professor manihar thesis
DESCRIPTION
METAL ION PROMOTED ADDITION OF ALCOHOLS TO PHENYLDICYANDIAMIDESTRANSCRIPT
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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
, S s&U sm
Ssjetim
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 *
1* E.N.Zil'bermann, Hu3s.Ch0m.Rev*, 1969, 331.
2. A.Pinner and ? .Klein, Ber., 1878, 11, 1478.
3. K.Hoeseh, Ber., 1916, 48, 1122.
4 . I*.Gattermann and J.Xoch, 3 e r ., 1897 , 30, 1622.
6 . H. Stephen, J . Chem. Soc• , 1926, 127, 1874 *
6 . ?.Tiemann and L.?riedlander, Ber., 1881, 14, 1967.
7. S.M.McElvain and M .A.Goese, J.Am.Chem.Soc.,1924,126,1348.
8 . K.Sakai, T.Ito and K.Watanabe, Bull.Chem.Soc.Japan,
1967, 40, 1660.
9. S.Komiya, S.Suzaki and K.Watanabe, Buil.Chem.Soo.Japan,
1971, 44, 1440.
10. P.Friedlander and T.Weisberg, Ser ., 1S96, 28, 1841.
11. A.Cahours, Compt.rond., 1848, 27, 239.
12. F.V.Dechend, Ber., 1874, 7, 1273.
13. J.U .Nef, Ann., 1896, 287, 266.
F.C.Schaefer and G.A.Peters, J.Org.Chem.,1961,26,412.
14. R.L.Dutta and P.Hay, J.Indian Chem.Soc.,1969,36,499.
16. F.Klein and A.Pinner, Ber., 1878, 11, 1826.
16. H.Beckurtz and R.Otto, Ber., 1876, 9 , 1690.
17. G .J.Janz and S.S.Danyluk, J.Am.Chem.Soc. ,1969,81,3°4«:.
18. J.Troger and O.Lunning, J.Prakt.Chem., 1909,69,347.
19. A.Ya.Lazaris, S.S.Zil'bermann and 0. D. Strizha.cov,
Zhur.Obseh.Khim., 1962, 32, 900.
20. A.V.Cobb and J.H.Walton, J.Phys.Chem.,1937, 41, 361.
21. R.Pschorr, 0 .Wolfes and V.Buckov, Ber., 19CO,33,170.
22. A.Colson, Compt.rond., 1896, 121, 1166.
r- 42 -
23. M.T.Bogert and A.H.Gotthelf, J . Am.Chem.Soc. ,1900,22,622,
24. A.Bernthsen, Ber., 1876, 9 , 429.
25. E .Cornell, J .Am.Chem.SoG., 1928, 50, 3311.♦
26. E.A.Werner and J.Bell, J.Chem.Soc.,1922, 121,1790.
27. P.Ray, Chem.Revs., 1961, 61, 313.
28. E.Nordmann, Ber., 1884, 17, 2746.
29. E.Muller and L.Herrdegen, J.Prakt.Chem.,1921,102,113.
30. C.Engler, Ann., 1867, 142, 65.
31. A.Gautier, Ann., 1867, 141, 122.
32. E.E.Blaise, Compt.rend., 1901, 132, 38.
33. L « S.HinKel and R .T . iXtnn, J .Chem. Soc. , 1931, 3343 .
34. E.Klarmann and W.Figdor, J.Am.Chem.Soc., 1926,48,803.
E.Klarmann, J.Am.Chem.Soc., 1926, 48 , 791,2358.
35. V.Migridichian, *The Chemistry of Organic Cyanogen
Compounds1, Reinhold Publ.Corp.,1947,p .349.
36. R.Fioltzvart, J.Prakt.Chem., 1889, 39, 230.
H.Adhins and G.Whitman, J.Am.Chem.Soc. , 1942, 64,152.
37. A.H.Cook and D.G.Jones, J.Chem.Soc., 1941, 278.
38. S.Yamaglda, M.Yokoe, I.Katagiri, M.Ohoka and S.Komori,
Bull. Chem. Soc. Japan, 1973, 46 , 306.
39. R.L.Dutta and A.Syamal, Coord.Chem.Rev. ,1967, 2, ^41.
40. P.?.B.Barnard, J.Chem.Soc.(A), 1969, 2141.
^1. I.M.Procter, B.J.Hathaway and P.Nicholls,
J.Chem.Soc.(A), 1968, 1678..
42. R.A.Walton, J.Inorg.Nucl.Chem., 1966, 28, 2223.
43. S.Suxuki, M.Nakahara and K.Wantanabe,
Bull .Chem. Soc. Japan, 1971, 44, 1441.
44. R.L.Dutta and S.Lahiry, J.Indian Chem.Soc.,1960,37,7P9.
43 -
45. R.L.Dutta and S.Lahiry, J.Indian Chem.Soc.,1961,38,689,
46. K.Kawano and K.Odo, J.Chem.Soc.Japan, 1961,82,1672*
47. F.H.S.Curd, D.G.Davey and D.N.Richardson,
J • Chem • Soc • , 1949, 1732 •
48. G.A.Diana, S.S.Zalay and R.A.Cutler Jr .,
J •0pg•Chem., 19€f , 30, 298.
