 kK, £, 50.5 in water)29, bis(ethylenediamine) copper(II)

(18 .2 kK, 6, 63 in water)3^, bis( 1-ami dino-O-alicylurea)

copper(II) (1^.5 kKf £, 43 in water)^\ tetrakis(benzimi-Qp

dazole) copper(IT) perchlorate (19.0 kK, solid phase) .

A perusal of the absorption bands of bis(l-amidino-3-

alkyluroa) copper(II) (18.5 kK) and of bis(1-phenylamidino-

O-methyl/ethylurea) cop er(II) (18.8,kK) indicates t'jat

these ligands introduce similar crystal field effects on

copper(TI). However in the spectra of the present

bis(lieand) copper(II) chloride or nitrate tnere occurs

considerable shift of band positions on changing the solvents.

For the complex L Cu(l-PhAMUH>2_7( NO^^H^O and

Z””Cu( 1-P-ClPhAMUH>2^701^20 the following tetragbnality

order was observed (Pig.l) i

\

80

Acetonitrlle Dimethylformamido Sthyleneglycol

Methanol Pyridine.

A comparable order of tetragonality was also observei for the»

bis(1-amidino-0-alkylureas) (alkyl = methyl, ethyl or propyl)

copper(II) complexes in different solvents'33

Table 8 . Electronic spectral data of some copper(II) complex*?'?.

6 maxCompound StateColour in solution

Absorption bands in

(kK)

/Cu( l -P h A M tlH )2_ 7 c i 2H20 Nitromethane Violet

BMSO Light violet

Methanol Bluish viole'

Pyridine Light green

ZCud-PhAMnHJgJ^CHOgJgHgO Acetonitrlle Violet .

DMP Light violet

/Cu(l-PhAMOH) Clg_7

Methanol

Pyridine

Solid

UMSO

Methanol

Pyridine

Light green

Green

Light green

Bluish green

ZCu( 1-PhAMUH) R04 Jfe20 Solid

18.8 71.8

18.2 33.0

18.1 52.0

16.7 46 .0

18.2 68.0

17.9 44.0

17.7 £4.0

17.4 66.0

17.1 73.0

16.2 -

16.8 3£ .0

I * . 2

OiCO

13.1 89. ■>

14 .4 -

>ntd.

I

Table 8'»(Cont<l.)

- 81 -•

•

Compound StateColour in Absorption solution bands in

(kK)

£ max

/Cu( 1-PhAKJH) C1J>7 DMSO Greer- 15.€ 34.0

Methanol Light green 14.6 49.0

Pyridine Bluish green 13.1 91.0

IC m ( 1-PhAEtJH) (K03)_7?!03 Solid - 14.6 -

DMSO Green 14.7 36.0

Methanol Light green 14.6 34.0

/Cu(l-p-ClPhAMCJH)2_/Cl2H20 Acetonitrile Violet 18.fi ee.o

DM? Violet IB. 2 63.0

Ethyl eneglycol Light violet . 13.0 ^9. J

Methanol Bluish violet 17.9 67.0

Pyridine Light green 16.1 60.0

£Cu(1-p-ClPhAMOH)Cl2_7 DMSO Green 16.9 36.0

• Methanol Light green 14.6 41.0

Pyridine Green 13.6 96.0

DM50 = dimethyl sulfoxide

IMF = dimethylformaraia e.

I

MO

LAR

EXTI

NC

TIO

N

CO

EF

FIC

IEN

T

vVA^EL^NGTH (nm)

82 -

It was noted that from propanol onwerds all higner

alcohol8 react with phenyldicyandiamide or p-chlorophenyldicy-

andiamide in presence of cupric chloride to provide only blue

or green dichloro~mono(ligand) copper(II) irrespective of

the ra^io of cupric chloride to substituted dicyandi anides,

examination of model shows that there is lot of steric hind­

rance when the two phenyl groups of the two 1-phenylamidino-

O-alkylurea ligands are Sil& to each other and lie on the same

plane as the Z CuN4-_7 square plane. Of course this steric

hindrance will be diminished if the two phenyJ. groups are

rotated in opposite direction away from the / CuN^_y square

plane. An obvious way to relief any such steric hindrance is

placing the two phenyl groups trans to each other, and auto­

matically the two alkoxyl groups also take up tr&na positions.

In this context it appears quite relevant to mention tnat

with simple unsubstituted dicyandiamide alcohol addition

reactions could be performed from methanol upto even n-hexanol to give red-violet coloured bis(ligand) copper(II) complexes. If a cl s structure is assumed for bisd-amidino-O-alkylurea)

copper(II) complexes, it again appears from examination of

model that there will be considerable strain beyond the

ethyl group. Of course if the alkoxyl groups pre twisted away

in opposite direction from £ CuN^_7 square plane strain is

distinctly relieved. Our experimental failure to prepare

the bis(1-phenylamidino-O-alkylurea) copper(II) complexes

beyond ethyl group has led us to prefer a trans structure for

all complexes. It is also our guess that phenyl substitution

83

and alkoxyl substitution tend to cluster on the molecular

plane* The cls structure for bis( 1-amidino-O-alkylurea)

copper(IT) complexes is also not prefered on the ground»

that the molecule continues to grow on one side of the /C

square plane* A better poise and stability can be gained by

distributing this alkoxyl substitution on ether side of the

molecular Z~CuN4_7 plane*

An examination of models does not reveal any great

sterlc hindrance towards the formation of bis(l-o-31PhAAUH)

copper(IT), with a trans structure. However our failure to

prepare any his(ligand) copper(II) complex with o-chloro-

phenyl substituent should be attributed to other factors.

Mono(ligand) sonplexes of oopperd.I).

The mono(ligand) copper(IT) complexes ware prepared

by allowing the appropriate coppor(II) salts to react with

phenyldicyandiamide* p-chlorophenyldicyandlamide or o-chioro-

phenyldieyandiamide in appropriate alcohols in 1 :1 ratio*

These reactions appear . to be general and occur with ease

with unsubstituted dicyandiamide as well (Table 3 ). This

aspect of alcohol addition reaction seems to have escapedA p 34

the attention of Dutta and Ray * . Originally i/atta ana

Ray2 prepared the blue coloured /. Cu(AMUHX^lg^/ ’ and

Z~Cu(AEUH) Clg^Z by reacting cupric chloride and AMUH/

AStfH in 1:1 ratio in aqueous solution at a pH 3.8 - 4 .0 .

This .method gave a mixture of CuClg and / Cu( AiflJH/AS'JHiClp^

from which CuClg had to be removed by repeated washing with

cold methanol. We now observe that these complexes can be

synthesised very cleanly by refluxing copper(IlJ chloride

and dicyandiamide in 1*1 ratio in methanol or ethanol when

the complexes crystallise readily. The mono(ligand) complexes

are amorphous, probably non-ionic solids, which ire soluble

only in coordinating solvents like methanol, dimethylforamide,

pyridine etc. but are insoluble in other common organic non­

polar solvents and in water.

*

DlchXoro-mono( 11 gw-id)__sgpr-.ar.C IX).. s w pXsx&js ■

The dichloro mono(ligand) copper(II) complexes were

prepared by reacting cupric chloride tnd substituted d icy an­

di amides in 1*1 ratio in appropriate alcohols.

Conductivity anfl mag not ic moment : The conductance values

of / “Cu(l-PhAMUH) ClgJ7, Z~Cu(l-PhA20H) C l a n d

Z”Cu( 1-p-ClPhAMUH) c i ^ 7 in methanol show an increase in

their conductivity with dilution (Table 4 ) . When the concen­

tration is 0.002M the complexes register A>j values of

2 — 161 - 62 mhos cm mole , whereas at 0.001M concentration,

2 -ithey ree-ister 103 - 104 mhos cm mole . These values strongly

indicate that the coordinated halides are being solvolysed.

i^Cu( 1-PhAAUH) Cl<>_7 ♦ solvent -— /Cu( 1-PhAAttH)Cl solvent/ ♦

85 -

It may be recalled here that dichloro-mono(2-phenyliminomethyl)

pyridine; (o-chlorophenyliminomethyl) pyridine and (p-chloro-

phenyliminomethyl) pyridine copper(II) complexes were found to3

be non-conductor In nitromethane , 1 :1 electrolytes (68 - 7£+

2 —1mhos cm mole ) in methanol indicating that the coordinated

halides are essentially solvolysed • The same nature may be

expected for our dichioro-mono(ligand) copper(II) complexes,

but insolubility of our complexes in nitromethane or nitro­

benzene and other non polar solvents precluded conductance

measurements in those solvents. All the dlchloro mono(ligand)

copper(II) complexes have normal magnetic moments around

1.8 B.M. (Table 4 ).

Infrared spectra s The infrared spectra of the dichloro

mono(litrend) cot)Per(II) complexes show the absence of the,9-11

nitrile (C = N) band at 2174 cm • Instead the complexes

have C-O-C stretch around 1190 cm-112’1" (Table 7) indicat-

lng that the alcohol addition product has structure (V I).

The infrared spectra do not exhibit any sharp band in ' the

1700 cm"1 area12 ’13, thus indicating the complexes do not

have substituted guanylureas (V) as ligands.

ftlkoxvl estimation : Estimation of methoxyl or ethoxy 1

jjroup of the dlchloro mono (ligand) copper(II) complexes

!methanol or ethanol derivative) shows the metal : alkoxyl

*atio as 1*1 (Table 1 and 2) in keeping wl th our proposed

‘ormulatlon.

86

ZLectronlc spectra : The electronic s p e c t r a of L Cu

(1-PhAMUH) ClgJ7, Cu( 1-PhAEUH) Clg_7 and ZCu( 1-p-ClPhAMUH)

Cl^JZ show a broad absorption band around 15*6 kK in dimethyl -

sulfoxide having a low molar extinction coefficient values tb e

around 36 (Table 8 )• The solid^electronic spectrum of

L Cu( 1 - P h A M U H ) r e c o r d e d a broad band, having absorption

maxima at 16.2 (Pig. 2 ). The spectra of the above mono(ligand>

copper(II) complexes are characteristic of systems with a

tetragonal environment with probably all the d-d transitions

under a broad envelope. The possibility of the above complexes

having a five coordinated geometry (IX) is unlikely, since

the solution spectra show a very low molar extinction coeffi­

cient and no absorption around 11 -12 kK. For a five coordi­

nated species a molar extinction coefficient above 200 is

,36-37expected

Cl

Cl

(IX) (X)

The observed properties will not be entirely inconsistent

with a chlorobridged ionic dimer (X). The conductance in

2 —1 •methanol however was around 60 mhos cm mole (Table 4)

- 87 -

at O.OO&M concentration (monomeric basis) a somewhat low value

for the structure.

A tetrahedral structure is eliminated by the electronic

spectra. We suggest that these complexes are four coordinated,

square planar (XI) y having a / CuNgCl^J? chromophore.

(XI)

The observed conductance against the expected non-electrolyte

value (for structure XI) is due to solvolysis in methanol.

Similar behaviour was observed in the complexes Z~Cu(PF)Cl2_7

(PP = 2-(phenyliminomethyl) pyridine), Cu(OCPP)Cl^_7

(OCPP = 2-(chiorophenvliminomethvl) pyridine, which are non­

conductors in nitromethane while in methanol they behave as

2 —1 381*1 electrolyte (67 mhos cm mole ) • Other square planar

copper(II) complexes having / OuN^Cl^^/ chromophore are found

in Z~Cu(Py)0Cl2__7 (Py = Pyridine) having onlv on© broad

absorption band at 14.6 kK # Barnard*s compound / ( MePy)Cullc_7

(page 1*, Table l) with a square planar geometry*

absorbs in the solid state at 14.4 kK. Our complexes are

quite likely to generate a still stronger field (band in the

solid state at 16.2 kK).

. ,oopp.er(II). coayj.exos

Reaction of one mole of phenyldi cyandiamide, p-chloro- t

phenyl dieyandi amide or o-chlorophenyldicyandiainide with one

mole of cupric sulphate pentahydr;..te Jn methanol results in

the Tormation of sulfato-mono(ligand) copper(II) complexes.

These form an altogether new type of amidino-O-al:<ylurea

complexes# It is Interesting to note that sulpnato-mono(ligand)

complexes could not be prepared in any other alcohol outside

methanol. This is evidently connected with the insolubility

of 0uSC4 .ea^0 in higher alcohols.

•

£,qn.3:&sti Vlty-m&_.maKPQUc. ,.fflPjnan.t * The conductivity of

sulfato mono(ligand) copper(II) complexes could not be studiei

due to its high insolubility in all the common solvents. The

complex L 2u( 1-PhAMUH)SO^JTh^O recorded normal magnetic

moment v^ilue 1.8 9 .M.(Table 4 ) . ♦

Infrared spectra x The infrared spectra of sulfato raono-

(ligand) co'Dper(II) complexes show the absence of nitrile,9-11 . 4

(CsR ) band at 2174 cm . There is also no C=0 bandT12-14

around 1740 cm indicating that the complexes do not

originate from substituted guanylureas (V). The bands due

— 1 ^to the sulfato -group appear at 1180, 1096, 1000 and 958 cm

(Table 7 ) . The band at 1180 cm” 1 is quite broad and medium

strong and also covers the C-O-C band. The C-O-C band in

Cu(1-PhAMUH) ClgJ appears as a sharp one at 1190 cm 1 .

89 -

Prom these band positions it is not possible to distinguish

unequivocally chelating sulfato groups from bridging sulfate

For our sulfato mono (ligand) copper (II) compl<2xes, we

however prefer a brid£?<ng bldentate sulphato structure (XIX),

to a chelating sulphato complex (X III ) ,

(XIII)

since our complexes are found to be highly insoluble in

various solvents. A chelating sulfato group is expected to

Mathoxvl ggtimatlon ; The methoxyl estimation of the

sulphato mono(ligand) complexes shows the presence of methoxyl

group, giving metal : methoxyl ratio as 1:1 (Table 1 and 2).

Electronic qpaotra : The solution sDectra of sulphato

mono(llgand) copper(IT) complexes could not be studied die to

group40

L (1-PhtfMCJH) Cu Cu( 1-PhA MUH)_7

4

(XII)

0 0

(1-PhA f«JH) Cu

0 0

induce some solubility in the complex.41

their highly insoluble nature in various solvent?. The solid

state spestrum of Z~Cu( 1-PhAMUH)SO^J7 HgO shows an absorp­

tion at 14*4 kK (Table 8 , Fig. 2) which is comparable to

that found for Z~Cu(1-PhAMUH) ClgJ7. This would indicate

that a chelating/bridging bidentate sulphate in a square

. planar chroraophore gives almost the same crystal field effect

as two coordinated chloride ions. In fact the following

snectrochoraieal series in well established^2.

I " < 3r“ < Cl” < U03- < ?’ and *SC>4 2~ < N03"

It is also known that crystal field strength of a similar

terminal and bridging ligand is nearly the s*me43 . Thus we

believe that the electronic structure is quite consistent

with structure (XII) and (X III).

»

l?llra.tg_g|gmCl-J?&.enil£flljli.aar.0rsthylur5aj-sgyp.9j.Li;.?. n.n m s

The reaction of phenyldieyandiamide with cupric nitrate

in ethanol resulted in the formation of / Cu(l-PhASUH)

• Attempts to prepare the nitr&to monod-PhAJ-CJHJ

copper(II) complex via reaction of cupric nitrate, phenyl-

dicyandiamide and methanol always resulted in the formation

the rose-red bis( 1-PhA.i'TH) copper (IT) nitrate. On the other♦

hand recctlon of phenyldicvandl amide and cupric nitrate

in 1*1 ratio in n-propanol or n-butanol at steam bath tempe­

rature gave green coloured crystalline compounds. Analyses

values of the green compound from n-propanol (Cu, 13.2>;

N, 6.2*) and n-butanol (Cu, 63.1#$ N, 6.3/,) were nowhere

near tfcose expected for nitrato-mono(ligend) copper(II)

complexes* The above values of copper and nitrogen indi­

cate the green compound obtained from n-propanol or n-butanol

is of the seme composition and agrees well for basic salt

3Cu(0H)g#Cu(N0^)g (Cu, £2.9^j N, 5*8#). The experiments

were also repeated in n-propanol and n-butanol in the

absence of phenyl dicyendiamide and the same green crystrds

were obtained. Phenyldicyendiamide, thus, does not perti-a

cipate in the formation of green compound. Z~Cu( 1-PhAK5.JH)

N0g_yN0g remains as the only example of nitrato ;nono( ligand)

copperXH) complex in the arena of metal 1-ami dino-O-

alkylurea complexes end also has no parallel yet in tne

metal biguanide chemistry.

gonduotlvlty and nmmetic moment J Unlike the dicnloro

monodigsnd) copper(II) complexes / Cu( 1-PhASJH)

is soluble in acetonitrile. The molar conductfjice in

acetonitrile end methanol at 0,002M concentration regis-

2 - 1ters 116 and 119 mhos cm mole respectively. Conducti­

vity does ry>t show any appreciable chenge with dilution

in acetonitrile but does change in methanol (Table 4 ) .

