ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Synthesis and Characterization of Some Cobalt(III) Complexes Containing Heterocyclic Nitrogen Donor Ligands

S. C. Nayak, P. K. Das, and K. K. Sahoo

Department of Chemistry, B. N. M. A. College, Paliabindha, Bhadrak, Orissa, India-756167

E-mail: saratnayak1@rediffmail.com

Received: 27 November 2001  Accepted: 3 December 2002

Abstract: A number of mixed-ligand complexes of the type trans-[Co(DH)₂LCl] where DH = dimethylglyoximatoanion, L = heterocyclic nitrogen donor ligand (pyridine, piperidine, quinoline, isoquinoline,triazole, indole, benzimidazole, benzotriazole, carbazole) have been synthesized and characterized.These complexes are not soluble in ordinary organic solvent but highly soluble in dimethylsulfoxide.The conductivity data show the nonelectrolytic nature of the complexes. The IR spectra reveal thecoordination from nitrogen of ligand to central cobalt atom and intramolecular hydrogen bonding. ¹H NMR data of dimethylglyoxime and its Co(III) complexes are in agreement with the trans structure. The ¹³C NMR spectra of the complexes show a sharp signal for carbon atom in the methylgroup. So the four methyl groups in the Co(III) complexes are equivalent and are situated in a plane.The thermal decomposition studies indicate the absence of water of crystallization or associationof solvent molecules. This fact is supported by IR measurement. The loss of heterocyclic nitrogendonor ligands does not take place up to 215°C. The ligand and chlorine atom are bonded strongly. The last product of decomposition is Co₃O₄ or CoO.

Full paper in Portable Document Format: 572a91.pdf

Chemical Papers 57 (2) 91–96 (2003)