49. R.L.Dutta and A. Syamal, J.Indian Chera.Soc.,1967,44 ,6f9.
50. W.A.Baker and H.Daniels, J.Inorg.Hucl.Chem. ,1963,26,1194.
61. H.Ley and P.Werner, 3er., 1913, 46 , 4O4O.
62. P.Ray and G.Bandopadhyay, J.Indian Chem.Soc.,
1962, 29, 866.
63. Dumount, Mettalvirtschaff, 1929, 7, 28.
54. H.Grossman and B.Schuck, 3 e r ., 1906, 39, 3366;
1910, 43, 674.
66. T.Joria, Gazzetta, 1907, 37, 661.
66. Hagg, Annalen, 1862, 122, 31.
67. P.Ray and B.Sur, J.Indian Chem.Soc., 1969,36,798.
68. P.Ray and N.Kundu, J.Indian Chem.Soc., 1962,29,811.
69. P.Ray, J.Indian Chem.Soc. , 1966, 32, 141.
60. K.H.Slotta and R.Tschesche, Ber., 1929, 62, 1390.
61. R.L.Dutta, J.Indian Chem.Soc., I960, 37, 499.
62. B.Das Sarma, J.Indian Chem.Soc., 1962, 29,217. .
63. P.Ray and B.Da3 Sarma, J.Indian Chem.Soc. ,1966,3"5,841.
64. R.L.Dutta and P.Ray, J.Indian Chem.Soc., 1969, 36, 667.
66 . D.Foster and D.M.L.Goodgame, Jnorg.Chem.,1966, 4 , 823.
66. M.Gobdgame and L.I.B .Hains, J.Chem.Soc.( A ),1966,174.
67. J.R.Wasson and C.Trapp^ J.Ph.Chem., 1969, 73, 376.3.
- 44
68. R.L.Dutta and D.De, J.Indian Chem.Soc., 1969,46f63.«
69. R.Drago, 'Physical Methods in Inorganic Chemistry’
Reinhold Publishing Corp., New York, 1966.
70. L.Coghi, A.Mangia, M.Nardelli, G.Pelizzi and L.£ozzi,
Chem.Comun., 1968, 1478.
71. R.L.Dutta, D.De and A.Syamal, J.Indian Che'n.Soc.,
1967, 44, 363.
72. R.L.Dutta and P.Ray, J.Indian Chem.Soc., 1959,36,676*
73. V .Rasmussen and V.A.Baker, J.Chem.Soc.(A), 1967,580.
74. R.L.Dutta and A.Syamal, J.Indian Chem.Soc.,1968,45,213.
75. P.Ray and S.P.Ghosh, J.Indian Chem.Soc.,1943,20,291,327.
76* R.H.Holm and ? .A.Cotton, J.Chem.Phys.>
1959, 31, 788; I960, 32, 1168.
77. P.A.Cotton, O.D.?aut and J.T.Hague, Inorg.Chem.,
1964, 3 , 17.
78. A.Truco, C.Pecile and M.Nicolini, J.Chem.Soc.,1962,3008.
79. L.Sacconi, M.Ciampolini and G.P.Speroni,
Inorg.Chem., 1965, 4 , 1168.
80. D.P.Graddon and 3 .C.Walton, Australian J.Chem.,
19.66, 18, 507.
81. M.M.Jones, 'Elementary Coordination Chemistry1
Prentice Hall, 1964, p. 155.
82 . R.L.Dutta, B.Sur and N.R.Sengupta, J.Indian Chem.Soc.,
1960, 37, 673.
83. R .L .D u t ta and A.Syamal, J.Indian Chem.Soc.,1968,45,115.
84. R .L .D u t ta and A.Syamal, J.Indian Chem.Sdc.,1968,45,127.
85. R .L .D u tta and A.Syamal, J.Inaian Chem.Soc. ,1968,45,1.38.
- 46 -
86 . B.Bosnich, M.L.Tobe and G.A.Webb., Inorg.Chem.,
1966, 4, 1109.
87. S.Lenzer, J.Chem.Soc., 1964, 6768.
88 . J.C .Bailar, 'Chemistry of Coordination Compounds ,
Reinhold Publishing Corp., 1966, p .338.
89. R.L.Dutta and A.Syamal, J.Indian Chem.Soc.,
1968, 46, 219.
90. R.L.Dutta and A.Syamal, J.Indian Chem.Soc.,
1 9 6 8 , 4 6 , 1014.
91. R.L.Dutta and A.Syamal, J.Indian Chem.Sod.,
1968, 46, 226.
92. C.K.Jnr^orsen, ’Absorption Spectra and Chemical Bonding*,
Pergramon Press, 1962, p .109.
93. P.A.Cotton and G.Wilkinson, 'Advanced Inorganic Chemistry’,
Interscience Publ. Inc ., New York, 1962, p .679.
94. R.L.Dutta, B.Sur and N.R.Sengupta,
J.Indian Chem.Soc., 1960, 37, 566.
96. R.L.Dutta and S.Lihary, J.Indian Chem.Soc.,
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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