Significant solvolysls of coordinated nitrate in methanol

with dilution is indicated. The infrared spectrum is

characteristic of both ionic and coordinated nitrate.

Also the electronic spectrum of the nitrato co«around

- 91 -

5!** WiPftttumimw ria Mmwr

• V * *

- 02 -

shows the 3&mo absorption band both in the solid state anj

in methanol at 0.006H cowoantration (Fig. 2 ), indicating’

that the compound does not undergo any urastic solvolytlc

change In solution at 0.003M level* The above observations

indicate that one of the nitrate ion remains coordinated

whereas the other nitrate is an anion suggesting a formula of

t*v type L Cu( 1-PfcAECJH) NC^_/^C^. The nifcrato conrlex has a

r.ormal magnetic rsonent 1-02 8.M (Table 4 ) , .

Infrared ' The spectrum of ^ CuCl-PhA^.') .i’C^ 7

shows the absence o° nitrile band around 2170 c.n - ?hs

soectrum also shews band? characteristic of both io’ ic

-I*71370 cm J‘ and bident ate (1600, 1260, 1010 c::i >

nitrate2 (T$ble 7) . The 1370 band is very weak in

£*Cu(l-PhAMUH)Cltf>ii7 but appears as a strong intense peak

in / “Cu(l-PUAMaH)2J'(N03)2H20 . The bar.is at 1£03, 1260 arid

1.03.0 are either absent or vorv woa< in / Cu( l-Phft.^7H)Cl.>_/.>

Hence the compound is formulated as /

The complex / l l t t e t b) H03J 7N03 (tet b = 5,7,7,12-14,14-

hexamethyl-1,4,3,11 tetra azacvclotetradeci.ne' may be

cited as a parallel case 1 vhere nitrate abncrations

are found at 1375 csf1 (ionic nitrate) and 149 >< 12BO <> 1

(bidentate nitrate).

fi,lkqryj nation : Estimation of ethoxyl i*rcur in

Cu( 1-PhABOH) ??03J7r:03 shows presence of ethoxvl ?rc i ,*

copper : ethoxy 1 ratio being 1:1 (Table 1) •

Electronic gpecfryft • The solid state electronic spectrum of

Z Cu( 1-PhABUH) K0^J7N0o shove absorption et 14#6 kK and it ipC> vJ

interesting to note that the spectrum virtually remains unchanged

(Pig. 2) having maxima et 14.5 kK; 34 and 14.7 kK, 6 , 36 (in

dimethylsulfoxide) Table 8 . The above observations suggest thpt

the donor environment around copper(II) atom of the complex uoes

not change radically in solution. A square planar Z CuN^Og^/

chromophore with a coordinated bidentate nitrate is suggested.

It may be noted that the band position is almost the same as that

in Z Cu(l-PhAMDK)Cl<w7« This only suggests that the ligand fieldCt

set by coordinated bidentate nitrate is slightly, different from

that given by two chloride groups. Given below is the form of

the established spectrochemicel series of anions^1 .

1“ < Br~ < Cl' < N03~ < P“

However,this result is not in conformity with the claim of Curtis

and Curtis27 that bidentate N03 is above Hg0 in the spectrochemi-

27cal series. It is disturbing to note that they present dste

which show at the same time that /~Ni(en)g(:,503 >_/C104 with

bidentate nitrate absorbs at about the same energy (10.6 kK.) as

Z^"Ni2(en)4Cl0J7ci2 (10 .2 kK) with bridging chloride ion.

Nftw eonrolexes of l-a;aldlnQ^Q-Alicylurfi£.

Reactionrof appropriate copper salts with'unsubstituted

dicyandiamide with appropriate alcohols in lsl retio provided

the following new compounds *

i Cu( 1-AAOH) Clg_7,. L Cu( l-AMlIH)§9.4r7 2 .6H20

( l-AAUH = l-amidino-0-alkylurea5 alkyl = methyl, ethyl or

n-butyl; ,1-AMUH^= 1-amidino-O-methylurea). The blue coloured

93 -

---------------------- J----------------------------------------------------- - J -

F I G - 2 . Electronic Spectra of

A - [Cu ( l - p h A E U H ) NO3J NO3 (Methanol)

B - [Cu ( 1- p h A E U H ) NO1Q.NO3 (Solid state)

C - [Cu ( 1- p h A M U H ) SO4] (Solid s t a te )

- 94 -

dichioro(1-amidino-O-alkylurea) copper(II) (alkyl = methyl

or ethyl) complexes were prepared originally by Dutta and

B&y^’^ by the addition of 3N HC1 to an aqueous solution

of their corresponding rose-red coloured bis(3.-AAUH)

copper(II) chloride salts till the solution turned to Jeep

blue (pH 3*8 - 4 .0 )* Complexes obtained by t:»eir xetnoa

were found to he contaminated with c ipric cnlori-ie wnich hai

to be removed by repeated washing with cold alcohol. Ve

now find that the dic:*loro-roono( 1-AA'JH) copper(II) complexes

could be* easily prepared in pure, crystalline for by the

direct copper(II) ion promoted alcohol addition to dievan-

diamide. The structure and properties of there compoands

are similar to those observed for the dichloro-mono(l-‘ henyl-

amidino-0-alley 1 urea) copper(IT) complexes described earlier

in this section.

The sulphato-mono( 1-AMtJH) copper(II) complex was

prepared by reacting dicyandiamide arid copper sulpnate pen-

tahydrate in methanol. Due to insolubility of copper solphate

in higher alcohols formation of such sulphato-mono(ligand)

copper(II) complexes in higher alcohols could not ie stu­

died. The structure and properties of / Gu(l-A fJJH)304^/2 .6H20

are the same as discussed for the Z Cud-PhAM'JH)SO^JThgO.

Attempts to prepare nitrato-raono(ligand) copper(II)

complexes have been made by reacting cupric rj trtte and

dicyandiamide in methanol or ethanol out the?a trials

/

•always ended in the formation of red-violet bis(iigand/

copperCIT) complex, "’his may be due to the high soiubilitv

of the nitrato-monoCligand) copper(IJ) complexes.

Attempts to isolate the ligand I-phenylauiidino-J-

alkylurea from its copper(II) complexes by following the

method of Outta and Ray34 (for the isolation of l-ami<iin6-

O-alkylurea from its copper(II) completes) were not fruitful .

Though a white crystalline compouna was obtained by following

their method, analysis of the compound recorded a variaoxe «

composition and suggested that it was mainly ammonium

chloride. Attempts were also made to isolate the lisrand

from its copper(II) complexes by sequestration with aisodium

ethylenediaminetetracetate, but no crystalline C0is*'0und

could be isolated. Thus the ligands, 1-phenylamidino-O-alKyl-

ure&s appear to be stable only in the for& of a metal complex.

A distinct difference in the range of stability of the parent

ligands, 1-amidino-O-alkylureas, and their phonyl analogues

i s thU3 in d ic a te d .

Failure to obtain any alcohol,,.addition ;cj 1iLc_t. s>JLJ_L=2-

chloroPhenvl-N» -methyl ilgyjmdlamjie :

Of the substituted dicyandiamldes which have been in­

vestigated 30 far the N ’-p-chlorophenyl-J'-aethyldie -andia-

mide (XIV) alone has failed to produce an ajidino-->-altylurea

- 95 -

96 -

(XXV)

compler. Two points need to be considered in tfcis connection.

One Is any possible steric hindrance that might be offered

by the substituents (p-chlorophenyl and methyl) on the

nitrogen during the attachment of the ligand to copr>*;r(II>.

The second is an inductive effect that -Aznt be car^ie-i

right upto the nitrlle carbon. It is interesting tc note

that N'-phenvl-N'-methyl biguanide has been obtained fror.

the reaction of the K ' -phenyl-N’-methyl dicyandiaf.il de ana

A 7an amine . This probably indicates that steric crowding

about the N*-nitrogen is not vital. A blguaniie or an

amidinourea has to be obtained by way of reaction of an

amine or an alcohol with the nitrile group of the lierandla-

mide. vrhile an alcohol is a very weak neucleophile an amir.0

is a strong one. It appears reasonable to argue that imposi­

tion of an electron-donating methvL group on the tom

over and above the electron-withdraw’ n^ phenyl f roup h-s

reduced the electrophllic char&ccer o:\nitriie carbon to

such an extent that the neucleophile alcohol Tails to

attack that carbon atom.

97 -

Bagg&aaaflft !

1. P. Hay, Chem.Revs., 1961, €1, 313.

2. R.L.Dutta end A.Syamal, Coord. Chem.Rev s. > 1967, 2, 441.

3. E.J.Halbert, Aust. J.Chem., 1975, 23, 314.

4 . P .F .Barnard, J .Chem.Soc.( A ) , 1969, 2143.

5. F.A.Cotton and G .’rllkinson, 'Advance Inorganic Chemistry’ ,

John Vlley and Sons, Ino, New York, 2nd Ed. ,1966, p .902.

6. D.M.L.Goodgame and ?. A.Cotton, J.Chen.Soc., 19fl,'229r.

7. N .S.Gill and R.S.>Jyholm, J.Chem.Soc. , 1959, 3997.

8. G.C.Kulansingara and W.R.iMc.T,rhinnle, J.Chem.Soc.C O >

1967, 1253.

9 . J.R.Dyer, 'Application of Absorption Or>ectroscopv of

Organic Compounds', Prentice Hall, In c ., 1966, p .37.

10. K.Nakaraoto, 'Infrared Spectra of Inorganic and Coorajna­

tion Compound', 2nd Ed., John viley & Sons, N*ew York,

1970, p .80.

11. R.A.Penneman and L.H.Jones, J.Chem.Phys.,1956,24,293.

12. R.L.Dutta and A.Syamal, J.Indian Chem.Soc. , 1967,44,571.

13. A .0 .Cross, 'Practical Infrared Spectroscopy', 2nd Ed.,

Butterworth & Co., 1964, p .67.

14. R.M. Silver stein and G.C.^assler, ' Spec tro me trie Id e n t i­

fication of Organic Compounds, , 2nd 5d., John *rlley & Sons,

Inc., New York, 19679 p .97.

15. Reference 14, p .85, 86.

16. Reference 13, p. 71.

17. C.M.Harris and !2.D.'lckenzie, Nature, 1962, 196, 67).

- 98 -

18. S.Suzuki, M.Nakahara end K. Watanabe,

Bull.Chen. Soc. Japan, 1971, 44 , 1441.

19. Reference 13, p. 66 .

20. L.J.Bellamy, 'The Infrared Suectra of Complex Molecules1,

Methuen & Co.Ltd. , London, 2nd B d ., I960, p .115.

21 . Reference 14, p. 79.

22. Reference 13, p. 63.

23. H .A.Szymanskl, ’Interpreted Infrared Spectra1,

Vol.3 , Plenum Press, 1967, p .91, 89 , 102, 109.

24. D.Hadzl and D.Prevose*, C .A ., 1968, 52, 97661.

26 . Reference 19, p. 23.

26. P .E.Pig gins and D.H.Busch, J.Phys.Chem.,1961, 65, 223f.

27. N. P.Curtis and Curtis, Inorg.Chem., 1966, 4,#804.

28. A.R.Nicholson and G .T. Sutton, Aust.J.Chem., 1969, 59.

29. M.M.Ray and P.Ray, J.Indian Chem.Soc., 1959, 36 , 349.

30. K.Sone and S.Htsuno, Bull.Chem.Soc. Japan,

1966, 39, 1813.

31. R .L .Dutta, B.Sur and N.R.Sengucta, J.Indian Chem.Soc.,

1960, 37, 673.

32. M.Goodame and L .I .B .H a in e s , J.Chem.Soc.( A ), 1366,174.

33. R .L .D u t ta and D.De, J.Indian Chem.Soc., 1969,46,70 .

34. R.L.Dutta and P.Ray, J.Indian Chem. Soc. ,* 1969 ,36 ,499.

36. R.H.Balundgl and A.Chakravarty, Inorg.Chem.,

1973, 12, 981.

36. M.Clampollnl and N.Nardi, Inorg.Chem., 1966, t\ 41.

37. V.N/-Tallis S.C.Cummings, Inarg.Chem., 1974, 13 , 988.

3R. E.J.Hfelbert, Aust.J.Chem., 197£, 28, 313.

39. K.Konlg and H.L.Sohlafer, Z.Phys.Chem., I960, 26, 371,

4 0. Reference 10, p .175.

41. K.Nakomoto and P.J.McCarthy, S .J . , 'Spectroscopy and

Structure of Metal Chelate Compounds', John Wiley & Sons,

In c ., 1968, p .261.• • •

42. C.S.G.Phillips and R.J.P.Williams, 'Inorganic Chemistry',

V ol.II, Oxford University Press, 1966, p .396.

43. R.J.H.Clark, J.Chem.Soc., 1964, 417.

*4 . Reference 13, p. 172.

45. N.F.Curtis, J.Chem.Soc., 1964, 2644.

46 . R.L.Dutta and P.Ray, J.Indian Chen.Soc .,1959, 36, 567.

47. K.Kurzer and S.D.Pitchfork, 'The Chemistry of Blguanidtss1,

Springer V e r l a g , New York, 196R, p .409.

- 99 -

j

£££2I0iL_J.

NlekelCXZ) p routed aciajUJ-on of alcohols to

subatltutad dlayendlamlde.

Nlckal( II) complexes of l-phenylepidiao-O-rlk.Alurea

and l-p-chlorophenylajnldlno-J-Eotfivl■4T.es.

It has been observed that anhydrous nickel(II) cnloridc?

promotes addition of alcohols to phenyl dieyandi amide and

p-chlorophenyldicyandiamide. NickaMII) is found to be l*ss

efficient then copper(II) in forcing alconol aaaition, a

much longer reflux being essential. The bis(iigind) ni n el (11)

complexes’ere all orange yellow in colour, diamagnetic aid

absorb around 22.7 kK. In the nick<i (II> complexes the nit­

rile band of the substituted dieyandi amides is completely

absent, instead new banas appear around 1210 cm*"1 . This

indicates thet the alcohol addition reaction has led to triew*

formation of 1- phenyl a^idi no-0- alkyl urea (I) and l-p-c..loro-

phenyl ami dino-O-me thy lurea ( I I ) , a con fir mat ion of whlcn is

found in the positive Z^Qs?l estimation of the methoxyl grcip..•

roh

C,Hk— NH — C - NH — C = N — C,H,-— NH - C - NH - 0 — OH 6 6 n N I 6 & II II

NH NH

(R = methyl, ethyl)

iCHoOH

P-CIC^H.— NK— C - NH- C = N ■■■§■--> P-C1C.H.— NH-C- iii-C-OC.U€ 4 || Ni € 4 II II J

NH NH Nh

. ui>

- 101 -

(i-gfaea7laail4inprifrflej?ftyjjg^^ >

nickel(II) chloride : Phenyldicyandiaaide (1 .6 g) was

dissolve^ in methanol (45 ml) to which wt s added a.ihyirous

nickel(IT) chloride (0.64 g ). The mixture wis refluxeu on a

steam bath until the light green colour changed to light

yellow (40 hrs.). The light yelLow solution was filtered,

the filtrate was concentrated (26 ini) and put in a refi'lg^ra-

tor overnight, /-n orange yellow coloured compound crystal!:!-

sed out, which was further purified from methanol and dri^d

in air.

*

? l a ( l- P h e n v le u ld ln o _- -J-aetjiyX «ree-;i) n l g k o i m ) : x’he abovo

complex nickel(II) chloride (0.4 g) was dissolved in

minimum volume of methanol (56 ml), treatea In the coid

with sodium hydroxide and concentrated (20 ;nl) • fne snlu-

tion was put in a refrigerator overnight, when ti,e orange

yellow coloured compo ind crystallised out. The compound

was recrystall!sed from methanol end dried 3n air.

^lsd-Phenvlamldlno-J-ethvlureaj nlcltalC XI). cfll.Qriaa Tills

compound was prepared li^.e the (1-phenylsunidlno-J-methrlurea;

( 1-phenyl ami dino-0-methylure8-H) nickel(TI) chloride, by

refluxing phenyldicyandiemlde and anhydrous nic^el(I« >

chloride 1n ethyl alcohol for 60 hrs. Tne compound wrs

recrystallised from ethanol and aired in tir.

(l-p-cM.oropboayXagldloo-OriaetbyXureR).(X-p-g^grPjPA8r>y.U‘aj-*

dlno-0-ffif»th -Xuraa-H) nl^el.d .U . ohlorijs : Ihis eoapouna

wfts obtained as for the 1-phenylamidino-O-methyluree complex,

by using p-chlorophenyldiqy andiajnide instead of phenyldicy-

andiamide and by resorting to a little longer reflux

(45 hrs.), Tho oompouni was recrystallised from methanol%

end dried in air.

- 103 -

Table 1» Characterisation data of nickel(II) complexes of 1-pfcenyl and dino-O-alkylurea and

related ligands.

