This article was downloaded by: [State University NY Binghamton] On: 02 May 2013, At: 00:33 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/lsrt19 Novel Mononuclear and Binuclear Zinc(II), Cadmium(II) and Mercury(II) Complexes of Macrocyclic Ligands S. K. Sengupta a & Shyam Kumar b a Department of Chemistry, University of Gorakhpur, Gorakhpur, 273001 b Oil and Natural Gas Commission, B.O.P., Bombay, India Published online: 05 Dec 2006. To cite this article: S. K. Sengupta & Shyam Kumar (1983): Novel Mononuclear and Binuclear Zinc(II), Cadmium(II) and Mercury(II) Complexes of Macrocyclic Ligands, Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry, 13:7, 929-941 To link to this article: http://dx.doi.org/10.1080/00945718308059355 PLEASE SCROLL DOWN FOR ARTICLE Full terms and conditions of use: http://www.tandfonline.com/page/terms- and-conditions This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to
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This article was downloaded by: [State University NY Binghamton]On: 02 May 2013, At: 00:33Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH,UK
Synthesis and Reactivity inInorganic and Metal-OrganicChemistryPublication details, including instructions forauthors and subscription information:http://www.tandfonline.com/loi/lsrt19
Novel Mononuclear andBinuclear Zinc(II), Cadmium(II)and Mercury(II) Complexes ofMacrocyclic LigandsS. K. Sengupta a & Shyam Kumar ba Department of Chemistry, University of Gorakhpur,Gorakhpur, 273001b Oil and Natural Gas Commission, B.O.P., Bombay,IndiaPublished online: 05 Dec 2006.
To cite this article: S. K. Sengupta & Shyam Kumar (1983): Novel Mononuclear andBinuclear Zinc(II), Cadmium(II) and Mercury(II) Complexes of Macrocyclic Ligands,Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry, 13:7, 929-941
To link to this article: http://dx.doi.org/10.1080/00945718308059355
PLEASE SCROLL DOWN FOR ARTICLE
Full terms and conditions of use: http://www.tandfonline.com/page/terms-and-conditions
This article may be used for research, teaching, and private study purposes.Any substantial or systematic reproduction, redistribution, reselling, loan,sub-licensing, systematic supply, or distribution in any form to anyone isexpressly forbidden.
The publisher does not give any warranty express or implied or make anyrepresentation that the contents will be complete or accurate or up to
date. The accuracy of any instructions, formulae, and drug doses should beindependently verified with primary sources. The publisher shall not be liablefor any loss, actions, claims, proceedings, demand, or costs or damageswhatsoever or howsoever caused arising directly or indirectly in connectionwith or arising out of the use of this material.
NOVEL IIOIU'ONUCLEAR AND BINUCLEkR ZIXC( 11) , CADMIUM( 11) AIuD
MFRCUFfY( 11) COG'LMES OF Y i C R O C Y C L I C LIGKNDS
S.K. Senguptaa and Shyam Kumar * b
a Department of Chemistry, U n i v e r s i t y of Gorakhpur, Gorakhpur 273001
O i l and I'iaturs.1 G a s Commission, B.G.2., Bombay, India .
ABSTRACT
A novel s e r i e s of complexes o f the type l M ( D A P T I i ) X 2 1
(M = Z n ( I I ) , Cd( 11) o r Iig(11) ; D U T H = pentadenta te l igand
der ived from 2 ,6-d iace ty lpyr id ine and th iocarbohydraz ide , X = C 1 ,
Br, CH3CO0) , have been synthes ized and c h a r a c t e r i z e d by e lementa l
a n a l y s e s , e l e c t r i c a l conductance measurements and i n f r a r e d
s p e c t r a l data. The 1igand DAPTfl i s found t o behave as a penta-
d e n t a t e l igand having coord ina t ion s i t e s a t t h e p y r i d i n e n i t r o g e n ,
two azomethine n i t r o g e n s and two thioamide su lphur a toms.
Tenta t ive s t r u c t u r e s have been proposed f o r t h e s e complexes.
