Metal complexes of 5-(o)hydroxyphenyl-1,3,4-oxadiazole-2-thione

450

Notes Table 2.

CI2HIINsOS 3060

M(CI2R9N3OS)X 3060

Assignments* st~egching

N-H, C-H

2650

--

S-H

1680

1680

C=N

710

600

C-S

480

M-N

430

M-S

450

M-O

e

CI2HilN302

M(CI2H9N302)X

Assignments

3100

356O

--

O-H

~

1680

1680

C=N

,

850

C-H, N-N

atl, e t e h i n g

3100

800

C-O

,,

500

M-N

~

450

M-O

I

All frequencies aze in cm -I

substantiated by the decrease in the C-S stretching[l 1-13] from 710 to 600cm-~. The presence of new bands at between 400 and 500cm-~ indicates coordination through N, O and S in the complexes. A square planar structure for the Cu(II) complexes is supported by their magnetic properties. The complexes have/~ between 1.73 and 1.76B.M. In case of a tetrabedral complex they would have been between 2.00 and 2.20 B.M. [14]. This structure is also supported by the maximum absorption band[15] at 13,000 cm-'. The magnetic properties and spectra of the nickel and palladium complexes indicate that they are square planar.

Post-graduate Department of Chemistry Y. THAKUR Mithila University BODH NARAIN JHA Darbhanga, Bihar India REIClgR£NCKS 1. V. Hovorka and V. Zatka, Chem. Listy. 51,410 (1957). 2. A. I. Vogel, A Text Book o[ Practical Organic Chemistry, p. 344. Longmans, London (1%2). 3. F. G. Mann and B. C. Saunders, Practical Organic Chem-

istry, p. 203. Longmans Green, London (1952). 4. J. Selbin, W. E. Bull and L. H. Holmes, J. lnorg. NucL Chem. 16, 219 (1960). 5. R. B. Penland, S. Mizushima, C. Curran and J. V. Quagliano, J. Am. Chem. Soc. 79, 1575 (1957). 6. A. Yamaguchi, T. Miyazava, T. Shimachi and S. Mizushima, Spectrochim. Acta 10, 170 (1957). 7. K. Nakamoto, IR Spectra of Inorganic and Coordination Compounds, p. 185. Wiley, New York (1%3). 8. T. J. Lane, D. N. Sen and J. V. Quagliano, J. Chem. Phys. 22, 1855 (1954). 9. A. Yamaguchi, R. B. Penland, S. Mizushima, T. J. Lane, C. Curran and J. V. Quagliano, J. Am. Chem. Soc. 80, 527 (1958). 10. D. K. Stranb, R. S. Drago and J. T. Donoghue, lnorg. Chem. I, 849 (1%2). 11. P. C. H. Milcbell and R. J. P. Williams, J. Chem. Soc. 3091 (1%1). 12. M. M. Chamberlin and J. C. Bailor, J. Am. Chem. Soc. 81, 6412 (1959). 13. J. Chatta and L. A. Duncanson, Nature 178, 997 (1%6). 14. M. Calcin and C. H. Berkelew, J. Am. Chem. Soc. 68, 2267 (1946). 15. R. S. Nyholm, J. Chem. Soc. 14 (1954).

J. inorg, nucL Chem. Vol. 42, pp, 450--453 Pergamon Press Ltd., 1980. Printed in GRat Britain

Metal complexes of 5-(o)hydroxyphenyi-l,3,4-oxadiazole-2.thione

(Received for publication 23 July 1979) Some 5-substituted-l,3,4-oxadiazole-2-thione(I) ligands have been reported to be biologically active[l, 2]. In our[3] previous work it has been reported that complexes of this ligand are also biologically active. In the present investigation we report the

formation of complexes of Cu(I), Ag(I), Fe(III), Co(lI), Ni(II) and Zn(II) with 5-(o)hydroxyphenyl-l,3,4-oxadiazole-2-thioneas ligandand established their structure on the basis of IR, UV analyticaland magnetic susceptibility data.

Notes

451

Table 1. Analytical and magnetic data for the 5-(o)hydroxyphenyl-l,3,4-oxadiazole-2-thionemetal complexes yound/(Catca)% complex (a)

C

Fel 3

Co~2

~o. of unpaired electron

Colour h

~

~iets.l

Violet

45.3

2.7

13.43

8.95

blac~

(45.5)

(2.5)

(13.23)

(8.79)

Srown

43.25

hi~ 2

Green

CUL

Pale Green

Oalcd.