Compound Colour Nickel (*) Kltrogen( Anion( £) Alkoxyl(^) Water (i)

Z_ Mi( 1-P h A M’JH) (1-P h '■ :PJ) _7cl. HgO Orange-yellow

11.6(11.8)* 22.2(22.6) 7 .0(7 .2) 12.1(12.5) 3 .6 (3 .6 )

L Ni(l-Ph*MU)2J 72H20 n 11.9(12.3) 23.1(23.6) - 12.8(13.0) 7.1(7.7)

l-Ph»EUH) g^-:i;,.H20 ’i 10.2(10.6) 19.6(20.0) 12.6(12.7) - 3.6(3 .2)

NI ( 1-p-OlPh * M'JH) 10.2(10.4) 19.6(19.9) 6.1(6.3.) 10.8(11.0) 3.-X3.2J

(l-p-ClPh<:,.J)_7ci.H20.

* Cclculfted vol'igs are in perentheses.

1-PJh AM JH -- 1- cnenyl a ..i dluo- ->-uethylurea

l-Fftf "J'TH = 1- ononyla.: 1 lino- )-eth/lurea

1-p-cl •-.viJli = l-prraciiioropi'ienyla^i ii..' - . ath' l aroa.

104 -

jfogrt.ta. srA M a n w i a a 1

* Phenyldicy 8ndiaraide reacts with methanol and ethanol in

the presence of anhydrous nickel(II) chloride to give orange

yellow compounds / Ni(l-PhAMUH)(l-PhAKUJ^/Gl.H^O and

/ Ni (1-PhAEUH) 2—/^1 2^2^ r9sP®ctiveJ-7* Use of* hydrated

nickel(II) chloride resulted in the formation of niekel(II)

hydroxide only# Reaction of p-chlorophenyldicyaniiamide,

methanol and nickel(II) chloride produced £ Ni( 1-p-ClPhAiiJn)

(1-p-ClPhAMU.)J/Cl.HgO. Attempts to prepare bis(l-p-ClPhAEJii)

nickel(II) complexes were unsuccessful. The nickel(II) pro no­

ted addition to o-chlorophenyl dieyandi amide could not be effec­

ted. Unlike copper(Il), nickel(II) does not form mono(ligcnd)

nickel (II) complexes, ljike the bis( 1-ami dino-O-al*yl urea)

nickel(II), the bisU-PhAAUH) nickel(II) (1-PhAAUii = 1-phenyl-

amidino-0- alkyl urea) and bis(l-p-ClPhAMUH) nickel(II) complexes

are formed in a single step\ From propanol onwards all the

higher alcohols fail to provide the bis(ligand) nickel(II)

complexes. This is not unexpected in view of the failure to

obtain similer complexes of copper(II) possibly due to the

steric hindrance between one phenyl group of one ligand and

the bulky alkyl group of the second ligand in a square plane

around nickel(II).

It may be noted that none of the above substituted

dicyandiamldes alone reactswith methanol and ethanol. These

dicyandiamldes can be recovered unchanged in sup. and nitrile

band position even after 40-60 hrs.reflux from the alcohols.

Magnetic nomgnt ♦ All the nl^kel(II) complexes of 1-Pft*« ?ii

end l-p**ClPhAMTJH were found to bo diamagnetic (Tabic 2 )•

These diamagnetic values and their strong absorption bends

2at 22.7 kK lend strong support to a square planar geometry ,

Like 1-amidlno-O-alkylureas1 and biguenldes^, 1-PhA/ Jii and

1-p-ClPhAMUH set strong enough a ligand field around nickel(II).

A planar complex of nick el (II ) may be either parc:magnotic

depending on the strength of the ligcnd field .

- 106 -

Table, Conductance

complexes.

and magnetic moment data o? rti-kni;il>

Compound Magneticmoment

310 x conc./V w methanol

( i) -1 mhos cm nsol.j

at 26°C.

Z~N1( 1-PhAMUH) i>iamagne tic 2 81

( 1-PhJUHJj/Cl.HgO 1 88

ZN1( 1-PhAE’JH) gJ^ClgHgO n 2 121

1 161•

Z»1(1-p-ClPhAMUH) n 2 81

( i-p-ciPh*Ma) J7c ih 2o 1 m

Conductivity x The molar conductance value of £ i(l-*':r’ ’’$■ -tc

ClgHgO.in methanol Indicates a bi-univalent electrolyte

(Table 2 ). The other bis(ligand) ni?kel(II) mono-chi.or 1 ie

2 -1salts recorded low conductance data ( ~ 30 mhos c^ mole )

(Table 2) for a bi-univslent electrolyte. These lev values

indicate thft one of the two ligands is coordinrtea to

nickel(II) In its deprotoneted fora, Analytical results

given in Table 1 for the mono-chloride sclt wo uld fit. either•

C Ni(1-PhAMUH)„_7(0H)CL or / “ ii( 1-Phi:'JH)( l-Ph*M'J)_7ci. .Cw -A

Previous works by Dutta ana Ray on nickel(II) complexes

of l-amidino-O-alkylureas have shown that the bases are ell

obtained in the anhyaro form - these having no wat :r of cons­

titution or crystallisation whatsoever. Moreover in the -pre­

sent cfises conductivity is very low Tor hydroxide ehlorid-r*

formulation. In fact An methanol they behave as uni-univalent

electrolyses. Thermal analysis also shows ready loss of water

indicating these as lattice water. Ta^i;:g: all these into con­

sideration we prefer the formulation L Ni( 1-PhAM’JH)( l- nA,'.

Cl.HgO.

Infrared spectra : The infrared spectra of the bis(ligcnd)

nick el (II) complexes show the absence of the nitriie band -i7,8

around 2174 cm . Instead, the complexes have new banas* .19,10

characteristic of C-O-C stretch around 1210 cm iXaole 3 ;.

The nickel(II) promoted alcohol adi? tion tnus 'appcrrv-to -ive

l-phenylamidino-O-alkylurea (I) and I-p-chlorophenylamidino-

0-methylurea ( I I ) . The infrared spectra ao not exhibit a tv /

sharp bend in the 1700 cm area, thus negating a

guanylurea structure ( I I I )«

Ta^le 3 . Infrered spectral data of nickel (I-:) complexes^

Compound Infrared bands

in caT^

Assignment of

^(C-O-j; in

coT'*'

•

Z-Ni(i-PhAMUH) 322Cmbr, 1696 s, 1493s, 1210 s

( l-PhlMUJ_/Cl.HgO 1336sb, 1210s, 1121m,

10S7s, 1016w, 962m.

(1-P hi SUHJ 7 0 1 2H20 317 fvf, 1661s, 149 0m, 1212 s

12£3vw, 1212s, 1110m,

962m.•

Ni( l-p-ClPbAMTJH) 322€m, 1667sh, 1490m, 1216 s

( 1- p-Cl Ph AMUjl/ ClHgO 1333vw, 1216s, 1124m,

1075m, lOlOw, 962w.

br = broad, ra = medium, 3 = strong, sh = shoulder

vs = very strong, vw = v?ry weak.

Alkoxvl estimation * The rnetnoxyl and ethoxyl estimations

of the bls(ligand) nickel(II) complexes snow the prosen ;e of

methoxyl and ethoxyl group. the analytical values agree with

metal * alkoxyl ratio as 1:2 (Table 1 ) . *he other possible

structures (III) and (IV) are thus rejected. ?he infrr-rea

dfta end elkoxyl estimation strongly support structure (v>

108

C-H-— NH— C - NH - C - NHR6 5 H II

NH 0

CrHk— NH —C—NH— C - OR6 6 II II

NH NH-H

( I I I ) (IV)

S L e a t r o n l e g p a o t r a t T h e s p e o t r a o f / ~ N 1 ( X-PhAHtJH) ( X -P W W U i7

C l . K g O , £~\N i ( 1 -P h A E U H ) 2 _ / C l 2 . H 20 and / f N l d - p - C l P h A M U H )

( l - p - C l P h A M U ) _ 7 c i .HgO i n a a t h a n o l show a b s o r p t i o n b a n d a t

2 2 . 7 kK ( T a b l e 4 ) . T h e d i a m a g n e t ic n a t u r e and b a n d p o s i t i o n s

o f t h e s e c o m p le x e s a r e r e g a r d e d as d i a g n o s t i c o f a s q u a re1 p#1 A

p l a n a r a r ra n g e m e n t • A l l t h e s p e c t r a show a definite s n o u l -

d e r a ro u n d Ij9*2 k K . E l e c t r o n i c s p e c t r a o f t h e c o m p le x e s * in

d o n o r s o l v e n t s l i k e d i m e t h y l s u l f o x i d e f p y r i d i n e show a s h i f t

i n t h e b a n d p o s i t i o n s compered to that in methanol (Table 4 ,

P ig * 1 ) , u n l i k e t h a t o b s e r v e d i n s q u a r e planar e t h y l enedibigua-

1 cn i d e n i c k e l ( I I ) • S in c e t h e r e a r e n o chan ge i n th e band

m axim a o f n l c k e l ( I I ) e t h y l e n e d i b i g u a n i d e i t was c o n s i d e r e d

t h a t th e d£ 2 o r b i t a l w h ic h h a s t o r e c e i v e t h e d o n o r s o l v e n t s

i n t h e t r a n s o p t i c a l s i t e s was n o t t h e o r b i t a l im m e d i a t e l y

l o w e r i n e n e r g y t h a n t h e d ^2 _ 2 o r b i t a l . Th e p r o p o s e d

o r d e r i n g w e s ^ ^ L y 2 *z 2 > * y z ' I n p r e s e n t

s e r i e s o f c o m p le x e s t h e s h i f t i n g o f t h e b a n d i n d i c a t e s a

t e t r a g o n a l ! t y o f t h e c o m p le x and a l s o a d i f f e r e n t d - o r b i t > a l

o r d e r i n g . A d - o r b i t a l o r d e r i n g dx 2 . y 2 > > dx y > ay z >&x z

w i t h 2 2 . 7 kK band r e p r e s e n t i n g dz 2 ___ ^ dx 2 - y 2 t r a n s i t i o n

I s s u g g e s t e d .

T i b i a 4 . S o l u t i o n s p e c t r a l d a t a o f n i c k e l ( I I ) c o m p le x e s .

Compound S t a t e C o l o u r A b s o r p t i o n b a n d i n kK £ max

C N i ( l-PhAMUK) M e th a n o l O r a n g e - 2 2 . 7 8 6 . 0

(l-PhAMU)_7ci.H20 y e l l o w1 9 .2 s h 5 0 .4

E t h a n o l n 2 2 . 7 7 4 .0

1 9 . 2 s h • 4 0 . 0

E t h y l e n e - w 2 2 . 7 7 2 .4g l y c o l

19 • 2sh 3 8 . 0

DM? n 2 3 . 2 ‘ 8 8 . 2

1 9 .2 a h 4 4 . 0

DMSO « 2 3 . 2 88.0

1 9 .2 s h 3 0 .8

*P y r i d i n e t* 2 3 . 2 8 5 . 0

1 9 . 2sh 3 0 . 8

C Nl( 1-PhAEtJH) g_7 .M e th a n o l n 2 2 .7 8 2 . 0

C 12H2° 1 9 . 2 sh 4 6 . 2

DMF ft 2 3 . 2 88.0

1 9 .2 s h • 4 2 . 0

DMSO w 2 3 . 2 8 4 . 0

19 • 2 s h 3 2 .0

Z“Ni(l-p-ClPhAMtJH) M e th a n o l ti 2 2 . 7•

7 3 . 6

( l-p-ClPhAMO) J7cih .P 1 9 . 2 i h 3 7 . 0

DMF u 2 3 . 2 88.0

1 9 .2 s h 3 6 .0

• DMSO ft 2 3 . 2 8 8 . 6

1 9 .2 s h 3 6 . 0

DMF « N N -dimethylformamide$ DMSO = dimethylsulfoxide;

sh * shoulder.

25 20 16-7 kK

WAVELENGTH (n m )

110

1 . R . L . D u t t a and A.Syamal, C o o r d . C h e m . R o v . , 1 9 6 7 , 2 , 4 4 1 .

2 . R . L . D u t t a and S . L a h i r y , J . I n d i a n Chem. S o c . , .1 9 6 1 ,3 8 ,6 8 9 i

3 . P . R a y , C h e m .R e v a . , 1 9 6 1 , 6 1 , 3 2 7 .

4 . C . J . B a l l a u a e n and A . D . L i a h r , J . A m . C h e m . S o c . , 1 9 6 9 , 8 1 , 5 3 8 .

6 . W .J .G e a r y ,* C o o r d . C h e m . R e v . , 1 9 7 1 , 7 , 8 7 .

€ . R . L . D u t t a and P . R a y , J . I n d i a n C h e m .S o c . , 1 9 6 9 , 3 6 , 6 7 6 .

7 . J . R . D y e r , ' A p p l i c a t i o n o f A b s o r p t i o n S p e c t r o s c o p y o f

O r g a n i c C o m p o u n d ', P r e n t i c e H a l l , I n c . , 1 9 6 6 , p . 3 7 .

8 . R .A .P e n n e m a n and L . H . J o n e s , J . C h e m . P h y s . , 1 9 6 6 , 2 4 , 2 9 3 .

9 . R . L . D u t t a end A .S y a m a l , J . I n d i a n C h e m .S o c . , 1 9 6 7 ,4 4 ,6 7 1 .

1 0 . R .M . S i l v e r s t e i n and G . C . B a s a l e r , ' S p e c t r o m e t r i c I d e n t i f i ­

c a t i o n o f O r g a n i c C o m p o u n d s ', J o h n W i l e y & C o n s . I n c . ,

2 n d E d . , New Y o rfc , 1 9 6 7 , p . 9 7 .

1 1 . A . D . C r o s s , ' P r a c t i c a l I n f r a r a d S p e c t r o s c o p y ' ,

B u t t e r w o r t h a P u b l i c a t i o n L t d . , 1 9 6 0 , p . 6 4 .

1 2 . R . S . N y h o l m , C h e m .R e v s . , 1 9 6 3 , 6 3 , 2 6 3 .

1 3 . J . R . M i l l e r , A d v a n . I n o r g . R e d i o c h e m . , 1 9 6 2 , 4 , 1 6 7 .

1 4 . R . G . H a y t e r and P . S . H u m i e c , I n o r g . C h e m . , 1 9 6 6 , 4 , 1 7 0 1 .

1 6 . D . J . M a c D o n a l d , I n o r g . C h e m . , 1 9 6 7 , 6 , 2 2 6 9 .

MEBPB.. n *

P a l l f t d l u m ( I I ) p ro m o te d a d d i t i o n o f s l o o h o l g to

P h 9 n y l d l e ^ » n d l j > m < d « a n d p - n h l n T - n n h a n v l d l n v a n r t l a m i d a .

lallA < tim ill)..aaaB ltz.a». a£, 1-paan/1a»l41flg.-2.-.. d^yJ-ur.ae

and l.-p-chlorophMiYlaaildlno-O-ftlkYluraa.

T h e p r e s e n t s t u d y shows t h a t p a l l a d i u m ( I I ) l i k e c o p p e r ( I I )

a n d n i o k e l ( I I ) p ro m o te s a d d i t i o n o f a l o o n o l s to s u b s t i t u t e d

d i c y a n d i a m i d e s * J D u tta , S e n g u p t a and S u r 1 h a d p r e p a r e d b i s ( l -

a m i d i n o - O - a l k y l u r e a ) p a l l a d i u m ( I I ) c o m p le x e s b y t h e r e a c t i o n

o f s o d iu m c h l o r o p a l l a d i t e w i t h e x c e s s o f 1 - amid i n o - O - a l k y l u r e a♦

l i g a n d s i n p r e s e n c e o f a l k a l i . So f a r no d i c h l o r o - m o n o ( 1 -

a r a i d i n o - O - a l k y l u r e a ) p a l l a d i u m ( I I ) c o m p le x e s h a v e b e e n r e p o r t e d

n o r i t i s known w h e t h e r p a l l a d i u m ( I I ) c a n p r o m o te a d d i t i o n o f

a l c o h o l s t o d i c y a n d i a m i d e end s u b s t i t u t e d d ic y e n d ia m id e s *

2Simultaneously w i t h this p r e s e n t w o r k D u t t a and Ray had taken

u p t h e w o r k o f i n i t i a t i n g a l c o h o l a d d i t i o n to u n s u b s t i t u t e d

d i c y a n d i a m i d e b y p a l l a d i u m ( I I ) , w h i c h l e d t o t h e s y n t h e s i s o f

h i t h e r t o unknown d i e h l o r o - m o n o ( l - a m i d i n o - O - a l k y l u r e a ) palla-

d i u m ( I I ) c o m p le x e s . We d e s c r i b e i n t h i s s e c t i o n t h e w o rk done

w i t h p h e n y l d i c y a n d i amide and p - c h l o r o p h e n y l d i c y a n d i a m i d e .