A l l o f t h e s e complexes conta in t e r m i n a l h y d r a z i n i c n i t r o g e n
atoms with an unshared e l e c t r o n p a i r and may take p a r t i n
n u c l e o p h i l i c condensations. Therefore , t h e r e a c t i o n s of t h e s e
complexes w i t h 2 , L d i a c e t y l p y r i d i n e have a l s o been s t u d i e d
which cause r i n g c l o s u r e and formation o f macrocycl ic l igand
complexes. Two t y p e s o f c y c l i c products , v i z . mononucl.ear
[M(L')X2] and b i n u c l e a r [M2(L' )X4]
L' = macrocycl ic l igand d e r i v e d from DAPTH and 2,6-diacetylpyridine ;
X = C 1 , B r o r Ca3COO) have been i s o l a t e d by c a r r y i n g out t h e
(M = Zn(I1) , Cd( 11) or Hg(I1) :
929
Copyright @ 1983 by Marcel Dekke, Inc. 0094-5714/83/13070929$3.50/0
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9 30 SENGUPTA AND KUMAR
r e a c t i o n s by d i f f e r e n t methods. The i n f r a r e d s p e c t r a o f t h e s e
c y c l i c products are r e p o r t e d .
I n r e c e n t y e a r s a g r e a t d e a l of i n t e r e s t i n t h e chemistry
o f metal complexes o f macrocycl ic l igands has been aroused on
account of t h e i r resemblance t o s e v e r a l b i o l o g i c a l systems l i k e
ch lorophyl l , v i tamin B , 2 end haemoglobin’ ,*. The major i ty o f
s y n t h e t i c macrocyclic l i g a n d complexes h a s been obtained by t h e
condensat ion of d i - o r polyamines with aldehydes o r ke tones . A p a r t i c u l a r l y usefu l p r e c u r s o r i s 2 ,6-d iace ty lpyr id ine , having
two r e a c t i v e carbonyl groups capable of undergoing S c h i f f base
condensat ion with a v a r i e t y of d i - and polyamines. The use of
meta ls as templa tes i n such r e a c t i o n s h a s l e d t o the s y n t h e s i s
of a l a r g e number of meta?. complexes o f macrocycl ic l i g a n d s . However, v e r y few b inuc lear macrocycl ic metal complexes have been
repor ted . The i n t e r e s t i n such complexes a r i s e s due t o s e v e r a l
reasons inc luding the s tudy of metal-metal exchange i n t e r a c t i o n ,
e l e c t r o n t r a n s f e r p r o p e r t i e s , t h e binding and t h e p o s s i b l e
a c t i v a t i o n of small s u b s t r z t e molecules between t h e metal c e n t r e s
and 8s s y n t h e t i c models f o r some m e t a l l o p r o t e i n s i n which t h e
b i o l o g i c a l f u n c t i o n i s be l ieved t o be a s ? o c i a t e d with t h e
occurrence of metal c e n t r e s i n pairs4-’.
1
1
2
With t h i s view a high d e n t i c i t y l i g a n d , 2 , L d i a c e t y l -
pyridine-bis( thiocarbohydrazone) ( GliPTH) , capable of undergoing
c y c l i z a t i o n u t i l i z i n g t h e meta l template e f f e c t has been designed.
This paper r e p o r t s the s y n t h e s i s and c h a r a c t e r i z a t i o n of z inc( 11) , cadmium( 11) and mercury( 11) curoplexea of DWTH and t h e i r r e a c t i o n s
with 2,6-diace t y l p y r i d i n e ,
EXPERIMENTAL
Thiocarbohydrazide was prepared as r e p o r t e d i n t h e 8 l i t e r a t u r e . 2,6-l)iacetylpyrFdine-bis( thiocarbohydraeone) (DMTH)
wae prepared by t h e following method.
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COMPLEXES OF MACROCYCLIC LIGANDS
-Preparat ion of the l igand D U ?
2,6-Diacetylpyridine ( 1 mol) was added t o an aqueous
e t h a n o l i c s o l u t i o n ( 6 Q , 60 ml) of thiocarbohydrazide ( 2 m l )
i n t h e presence of sodium a c e t a t e ( 2 mol). The r e a c t i o n mixture
was re f luxed f o r about 45 min., and a yellow product separa ted
out which w a s f i l t e r e d , washed w i t h an e t h a n o l i c s o l u t i o n ( 6 @ )
of sodium a c e t a t e and d i s t i l l e d water and d r i e d i n =LO.