S.~. foumd

5

5.838

3

4.435

4.1-5.2

5.9

2.4

12.45

13.3

(43.4~

(2.3)

(12.58)

(13.24)

43.2 (43.4)

2.45 (2.4)

12.65 (12.57)

13.36 (13.20)

2

~.085

2.8-4.0

37.1

1.99 (1.96)

11.2 (10.92)

24.35

1

0.8730

1.7-1.8

(37.4)

(24.7)

9.35 (9.33)

34.9 (35.6)

-

-

Ag~

~hite

32.3 (31.99)

1.69 (1.6b)

Zn~ 2

White

42.2 (4~.5)

2.2 (2.2)

12.57 (12.4)

14.7 (14.48)

(a) ~ = 5-(o)hydroxyphenyl-l,3,4-oxadiazole-2-thione.

Table 2, Assignments and shifts of IR bands of the ligand and complexes .

.

Ligand cm "I

.

.

.

.

.

=

Complexes cm "I

-

.,

•

Assignment

In ligand ~ due to superimpositions of ~ N-H and C-H

2600

-

1610

1610

1570

-

Interaction of 9 C=C and ~ CmN

]~15

-

Mixed H-N-C=S(.~; 6 N - H + 6 C-H

1450

1450 -

Oxadiazole ring skeletal

I

1

"T"

due to

Oxadiazole ring vibration

lowering but in present case shifts by 20 cm-1

1£60

i~60

Characteristics of five membered heterocyclic ring t

1030+i0

970

970

~58 755

885 e,~ 5 0 0

-

~v400

-

Disappears

Oxadiazole skeletal vibrations

lOSO

Disappars

H-N-C=S(II); due to ~ C=N + ,(C-H) ÷ ~(N-H)

I~05÷20

-

Splitting takes place

|

I~05

1045

Disappears

Indicate, dlsappearence of S-H bond

i

I~60

Shift in t h e . frequency and change in intensity

I

H-N-C=S(III) bond due to V C=S + ~asym (C-N)

Disappears

oxadiazole 5-thione vibrat~ on Major contribution from ~asym (C-N) and ~ C=S due to 8 C-O-C vibration H - N - ~ S band(IV), due to C=S ~ M-N ~

M-S

Disappears Disappears

Notes

452

Table 3. Electronic spectra for the 5-(o)hydroxyphenyl-l,3,4-oxadiazole-2-thione Complexes

Spatial arrangement

FeL 3

Oetahedral

Bands

Transition spin allowed

(CoLs) 3

(NI[.2)~

Octahedral

Oetahedral

Transition spin for bl dden

550 m/Z(2,.%571) em -I 600 m~(16666) cm -I

metal complexes

-

References

6 Alg -~ 4Eg(D )

12

G Alg -~ a"TIg(G)

1.?,

390 m~(25641) cm -I

4Tlg(O ) 2: 4Tlg(P )

12

660 m~(15385) cm -I

4TIg(F ) -~ 4~g(F)

12

400 m~(E5300) cm -I

3A~g(F) -~ 3Tlg(P )

650 mU(15385) em -I

3~2g(~ ) -) STIg(F)

N

EXPERIMENTAL

Materials and methods The chemicals used were of AnalaR chemically pure grade. The ligand was prepared by the method given by Young and Wood[4]. It was prepared by catalyzed cyclization of salicyl bydrazide with carbon disulphide (in 60% yield) and crystalized from aqueous ethanol. IR spectra of the ligand and complexes were recorded in the range 4000--400 cm -~ using KBr pellets on a Perkin-Elmer spectrophotometer model 221. Magnetic susceptibilities were determined by the Faraday method. The electronic spectra were also recorded in Nujol mull on a Carey-14 recording spectrometer between 200 and 750 m#. Vogels methods were used to estimate the metals [5]. Analyses of the complexes were carried out at the central Drug Research Institute, Lucknow and at Banaras Hindu University, Varanasi. Preparation o/complexes 5-(o)Hydroxyphenyl-l,3,4-oxadiazole-2-thione Cu(1), Ag(1) and Zn(ll). Aqueous solutions of copper acetate (0.7 g, 3.6 m mole silver nitrate (0.7 g, 4.12 m mole) or an ethanolic solution of zinc acetate (0.7 g) were mixed with a hot ethanolic (20 cm 3) solution of the ligand (0.7g, 3.6 m mole) with continuous stirring. The solid complexes separated and were filtered, washed several times with water and then with hot ethanol to remove unreacted ligand. The solids were then dried in vacuum. The copper complex was green. 5-(o)Hydroxyphenyl-l,3,4-oxadiazole-2-thione)iron(lll). A mixture of ferric chloride (0.6 g, 3.7 m mole) and ligand (0.7 g, 3.6 m mole) containing sodium acetate (0.8g) was refluxed in ethanol (60 cm~) for 4 hr on a water bath. The violet black solid, thus obtained was washed several times with water and hot alcohol to remove excess of reactants. Similarly, the complexes of cobalt (using cobalt(ll) chloride), Nickel (using nickel(ll) chloride) were also prepared. The complexes are insoluble in all common organic solvents however the Ni(ll), Co(ll), Fe(lll) and Zn(ll), complexes are soluble in hot DMF. All complexes melt and decomposed at high temperatures (> 250°C).

