INDIAN J. CHEM., VOL. 14A, NOVEMBER 1976

characterization by magnetic susceptibility measure-ments. The ligands belong to a series of2-pyridylazo compounds! known for their analyticalapplications, particularly as spectrophotometricreagents. Ruthenium(III) complexes have a possiblerole to play in homogeneous catalysis.

The ligand PAN) and PAPV were prepared andpurified by the literature methods. Purity of thecompounds was checked by TLC·.

For preparing the complexes aqueous solutionof ruthenium(III) chloride trihydrate and ethanolicsolution of the respective ligand were mixed togetherin the metal-ligand ratio of 1 :2. Intense redcolouration developed. The contents were refluxedfor 2 hr and concentrated, when the complexes,separated out as crystalline granules which werefiltered, washed successively with water, ethanoland acetone and dried at ,.....60°.

Analysis for Ru(III)-PAN complex [Found; Ru,14·83; C, 55,7; H, 3·18; N, 12·3; CI, 5·10.Ru(C16HloNaO)zC1.2HsO requires Ru, 15·1; C, 53'8;H, 3·60; N, 12,6; CI, 5·31 %]. Analysis for Ru(UI)-PAPL complex [Found: Ru, 12,9; C, 60·0; H, 3·90;N, 10'7; ci, 4·50. Ru(C1,HlIN.O)zC1.2H20 requiresRu, 13·1; C, 59·3; H, 3'64; N, 10·9; CI, 4·62%].

Complexes are insoluble in water, ethanol andacetone and dissolve in other common organicsolvents, viz, chloroform, pyridine, dirnethylforma-mide and nitrobenzene. Conductance measure-ments in nitrobenzene medium show them to benon-electrolytes.

Magnetic susceptibility measurements (Table 1)on the solid complex were made by Gouy methodusing mercury tetrathiocyanatocobaltate(II) ascalibrating agent (Xg=16'44X 10-6 cgs).

Rntheniumtl l Ij'', although isoelectronic with Fe(III)and Mn(II), assumes invariably the ground state2T 2g(t~g) in its complexes. Magnetic moments oflow-spin octahedral Ru(III) complexes are expectedto lie around 2·0 BM (1.= -1180 cm'"), with verylittle temperature dependence. However, the com-plexes under study show room temperature magneticmoments of 1·45 BM for Ru(llJ)-PAN and 1,77BM for Ru(III)-PAPL. Also the low temperaturemagnetic susceptibility measurements on theRu(JII)-PAPL complex reveal that the magneticmoment decrease with decreasing temperature(Table 1). A plot of 1{X vs T shows th at the compoundobeys Curie-Weiss law (6 = -205°K) in the tempe-rature range 3000K > T > 1000K. Below 1000Kthe susceptibility shows a sudden drop. These

TABLE 1 _ MAGNETIC SUSCEPTIBILlTY DATA OF Ru(III)-PAPL COMPLEX

Temp. 'Xg X 10' 'XMcorr X 10' j.Lefi(OK) (cgs) (cgs) (B.M.)

300·0 1·240 1307 1·772210'0 1·755 1684 1·684178·0 1·839 1745 1·577140·0 2-113 1945 1·477123·5 2·220 2026 1·400111·0 2·378 2141 1·379101·0 2-453 2196 1·33285·5 1·839 1751 1·095

908

obs~r~ations ~ndic.ate the presence of antiferromag-- netic interactions m the complex with the Neel pointof 1000K .. For lo~-spin Ru(III) complexes involvingexchange interactionsbetween the ruthenium atomsof spin 5, = 58 = 1, the susceptibility may be givenby"

3K 1XA = T3+x~ +Na.

Ng2~Zwhere x = exp(j/I{T), K = 3K (= 0·1251 gl) Uis the exchange coupling constant). The best fitbetween the theoretical values and the experimentalvalues in the present case is obtained for J = 45 cm+,However, the value of J is comparatively smaller,while the value of 6 is quite large. In fact,use of spin-only two-centre interaction formula inthe case of a Ru(III) complex, where sjin orbitinteraction is quite large (A, -1180 crrr-), involvesbig approximation.