P r e p a r a t i o n of complexes of DAPTH, [M(L)X21 (N = Zn, Cd or Hg;
I, = DAPTH; X = C 1 , B r , CE,COO) --------- ----
A g e n e r a l procedure was followed t o s y n t h e s i z e these
complexes. The procedure i n v o l v e s the a d d i t i o n of t h e l igand
DAPTK (0.02 mol) t o an aqueous e t h s n o l i c (6@, 60 m l ) s o l u t i o n
of the a p p r o p r i a t e metal salt (0.02 mol). The mixture was
re f luxed f o r s. 6-7 h r s on a water bath. A l i g h t yellow o r
l i g h t orange mas8 which appeared immediately o r on keeping t h e
s o l u t i o n overn ight was f i l t e r e d , washed w i t h e t h a n o l and h o t
water and d r i e d i n ~ c s a t room temperature .
[ H @ ; ~ ( ~ ~ C ) ( C H ~ C O O ) ~ - J Orange 55 30.5 3.0 12.7 36.5 - (30.5) ( 3 . 1 ) (12 .7 ) ( 3 6 . 4 )
a D d ? T H = 2,6-Diacetylpyridine-bis( t h i o c a r b o h y d r a z o n e ) ; mac = m a c r o c y c l i c l i g a n d d e r i v e d from DWTH and 2 , 6 4 i a c e t y l -
p y r i d i n e
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934 SENGUPTA AND KUMAR
g r e p a r a t i o n of mononuclear conlplexes of t h e m a c r o c ~ c l . i c l igand , [h!(L')X2] (I4 = Zn, Cd o r Lg; X = Cl, B r o r l;?i3COO; L' = new
macrocycl ic l iRand der ived by condensat ion o f D U T B with
2 & i a c e t y l p y r i d i n e )
-------1_
--
A comon procedure was adopted t o s y n t h e s i z e 'these
conplexes. 2 ,6-Liace ty lpyr id ine d isso lved i n aqueous e t h a n o l
(60%) (0.C1 mol i n 5 0 ml) was a d d e d t o t h e a p p r o p r i a t e DWTh
complex (0 .C1 mol) and re f luxed f o r 16-20 h r s . The c o l o u r of t h e
mixture i n t e n s i f i e d and t h e p r e c i p i t a t e ob ta ined was f i l t e r e d ,
washed wieh e t h a n o l and h o t water and d r i e d i n vacuo a t room
temperature.
P r e p a r a t i o n of b i n u c l e a r complexes o f t h e macrocycl ic l igand ,
[M2(L ' )X4] ( M = Xn, Cd o r H g ; X = C1, E r or CHgCOO) ------------- A g e n e r a l krocedure was adopted t o s y n t h e s i z e t h e s e
complexes, involv ing t h e a d d i t i o n of an e x c e s s of t h e a p p r o p r i a t e
metal s a l t t o a n aqueous e t h a n o l i c s o l u t i o n (6@, 50 ml) of
2 ,6-d iace ty lpyr id ine (0.01 mol) and th iocarbohydras ide (0.01 mol).
The s o l u t i o n was re f luxed f o r s. 20-22 h r s , and a dark yel low
or orange coloured p r e c i p i t a t e appeared which was f i l t e r e d ,
washed thoroughly with e t h a n o l and d r i e d i n vacuo a t room
temperature .
P h y s i c a l Eieasurements
The d e t a i l s of phys ica l measurements a r e t h e same as 9 descr ibed e a r l i e r .
A n a l y t i c a l Procedures
Microanalyses f o r carbon and hydrogen were performed by
t h e C.D.R.I., Lucknow, and by t h e Department of Chemistry,
B.H.U. , Varanasi . Ni t rogen was es t imated by X j e l d a h l ' 8 method.
E e t a l s w e r e es t imated by s tandard l i t e r a t u r e procedures . 10
A n a l y t i c a l d a t a of t h e complexes prepared are g iven i n
Table 1.
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COMPLEXES OF MACROCYCLIC LIGANDS 935
The zinc( 11) , cadmium( 11) end nerct , ry( li) con:plexes of
the pentadenta te l igand 2,6-diacetylpyrid ine-b ie( thiocarbo-
hydrazone) ( LiMTH) have been synthes ised by r e f l u x i n g equ.irnolar
s o l u t i o n s of the a p p r o p r i a t e x e t a l salt w i t > : Z d T i ; , both
d i s s o l v e d i i i aqueous e thanol . The r e a c t i o n s appecr t o proceed
according t o t h e io l lowing equat ion :
The e lementa l a n a l y s e s of tnc cm:,lexes sh3w 1 : 1 p e t a l
t o l igand s toichiouietry. These complexes a r e s o l u b l e i n
d i n e thy1 f o mamid e , d i n e t h g l mi l p h ox i d e end p a t i a l l y s olr. $1 e
i n n i t robenzene . The complexes do n o t m l t u p t o 25O0C. The
e l e c t r i c a l conductance o f t h e s e comglexes i n dimethylformamicle
i n d i c a t e s t h e i r n o n - e l e c t r o l y t i c na ture . a c c o r d i n g l y , t h e s e
complexes can be formulated as [M(L)X2] (where I?: = Zn, Cd.
or Hg; L = t h e p lanar pentadenta te l igand 2 ,6-d iace ty lpyr id ine-
h i s ( thiocarbohydrazone) ( DMim;) ; X = C1, br , CIijCOO).
