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

Spectroscopic and thermodynamic studies of complexation of some divalent metal ions with isatin- β -thiosemicarbazone

S. S. Konstantinović, B. C. Radovanović, Z. B. Todorović, S. B. Ilić, and B. V. Konstantinović

Faculty of Technology, University of Niš, Bulevar Osloboenja 124, 16000 Leskovac, Serbia

E-mail: andjelkovic_s@yahoo.com

Received: 24 January 2007  Revised: 10 April 2007  Accepted: 16 April 2007

Abstract: Metal complexes of some divalent metal ions (Co, Ni, Cu, Zn, Hg, and Pd) with isatin-β-thiosemicarbazone (ITS) as the Schiff base have been investigated potentiometrically and spectrophotometrically. The dissociation constants of the ligand and formation constants of the metal complexes, as well as the corresponding thermodynamic functions (ΔG, ΔH and ΔS) have been determined at different temperatures in ethanol—water solution. The full stability constants were also evaluated spectrophotometrically by the Job method. The experimental results indicate that Cu(II), Zn(II), Pd(II), and Hg(II) form one-to-one molecular complexes (ML) with the studied ligand, whereas Co(II) and Ni(II) form both ML and ML₂ species.

Keywords: isatin-β-thiosemicarbazone - divalent metal complexes - formation constant - spectrophotometric study

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-007-0066-8

Chemical Papers 61 (6) 485–489 (2007)