~11

-

12

NH

,.,, ,,~11

I )--- C,.o..C

12

S~

N~N

II

•~L._j~--C.~ 0 C ~ S H

OH

OH Or)

(i)

A systematic interpretation of the vibrational spectrum has not been made. It has been reported by Rao et aL and Suzuki[8-10] that there exist four thioamide bands in the ligand due to mixed vibrations of p(C=S), J,(C-N), 8(C-H) and ~(N-H). On the basis of earlier workers[7-11] tentative assignments for ligand and complexes are suggested Table 2. The electronic spectra (Table 3) and magnetic measurements (Table 17113] on the cobalt, nickel and zinc complexes suggest octahedral coordination of the metal ion, so that these complexes must be polymeric. As the electronic spectra of Cu(1) and Ag(1) complexes do not show any transition and magnetic measurement show diamagnetic behaviour, these complexes are suggested to be linear.

Acknowledgements--The authors thank Prof. R. P. Rastogi, Head of the Chemistry Department, University of Gorakhpur and Dr. Nitya Nand, Director, C.D.R.I., Lucknow, for providing necessary laboratory facilities. They also thank Prof. O. P. Malhotra, Head of the Department of Chemistry, B.H.U., for providing necessary laboratory facilities. Dr. V. J. Ram and Dr. H. N. Pandey (S.C. College, Ballia (U.P.) for valuable suggestions. Thanks are also due to C.S.I.R. for providing financial assistance to (R.A.R.). Department o/Chemistry University o/Gorakhpur Gorakhpur-273001 U.P. India

MRS. LAKSHMI* R. A, RAt

RESULTS AND DISCUSSION

REFERENCES

The ligand has been attributed the structure (I) by Pandey et al.[6] but the possibility of the tautomeric thiol form (II) being concerned in the reaction cannot be over looked. In this case complexation would take place by replacing the proton of the thiol group with the metal ion. However, thione form (I) of the ligand has been used here, a coordinate bond being formed by donating a lone pair of electron from the thiocarbonyl sulfur to the metal. According to Agrawal et al.[7], the ligand behaves as bidentate one, it either forms inner complex or polymer complex.

1. I. Mir, M. T. Siddiqui and A. M. Comrie, J. Chem. Soc. 2798 (1971). 2. O. Kurihara, O. Tozaburo, Takeda, Hideo, lto, Hideo, Sagawa, Keiko, Tobokuyakka Diagaku Kenyku Nempo (Japan) 17, 43 (1970); Chem, Abstr, 75, 110246r (1971). 3. Shankar P. Agnawal and Ram A. Rai, Transition Met. Chem. 1, 238 (1976). 4. R. W. Yong and K. H. Wood, J. Am. Chem. Soc. 77, 400 (1955). 5. A. I. Vogel, A Test Book of QuantitativesInorganicAnalysis,pp. 389, 390,483,486,498, 509, 511 and 549. LongmanGreen, London (1961).

*Author for correspondence.

Notes 6. V. J. Ram and H. N. Pandey, Agric. Biol. Chem. 37, 1465 (1973). 7. Lakshmi and U. Agrawal, J. lnorg. Nucl. Chem. 34, 225 (1972). 8. C. N. R. Rao and R. Venkataragbavan, Spectrochim. Acta 18, 541 (1962). 9. C. N. R. Rao, R. Venkataraghavan and T. R. Kasturi, Can. J.

453

Chem. 42, 36 (1964). 10. I. Suzuki, Bull. Chem. Sac., Japan 35, 1286, 1449 (1962). 11. D. Hadzi and D. Prevursek, Spectrochim. Acta 10, 38 (1957). 12. B. N. Figgis, Introduction to Ugand Fields, pp. 226, 223,220. Wiley, New York (1966). 13. F. A. Cotton and G. Wilkinson, Advanced Inorganic Chemistry, 2nd Edn, p. 637. New York (1966).