On t r e a t i n g one mole of t h e z inc( i1) , cadmium( 11)
o r rnercury(I1) complex of DMTL with one mole o f 2 ,6-diacetyl-
pyr id ine , i n t e n s e l y coloured products were i s o l a t e d . It appears
t h a t i n the zinc( 11) , cadmium( 11) and mercury( IT) complexes
of DAPTH t h e t w o te rmina l hydraz in ic groups remain uncoardinated
and can t a k e p a r t i n n u c l e o p h i l i c condensat ions wi th
2 ,6-d iace ty lpyr id ine , g iv ing r i s e t o metal complexes o f
macrocycl ic l igands . The r e a c t i o n s appear t o proceed accord ing
t o Scheme I.
However, i f t h e r e a c t i o n s are c a r r i e d o u t i n s i t u , i . e . ,
t h e meta l s a l t , th iocarbohydraz ide and 2 , 6 4 i a c e t y l p y r i d i n e a r e
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936 SENGUPTA AND KUMAR
I BH I IJH 2
PX
e than01 --- 2
Scheme I
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COMPLEXES OF MACROCYCLIC LIGANDS 937
rrixed t o g e t h e r i n e t h a n o l and r e f l u x e d , an e n t i r e l y d i f f e r e n t
b i n u c l e a r , , r oduc t i s o b t a i n e d . The r e a c t i o n s may be proposed
t o p roceed a c c o r d i n g t o Scheme il.
The metal t o l i g i ind s to ic ! i iomet ry o f all o f t h e s e
p r o d u c t s h a s been e s t a b l i s h e d on t h e b a s i s gf e l e r e n t a l
a n s l y - e s ( T a b l e 1 ) . These complexee have h i g h E e l t i n & p o i n t s
( ) 2 C O o C ) and a r e so lu .b le i n d i m e t h y l f o r m r i d e and dia3ethql-
su lphox ide . The complexes Sehave a,c n o n - e l e c t r o l y t e s i n
d in le thyl formamide . S i n c e t h e s e c y c l i c p r o d u c t s cou ld n o t b e
i s o l a t e d i n t h e absence of an p e t a l i o n , t h e B n ; l i ) , C d ( 1 i )
and Elg(I1) i o n s a p p e a r t o a c t as k i n e t i c ' t e m p l a t e s ' .
e t h a n o l 1 h3c / m 3
\ c N c
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938 SENGUPTA AND KUMAR
The pentadenta te l igcnd 2 , G-d iace t y l p y r id ine-b i o -
(t;iiocurbohyi'razoue) ( D , d T L ) showe bands due t o the pyridi ' le
r i n p , the thioamide group, t h e apiino q r o u p 3nd t h e hyclrazine
o r azomothine g roup .
Tile i n f r a r e d s p e c t r u x of t h e l i f m d IJMTi i shows
b ~ i i c ; ~ ::.t 1560, 1210, 1080 tnd 770 c111-l which a r e nseigned t o
triioai;!iae-I, -ii , - ;.:;ia -;i' v i k a t i o n ? , resQect ive ly
The l i g z n u s conta in ing the hlI-C=S group c m vnaerzo thioi le t h i o l
t:Automerim. iiowever, the ap,eer:-Nnce of f o u r tkiioazide barids
i.; t h o o jec t ru i , i of the y r e P e i t l i ~ c ; ~ t c - t h e e x i s t e n c e
01 the l igand in t;i e t k i o n e fornll'. The thionmide-iV band has
been fou.nd t o have a maximum 3 C = S cont r i 'u id ion . I n the complexes
t h i s bznd s h i l ' t s t o lower frequency ( - 2 5 cin- j sugzes t ing t h e
c o o r d i a i - t i o n 01' $he s u l p h u r &tom t o the n e t e l 1 2 ' 1 3 . The new bands
appearing i n t h e complexes a t 2. 340-300 cm-l nay be ass igned
11,12
1
t o J(I4-S).