L l t h i u m c h l o r o p a l l a d i t e r e a c t s w i t h p h e n y l d i c y a n d i am ide

i n a l o o h o l u n d e r r e f l u x f o r 6 - 8 h r s t o g i v e a c ream c o l o u r e d

c r y s t a l l i n e compound w h i c h h a s b e e n i d e n t i f i e d as d i c h l o r o -

m o n o ( 1 - p h e n y l a m i d i n o - O - a l k y l u r e a ) p a l l a d i u m ( I I ) . B y f o l l o w ­

i n g t h e same c o u r s e o f r e a c t i o n w i t h l i t h i u m c h l o r o p a l l a d i t e

and p - c h l o r o p h e n y l d i c y e n d i a m i d e d i c h l o r o - n i o n o ( 1 - p - c h l o r o -

p h e n y l a m i d i n o - 0 - « l k y l u r e a ) p a l l a d i u m ( I I ) h a s b e e n o b t a i n e d .

- 112 -

c€h6— NH-C-NH-C=N *► P d C l ^

NH

( c6h6— NH- C - NH - C -OR) PdCl2

NH NH

(R = methyl, ethyl, n-propyl)

Palladium(II), unlike copper(II) or nickel(II), has not

as yet been found to form bis(1-phenylamidino-O-alkylurea) or

bis(l-p-chlorophenylamidino-O-alkylurea) palladium(II) complexes

(inspite of its greater ionic size compared to copper(II) or

nickel(II) ) . Attempts to prepare bis(ligand) palladium(II)

complexes via reaction of lithium chloropalladite and the subs­

tituted dieyandiamides in 1:2 ratio in refluxing slcohol were

not successful. Reaction of phenyldieyandiamide or p-chloro-

phenyldieyandiamide with alcohol in presence of palladium(II)

always provides mono(ligand) palladium(II) complexes irrespec­

tive of the ratio of palladium chloride to substituted dicy&i-n Q J

diamide. It may be noted here that 1-amidino-O-alkylureas * ’ ,

6 6 7guanylurea * and biguanides formed well defined bis(ligand)

complexes with palladlum(II) via reaction of the respective

ligands with sodiumchloropalladite in presence of strong

alkali# Unfortunately the ligands 1-phenylamidino-O-alkylurea

and 1-p-chlorophenylamidlno-O-alkyl urea could not be obtained

so far in a solid crystalline form. The direct metal Ion pro­

moted synthesis remains as the only possible route to the

formation of complexes. It is a common knowledge that complexes

with higher ligand i metal rttio are likely to be formed at

113

a higher pH. In the absence of the free ligands, therefore^

the possibility of formation of bis(ligand) palladium( II)

chloride with 1-phenylamidino-O-alkylureas could not be

tested.

Sxparlflgrrtfll 1

Palladium chloride from Johnson, Mathey and Co., Analar

Lithium chloride end Analar methanol were used. Phenyldicyan-

diamide and p-chiorophenyldicyandiamide were prepared throughg *

published method .

•

Palladium chloride (0.44 g) and lithium chloride (0 .5 g) were

dissolved in A.R. methanol (20 ml) under reflux on steam

bath (26 mins.) and filtered. The filtrate was added to a

solution of phenyl dicy andi amide (0.49 g) in A.R. methanol

(20 ml) and refluxed on a steam bath (6 hrs) when a cream

coloured dichloro-mono(l-phenylamidino-O-methylurea) palla-

dium(II) separated out. The crystals were washed repeatedly

with hot methanol and dried in air.

Piehloro-mono(l-Ptaenylamldlno-O-.ttiYlurea) P&lladlum CII) :

This compound was prepared like the analogous methyl compo-

und by using ethanol in place of methanol end re fluxing for

a longer period (8 hrs). The compound was washed with hot

ethanol and dried in air.

114

fllehloro-jponoC 1-Phenvl midlnor0=n=figcaByljgj a ) .J A U .aAlmntII > •

This eompound was obtained as described for the previous com­

pounds by using n-propyl alcohol as solvent in place of methanol

or ethanol and refluxing for 10 hrs. The crystals were washed

with n-propyl alcohol and dried in air.

D l c h l o r o m o n o C l - p - c h l o r o p h e n v l a a d A l n o - O - a e t h y l u r e e J . J a l l a d l u a C I I ) >

Palladium chloride (0.44 g) and lithium chloride (0 .6 g) were

dissolved in A.R. methanol (20 ml) and the mixture was refluxed

for 26 mins.and filtered. The filtrate was then added to a•

solution of p-chlorophenyldicyandiamide (0.48 g) in A.R. metha­

nol (20 ml) and refluxed for 8 hr s. Then the solution wes

allowed to stand overnight at room temperature when a cream

coloured complex dichloro-mono(1-p-chlorophenylamidino-O-

methylurea) palladium(II) separated out. The crystals were

washed with hot methanol and dried in air.

DI chi oro-mono ( 1-p-chlo roPhenvlamldliiP-O-ethyl u r e a ) 41 W.C.%1) *

Thi* compound was prepared as for the above methyl compound by%

using ethanol in place of methanol. The compound was washed

with hot ethanol and dried in air.

Estimation of chlorine i The chlorine content of the palla-

dium(II) complexes wea determined after decomposing the samples

by alkali fusion. This estimation, therefore gave the ring

chlorine as also the coordinated chlorine.

115

Characterisation data of palladium(II) complexes.

Compound Colour Palladlun(.i) Nltrogen(/b) Chlorlde(^) H.koxyl(jl) WBter(ji)

C Pd(l-PhAHUH)Cl2y H 20 Cream 27.3(27.5)* 14.6(14.5) 18.4(13.3) 7 .9 (8 .0 ) 4 .4 (4 /7 )

L Pd<l-PhAEDH)Cl2_7 27.5(27.7) ' 14.4(14.6) 18 .3( 18.5) 11 .5( 11.7) -

L Pd( l-PhJpH'JH) GlgJ^HgO *» 25.7(25.6) 13.3(13.6) 17.3(17.1) - 4 .4 (4 .3 )

L Pd(l-p-ClPhJlMaH)Cl2_7K20 n 26.6(26.5) 13.2(13.4) 26 .7(26 .6)** 7 .3(7 .4) 4 . 6(4.3)

Z"pd( 1-p-ClPhAKfJH) C lg_7 tt 26.4(26.7) 13.3(13.6) 26.4(26.7)** - -

♦ Calculated values are in parentheses. ** Includes also the chlorine in the aromatic ring.

1-PhAMCJH = 1-phenyl ami dino-O-methyl urea

1-PhAEtfH = 1-phenyl amidlno-O-ethylurea

1-p-ClPhAHUH = 1-p-chloro phenyl amidino-O-methylurea

1-p-ClPhASUH * 1-p-chlorophenylamidino-O-ethylurea.

• 4 •

116 -

RflmlJ&g. jt e O J jf f l i it a a J

The mono(ligand) palladium(II) complexes are cream

coloured, very'stable and highly Insoluble. Owing to their «

high insolubility in water and various organic solvents solu­

tion spectra, conductivity etc.could not be determined. The

complexes are all diamagnetic, which ia indicative of a

7 9square planar structure 1 .

The infrared spectra of £ Pd(1-PhAMUH)Cl^^ and

£\Pd( 1-p-ClPhAMUH)Clg./ show the absence of the nitrile (CsN)

band around 2174 cm"1 and reveals new band around 1186 cm"^

(Table 3) which is characteristic of C-O-C stretch1^.*11.

The farinfrared spectra of Z Pd( 1-PhAMUH) Cl _/ and £ Pd(l-p-

ClPhAMUH)Cl««7 show bands at about 340 and 360 cm"1(Table 3 ) ,

12 13which can be assigned to Pd-Cl stretch . The correspond­

ing Pd-Cl stretch in the compound / “Pd(2-2,-dipyridyl)Cl2J7

appears at 364 and 343 cm . The Pd-N stretch appears at

486 and 490 cm"1 respectively14 (Table 3 ).

The estimation of metnoxyl and ethoxyl group of the

aono(ligand) palladium(II) complexes shows the presence of

alkoxyl groups. The analysis values agree well with a metal ;

alkoxyl ratio as 1*1 (Table 1)#

* u ? -

Tfrbla 2 . In fr a r e d•Paotpal <uu

Compound

P * * ^ M l u * ( i i ) c o m p l e x . * .

^ n f r i p #4 b a n d s t i n ont” ^

L P d d - P h A M O H J C l ^ H 0

cPd( l- Ph^EU H )Clg_y

Z~Pd( l- p- ClPhiM 0H)Cl2_7H 2O

p<|( 1-p-ClPh^HSJH) Cl g^7

3460a, 3420*, 3270* t 3170wbr, 3100wbr,

290Ovw, 2276w, 2220wbr, 1700rbr,

1620m, 1680wbr, 1620m, 1476s, 1460vs,

1410s , 1360mbr, 1270s, 1236m, 1220s ,

1186vs, 1126s, 109Ov, 1010s , 99O s,

9 3 6 s , 816vs, 770wbr, 636m, 630wbr,

4 8 6 s , 440m , 360 s, 340m, 326m.

3226s, 1681vs, 1603s, 1660m, 1493w,

1449m, 1389m, 1370w, 1326m, 1260m,

1190vs, 1124 s , 1016mbr, 901vw,

810wbr, 714m, 694mbr.

3460s , 3426s , 3320wbr, 3180w, 3130m,

2280w , 223Ovw, 1736s, 1700m, 1620w ,

1680w , 1610m, 1480m, 1466s, 1430s ,

1406m , 1346mbr, 1290m, 1266s ,

1236w , 1200m, 1180vs, 1130s, 1096sn ,

1030vs, 986s , 886m, 846vs, 830s ,

770m, 730s, 640m, 670wbr, 630wbr,

490s , 366s , 360m.

3226s , 1709VS, 1687w , 1663w , 1471m,

1389W, 1326w , 1260vw, 1190vs,

1099m, 1016s , 840m br, 714w , 686vbr.

weak, br * broad

s s strong 9 111 ~__ gh s sboulder.

118

Table 3 . Assignment of some of the main infrared bands of

palladium(II) complexes*

■>)Compound

(C-O-C)

in cm*1

^(Pd-Cl)

in cm"1

^(Pd-N)

in cm"1

L Pd(1-PhAMUH)Clg^/HgO 1185Vs 340s 485 sA

L Pd(l-PhABUH)Cl2J7 1190vs - -

L Pd( l-p-ClPhAMUH)Cl2J 7H20 1180vs 350m 490s♦

I Pd(1-p-ClPhAEUH)Clg_7 1190v s - -

A parallel ana simultaneous study of the reactions of

lithium chloropallsdite and dicyandiamide has resulted in the

syntheses of dichioro-mono(1-amidino-O-alkylurea) psiladium(II) g

complexes • These compounds rapidly equate In water giving a

bi-univalent electrolyte conductance. A complex Z Pd( 1-AAUri)Cl - 7/

(1-AAUH = 1-amidino-O-alkylurea) can also be formulated as a

I dimer L 1-AAUH) J L ?d ClAJ . An authentic L P d( 1-AMUH)

L~ **C1aJ ( 1-AMUH « 1-amidino-O-methylurea) was obtained* by

the reaction of Z*“Pd( l-AMUHJ^Clg on L i ^ P d C ^ J 7. Contrary

to the light orange colour of Z Pd(1-AAUH)Cl^^ complexes

! /^Pdd-ArtUHJg^/Z*"^^^-? a dark orange brown colour.

‘ Besides, Z~Pd( l- AM U^gJ/Z^dC^J7 was highly insoluble in

water while Z~pd( 1-AAUH)Clcomplexes were soluble in water

- 119 -

to soma extent. Drawing a parallelism from these studies by

Dutta and Ray2, we adduce a dichloro-mono( 1-phenylamidino-O-

alkylurea) palladium(II) formulation (II I ) to our complexes.

NH-C — HH-C-ORII IINH NH

/ \Cl Cl

( X * H o r P-Cl)

( I I I )

Rgffirgflflafi :

1. R.L.Dutta, N.R.Sengupta end B.Sur, J.Indian Chem.Soc.,

1960, 37, 666.

2. R.K.Ray, ’Chromatographic Studies on Metsi Complexes',

©•Phil thesis, The Jniversity of Burdwan, 1976.

3 . R.L.Dutta and S.Lahiry, J.Indian Chem. Soc., 1960,37,789.

4 . R.L.Dutta and S.Lahiry, J.Indian Chem.Soc., 1961,35,689.

6# P.Riy and G.Bandopadhyay, J.Indian Chem.Soc.,1962,29,866.

6. H.Grossmann and B.Schuck, Ber., 1910, 48 , 674.

7 . P.Ray, Chem.Revs., 1961, 61, 313.

8 . P.H.Curd end F.L.Roso, J.Chem.Soc., 1946, 729.

9 . R.L.Dutta and A.Syamal, Coord.Chem.Rev., 1967,2,441.

10. R.L.Dutta and A.Syamal, J.Indian Chem.Soc.,1967,44,671.

11. R.M.Silvfer»tin and G.C.Bassler, 1 Spectrometric Identiflo­

cation of Organic Compound#1, John Wiley & Sons., Inc.

1964, p .66.

12. L.Caglioti, L.Cattalini, M.Ghedini, F.Gasparrini and

P.A.Vigato, J.Chem.Soc. Dalton, 1972, 614.

13. R.A.Walton, Spectrochim.Acta, 1966, 21, 1796.

14. J.Lewis and R.J.Wilkins, 'Modern Coordination Chemistry',

John Wiley & Sons, Inc ., 1967, p .36.

ftECTIQH V II *

Cobelt(II) promoted addi tion of. aethfifiQl %<? P^en.7

Cnbait(IIl) complexes of

and 1-p-fthlor o Phenvl amid Ino - 0 -gi et hv 1UTfl£ *

Originally the tris(1-amidino-C-methylarea) cobalt(III)

complexes were reported by Dutta, Sengupta and Sur1. The■

2ligend 1-amidino-O-methylurea first synthesized via

reaction of eopper(II) with dicyandiamide being followed by

reaction with HgS. The ligand wes allowed to react witn

cobalt(II) salt in alkaline medium end the resulting cobalt(II)

complex was oxidised to cobalt(III) with hydrogen peroxiae.

1-phenylamidino-O-methylurea and 1-p-chlorophenylamidino-O-

methylurea could not be obtained so far in a solid crystalline

form and hence complexes of the above two ligands could be

studied through direct metal ion promoted syntheses.

We report for the first time that cobalt(II) ion can

promote addition of methanol to dicyandiamide, phenyl*ii cyen-

diamide and p-chlorophonyldicyanaiamide. Reactions of cobalt(II)

acetate with dicvandiamide and phenyliicyanaiamide In presence

of refluxing methanol give rose-red trls( 1-amidino-O-methyl-

urea) cobelt(III) end tris(l-phenylamiaino-O-methvluree)

cobalt(III) complexes. Interestingly it has been founa that

by following a similar course of reaction with p-crilorophen-

yldieyandiamide a rose coloured mixea chelate comDlex, p-

c hi oro phenyl dieyandi amide bis( 1-p-chlorophenylan.i dino-O-

methylurea) cobalt(III) is obtained* It is also for tiie

first time that such a mixed ligand complex containing a

dicyandiamide and two amidino-O-alkylureas is reported in

the family of 1-amidino-O-alkylurea complexes. It has not

been possible as yet to obtain any cobelt(II) complex of

these ligands*

Phenyl dicyandiamide (1*6 g? 0,01 mole) was dissolved in

A.R.methanol (60 ml) by little warming. To the solution was

added cobalt(II) acetate tetrahydrate (0.83 g; 0.003 mole)

and the mixture refluxed on a steam bath for 26 hrs. The

unreacted cobalt(II) compound was filtered off and the dark*

chocolate coloured filtrate was concentrated to about 26 ml

and kept in a stoppered flask at room temperature for 48 hrs.

when rose-red tris( 1-phenyl ami dino-0-methyl urea) cobeltCIID

base crystailised out* The compound was purified from not

methanol and dried in air.

Too mucn water in methanol seems to spoil the alcohol

addition reaction.

T rls (lr P ^- y l^ id iD g - ^rr .th y lttr^a ) _ ^ o ^ i v ( H P .stUffXlls :

Tris(1-phenylamidino-O-methylurea) cobalt(III) base was

suspended in A. ft. met hand and neutralised by aropwise auai-

tlon of dilute HG1 at room temperature. The resulting

solution was concentrated almost to dryness and finally

the rose-red complex was precipitated by the addition of

acetone* The crystal? were filtered, washed witn acetone

and dried in air.

- 122 -

- 123 -

Irla.U^P&anyi. .ggfcriitri .1? JJL ai-.trate ■

This compound vss obtained as above by neutralising the base

with dilute nitrio acid In methanol end precipitating with

chloroform* The crystals were washed with chloroform 8nd

dried in air.

Trlsd-Phenvlanddlno-^-methylurea) cobalt(I.IX) suluoeto i

This compound was prepared by following the above metxiod

using dilute sulphuric acid in place of nitric acid.

