Vol. 2, Issue 11, Part G (2016)

Abstract
The mixed- ligand copper (II) complexes [Cu (2-ClNA)2(bipy)] 1; [Cu(2-ClNA)(phen)(H2O)](NO3) 2, and [Cu(2-ClNA)2(dmp)(H2O)] 3, were synthesized by using 2-chloronicotinic acid (2-ClNA) and the aromatic diimines, viz., 2,2’-bipyridine (2,2’-bipy), 1,10-phenanthroline (1,10-phen) and 2,9-dimethyl-1,10-phenanthroline (dmp) in aqueous / non aqueous media. Synthesized complexes have been characterized by elemental analysis, molar conductance measurements, (FT-IR, UV-Visible) spectroscopic technique and room temperature magnetic susceptibility measurements. Molar conductance measurements have been carried out in DMSO and DMF, complexes 1 and 3 correspond to non electrolyte and complex 2 represents mono cationic nature. The redox properties of the all these complexes were extensively investigated by electrochemical method using cyclic voltammetry (CV). The electrochemical behavior of complex 3, involving dmp as the auxiliary ligand is different from rest of two mixed-ligand Cu (II) complexes. Based on these studies, a distorted square-pyramidal coordination geometry around the Cu (II) ion has been proposed in solid complexes 2 and 3, while complex 1 is square planar. In DMSO and DMF solutions, complexes 2 and 3 possess distorted octahedral and complex 1, shows tetragonally distorted octahedral geometry due to solvent coordination.