The l igand chows a weak band t i t s. 1 6 5 C c m - ' , which c x i be 14 a s s i g i e d t o the J ( C = h ) v i b r a t i o n of the azoniethine l i n k a g e .
The apQearance of a weak J ( C = A ) i s ii? :Iccord w i t h the observa t ion
of s e v e r a l o t h e r workers 1 4 , 1 5 . The band due t o
a t a s l i g h t l y lower r e g i o n (- 1620-1610 cm-l) i n the complexes
sugges t ing t h a t t h e n i t r o g e i atom of t h e azomethine is coordin'ated
t o t h e metal atom14. The bands ap jear i i ig i n the r e g i o n 400-360 em-
may b e assigned t o J ( P 1 - N ) v i b r a t i o n s
J(C=L>I) apL3ears
1
16 . The p y r i d i n e r i n g v i b r a t i o n s most a f f e c t e d by p y r i d i n e
n i t r o g e n coord ina t ion t o a metal atom are 8a ( p y r i d i n e ring
deformat ion) , 6a ( in-p lane r i n g deformation) and 16b (out-of-plane
deformation) 17'18. These v i b r a t i o n s ap$ear a t 1580, 620 and
410 cm-', r e s p e c t i v e l y i n the f r e e l igand . I n a l l the complexes
these bands Show a s h i f t t o h i g h e r energy (-30-lC cm-')
i n d i c a t i n g c o o r d i n a t i o n of the p y r i d i n e n i t r o g e n t o the metal
atom I7*l8. The J(M-Py) v i b r a t i o n s are l o c a t e d a t 2 .275-250 cm- . 1
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COMPLEXES OF MAcBocycL1c LIGANDS 939
1 The l igand DAPl% n7so T:ID'IO ?, .!poac' k . : C ; t 3250 cm- , a long with t w o shoulders a t 1280 and 3230 cm-l which may be ciue
t o 3 sym(XH) and
t h e s e bands p e r s i s t , i n d i c a t i n g the non-coordination of t h e
te rmina l a r i n o group t o the metal atom.
Jasym(iW) ~ i b r a t i o n s ' ~ . In the complexes
On t h e b a s i s of t h e above s p e c t r a l f e a t u r e s a seven
coordiinated s t r u c t u r e nay be sugpested f o r t h e Zn(LI) , Cd(I1)
and hg(Ii) complexes of DAYTk i n which t h e l igand coord ina tes
v i a t h e p y r i d i n e n i t r w e n ) t w o azorm th ine n i t r o e e n s and two
thioamide su lphur atoms and t h e two a x i a l pos i t io i i s a r e
occupied by d i f f - e r e n t anions.
The i n f r a r e d s p e c t r a of the macrocyclic complexes d o n o t show
any s igni f i . can t changes. however, t h e
Only one band i s observed i n t h e J ( N h ) reg ion a t 3210 cm-', which
may be due t o t h e secondary amino group, e s t a b l i s h i n g the
condensat ion o f the p r i n a r y amino group with the carbonyl group
of 2 ,6-d iace ty lpyr id ine . This i s f u r t h e r supported by the appearance
of a very weak band a t 1 6 4 0 cm-' i n t h e [M(L')X2] complexes,
e s t a b l i s h i n g t h e f o r n a t i o n of a n azsmethine l inkage . I n t h e
b i n u c l e a r complexes t h i s band d i s a p p e a r s , which may be taken a s
evidence f o r t h e coord ina t ion of t h e azomethine n i t r w e n t o
a n o t h e r metal atom. F u r t h e r , t h e medium o r weak bands apaearing
a t 9. 1570, 620 and 420 cm-' i n t h e [M(Lt)X2] type complexes,
may be due t o 8a, 6a and 16b v i b r a t i o n s of t h e non-coordinated
p y r i d i n e moiety17. I n b i n u c l e a r complexes t h e s e bands s h i f t t o
h i g h e r f requency and overlap with t h e coordinated pyr id ine r i n g
v i b r a t i o n s of the f i r s t metal. A s a r e s u l t broad bands appear a t
2. 1590, 630 and 425 crn-'. This confirms t h e coord ina t ion of t h e
second p y r i d i n e n i t r o g e n t o another metal atom. The s p e c t r a l
f e a t u r e s i n conjunct ion with t h e i n t e n s e c o l o u r o f the complexes
support t h e formation of macrocycl ic l igand complexes. The i n t e n s e
colour o r i g i n a t e s from a high degree o f conjugat ion p r e s e n t i n
t h e macrocycl ic systems.
d(Nh2) bands d isappear .