P^hlorophenyldicy^dJai)ld^_bU(l-r-chlorQ^tLenYl&;rlalrio-0-

methylurea) c o b a ltd U J * P-chlorophenyldicyaniia-niie

(2 g; 0 .01 mole) was dissolved in A.R♦methanol (80 ml) with

little warming to which was added cobalt(II) acetate tstra-

hydrate (0.3 g; 0.003 mole). The mixture was refluxed on a

steam beth for 40 hrs end filtered. The dark chocolate colo­

ured filtrste was concentrated to about 20 ml and cept in a

stoppered flask at room temperature (48 hrs) when the rose-

red complex crystallised out. The compound was purified

from hot methanol and dried in air.

PrchlorQPhenyldicyandia;aide..biA(J^P"crJor.^ii^J^-ljiii2-

0-pie thvl urea) cobalt(XII) chloride : This compound w*.s

prepared by neutralising the above base in methanol with

dilute HC1 end concentrating almost to dryness ana finally¥

precipitating with acetone.

P-ohlorophenyldloyenfllamide, blj(l-p-ehJ.orgJBhflnylBElsllaa-

O-mai-.hvliiraa) eobalt(III) nitrate s This was prepared as

for the above by neutralising the base with dilute nitric

acid in methanol and precipitating with acetone.

P-chlorophenyldicyandiamide bisd-p-chlorophonylamldlno-

O-nsethvlurea) eobfllt(III) a.ulPhc_t-3 : This was prepared

by neutralising the base with dilate sulphuric acid in

methanol at room temperature. The crystals were washed re­

peatedly with methanol and finally dried in air.

t

Trls( 1-a.T.ldlno-O-inethylurflpj a.obcltCIH.i sulBhftfcii =

Dicyandiamide (0.84 g* 0«01 uiole> was dissolved in Aa.il.

methanol (40 ml) and to this solution was added cobalt(II) *

acetate tetrahydrate (0.83 g; 0*003 mole). The mixture

was refluxed on a steam bath for 26 hrs and then filtered.

The filtrate was neutralised with dilute sulphuric acia.

The rose crystals formed were filtered, washed with

methanol and dried in air.

- 124 -

- 126 -

Table 1 . Characterisation data of cobelt(III) complexes of 1-phenylamidino-O-methylurea

and 1-p-chlorophenylami dino-O-methylur ea•

Compound Cobalt(g) Nitrogen(J() Anion (j(J) MetboxyK#) Water(^)

/~Co(l-PhAMUH)3_7 9 .6 (9 .3 )* 26.6(2616) - 14.7(14.7)

£ Co( 1-PhAMUH) 3_7C13 • 2Hj,0 7 .6(7 .6) 21.8(21.6) 13.4(13.7) 11.8(12.0) 4 .4 (4 .4 )

Z“ Co ( 1-PhAMUH) g_7( NOg) 3 .1. 6HgO 7.1(7.0) 24.6(24.8) - - 2.9(3 .2)

C Co(1-PhAMUH)3_7(S04 )1>64H20 7.0(6 .9) 19.8(19.7) 17.1(16.9) - 8 .6 (8 .5 )

Z~Co(l-p-ClPhAMU)2 8 .4(8 .2) 23.6(23.3) - 8 .7 (8 .6 ) 2 .1(2 .5)

(p-ClPhdcda-H)_7HgO

C Co(1-p-ClPhAMUH)2 7.2(7.1) 20.6(20.3) 12 .6( 12.8) 7 .6(7 .6) 2 .0(2 .2)

( p-ClPhdcda)_7d3H20

L Co( 1-p-ClPhAMUH) 2 6.6(6.3) 22 .7(22.6) - - 3.4(3 .9)

( p-ClPhdcda)_7(N03)32Hg0

Z_ Co(l-p-ClPhAMUH)2 6.6(6.4) 18.6(18.2) 15.8(16.6) - 7 .6(7 .8 )

(p-ClPhdcdai7( s04 > x. 54fI20♦ •

Z"Co( 1- A.TJH) 3_?( S04 ) £4HgO*

9.6(9 .6) 27.1(27.0) 23.3(23.1) 16.0(14.9) 11.3(11.5)

* Calculated vrlues are in parentheses.

1-PhAMUH = 1-pir.enyla^idino-O-methylurea; l-p-ClPhA*lrJH = l-porecnlorophenylainiaino-O-aetaylarQa;

1-AM-JH = l-amiiino-O-methylurea; p-ClPhacda = ParachloropnenyLviicysndia.iiae.

- 126 -

Basalt3 and Iflsausal-Qn.

Reaction of phenyl dicyandiamide with cobal.t(II) acetate

in methanol resulted in the formation of rose-red tris(l-

phenylamidino-O-methyl urea) oobalt(III) complex. The complex

conforms to an anhydrobasa(I); indicating that the ligand

can behave as a monobasic acid. The ligand occurs in a depro-

tonated form in this complex# Neutralisation of the base with

dilute nitric acid, hydrochloric acid or sulphuric acid in

methanol give the respective salts ( I I ) .

(C6H5— NH - C - NH - C -0CH3)3Co

N NH

( C6H5— NH— C — NH—C — OCiLj) 3Co

NH NH

*3

(I) (II)

Conductivity and Magnetic snoiaent * The molar conauctance

value of the complex /~Co( 1 - P h A M U H ) r e g i s t e r *

389 mhos cm mole*^ in methanol at 25°C, which is in the

1 3range of trl-univalent electrolytes * . The cobalt(III)

base and ;Lts salts are diamagnetic indicating a low spin

octahedral geometry.

Infrared spectra * Phenyldicyandiamide has a strong

nitrile (C=N) band et 2174 cm (Fig. 1). The infrared

studies of the compounds Z ~ C o (1 - P h A M U H )a n d

TRA

NSM

ITTA

NC

E (•

/. )

3000 ~1--

2000

A. Ph enyldicyan di an 'e

B. [CO (.l-phAM U H )^] C i3 H20

3000 2 0 O"I--------- 1“

C. P — Chloropheny'dicy^D«Jiar‘

D. Qco (1-p-ClphAMUH;^(p-Clphdcda ) j C !3 w20

WAVELENGTH (MICRONS)

FIG . 1.

CoI!X:OCH3 = 1:3

In fra re d spectra of phenyldicyandiaroide or j. <ny -v and their cobalt (H i) complex* s

- 127 -

Co( l-PhAM'Jin^.yci^.HgO do not exhibit any bsnd around

-1 *» I - ^2174 cm and thore is also no C=0 stretch around 1740 cm

indicating that the complexes are not cobalt(III) guanyl-

ureas. Instead, the complexes have new C-O-C stretches at

1200 and 1205 cm respectively. This indicates that the

alcohol addition reaction has led to the formation of 1-

phenylamidino-O-methylurea. Ziesel estimation confirms the

presence of methoxyl group, the cobclt : methoxyl ratio

being 1*3 (Table 1).

Electronic spectra * The electronic spectrum of

/~Co( l-PhAMUHJ^J/Clg.HgO in methanol gives only one band at

21.3 kK (Fig. 2 ) , corresponding to the transition

— * 1<rig* whereas the anhydrobase /*Co(1-PhAMUH)

registers a slightly lower absorption st 20.6 kK in metnanol.

The second transition 1Alc, — > ^ 2 g GO llcl not be id®ntified

in any of the complexes presumably because of the closeness

of the aromatic transitions. These values are comparable

with those of tris(biguanide) cobalt(III) chloride .(21.1 k K )^ ,

tri s( 1-amidino--)-methylurea) cobelt(III) chloride end solpnate

(20.6 kK)\ tris(ethyleneaiamine) cobelt(III-> chloride

(21.3 kK) . Thus 1-phenylamidino-O-methylurea is almost

es strong llgend as biguaniae, ethylenediamine etc.

- 128 -

P-chlorophenvlalcvandlamlde blsCl-P-chloroaalclino-O-setr.yl-

arag). gpb.e-XtCi.i i i>.. sggplMsa :

The reaction of p-chlorophenyldicyandiodide with cobclt(II)

acetate in presence of methanol gives a rose-red coloured

mixed chelate complex, whicii very surprisingly hrs been iden­

tified as p-chlorophenyldicyandianide bis(1-p-chlorophenyl-•

amidino-O-methylurea) cobelt(III) through infrared spectre

elemental analyses and methoxyl estimation. The complex is

found to be an anhydrobase (III) and can be neutralised with

dilute hydrochloric acid, sulphuric acid or nitric acid in

methanol to give respective salts (IV ). In tnis anhydrobase

formation l-p-chlorophenylaj:i dino-O-methyl urea occurs in a

dsprotonated form.

(Cl-C-H.— NH — C — NH— C — 0CHo) 0 (C1-C*H„— MH-C-NH-C*N)Co H,,0 6 4 || || 3 2 6 4 ||

_ N NH N _

(III)

(C1-C6H4'-NH-C-NH-C-0CH3 )2 (C1-C6H4— NK-C—»H—C«M)Co X3

*iii NH NH

(IV)

Conductivity and magnetic reo-nent '• The molar conductance

value of /~Co(p-ClPhdcda)(l-p-ClPhAMaH)2J 'C l3 .ri20 in methanol

at 26°C indicates a tri-univalent electrolyte, (320 mhos caT

mole'1)1 ’3 . Low conductivity ( 40 mhos cm2 mole'1) in

129 -

methanol for the base strongly contra-indicates an alternative

formulation /Co(l-p-ClPhMlJ)g (p-ClPhdcda/_/(OH). The

chelate cobalt(III) base end its salts were found to be

6diamagnetic. They, therefore, conform to low spin t ^ octa-

hedr8l stereochemistry.

Infrared spectra t P-chlorophenyldicyanularaide has a /cry

strong ni'trile (C=N ) band at 2170 cm . The spoctra of

/"CoCp-ClPhdcda-HXl-p-ClPhAMUigJ7 and /"Co(p-ClPhdcaa)

( l-p-ClPhAMU^^/ci^.HgO exhibit strong C-O-C bands f t 121)?9

and 1200 cm , alongvith a medium strong nltrile band rt

2170 cm"1. The spectra do not record an;y C=0 band around

-I6 ’71740 cm . The presence of both nltrile and.C-O-C band

suggests the presence of both p-chlorophen.yldicyar.ila.aide

and l-p-cnlorophenylamidlno-O-aiethylurea in the complex.

Z^epel estimation of the above two complexes invariably

shows the presence of methoxyl group end cobalt : metnoxyi

ratio wfs found to be 1*2 (Table 1 ). These observations

show that for erch molecule of tne Comdex tnere are two

molecules of l-p-chiorophenylatnidlno-O-methylurea and one

molecule of p-chlorop;ienyldicyendlamide. The methoxyl esti­

mations are consistent with the presence of a medium strong

nitrlle band in the complexes (?ig. 1).

- 130 -

Electronic spectra * The electronic spectre of £ Co(p-

ClPhdcda)( l-p-ClPhAMUHJg^/Cl-.HgO and £ Co(p-ClPhdcda-H)

(l-p-ClPhAHlDg^HgO show absorption at 21.1 kK ana £0.C &K

in methanol-respectively (P ig .2)* The absorptions ere com­

parable to the transitions for cobalt(III) complexes having — — —

L CoK0-/ chromophore, for example £ Co(en) ( Bigli)

(en 3 ethyl enedi amine\ 3igH = biguanide), 20.9 kK11, /Co(dipy)TO —

( B i g H ) ^ (dipy = 2-2'-dipyridyl) , 21.4 kK , / Co(o-phen)__3+ |2

(BigH)^__/ (o-phen = orthophenanthroline) , 21.3 kK , tne

overall ligand field in these mixed chelates being quite

comparable. A dicyandiamide coordinated to eobalt(III)

provides es string a ligznd field as 1-p-cbloropnonyla..*1 dino-

3-methylurea.

The above mixed ligand formation case to us fa a

surprise. The synthetic reactions were repeated r s rlsn th?

IR spectra and methoxyl estimations. Results of all sucj;

studies have only confirmed our proposed Trixed ligana fo r a ­

tion. A still longer reflux (60 hrs) also did not lead to

alcohol addition to the remaining p-chloropbenyl dieyandi ami io

inside the coordination sphere. This mixed cnelrrte is ->sonr-

ble also from another point of view. Cooalt(III) being ion si s-

tently six coordinate the p-chloropr.onyldicyandiaroide has to

function here as a bidentate ligand. Simple iicyandiajniie is

known to function as a raonodentate through its nitrllio

nitrogen atom in the square planar mixed cnelate l-(2-

13aminoethylbiguanide)(aicyandiamiae) cot. er(II) ' .

- 131 -

Tr 18(l-agld ino-O-iae.thy 1 irea)_ cotoltCIII) splshiJte. ■

Reaction of di<syandi£j&ide with cobalt(II) acetate in

methanol provides e dark chocolate solution of complex

tris(l-amidino-O-aethylurea) cobelt(III) , but no comjlex

could be crystallised from solution presumably due to nign

solubility of the complex base* Neutralisation of the solu­

tion with dilute sulphuric acid resulted in the crystallisa­

tion of tri s(l~amidino-0-methylurea; eobeltCIIIJ sulphate*

The methoxyl estimation of the compouna shows tne•

presence of three methoxyl groups* The analysis values fit

well with the cobalt : methoxyl retie as (1:3) (Table 1 ) .

The electronic spectrum of the complex recorded two

absorption bands at 29 icK snd 21 these are exactly the

bands reported by Dutta and Syamal^ for the same compound

prepared through a different method, i .e . by the direct use

of the 1-amidino-0-methyl urea ligand.

Cobalt(II) ion assisted alconol addition* reacti ons

to dicyandiamide and phenyl substitutea dicyandiamides coula

not be studied beyond methanol because of ti.e fact that the

starting cobalt(II) acetate was found insoluble in ethanol

and other higher alcohols. Reactions with cobalt(II) cnloriie

as the starting material were not very encouraging.

- 132 -

1. R.L.Outta, N.R.Sengupta and B.Sur, J.Indian Chera.Soc..

1960 , 37, 673.

2. R.L#Dutta and P.Ray, J.Indian Chem.Soc., 1069,36,499.

3. W.J.Geary, Coord.Cnem.Rev., 1971, 7 , 81.

4 . K.Nalcamoto, 'Infrared Spectra of Inorganic and Coordir:

tion Compound* , 2nd rid., John Wiley cc Sons, New K o k ,

1970, p .80.

6. R.A#?ennemsn and ij.B. Jones, J.Chec.Phys., 1966,24,29.^.

6. 4«D.Cross, 'Practical Infrared Spectroscopy’ ,

Butterworths Publications Ltd ., I960, p .64*

7. R.L.Dutte, and A.Syamal, J.Indian Chem.Soc#,1967,44,571.

8. L# J •Bellamy , 'The Infrared Spectra of Complex Molec iles

Methuen & Co.Ltd., London, 2nd Sd., 1960, p .116.

9. R.M.Silverstein and G.C.Bassler, 1 Spectrometric Indent!

fication of Organic Compounds’ , John Viley & Sons. Inc.

New Yorl-c, 1964, p. 61.

10. R.L. Dutta, J.Indian Chem.Soc., 1967, 44, 863.

11. R.L.iXitta and S.Sarkar, J.Indian ChenuSoc. ,1973,60^236.

12. R.L.Dutta end S.Sar'car, J.Indian Chen. 5oe. , 1 9 6 7 ,c 3?.

13. L.Coghi, A.Mangia, *.fvsrdelli, G.ioxizzi and L. j»oz^i.

Cheni.Qomm., 1968, p. 1476.

14. R.L.Xnitta and A.Syamal, Coord, vhem.xvev., 1967, 2, ^41.

H&isipnsssi 1

SECTION VIII

P r e p a r a t i o n o f p - t o i u o n e 3 a lg i .p i a y .U l c y m ql.ar»il -4e .

Copper (II.) end .Ptqiiia3.mCI.Ij- .prompted. A^J.-y,cin_oi:

alcohols-.to P-tolu en o sul p h o n v 1 Alev and 1 a.;ii 4 a.

It is nov well established that some transition metal

ions can promote addition of alcohols to dicyandiamide*»»

phenyl-, parachlorophenyl-, and orthochlorophenyllicyandiamiae

resulting in the formation of complexes with the alcohol

addition products. In our search for suitably substituted

dicyandiamldes with a view to extend the area of such studios

our attention was drawn to the compound p-toluenesulphonyldicyp

and!amide (I) reported by Sen end Gupta . This compound was

chosen in order to study any influence of the sijilphonyl group

on the alcohol addition reactions.

S0o— NH- C- NH- CSN

2 iiNH

(I)

Preparation of p-toluenesulphonyldieyandiamide by follow

ing Sen and Gupta's method posed some problem. Unfortunately

the compound could not be obtained by following their proce­

dure even exactly. We have now established that the co .pouna

obtained by them was not in fact p-toluenesulphonyidicy&ndi?:-

mide but a p-toluenesulphonic acid salt of simple dicyanclio-

mldine ( I I ) . The formation of this salt was unequivocally

proved by preparing a p-toluenesulphonic acid salt of dicyr i-

diaraldine by straight forward methods (vide experimental) and

- 134 -

examining the compound through elemental analyses* chemical

end infrared studies.