Considering the composition of Ru(JIJ)-PAPLcornplex ana assuming the ligand to be bidentatein nature, it is possible to construct two models, onea binuclear complex involving two chlorine bridgesand the other, involving only one chlorine bridgeleading to a chain polymer. However, the lowvalue of J (= 45 cm+) forbids a chain polymerand favours coupling between ions bridged by twochlorine atoms.

Thanks are due to the authorities of Tata Insti-tute of Fundamental Research, Bombay, forproviding facilities for magnetic susceptibilitymeasurements.

References1. FLASCHKA, H. A. & BARNARD, J. A., Chelates in analytical

chemistry, Vol. 4 (Marcel Dekker, New York), 1972.2. CHISWELL, R, LIONS, F. & TOMLINSON, M., Tnorg, Chem.,

3 (1964), 492.3. POLLARD, F. H., NICKLESS, G., SAMUELSON, T. S. & ANDER-

SON, R. G., ]. Chromatog., 16 (1964). 231.4. EARNSHAW, A., Introduction to magnetochemistry (Acade-

mic Press, London), 1968, 77.

Complexes of Zn(II), Cd(II) & Hg(lI) withSchiff base Derived from 0- Vanillin & Aniline

A. C. HIREMATH, M. A. PU]AR & A. S. R. MURTHY

Department of ChemistryKarnatak University Postgraduate Centre, Gulbarga 585105

Received 18 December 1975; accepted 17 February 1976

Solid 1: I, non-electrolytic complexes of Zn(II),Cd(I1) and Hi(I1) with the SchUl base derived fromo-vaniWn and aniline have been prepared and charac-terized on the basis of analytical, conductance, electronicand IR spectral data. The complexes are amorphouand reddish-yellow in colour. The IR spectra of thecomplexes show that coordination takes place throuihazomethine nitrogen while phenoltc iroup remainsundissociated. A chtoro-brtdged dlmeric structure t8proposed for the complexes.

IN con~i~uation of our earlier work on the bivalenttransition metal complexes of the Schiff bases

derived from vanillin", we now report the complexes

TABLE 1 - ANALYTICAL DATA OF THE COMPLEXES

Found (calc.), (%)

Complex Metal N Cl

ZnCI2: L 18'45 3·75 19-40(18'10) (3'85) (19'55)

CdClz: L 27·60 3·28 17·38(27-40) (3040) (17'20)

HgClz: L 40·45 2·55 15·88(40'25) (2'81) (15'95)

of Zn(II) , Cd(Il) and Hg(II) with the Schiff basederived from o-vanillin and aniline. All thechemicals used were of AR grade. The Schiff basewas prepared by condensing o-vanillin with aniline,in stoichiometric ratio (1 :1) in ethanol. The Schiffbase, which separated on cooling, was recrystallizedfrom ethanol and dried in vacuo over fused calciumchloride. Complexes were prepared according tothe method reported earlier-.

Zinc was estimated gravimetrically as pyrophos-phate. Cadmium was estimated as oxinate.Mercury was estimated using e-nitroso-Beiaphthols.

Analytical data (Table 1) show that Zn(II), Cd(II)and HglII) chlorides form 1:1 complexes with theSchiff base. The complexes are soluble in DMFand DMSO. The observed low conductivity valuesof the complexes in DMF indicate that the complexesare non-electrolytes.

Electronic spectrum of the Schiff base exhibitsthree bands at 240, 282 and 340 nm. Of these thebands at 240 and 282 nm are assigned to 7t-7t*

transitions in analogy with similar assignmentsmade earlierl,3,". In the complexes, the 240 nmband remains undisturbed whereas the other twobands show considerable shifts. The 340 nmband of the ligand appears in the region 460-470nm in the complexes indicating coordination.An additional band appearing in the complexesin the region 315-360 nm may be due to ligand-metal charge- transfer+",

In the IR spectra, a broad band appearing around2650 cm', both in the ligand and the complexes,is assigned to the intramolecular hydrogen-bondedOR. This assignment agrees well with the previousreports", The retention of the broad band in thespectra of complexes suggests that the ligand doesnot undergo deprotonation by coordinating withthe metal ions through hydroxy oxygen.

The strong ligand band observed at 1620 crrr",attributable to vC=~N, appears in the region1645-1630 crrr? in the complexes. This positiveshift indicates the coordination through the azome-thine nitrogen.