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SENGUPTA AND KLIMAR 940
I n a d d i t i o n t o t h e above bands t h e c h l o r o and bromo
complexes of Z n i L i ) , C d ( I i j and &(Xi) show bands ;it c g . 360-740
and 310-700 cm-' which may be a s s i g i e d t o ~ ( N - C l ) and J(?!-iir)
v i b r a t i o n s , r e ~ p e c t i v e l y ' ~ . The i n f r m e d c p e c t r a o f tk.e a c e t a t o
complexes s h o w bands a t s. 154@-153C and 1270-1260 cm-' due t o
asymmetr ic arid e y m e t r i c COO s t r e t c h i n g v i b r a t i o n s and conf i rm
t h e p r e s e n c e o f a c o o r d i n e t e d a c e t a t e g roup i n t h e con!?lexes.
I? EFER LdCES
1 . G.A. F e l s o n , " C o o r d i n a t i o n C h e n i - t r y of M a c r o c y c l i c Compounds"
Plenum y r e s s , New Y o r k , ( 1979) .
2. F. L i o n s , Rev. k p A ~ l . P u r e Chen . , 2 , 177 (1369).
3 . S.1.l. N e l s o n , Pure and Ap21. Chem. 2, 2461 ( 1 9 8 0 ) .
4. J.S. P i c h a r d s o n , K . d . Thomas, L.U. R u b i n and D.C. R i c h a r d s o n ,
r r o c . Nat. acad . S c i . U . S . A . , 'p, 1349 ( 1 9 7 5 ) .
5. K.K. beem, D.C. R i c h a r d s o n , and K.V. R a j g o p a l a n , B i o c h e m i s t r y ,
-- 1 6 , 1930 ( 1 9 7 7 ) .
6. A.F. Tweedle, I,. J. b i l s o n , I,. G a r c i a I n i g u e z , G . T . Babcock and
G. P a l m e r , J. 3 i o l . Chem., a, 8065 ( 1 9 7 8 ) .
7. M.Y. Okamura, I.M. Kota , C.E. Johnson , M . R . C . Winter and R.J.?.
Williams, i j i o c h e m i s t r y , 8 , 1951 (1969) .
8. G . R . Burns, I n o r e . Chem., 9 , 227 ( 1 9 6 8 ) .
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- 1 2 , 113 ( 1 9 8 2 ) .
10. A . I . Voge l , "A Text Book of Q u z n t i t a t i v e I n o r g a n i c A n a l y s i s " ,
Longman's Green Co. L t d . , London, 1360.
1 1 . S.K. S a h n i , and V.B. Rana, I n d i a n J. Chem., m, 890 ( 1 9 7 7 ) .
12. S.K. S e n g u p t a , S . K . S a h n i and R.N. Kapoor , Synth . React.
Ino rg . Met.-Org. Chem., lo, 269 ( 1 9 8 0 ) ; I n d i a n J . Chem. a, 707 (1980) .
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COMPLEXES OF MACROCYCLIC LIGANDS 941
13. S.r.. S z ? , ~ u ; , t a , R.1;. S b h n i , 2nd l ? . , d . k a p o m , Acta Chiz1. licr;d.
S c i . Lung. , SA, 69 { 13PO).
1 4 . S . kher , S.2.. St lhni , P. Luxar i and R . i . Aapoor , Inor:-. Chi:?.
i icta, 2, 121 ( 1 9 7 9 ) .
15. S.L. StJ.hni, I r a n s i t i a n Ket. Chem. 4, 73 f 1979).
16. J . R . E'eq-raro, "LOW Frecuency V i t i r a t i o n s o f 1nmgr .n ic end
C o o r d i c t t i o n Comp~unds" , Plenum 2 - s ~ ;Jew York, 1371.
17. D.P. hiadden, I;.i'I. d a h o t a , and S.!,. N e l s o n , J. Chern. S o c . ,
A, 890 ( 1 9 7 0 ) .
1 E . 2.1. hcdden , and 9.11. d e l P o n , 2. Cheo.. Soc. , ,k, 2342 (1968) .
19. Y. l a lczrnoto , " I n f r a r e d S p e c t r a o f I n o r q a n i c and Co3rdinTtiorl
C si., 0 7 1 i c 7 'I , W i l o j I.iter s c i e n c e , new Y ork , 19 70.