Having fallen to obtain an authentic sample of p-toluene-

sulphonyl dieyandi amide by Sen and Gupta’ s method .we have .10w

developed a method for its synthesis. The authenticity of

this compound as a substituted dicyandiamide has been adequatly

established by elemental analysis, infrared studies and via

complexation reactions.

Experimental.

P-toluenesulphonyl. ghlorlAfi * Commercial p-toluenesulpnonyl

chloride vss freshly recrystallised from petroleum ether.

Picv/andlemidQ : American Cyanamide Company analar grade wr s

used.

Sodium acetate * B.D.H. analar grade was used as obtained.

P-toluenesulp;.onic acid : B.D.H. laboratory reagent grade was

used.

/

Plcvend! ami a In e p- toluene_sul vbaxu&s.

oMethod 1 . (San and Gupta's alleged method) : P-toluene-

sulphonyl chloride (10.5 g;- 0.056 mole) > dieyandi amide (4 .2 g*

0.05 mole)| sodium acetate (10.2 g; 0.075 mole) and wat~r

(25 ml) were refluxed for 2 hrs. P-toluenesulphonyl chloride .

formed a separate layer (on melting) in the boginrii which

gradually disappeared with the completion of the reaction.

The resulting solution was allowed to stand overnight and the

crystals separating were filtered. The compound was recrysta­

ll ! sed from aqueous ethanol.

Method 2 . . P-toluenesulphonyl chloride (10.5 g: 0.055 mole, ,

and dicyandiamide (4 .2 g; 0.06 mole) in water (60 ml; vero

refluxed on a steam bath until the mixture formed o homogeneous

solution (2 hrs.). The solution was then filtered and the

filtrate wss left overnight in a refrigerator when a colour­

less crystalline compound separated out. Tne compound was

purified from aqueous alcohol end dried in air.

Method 3 . P-toluenesulphonic acid (9 .6 g; 0.05 mole) and♦

dicyandiamide (4 .2 g; 0.05 mole) were refluxed ir. presence

of water (60 ml). After refluxing for 1 hr.the solution was

filtered and cooled in a refrigerator when colourless crystals

of dicyand’iamidine p-toluenesulpnonate separated out. The

crystals were purified from aqueous alconol and dried in air.

- 135 -

7t

P-toluenesulPhonv^dlcy and!amide : i>icyand!amide (8.4 g;

0 .1 mole) was suspended in acetone (120 ml) and sodium hydro-

yide (10 g? 0 .25 mole) dissolved in water (20 ml) was tcUed*

The mixture was cooled to 20°C and p-toluenesulphonyl chloride

(19 .1 g; 0 .1 mole) was added gradually with stirring, while

the temperature was maintained at 18 - 20°C. After the reac­

tion mixture had been stirred for four hours at room tempera­

ture* 3t was allowed to stand overnight. It was tner di.uted

with water (100 ml) and neutralised with acetic acii. P-tolue­

ne sulphonyldicyend!amide separated as wnite crystals. The

compound wag recrystallised from methanol and dfrled in rlr.

B_e.sc_tipn_3 of p-toluene sol phony! dlcyandl ami —ft

a) With cuprlc chlorlie * P-toluene solpnonyl-

dicyandi amide (2 .3 g$ 0.01 mole) w p s dissolved In methyl

alcohol (60 ml) by little warming end to this solution vas

8dded cuprlc chloride dihydrate (0.86 g; 0.006 mole). Che

mixture was refluxed on a steam bath for 3 hr3. when a

■tr 1 r>i fit compound separated out from a &r.S£A ffP-k&lgJQ* ?he

Compound wes washed with methanol and dried in air.

b) With cuprlc nitrate ana.maiMngl j This reaction was

carried out by following the above procedure using cuji-rie

nitrate in place of cuprlc chloride. The violet. co.msoaajA that,

crystallised from a grr^en solution wes washed wi’th methanol

end dried in air.

A> /sr 4 ,

- 136 -

J a o -rrf# A 0 r%_

— ' ‘*J01 H , * r .v /7 %r> • -vj?

- 137 -

c) trlth currlc chloride ; Tills reaction w?.s%

carried out as described for the above compounds, by usi *g

etnanol and cupric chloride. The compound was washed with

ethanol and dried in air.

d) Wjjth palljtdium chlor 1 ae.. jan.d.jafLtnaxiol s Palladium enloride

(0 .44 g; 0.0026 mole) and lithium chloride (0 .43 g$ 0.006

mole) were dissolved in fl.R. methanol (20 ml). The mixture

wes then refluxed on a steam bath (25 mins.) ana filtered.

The filtrate was added to a solution of p-tDluenesuipnonyl-

dicyandiamide (1.26 g; 0.006 mole) in A.R. methanol (30 ml)

and refluxed further (8 hrs). A crec.m coloured compound sepa­

rated out, which was washed repeatedly with methanol e* a

finally dried in sir.

Results apd iflgcgaajLap* t

P-to 1 uenesulphon 1 c acid 5&l_t of. 31 cy^dj j^Adjjag •

P-toluenesul phonic acid salt of dieyandi ami dine has

been obtained by three methods (vide experimental). The ele­

mental analyses and melting points agree (Table 1). ?ho .ifh

Sen and Gupta2 cleimed to have prepared p-toluenesulphonyl-

dicyandiamide through their method the elemental analyses

are at variance with t ioso expected for an authentic o-trl.i-

enesulphonyldicyandlamide (Table 1).

- 138 -

Table 1 . Characterisation data of p-toluenesul phonic eci x r>c. I z

o f dicyandismiaine (CgH^N^O^S) p-toluenesulphonyl-

dicyandiamide (C^ii^QN^OgSJ,

Compoundm.p«

( °c)

Carbon

(*)

Hydrogon

<*)

Nigrogen

(*)

Sulphur

(*)

C9H1 4 W

Method - 1 234.6 - - 20.3( 20 ♦4)* 11.9(11,7)

Method - 2 236.0 - - 20.4(20.4) ll«£( 11.7)

Method - 3 236.0 40.0(39.4) 6 .4 (5 .1 ) 20.3(20.4) 11.f ( lie?)

V l o W191.0 45.1(46.4) 4 .5 (4 .2 ) 23.7(23.5) 13.8(13.6 ;

* Calculated values are in the perenthesen.

The compound, as prepared by the three different methods,

reacts immediately with coppor(II) or nictcel(II) sals in aqueous

medium in presence of sodium hydroxide, providing a violet and

an orange coloured complex respectively* The above reactions ere*

typical of d icy and lend dine (guanylurea) ana the copper(II) and

nic'iel(IX) complexes mptcned very well with those prepared by3

using dicyendi ami dine sulphate •

(a) Found for the violet bis( dicyandi ami dine copp©r(II) obtained

via reaction of CuClg, dicvandiamiaine p-toluenesulphonrte in

presence of alkali * Cu, 23.6^; N, 20.9,#.

♦

- 139 -

(b) Found for similar violet compound obtained from CuClg,

dieyandi ami dine sulphate and alkali : Cu 23.7$; N, 20.9,*,

(c) Requires for / CuCCgM^OH^)^^/

Cu 23.9#; N, 21 .I f .

The Infrared spectra of the above compounds shov s4P;ri«j-

poslble bands having characteristic C=0 stretch around

-I4 ’61740 cm (Table 2 ). There Is no C=~fi stretch around

-16 »72174 cm indicating that the compounds are not derived from

substituted dicyandiamldes. It 13 to be noted that dicvrndis-

•l4midine sulphate does have a C=0 stretch at 1740 cm

fr&o lv&naa 'JlP h o •

The formation of p-toluenesulphonyldicyand!amide is

supported by the elemental analyses ( faole 1) of tne product.

The infrared snectrum of the compound snows tne absence of

-i4 *6C=0 band around 1740 cm and a sham nitrile (C = \T) * band

.1^ ,7is observed at 2174 cm (Table 2) indicating thet the

compound Is a substituted dicyandiamide. It has a charccteri'j-

8 —1tic sulphonyl stretch at 1163 cm . Unlike dicyanal a-uidine

the compound fails to give an immediate reaction with copper(Il)

and nickel(II) ions in pres3nce of alkali.

Dicyandiamide (II I ) is well known to add a molecule of

water to its nitrile group in presence of aqueous adds givl.ip

- 140 -

1-ftbl.e. 2< Infrared spectral data of dicyandiauidine and p-toluene-

sulphonyl dicyandiamide*

Compound Infrared bands

in cra“^

Band assignment

in cm“ ^

Dlcyandiamidlne

p-toluenesulphonate.4

Method 1 1740s| 1690s, 1585s,

1450m, 1350w, 1250w,

Il60vw, 1030s, 1010s,

810m, 750v, 680m.

1740 s

^ (C = 0 )•

Method 2

•1754s, 1695s, 1600s,

1449m, 1361w, 1250w,

1163w, 1031s, 1010s,

813m, 74lw, 690m.

1754 s

^(C=0)

Method 3 1754s, 1695s, l€00s,

1449m, 135 lw, 1250m,

ll€3w, 1031s, 1010m,

813m, 74lw, 690m.

1754 s

^(C=0)

P-toluene sulphonyl-

dicyandiamide.

2174 s , 1667 s, 1600m,

1449w, 1429vw, 1351s,

1163mf 1099w, 1050m,

877a, 820m, 74lw, 690w.

2174 s

^ (0 = 1 0

1163m,1351s

tsop)

s = strong, m = medium, w = weak, vs =

vw = very weak.

very strong

/

*

4

141 -

dieyandiamidIne (IV) which generally crystallises out rs the3

salt of the added acid . For example, in presenc.e of aqueous

sulphuric ecid the following reaction ta*e place.

steamNH0-C-NH-C=N + HoS0. + Ho0 ----* (NH0-C-NH-C-NH„)0.K0s6-

2 I 2 4 2 bath 2 j ||

NH NH 0

(II I ) (IV)

Our results, as given above (Table 1), show that in pre­

sence of aqueous p-toluenesulpnonic acid dicyandiamide gives

dicyendiamidine p-toluenesulphonate (Method 3).

NHg— C—NH — C-N -v CH3-\ / ~ S03ri H2°ii NH

NH^- C-NH— C — NH2 .HS03-h h-

NH 0

The same compound is also obtained when dicyandiamide

is reacted with p-toluenesulphonyl chloride in aqueous medium.

Evidently p-toluenesulphonyl chloride gets hydrolysed to

p-toluenesulphonic acid which aids in the addition of water

to dicyandiamide under refluxing conditions (Method 2 ;.

Sen and Gupta used p-toluenesulphonyl chloride in presence

of sodium acetate* As our results show tne added sodium

\

- 142 -

acetate was not sufficient enough to protect the nitrile

group from water addition refection in presence of acid. %The

p-toluenesulphonic acid and hydrochloric acid, liberated

during hydrolysis of p-toluenesulphonyl chloride, created

an acid condition which was favourable enough for conversion

of dicyandiamide to d icy and i ami dine.

An authentic sample of p- toluene sulphonyl dicyandiamide

was finally obtained by reacting dicyandiamide with p-toluene-

sulphonyl chloride in alkaline (sodium hydroxide, 0.26 &ole)

wster-aoetone medium and operating at about 18-20°C. Under

these reaction conditions the nitrile group was not sensitive

to hydrolysis* Instead, the dicyandiamide-NHg reacted with

the -SOgCl group liberating HC1 which was immediately removed

by the excess alkali. The medium was all tiirough strongly

alkaline. At the end the reaction medium was neutralised with

acetic acid and desired dicyandiamide crystallised*

- 143 -

Copperd!*). and palladium II) promoted addltipn...oi,_ .al.coci-As

to p- tol uene sul Piaonyl a 1 cy andlsaid g.

Copper(II) and palladium(II) ions promote addition of

alcohols to p-toluenesulphonyldieyandiamide. Other transi­

tion metal ions like nickel(II) and cobalt(II) however do

not seem to be effective towards such alcohol‘addition

reactions. P-toluenesulpnonyldicyandiamide reacts with

methanol or ethanol in the presence of cupric chloride or

cupric nitrate to provide a violet coloured insoluble com­

plex irrespective of the ratio of cupric chloride or cupric

nitrate to the p-toluenesulphonyldieyandia aide. Ho blue or

greenish blue compound could be isolates, uu.e to the insolu­

ble netxire of the complex in water and eommon organic sol w it s

its solution spectrum and conductivity could not be studied*

The analyses of the isolated complexes are given in fable 3.

Analyses of the violet compound obtained by reacting

cupric chloride or cupric nitrate with p-toluenesulphonyl-

dicyandiamide in presence of methanol provide comparable

values. The values fit quite satisfactorily with two different

types of formula : /_ Cu(LH)g^/C'a01 O.CHgO and Cu/CuI<,>yj*{...pO

(LHg = a molecule of l-p- toluene sul pi. onyldi amid ino-O-

methvlurea). The extreme insolubility of the violet compound

did not allow any conductivity measurement,which hop 3fully

could have easily d1 stinguished between the two for;ia_Las*

144

Table 3* Analyses of copper(II) and palladium(II) complexes of

1-p-toluenesulphonylami d ino-0-alkylur ea.

Analyses of thePound {%)

violet compounds. Cu C H N S OCH3 Hp0

Method ( a) 18.3 35.8 3.6 16.9 9.0 8.9 1.6

Method W 18.3 - - 16.0 9.1 8.8 1.6

Method (c) 17.1 37.0 4.2 16.0 9 .0 - 3.8

Calculated forCalculated (,£)

Cu C H H s • OCH3

/Cu(LH) g_7cu0,0 -SHgO 18.4 34.8 3.9 16.2 9 .3 9 .0 1.3

cuZ~ 1 c v n ^ y o . 6H2o 18.8 36.7 4.3 16.7 9.6 9 .2 . 1.3

/Cu( l'h) 2_/CuD , 1 .5HgO 17.3 36.6 4 .6 16.2 8 .7 - 3.7

Cu/~CuIi^J/l.SHgO

•17.7 36.8 4.3 16.6 8.9 - 3.8

Analysis ofFound (#)

cream compound. Pd N S Cl0CH3 H2°

Method (d) 24.2 12.3 7.3 7 .6 7.0 3 .7

Calculated forCalculated

Pd N S Cl . 0CH3 *2 °

^Pd(LH2)(0H)ClJ7H2O 23.8 12.6 7 .1 7 .9 6.9 4..,)

LH2 « a raoleeule of l-p~toluenesulphonylamidino-0-:aethyI-xc f e

L'Hg = a molecule of l-p-toluenesulphonylamidino-0-ethylurs»&.

146 -

The violet complexes are quite remarkable in that they

do possess tne typical violet colour characteristic of*

square planar / CuN^_/ chroraophore but give an unusual metal;

lig8nd empirical retio as 111, All the violet copper(IIJ

complexes described in Section IV (p. 67, Table 1) gave a 1:2

copper : ligand ratio. The situation could be explainea by

assuming the two possible alternetive formulas cited above.

Of these two structures Cu . CuLg_/ type finds less favour

with us because in the whole family of motel biguanides or

metal l-amidino-O-alkylureas we do not know of any example

where the ligcnd functions as a dibasic acid. The other

structure shows the ligand as a monobasic acid ana calories

CuO as a non-electrolyte component, which being red brown

should not have any absorption in the green or blue region

of the visible spectrum. In fact a solid reflectance spectrum

of the violet compound of LH2 does not show any absorption

in this region but shows an absorption et 18.8 kX. Note

square planar ( /~CuN AJ chromophore ) bis( 1-phenylamidino-

O-methylurea) copper(II) chloride absorbs at 18.8 kK in

nitromethane (Fig. 1).

The infrared spectrum of p-toluenesulphonyl-dicv?ndi.a-

-l6 ’ 7mide has a sharp nitrile (C=N) band at 2174 ciii . The

•

infrared spectra of the violet compounds obtained from

methanol or ethanol also show the absence of the nitr'le

band and also show that there is no C=0 stretch around

25.0

CD

cco

I— 2 UJ

O

u_IdCCJ

zo

CJ

cr<

oS'

20-0 fe'* k-K- n

Solid state electronic spectrum of violet compoundObtained by reacting Cupric Chloride, p -toluene sulphonyldicyandiamide in methanol

- Electronic sp-"** r urn of

!_Cu (J-phAMUH)^j Ct2 H,Gm nitromethane

1740 cm . The complexes have a strong C-O-C stretch

-l9 ’10 ,around 1210 cm (due to mixing up with the sulphonyl

band which appears in p-toluenesulphonyldicyandiamide at

1163 cn~^)« C-O-C stretch in the alcohol addition products

of phenyldicyandiamide and related dicyandiamide appeared

around 1180 to 1214 cm'^ (page 78).

The cream coloured complex £ Pd(LR2) (0H)CI_/K20* was

found to be highly Insoluble in organic solvents* The infrared

spectrum shows a broad C-O-C stretch around 1179 cm*"1 and

there is*no band around 1740 cm“^ due to C=0. ZIesel estli-t—

tion gives a positive methoxyl result. An alternative for::va-

letion /"Pd(LH)(Kg0)Cl_7 with a deproton^ted ligwid would CI30give a good fit with the analytical results* On dehydration

the compound should change to a chlorobridged dimer

.Civ/ (LH)Pd* ✓ Pd(LH)_ / In order to satisfy tha four coordinate

N C1square planar geometry of palladium(II). Such a complex

should have en intense colour* However no such intensifies-

tion of colour was noticed on dehvdrstion. The formulatic

PddiHg) (0R)C1__/ i» tentatively favoured.