Strong bands appearing at 506, 522 and 481 cnr?in the spectra of Zn(II), Cd(II) and Rg(Il) complexesrespectively are attributed to vM-N. This assign-ment agrees well with the previous reportsIO-l8•

Taking into consideration the elemental analysis,non-electrolytic nature of the complexes, spectralevidences and the usual tetra-coordination of thepresent metal ions, we propose a halogen-bridgedstructure for these complexes. This structure agreeswell with the previous work14.

NOTES

The authors are grateful to Shri K. Subramanyaof CISL, Indian Institute of Science, Bangalore,for IR spectra.

References1. PUJAR, M. A., HIREMATH, A. C. & PRABHAKAR, B. K.,

J. Indian chem. Soc., 21 (1974), 494.2. PATIL, S. V., Proc. Indian A cad. Sci., LXIV (1966), 233.3. CHATTERJEE, K. K. & DOUGLAS, B. E., Spectrochim, Acta,

21 (1965), 1625.4. BIRADAR, N. S. & KULKARNI, V. H., J. inorg, nucl. Chem.,

33 (1971), 2451.5. BARNUM, D. W., J. inorg. nucl. Chem., 21 (1961), 221.6. (a) WATERS, T. N. & WRIGHT, P. E., J. inorg, nucl,

Chem., 33 (1971), 359.(b) SHEAT, S. V. & WATERS, T. N., J. inorg, nucl. Chern.,

25 (1964), 1221.7. KAZITSYNA, L. A., KUPLETSKAYA, N. B., POLSTYANKO,

L. L., KIKOT, B. S., KOLESNIK, Yu. A. & TERENTEV,A. P., J. general Chem., U.S.S.R., 31 (1961), 286.

8. BIRADAR, N. S., MAHALE, V. B. & KULKARNI, V. H.,Inorg. chim. Acta, 7 (1973), 267.

9. FREEDMAN, H. H., J. Am. chem., Soc., 83 (1961), 2900.10. NAKAMOTO, K., in Advances in the chemistry of coordi-

nation compounds, edited by S. Kirschner (Macmillan,New York), 1961,437.

11. NAKAMOTO, K., in Spectroscopy and structure of metalchelate compounds, edited by K. Nakamoto & P. J.McCarthy (John Wiley, New York), 1968, 216.

12. (a) PRABHAKARAN, C. P. & PATEL, C. C., J. inorg . nucl,Chem., 31 (1969), 3316.

(b) SHARMA, B. C. & PATEL, c. c., Indian J. Chem., 8(1970), 747.

13. BIRADAR, N. S., KULKARNI, V. H. & SIRMOKADAM,N. N., J. inorg, nucl, Chem., 34 (1972), 3651.

14. AHUJA, J. S. & GARG, A., J. inorg. nucl. Chem., 34 (1972),2074.

Complexes of (Cull) with Schiff BasesDerived from 5-Chloro-2-hydroxyacetophenone

& Aniline, 0-, m- & p- Toluidines

M. N. PATEL & R. P. PATEL

Department of Chemistry, Sardar Patel UniversityVallabh Vidyanagar 388120

Received 11 Aoril 1975; revised 13 f anuary 1976;accepted 12 February 1976

Complexes of Cu(I1) with bidentate Schiff basesderived from 5-chloro-2-hydroxyacetophenone and theamines like aniline, 0-, m- andp-toluidines have beenprepared. Elemental analysis, magnetic susceptibility,infrared, solution visible and solid reflectance spectrahave been recorded. A trans square planar structurehas been suggested for these complexes.

SCHIFF bases as chelating ligands havereceived considerable attention", In view of

the importance evinced in this field, we undertookthe study of Cu(II) complexes with the Schiff basesderived from 5-chloro-2~hydroxyacetophenone andamines like aniline, and 0-, m- and p-toluidines andthe results are reported in this note.

The Schiff bases were prepared by refluxing equi-molar quantities of aryl amine and 5-chloro-2-hy-droxyacetophenone in ethyl alcohol. The reactionmixture was kept overnight during which time fineyellow coloured crystals were obtained. The com-plexes were prepared by refluxing the solutions ofCu(lI) acetate and the Schiff base in ethanol in 1:2molar ratio. The neutral reddish-brown Cu(II)

909