Nickel(II) heterochelates

|NOEG.

NUCI..

CHEM.

LETTERS

¥oL

4,

pp.

625-629,

NICKEL(II)

1968.

Pergamon Press.

Printed in

Great

Britain.

HETEROCHELATES*

A. Syamal Dept. of Chemistry, Emory University Atlanta, Georgia 30322, U.S.A. ~R~,d1!

July 1968)

As a part of our work on the synthesis, resolution and kinetic metals

characterization,

studies on heterochelates

of transition

(1-7), this communication reports the synthesis of some

nickel(ll)

heterochelates,

orthophenanthroline

the ligands used being picolylamine,

and ~ - ~ ' - d i p y r i d y l

having N-C-C-N chelating

group in common. Heterochelate

complexes

of metal ions may be readily

thesized provided that the complexes are inert.

syn-

A number of

working schemes could be conceived so as to lead to such synthesis: (i)

The addition of bidentate

ligand(s)

to the mono or bis

complex. (2)

The breaking o f ~ - d i o l

type complex by a bidentate

ligand at a suitable pH. (3)

Ligand exchange in the tris complex.

(4)

Direct synthesis.

Whereas

the third and fourth schemes are in exploratory

stage in

this laboratory for the synthesis of Mn(lll), Fe(III),V(IV) Mo(VI) heterochelates,

and

the outcomes of the first and second schemes

have been reported earlier

(1-7).

In the present work the first

scheme has been utilized for the synthesis of nickel(ll)

This work was carried out at the Dept. of Burdwan, Burdwan, India.

625

of Chemistry,

heteroche-

University

(P21

lates.

HICKEL(II) HI[TIEROCHELATIES

Y*I. 4, He. 10

The probable drawback for the isolation of heterochelate

complexes is the danger of formation of homochelate However, thls difficulty

complexes.

could be overcome by working at a suit-

able pH and under controlled conditions. Dichloro mono-plcolylamlno react wlth two molecules orthophenanthrollne,

nlckel(II)

(8) has been found to

of strongly chelating llgands such'as

0(- ~'-dlpyrldyl,

etc. in methanol solution

at the temperature of steam bath, resulting In the formation of new nlckel(II)

heterochelate

complexes.

In aqueous medium indicate bl-unlvalent

Conductance measurements nature of the complexes.

The room temperature magnetic susceptiblllty measurements were done on solid specimens In a Gouy Balance and the complexes were found to be paramagnetlc

(~B

= 2.9 - 3.i B.M.).

The electronic

absorption spectra In aqueous solution were recorded In the range 10,000 ~ 25,000 cm "l In a Hllger Uvispeck Spectrophotometer

using

one cm. cells and the complexes were found to exhibit bands around 12,600 cm -1 and 19,200 cm -1.

The appearance of these two

bands wlth low intensity Is typical of octahedral nlckel(II) plexes

(9, 10).

com-

The complexes are quite stable In the solid state~

being not decomposed on heating at 120°C for hours.

The colour

of these complexes Is plnk In contrast to the bright green colour of the he~a-aquo nlckel(II)

ion.

Thls Is because of shifts in

the absorption bands when aquo molecules are replaced by strong field llgands llke plcolylamlne dlpyrldyl.

and orthophenanthroline

or

~-~'-

Magnetic moments are also In accord with the octahed-

ral configuration

(9, 10).

Equivalent weights of the complexes were determined by runnlng the aqueous solutions through H + form of a cation exchange resin (Amberllte IR 120) column and then tltratlng the eluate wlth standard NaOH.

Equivalent weight values agree well wlth the the-

%N

%ci

Analytical results

%Ni

8.57 12.20 10.31 13.08

Reqd:

318

350

315

344

Found Reqd~*

235

230

Molar conductance *** mhos ~m 2 mole -~

2.95

3.11

Magnetic moment (B.M.) T=3030

11.5

19,420 I19,230-

Chemistry", Prentice Hail, 1964, p-254.).

*** Expected range of A M for 1:2 electrolyte is 225-270 mhos (M. M. Jones,

"Elementary Coordination

** These values have been deduced on the basis of elemental analysis and conductance measurements.

7.0

6.8

12,50012,660

12,50012,660

11.3

&nee

Molar absorb-

19,230

~ max cm-i

* The water is lost in all cases at IIO°C and hence it is outside the coordination zone.

= orthophenanthroline and dipy : c-~'-dipyridyl.