«

147 -

1. R.L. Dutta and P.Ray, J.Indian Chem.Soc.,

1959, 36, 499.

2. A.B.Sen end S.K.Gupte, J.Indian Chem.Soc.\

1963, 40, 678.

3 . F.J.Welcher, ’Organic Analytical Reagents1, Vol.l,

D.Van Nostrand Co., Inc ., New York, 1947, p .^17:

4 . R.L.Dutta and A.Syamal, J.In-lien Chem.Soc.,

1967, 44, 669.

5 . A.D.Cross, ’Practical Infrared Spectroscopy',

Butterworths Publication Ltd ., 1960, p .64.

6. J.R.Dyer, ’Application of Absorption Spectroscopy of

Organic Compound', Prentice Hall, Inc ., 1965, p .37.

7 . R.A.Penneman and L.H.Jones, J.Chem.Phys.,1965,2^,293.

8 . Reference 6, p. 38.

9 . R.L.Dutta end A.Syamal, J.Indian Ch9m.Soc.,

1967, 44, 671.

10. R.M.Silverstein and G.C.Basseler, ’Spectrometric

Identification of Organic Compounds’ , John Wiley «. tons,

In c ., New York, 1964, p. 61.

SECTION IX :

ghroffliJ»nXIIlJ-..cc?fflPl.exes of Jl-aaiaino-O-metir/lursa.

1-Amidino-O-alkylureas have been shown to be powerful

coordinating ligands as biguanides ( I ) . They form complexes

with various transition metal ions such as copper(II),

fcickel(II), cobelt(II/III) , oxovanadium(IV), palladium(II)

and zinc(Il)1 . These studies have revealed a close similarity

between biguanide and 1-amidino-O-alkylureas as ligands * •

Our present study reveals that chromium(III) ion reacts with

sn excess of 1-amidino-O-methylurea (II) in presence of sodium

hydroxide to give tris(1-amidino-O-methylurea) chromium(III)

complex base. In the absence of sufficient excess amount of

ligand chromium hydroxide was formed. The tris(ligand) chro-

mium(III) base can be neutralised with or

alcohol to give the salts.

HoN- 0—NH —C-NH2 11 11

NH NH

(I)

Sxperimental ;

The ligand 1-amidino-O-methylurea sulphate was prepared

A* 3by following the published raethoa of Dutta and Hay .

XrlsCl-amldlno-O-methylurea) chromlumCIII) bass ; l-amidino-*

O-methylurea sulphate (€ g) was dissolved in water (20 ml) by

little warming and to the solution was added in portions

HgN— C —NH— C —O C ^

NH NH

(II)

under stirring chrome elum solution (2 .6 g in 10 ml of water)

with portionwise addition of sodium hydroxide (total quantity,

3 g ) . The dark rose-red coloured solution was cooled in icy

(3 hrs) when the complex tris( 1-amidino-0-methylurea) chro-

mium(III) base crystallised out. The compound was filtered

through a sintered funnel and recrystallised from hot metuanol

(60 ml) and dried in a desiccator over KOH (yield = 0.35 gi.

Tri s (1-ami dino-0-&etfryl:y^eiO-.jite^ - Tris(l-

amidino-O-methylurea) chromium(III) base (0.3£ g) was dissol-

ved in a minimum volume of not alcohol (60 ml) , concentrated

(20 ml) and neutralised in the cold with dilute nitric acid.

Prom the resulting solution lignt rose coloured co;u|.iex was

precipitated by the eddition of acetone. Tne crystals were

filtered, washed with acetone and dried in air (yield = 0 .27 g).

Tri fid-a&ldlno -0-methyLur.a&i. chro mi u?ut111L jte4pj)j&a • -he

sulphate was obtained as above using dilute sulphuric acM

instead of nitric acid (yield = 0 .3 g).

- 150

Tab -e 1 . Characterisation data of chromium(III) complexes of 1-amidino-0-methylurea.

Compound Colo’ir Chromlum(^) x^fitrogen(^) Anion(^) MethoxylU) Water(^)

L C r C l -A M t O g J R o s e - r e d 1 3 . 0 ( 1 3 . 1 ) * 4 2 . 3 ( 4 2 . 3 ) - 2 3 . 1 ( 2 3 . 4 ) -

Z ~ c r ( 1 - * M 0 H ) 3 _ 7 ( N 0 3 >3 Rose 9 . 1 ( 8 . 9 ) 36.4(36.8) - 1 6 . 6 ( 1 5 . 8 ) -

Z~c r ( 1 - AMOH) 3J7( S04 ) i _ s 7H20 n 7 . 6 ( 7 . 8 ) 26.3(25.0) 2 1 . 6 ( 2 1 . 5 ) - 1 8 . 9 ( 1 8 . 8 )

* Calculated values are in parentheses.

1-AKIJH = l-aaidino-0-methyl urea.

161 -

4

1-amidino-O-methylurea sulphate resets with chrome

alum in presence of sodium hydroxide to give rose-rod

coloured tris(1-amidino-O-methylurea) cobalt(III) base.

The compound conforms to an anhydrobase, indicating that

the ligand can behave as a monobasic acid, Tne correspond-♦

ing blguanide complex base separated first as e crimson-

red coloured monohydrate which coula^aehyarated to a brie -

red coloured anhydrobase4 . The base Z Cr(l-AMU)^/ nan bo

neutralised with and HNO^ in alcohol to give the

salts. The complex / Cr( 1-.AMUH) J7( 3 0 ^ ) loses the

hydrated water only very slowly at 120°C. Attempts to iso­

lated chloride and perchlorate 3alts by neutralising the

complex base with the respective acids were not successful

presumably due to high solubility of these salts* Ziesel

estimation of the methoxyl group from the complex

/~Cr(l-AMU)3^7 and /~C r(1-AMUH) 0 ^ shows the presence of

methoxyl group. The analysis values fits well with the

chromium * methoxyl ratio as 1*3 (Table 1). The infrared

spectrum study of the complex /_ Cr( l-AMUHj^^/CSO^)^g7HgO

shows the presence of a strong C-O-C stretch at 1200 cm

Conductivity and : The molar conductance

of Z~Cr(l-&MaH)3^7(N03)3 in water st 0.001X concentrr;3or

registers 340 mhos cm2 mole-1 at 2£°C, whicii is in the range6

of tri-univalent electrolyte . Complex has a magnetic moment

162 -

value around 3*77 B.M. which is in accord with the expected

spin only value for chromium(III) with three unpaired eleo-7

tron3 •

■&.PP.teBlUQ 2PPJ&Z& * The electronic spectrum of /~Cu(l-4;-iJh)

( ^ 3)3 in water gives a band at 3D.4 kK; £, 86 and at

27.3 kK; £, 62 (Fig. 1 ). These two transition.'' can be as singed

as 4 *2 g — ^ 4l2g ^ as 4*2g — ^ 4Tlg(? )* Th0 third

transition is in the ultraviolet. 2ho first

transition gives a 10 jq value of 20.4 fcK for the complex

nitrate. This 10 Dq value is comparable to the 10 Dq (2D.7 kK)

of tris(biguanide) chromium(III) chloride8 and is littxe less

than (21.9 kK) of tris(ethylenediamine) chromium(III) chloride®.

The anhydrobase tri s( 1-amidino-O-methyl urea) chromium( III)

also gives two absorption bands at 20.0 kK and ‘26.9 kK (Fig. 1).

Thus the anhydrobase registers a slightly lower 10 i>q than

the protonated nitrate salt. The same situation may bo expected

in the biguanide series since the chrooium(III) complex base

Z Cr(Big)g_7 * 8 crimson-red while the salts L Cr(High)-3_/X

(BlgH = biguanide) ere orange coloured^.

Attempts were made to obtain the cnromium(III) compl­

exes of 1-amidino-O-ethylurea. A dark red solution of the

complex base was obtained as for 1-amidino-3-methylurea com­

plex but no complex could be crystallised from the solution

presumably due to high solubility.

Electroric :pectra of-Or (JIL) t-am idi^'i-0-m ethylur?3 Complexes ir* wate1

A -[C r ( |-A .M U )3 ]

B - [ C t (I-AN!UM>3 ] ‘ .03^ 5

References :

1, R.L.Dutta and A. Syamal, Coor4.Chem.Revs.,

1967, 2, 441.

2• P#Rav, Chem.Rev., 1961, 61, 313.

3* R.L.Dutta and P.Ray, J.Indian Chem.Soc., 1969, 36, 499.

4 . P.R6y and H.Saha, J.Indian Chem.Soc., 1937, 1*, 677.

5. R.L.Dutta and A.Syamal, J.Indian Chem.Soc.,

1967, 44, 671.

6. G.Milazzo, 'Electrochemistry1, First English Edition,

Elsevier Publishing Co. , 1963, p .60.

7. F.A.Cotton and G.Wilkinson, 'Advanced Inorganic Chemistry’ ,

2nd Ed., Wiley Eastern (P) Ltd., 1970, p .637.

8 . S.P.Ghosh and A»Mishra, J.Indien Chem.Soc.>

1970, 47, 80.

9. P.Ray and H.Saha, J.Indian Chem.Soc., 1937,14,676 U 6-0.

- 163 -

♦

Apj.ajfc&K :

Published Papers*

J. INDIAN CHEM. SOC., VOL. I.H, OCTOBER 1975

J . Indian Chem. Soc.,Vol. L1I, October 1975, pp. 1000-1001

Addition of Alcohols to Substituted Dicyandiamides

R. L. DUTTA* & AKOIJAM M ANIHAR SIN G H 4*

Inorganic Chemistry Laboratory, The University of Burdwan, Burdwan-713101

M anuscrip t received 23 September 1974 ; revised 22 A p r il J975 : acceptcd 29 M a y 1975

T HF. inaugural re p o r t o f D u tta an d R a y 1 on the ad d itio n o f a lcohols to d icyandiam idc in the presenceo f cu p ric <alts has genera ted a good deal o f in te r­

e s t2 ' 1’'. W c describe herein som e p re lim inary results o f sim ilar stud ies w ith phcnyld icyandiam idc (and som e o th e r su b s titu ted d icyand iam ides).

Pheny ld icyand iam ide (2 m o ls.) reac ts w ith alcoho ls in the presence o f cupric sa lts (1 m ol.) to give violet crystals o f bis (l-p h en y la m id in o -0-aIky lu rea) co p p e r(Il) salts. R eaction o f I m ol. phenyld icyandiam ide and 1 m ol. cupric ch lo ride in presence o f an alcohol gives

q u ite readily deep b lue to b lue green sp a rin g ly soluble d ich lo ro m o n o (l-pheny lam id ino-O -alky lu rea) coppcr(IJ) in a lm ost q u an tita tiv e yield. T his la tte r reac tion appears to be general and occurs w ith ease w ith unsubstitu tcd d icyand iam ide as well, which hgs escaped the a tten tio n o f D u tta an d R ay1 .

R eaction o f co p p er(II) n itra te w ith phenyld icyan- d iam ide in 1 : 1 ra tio in e th a n o l gives a g reen pow der w h ich has been identified as d i(n itra to ) m ono (l-p h en y l- am idino-O -ethylurca) co p p e r( ll) . C o p p er(II) su lp h a te (1 m ol.) an d phenyld icyandiam ide (1 m ol.) in m e th a n o l gives g reen co lou red su 'p h a to m ono(l-p h cn y lam id in o - o -m ethy lu rea) c o p p c r(Il) . Pheny ld icyand iam ide has a s tro n g sh a rp n itrile b a r d a t 2222 cm 1 w hich is com pletely absen t in the a lcoho l a d d itio n p roducts. T here is no C = 0 s tre tch a t 1740 c m -1 ind ica ting tha t th e p ro d u c ts a re n o t su b s titu ted guany lureas. Instead all th e com plexes have C - O R s tre tch a t — 112-1 c m " 1 to su p p o r t th e l-p h en y lam id in o -0-a lky lu rea s truc tu re .

T he in fra red spectrum o f the su lp h a to com plex (1166, 1CK6, 1000, 958 c m -1 ) show s evidence o f b iden- ta te su lp h a to g ro u p 7 . T h e b is(ligand) copper(II) n itra te and chloride sa lts a re as expected b iun ivalen t trec tro ly tes in m e th an o l w hile th e d in itra to an d the d ich lo ro m o n o (ligand) coppcr(II) com plexes are su b stan ­tia lly ionised in m eth an o l, the ir conductiv ity increasing w ith d ilu tio n . T h is ind ica tes th a t th e co o rd in a ted n itra te an d ch lo ride a re being solvolysed. T h e su lp h a to - an d the n itra to m ono(ligand) co p p er(II) com plexes have no parallel yet in the meta* b iguan idc chem istry8, an d they also con stitu te the first exam ples rep o rted in the fam ily o f 1 -am id ino -o -a lky lu rea m eta l com plexes.

T h e e lec tron ic sp ec tra o f b is (l-p h en y lam id in o o- a lky lu rea) co p p er(Il) sa lts co n fo rm to a sq u a re p lanar [ C u N j ch ro m o p h o re (;.m„ 18 kK in ace ton itrilc ).

• Senior author.** On leave from Tmphal College, Im phal, Manipur.

C om pare square p lanar b is(b iguanidc) coppcr(IT )0 (19.1 kK in w ater) ; bis( 1 -am id ino-o -a lky lu rea) c o p p c r(J l)2 (18.5 kK in w ater), b is(ethylcnediam ine) c o p p c r( II)10 ( lS .2 k K in w ater), te trak is(bcnzim idazo le) c o p p c r( ll) p e rch lo ra te11 (19.0 k K , solid phase).

C o m pared to c o p p c r( ll) , n ickel(II) is m uch less efficient in fo rcing a d d itio n o f a lcohol to phenyld icyan­d iam ide. A reaction o f 1 m ol. o f nickcl ch lo ride and tw o m ols. o f pheny ld icyand iam ide takes a ro u n d 40 hrs to go to com p le tion w hile th a t w ith co p p e rf ll) takes 6-8 hrs. (bo th o n steam ba th ). T h e n ickel(U ) com plexes a re o range yellow , d iam agnetic an d hence con fo rm to [N iN .i] sq u are p lan a r geom etry .

o-C hloro* and /7 -chlorophenyldicyandiam ide also give sim ilar reactions.

It is in teresting to n o te th a t p h cn v ld icyand ian jidc ' 2 (m .p . 197°) can be recovered in ~ 95% y ield after refluxing in m e th an o l fo r 40 h r (F o u n d , m .p 196° : N . 35.3 ; C alc. N , *5.0 per ccn t). Phenyldicyandiam ide a lso rem ains unchanged a fte r 60 h r reflux in e thanol (recovery ^ 95%. m .p . 196°, N , 35.1 p e rc e n t) .

D etails o f these stud ies w ill be rep o rted in due course.

References

1. R . L. D u t t a and P. R ay. J. Indian Chem. Soc., 1959.36, 499, 567, and 576.

2. R . L- D u t t a , B. S u r and N. R . S e n g u p ta , J. Ind ianChem. Soc., 1960, 37, 565, and 573.

R. L. D u t ta and S. L ah iry , J. Indian Chem. Soc., 1960, 37. 789 ; 1961. 38, 639.

R. L. D u t t a and A. S y a m a l, J. In d ia n Chem. Soc., 1967. 44, 5 6 9 ; 1 9 6 8 .45 ,115 ; 127. 138, 213. 219 and 226.

R. L. D u tt .v and A. S y a m a l . Coord. Chem. Revs., I 967,2. 441

3. G . D . D ia n a . E. S. Z a l a y R. A. C u t l e r J r . , J '. Org.Chem., 1965, 30,298.

4. W. A- B a k e r and M. D a n ie l s , J. hung. Nuclear Chem.,1963,25,1194.

5. J. R. W a sso n and C . T r a p p , J . Physical Chem., 1969,73, 3763.

6. P. F. B . B a r n a r d , J . Chem. S o c ., (A). 1969. 2140.

7. K. N akamato, ‘Infrared Spectra o f Inorganic andCoordination Compounds’, John Wiley & Sons., New York, 1970, p. 175.

8. P. R ay , Chem. Revs., 1961, 61, 313.9. M. M. R ay and P. R ay, J. Ind ian Chem. Soc.. 1959.

36. 849.

10. K . S o n e and S. UTSUNO. H u ll. Chem. Soc. Japan, 1966.39, 1813.

J I . M . Goodgam e and L. I. B. Haines. ./. Chem. Soc..1966, (A), 174.

12. F.H. S. C u r d and F. L. Rose, J. Chem. Soc., 1946, 733.S. N. P o d d a r and P. R ay , J. Indian Chem. Soc., 1952.

29, 381.