J. inorg, nucl. Chem. Vol. 42, pp. 453-454 Pergamon Press Ltd., 19~0. Printed in Great Britain

Adduct

formation by certain nickei-8-quinolinates with heterocyclic

nitrogen bases

(Received for publication 23 July 1979)

In an earlier study on adduct formation using liquid-liquid extraction[l], nickel(II) was found to extract with 8-quinolinol (HQ) in the form of a self-adduct, NiQ2. HQ, in which the HQ was believed to be acting as a monodentate ligand involving the quinoline nitrogen atom. On extending the study to pyridine adducts, it was observed that the pyridine and its methyl analogues enhanced the extraction of nickel(II) into chloroform with either 8-quinolinol or its derivatives [2]. This communication is an extension of this work. EXPERIMENTAL Apparatus. A Cary 17D spectrophotometer with 10 mm quartz cuvettes was used for absorbance measurements. Material. 8-Quinolinol and 5-chloro-8-quinolinol (Aldrich Chemical) were recrystallized from ethanol (m.p. 73 and 126°C resp.). Pyridine and collidine (B.D.H. AnalaR), picolines and lutidines (Eastman Kodak) were dried over KOH and distilled. Chloroform, neocuproin, 2,2'-bipyridyl (B.D.H. AnalaR) and 1, 10-phenanthroline (Fluka, AG) were used without further purification. The hydrated nickel chelates of 8-quinolinols were prepared by precipitating the chelates in an acetic acid buffer solution using a slight excess of the reagent in ethanol, after proper digestion they were collected, washed and dried to constant weight at 170'C to make them anhydrous. The nickel content of these chelates was determined first thermogravimetrically and checked further by the dimethyl glyoxime method. PROCEDURE Equilibrium absorbance measurements. Solutions were prepared afresh everytime dissolving known amounts of the anhydrous nickel chelates in chloroform. Aliquots of the chloroform solution containing the appropriate amounts of nickel were pipetted into 25 ml volumetric flasks containing varying amounts of the nitrogen base in chloroform and the volumes were adjusted to the mark with pure dry chloroform. Dehydration was essential because traces of moisture would render the nickel complex hydrated, resulting in its precipitation. The absorption spectra of solutions were then taken in both the UV and VIS regions, employing 10 mm cuvettes. The molar extinction coefficients for these complexes in chloroform (in absence of nitrogen base) were found to be e4~8= 22150 (for NiQ2) and ~ = 11573 (for Ni-5-CI-8Q). RESULTSANDDISCUSSION The spectrum of pure nickel-8-quinolinate in chloroform (in absence of any adducting base) gave two absorption bands at 456 and 345 nm. On addition of a base a hypsochromic shift was observed in the spectrum and the band at ,156nm decreased gradually with the development of a new band at 402 nm. Two isosbestic points were located around 426 and 365 nm. The spectrum of nickel-5-chloro-8-quinolinate gave three absorption bands at 480, 410 and 350nm. On addition of a nitrogen base, the band at 480 nm decreased gradually with an increase in

absorption around 415 and 355nm. Two isosbestic points were located at 463 and 366 rim. The decrease in the absorbance due to the shifts in the band of the spectra of the nickel complexes that accompanies the addition of the base is used here to determine the adduct formation constants as shown previously [3]. The formation of a monomeric adduct is represented by the following equation: NiQ2+nB. K~

='

NiQ2' nB.

(1)

Hence, as shown earlier[3] log KAD = npB + log A°A A

(2)

By plotting the data as log(Ao - A)/A vs log B, where Ao is the absorbance in absence of the adducting base B and A, the absorbance in its presence, linear curves were obtained. These are depicted in Figs. 1 and 2, for nickel-8-quinolinate and its 5-chloro-analogue respectively. Intercepts for the plots of Iog(Ao - A)/A vs log B for various adducting bases on y axis give directly the values of the adduct formation constants. These are given in Table 1. The values, thus obtained are not strictly comparable to those obtained earlier by solvent extraction[2] since, in liquid-liquid extraction, the

3'0

2.0t

I

.

.

Loo

-3.0 B

.

.

<

-I'0! 0 -2.

' -4.0

-Z.O

-~.0

0

Fig. 1. Plots showing adduct formation between Ni-g-quinolinate and various nitrogen bases in chloroform. O 2, 4-Lutidine, [] 2Picoline, A 2, 4, 6-Collidine V Pyridine, x 4-Picoline, • 2, 9Neocuproin, + 1, lO-Phenanthroline, , 2, 2'-Bipyridyl, • Ethylenediamine