9.35 13.31 11.25 12.83

Found: 9.21 13.20 LI.O0 12.42

Reqd:

where Pic-am = picolylamine;ophen

4.5 H20

[Ni(Pic-am)(dipY)2]Cl ~"

5H20

Equivalent

0* weight

[Ni(Pic-am)(ophen)2]Cl 2- Found: 8.32 12.41 I0.I0 13.47

Compound

Analysis, Molar Conductance, Equivalent Weight, Magnetic Moment and Spectral Character of Nickel(II) Heterochelates

TABLE I

-4

p-

o

m

x

m r

R

z

62B

HICKEL(II) HETEROCHELATES

Yoh 4, No. 10

oretical values. The analysis,

electrical

spectral characteristics heterochelates

and magnetic moments of the nickel(ll)

data alone does not preclude the possibility

of homochelated

when the heterochelate nickel(ll)

equivalent weight,

are given in Table i.

Analytical 2:1 mixtures

conductance,

tris complexes.

picolylamino

of

It was observed that

bis(ortho-phenanthroline)

chloride was dissolved in 3N HCI, the original red col-

our gradually turned blue and on standing deposited blue shining crystals of bis(ortho-phenanthroline)nickel(ll) hydrate.

~ Found:

17,860 cm -I. CI, 1 2 . 2 4 ~ nickel(ll) cm -I.

Ni, 10.22; N, 9.60; CI, 12.02~;

[Ni(phen)2 .

chloride penta~max

=

C12]. 5H20 requires Ni, 10.17; N, 9.65;

x '-dipyridyl

The mono oft ho-phenanthroline/

ion usually absorbs

(ii, 12) around 16,390 - 16,660

In 3N H2S0 ~ solution the heterochelate

[Ni(Pic-am)(ophen)2]Cl 2.

5H20 exhibits a peak around 18,510 cm -I, it shifts further to 16,660 cm -I in 5N H2SO 4 solution and still retains the blue colour. These changes on increasing acid concentration the presence

is reminiscent with

of firstly a bis and then a mono ortho-phenanthroline/

-~' -dipyridyl complex of nickel(ll)

(11,12).

Experimental Dichloro mono-picolylamino

nickel(ll)monohydrate

was prepared

according to the method presented by Utsuno and Sone (8). General method of syntheses

of the nickel(ll)

Dichloro mono-picolylamino

nickel(ll)monohydrate

mole) and o r t h o p h e n a n t h r o l i n e / ~ - ~ ' - d i p y r i d y l dissolved separately

heterochelates: (i.3 g, one

(two moles) were

in minimum amount of methanol.

These two

solutions were then mixed and the resulting pink solution was refluxed on a steam bath for half an hour.

The solution was then

Voh 4, He. 10

FIICKEL(II) HETEROCHELATES

629

cooled and to this was added few millilitres The separated imum amount

pink crystals

of methanol

washed with ether. solid CaCI 2.

were filtered

of ether with stirring.

off, redissolved

and again precipitated

with ether and

The compounds were dried in a desiccator

over

Yield = 70%.

Further work on similar other nic~el(ll) copper(ll)

in min-

heterochelates

and.corresponding

is in progress.

Acknowledgement~s: The author wishes Dutta of Department U.S.A.,

to record his heartfelt

of Chemistry,

for keen interest

thanks to Dr. R. L.

Ohio State University,

and constant

Columbus,

encouragement.

References i.

R. L. DUTTA and A. SYAMAL, (1965).

J. Inorg.

Nucl.

Chem.,

2.

R. L. DUTTA and A. SYAMAL,

Coord.

3.

R. L. DUTTA, 526 (1966).

A. SYAMAL and S. GHOSH,

4.

R. L. DUTTA,

D. DE and A. SYAMAL,

5.

A. SYAMAL,

6.

R. L. DUTTA and A. SYAMAL,

7.

A. SYAMAL, et al., Ind. J. Chem., (India), (in press).

8.

S. UTSUNO and K. SONE, Bull.

9.

C. J. BALLHAUSEN, Introduction to Ligand Field Theory, Hill Book Co., I n ~ . ] - ~ Y - ~ 7 3~-[ ~

Chem. Revs.,

2_~7, 2447

2, 441 (1967).

J. Ind. Chem.

ibid,

Soc.,

43,

4~4, 353 (1967).

ibid, 45, 74 (1968). ibid, 45, 219, 226 (1968).

Chem.

(in press);

J. Inst.

Soc., Japan,

Chem.

37, 1038

(1964).

McGraw

i0.

F. A. COTTON and G. WILKINSON, Advanced Inor@anic Chemistry, Interscience Publishers, Inc., New York, 735 (1962).

Ii.

F. BASOL0, J. C. HAYES and H.M. NEUMANN, 5102 (1953).

12.

R. G. WILKINS and M. J. G. WILLIAMS, P. ELLIS, R. HOGG and R. G. WILKINS~

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