J. INDIAN CHEM. SOC., VOL. 1.11, OCTOBER 1975

J . Indian Chem. Soc.,Vol. L1I, October 1975, pp. 1000-1001

Addition of Alcohols to Substituted Dicyandiamldes

R. L. DUTTA* & AKOIJAM M ANIHAR SIN G H 4*

Inorganic Chemistry Laboratory, The University of Burdwan, Burdwan-713101

M anuscrip t received 23 September 1974 ; revised 22 A p r il 1975 : accepted '29 M a y 1975

T HF, inaugural re p o r t o f D u tta an d R a y 1 on the ad d itio n o f a lcohols to d icyandiam idc in the presenceo f cupric .^alts has genera ted a good deal o f in te r­

e s t2 '’. W c describe herein som e p re lim inary results o f sim ilar stud ies w ith phenyld icyandiam ide (and som e o th e r su b s titu ted d icyand iam ides).

Phenv ld icvand iam kle (2 m o ls.) rcac ts w ith alcoho ls in the presence o f cupric sa lts (1 m ol.) to give v iolet crystals o f bis (l-phen y lam id in o -o -a lk y lu rea ) co p p e r(Il) salts. R eaction o f 1 m ol. phenyld icyandiam ide and 1 m ol. cupric ch lo ride in presence o f a n alcohol gives

q u ite readily deep b lue to b lue green sp a rin g ly soluble d ich lo ro m o n o (1-pheny lam id ino-o -a lky lu rea) copper(II) in a lm ost q u an tita tiv e yield. T his la tte r reac tion appears to be general and occurs w ith ease w ith unsubstitu tcd d icyand iam ide as well, w hich hgs escaped the a tten tio n o f D u tta an d R ay1 .

R eaction o f co p p er(II) n itra te w ith phenyld icyan- d iam ide in 1 : 1 ra tio in e th a n o l gives a g reen pow der w h ich has been identified a s d i(n itra to ) m ono (l-p h en y l- am id ino-0-e thy lurea) co p p e r( ll) . C o p p er(II) su lp h a te (1 m ol.) and phenyld icyandiam ide (1 m ol.) in m e th a n o l gives g reen co lou red su 'p h a to m ono(l-p h cn y lam id in o -o-m ethy liirea) co p p cr(II). P heny ld icyand iam ide has a s tro n g sh a rp n itrile b a r d a t 2222 cm 1 w hich is com pletely absen t in th e a lcoho l a d d itio n p roducts. T here is no C = 0 s tre tch a t 1740 c m '1 ind icating that th e p roduc ts a re n o t su b s titu ted guany lureas. Instead all th e com plexes have C - O R s tre tch a t — 1124 c m " 1 to su p p o r t th e l-p h eny lam id ino -o -a lky lu rea s truc tu re .

T he in fra red spectrum o f the su lp h a to com plex ( t 166, 1CK6, 1000, 958 c m " 3) show s evidence o f b iden- ta te su lp h a to g ro u p 7 . T h e b is(ligand) copper(!I) n itra te and chloride sa lts a re as expected b iun ivalen t trec tro ly tes in m e th an o l w hile th e d in itra to an d the d ich lo ro m o n o (ligand) co p p e r( ll) com plexes arc su b stan ­tia lly ionised in m eth an o l, the ir conductiv ity increasing w ith d ilu tion . T h is ind ica tes th a t th e co o rd in a ted n itra te an d ch lo ride a re being solvolysed. T h e su lp h a to - an d the n itra to m ono(ligand) coppcr(II) com plexes have no parallel yet in the m etai b iguan ide chem istry an d they also con stitu te the first exam ples rep o rted in the fam ily o f 1 -am id ino -o -a lky lu rea m eta l com plexes.

T he e lec tron ic sp ec tra o f b is (l-pheny lam id ino -o - a lkv lu rea) co p p er(Il) sa lts co n fo rm to a sq u a re p lanar [C u N ,) ch ro m o p h o re (;.m„ 1*S k K in ace ton itrile ).

' Senior author.** On leave from Im phal College, fm phal, Manipur.

C om pare square p lan a r b is(b iguanide) coppe^IT )* (19.1 kK in w ater) ; bis( 1 -am id ino-o -a lky lu rea) co p p cr(JI)2 (IS .5 kK in w ater), b is(ethylcocdiam ine) c o p p c r( II)10 (18.2 k K in w ate r) , te trak is(bcnzim idazo le) coppcr(II) p c rch lo ra te11 (19 .0 k K , solid phase).

C o m pared to c o p p e r( ll) , n ickel(II) is m uch less efficient in fo rcing a d d itio n o f a lcohol to phenyldicyan- d iam ide. A reaction o f 1 m ol. o f nickcl ch lo rid c and tw o m ols. o f pheny ld icyand iam ide takes a ro u n d -10 hrs to go to com p le tion w hile th a t w ith coppor(II) takes 6-8 hrs. (bo th o n steam ba th ). T h e n ick c l(ll) com plexes a re o range yellow , d iam agnetic an d hcncc con fo rm to [N iN j] sq u are p lan a r geom etry .

o-C hlo ro - and /> -chIorophenvldicyandiam ide also give sim ilar reac tions.

It is in teresting to n o te th a t p h c n y ld ic y a n d ia m id c '2 (m .p . 197°) can be recovered in ~ 95*)' y ield after refluxing in m eth an o l fo r 40 h r (F o u n d , m .p 196* : N . 35.3 ; C alc. N , J5.0 per cen t). Phcnyldicyandiam idc a lso rem ains unchanged a fte r 60 h r reflux in e thano l (recovery — 95%. m .p . 196°, N , 35.1 p e rc e n t) .

D etails o f these stud ies will be rep o rted in due course.

References

1. R . L . D u t t a an d P . R a y . J. Indian Chem. Sac., 1959,3 6 , 4 9 9 , 567 , a n d 576.

2. R . L . D u t t a , B. S u r a n d N. R . S e n g u p ta , J. Ind ianChem. Soc.. I9 6 0 . 3 7 , 565, a n d 573.

R . L . D u t t a a n d S . L a j i i r y . J. Indian Chem. Soc., 1960, 37. 789 ; 1961, 38. 689.

R . L. D u t t a a n d A. S y a m a l, J. In d ia n Chem. Soc.,1967. 44 , 569 ; 1 9 6 8 .4 5 , 1 1 5 ; 127, 138, 2 1 3 .2 ) 0 a n d 226.

R . L- D u t t a an d A. S y a m a l . Coord. Chem. Revs.. 1967.2 . 441

3. G . D . D ia n a . E. S . Z a l a y R . A. C u t i .c r J r . . ./. Org.Chem., 1965, 3 0 ,2 9 8 .

4 . W . A- B a k t r ant! NT. D a n ie l s , J. Inorg. Nuclear Chem.,1 9 6 3 ,2 5 ,1 1 9 4 .

5. J . R . W a s so n a n d C . T r a p p , J . Physical Chem., 1969,7 3 . 3763.

6 . P. F- B . B a r n a r d , J . Chem. Soc., (A). 1969. 2140.

7. K . N a k a m a to , ‘I n f r a r e d S p c c tra o f I n o rg a n ic a n dC o o rd in a tio n C o m p o u n d s ’, J o h n W iley & S o n s ., New Y o rk , 1970, p . 175.

8. P . R a y , Chem. Revs., 1961, 6 1 , 313.9 . M . M. R a y an d P . R a y , J. Ind ian Chem. Soc.. (9 5 9 .

36 , 849.

10. K . S o n e a n d S. U i s u n o . R td l. Chem. Soc. Japan, 196^>.39 , 1813.

J I . M . G o o d g a m k a n d L . I . B . H a in e s . Chem. Soc.. 1966, (A), 174.

12. F.H. S . C u r d a n d F. L. R o se , J. Chem. Soc., 1946, 733.S . N . P o d d a r a n d P . R a y , J. Indian Chem. Soc., 1952.

29 , 381.

J . I n d i a n C h e m . S o c .,V o l. L1I, N o v e m b e r 1975 p p , 1063-101H

Donor Properties of 1 -amidino-O-alkylureas. P a r t X V -

Tris(l -amidino-O-methylurea) Chromium(III) ComplexesK.* L. DUTTA* and AKOT.TAM MANITTAR RIJfOIT** 1

Inorganic Ohonnsfcry Laboratory. Thn University of Burduan, Burdwan 71 it 101. Went Rental

M a n u s c r ip t re c c iv rd 8 M a y 1975; accepted 8 A u g u s t 1975

T h e p r e p a r a t i o n a n d p r o p e r t i e s o f i r i s l> a m id in o - 0 - m e tb y lu r e a ) c h r o m iu m iH I ) b a s e a n d i t s n i t r a t e a n d s u l p h a t e s a l t s a r e d e s c r ib e d . T h e n i t r a t e s a l t g iv e s t r i u n i v a l e n t e l e c t r o ly t e c o n d u c t ­a n c e i n w a t e r . T h e e l e c t r o n i c s p e c t r u m a n d m a g n e t i c m o m e n t a r e c h a r a c t e r i s t i c o f o c t a h e d r a l s t e r e o c h e m i s t r y . T h e 10 D q v a lu e (20 .4 k K o f t h e n i t r a t e i s c o m p a r a b l e t o t h a t o f t r x s ( b ig u a n id e c h r o m iu m ( I U ) c h l o r i d e (20 .7 IcK).

EX T E X S T V E stu d ies h av e Ixn-n m ade o f l- am id iao -O -^lky lu reas as co -o rd ina ting ligands w ith vario u s tra n s itio n m e ta l ions such as

eoj>pcr(TT), n ick c l(I[) , c o b a lt( ir ) , coball(TTf), oxo-v a iia rliu m (r\'!, paliadium (TO and zijio(TX)1. Thosestud ios h av e revealed a close s im ila rity botwe.cn biguanitlos an d 1 -ain id ino-O -alky lureas a,s ligands1.: Wo now rep o rt a s tu d y o f fclio p re p a ra tio n an d p ro . portios o f chromium(TTT) com ploxes o f l-am id in o -0 - m o thyhrrea(I).

X H — C— NH—C— O C H ,II IIN H X H

(T)

E x p e rim e n ta ll-A m idtno-O -nvahyhiron su lp h a te w as p repared

b y pub lished m e th o d 3.

T m ( 1 ■amidino-O-methi/lvrm) chromivin{l 17) ha*c. :

1-am idino-O -m ethylurea su lp h a to (0 g) was d is­solved in w a te r (20 m l) b y littlo w an n in g a n d to th<* so lu tio n w as a d d e d in p o r tio n s u n d e r st irring chroir.e a lum so lu tion (2.5 g in 10 m l o f w ater) w ith portion - wise ad d itio n o f sodium h y d ro x id e (3 g). T he d arx rose re d colourtjd so lu tio n w as cooled in ice 3 l.r w hen th e com plex tr is (1 -am id ino-O -m ethyhirea) ulironihim(ITT) base crysta llised o u t. T he corapou: <i was filtered th ro u g h a s in te red fuiuu l an d recry-- t.allisod from h o t o thano] ((U> m l) a n d d ried in ■ d es icca to r ov<jr K O H (yield — 0.35 g). (F ound Or, 13.0; K , 42.4 p a r e c u . Oaled. for | d r (0 3H ,N 40 l,1 : Or. 13.1: N . *12.3%).

Vfi*( I -(imidino-O-rn/'Jhi/lure/t) t h r o m i"m i1 II ; . :

T ris(l-am id ino-O -m othy lu roa) c h ro m iu m (III a.-*- (0.35 g) w as d issolved in ft m inim um volum e of hr,1.

* S en io r a u th o r .** On leave from Imphal Oollogo, Imphal, Mar.■ par

(60 m l), co n cen tra ted (20 m l) an d neu tra lised in * -if* m id w ith d ilu te n itr ic acid. I 'rom tb<- resu lting

ligh t rose co loured com plex w as p rec ip ita ted b y ad d itio n o f acetone. T h e c ry s ta ls were !:i• • —> <1. wa^liw l w ith acetone an d d riod in a ir (yield

-•.27 - . (P o u n d ; Cr, 0.1; N, 35 .4 % . Oale. fo r Or r . H bN40 ) 3]fN 0 9)s : Or. S.0: N. 35 .8% ).

■ I nm iSino-O -tM thylvrea) c h ro m im n (lI / ) sulpha)r : r .. -u lp h a t. was o b ta in ed as above using d ilu te

- in '. .. .. id in s tead o f n itr ic ac id , (y ield 0.3 g).i ' . (V. : • N. 25.3; S O ,2 . 21.0; I I O 18.0% .

t ’alod for [C r ,0 3H RN 40 ) Jll (S 0 ,)1.(i7lT.,0 Of. 7.S: V 2--.0 S O , - . 21.5; H .O . 18.8% ).

T h e com pound loses th e h y d ra te d w m ^r only \«*ry slow ly a t 120' .

M<vjnrJic m ot»rut : T h e su sc ep tib ility o f th e eom-\ was d ' tojrmined w ith th e help of a (}o\iy

r.H .T.-i te m p era tu re . iTtamagnH ie corrce- r^iwle from P a sc a l’s co n s tan ts .

F ound : v - I 4 .5 2 x l0 _n; Xm ~ 57G3; ll» ": M;corr) - 5 9 0 0 .5 y |<> ,, ^ .3.77 1* M.

-iudahC f ■ O onduetanee o f 0.001 ii/ arpieous so lu tion o f th e n itra te s a l t was d e te rm in e d a t 2.V

- P.hillips O ojiduo tiv iiv Bridge.

R e s u l t s a n d D i s c u s s i o n

; ;. lc : )\i'. p m s rn t invt’s tig a tio ii tlu ,e«' eowjvnnwU• : ekr»nninm(TIT) w ith l-ajuidino-O-inolJiylnrtM i jk a_ ‘..'.ve l>eeji iso la ted . TJic base is n»se re d iji.»!r*::r a ju l conform s to an an h yd robase . ind icating

• i;a: ligand eajv behavei a s a m onobasic acid. T’ c orresponding b iguan ide com plex base se.j ivj attnX firs* as a m tm oh jv lra te •w h ich could Ik- (h 'U yrbated

an an jiy d ro b aso '. T h e luusc ca n Ih' neut rali«4‘<l p r .s d , o r H N 0 3 in alcolio) to give th e salus.

H u o rid e a n d perchlorau^ salUs wero too soluble to be - T h e m olar* conduc tance value o f the

rr.p’ex n i t r a te (0.001 M ) in w ate r (340 ohm cm 2, rno!.*- • a t 25°) ind ica tes t h a t it is a Iri univaienl

' f

J . I N D I A N C H E M . SOC. V O L . M I , N O V E M B E R 1975

.•U^trolyu^. The magnetic moment (3.77 li.M ) of the complex base is in accord with the expocted spin only value for cluomium(I I I ) with three im­paired electrons*. The electronic spectrum of the nitrate sail in water gives hands a t 490 nm (20.4 kK, i: . Sti) and at 370 nm (27.3 kK, c — 02). These' two transitions can be. assigned as —> lT.JI7 and ns -> 4,1',„( !•’). TJie third transition *A2g -> 4T1(, (P) is" in the ultraviolet. The first transition gives a 10 Dq value of 20.4 kK for the complex nitrate. This 10 T)q value is comparable to the JO Dq (20.7 kK) of tris(biguanide) chromium(IJl) chloride7 and is Jittle less than th a t (21.9 kK ) of tris(ethylenediamine) ehromium(TTT) chloride7. I t is also interesting to note that, the anhydrobase tris(l- amidino-O-methylurea) ohromium(TTT) also gives two absorption bands at 20.0 k K and 25.9 kK. Thus the ajvhydrohaxc i-ogist«rs a slightly lower 10 Dq than the protqnated n itra te salt. This m ust also be the case ii\ th f higwanide series since the chromium (IT I) complex base is crimson red while the salts are orange coloured8.

Attempts were made to obtain the eliromium(lil) complexes of 1-amidino-O-ethyhuea. A dark red

solution of the complex base was obtained as for th1 -amidino-O-methylurea complex bu t no comple. could bo crystallised from solution presumably du( to* high solubility.

R e f e r e n c e s

1. It. L. D u t t a and A. S y am ai- , Coord. Chem. Itn -* .. 19672. 441.

2. 1\ R a y , Chem. licv .. 1961, 61, 313.

3 . R . L. D u t t a an<l P. R a y , J . In d ia n Chem. Soc.. 19536. 499.

4. p . K a y and H. .Saha. ./. In d ia n Chem. Soc., 1937, 1077.

*». <!. MitjAZKO, ‘Elcctrochomjfttry' : Firwt English Erl Elsevier Publishing Co., 1963, p. 60.

li. F. A. Cotton and CL W ilkiksox , ‘Advanced Inorgan Chemistry*, 2nd Ed., Wiloy Eastern P v t. L td.. 197 p. 637.

7. S. P. G h o s h and A. M is h k a , ./. In d ia n Chem. Sor., 19740. 80.

8. P. R a y a n d IT. S a h a , .7. In d ia n Chem. Soc.. 1937, 1675, 680.

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