Cyclic voltammetric studies of oxovanadium(IV) complexes derived from 2,2'-bipyridine and 1,10-phenanthroline in nonaqueous media

Abstract

The electrochemical behaviour of oxovanadium(iv) complexes, [VO(bipy) 1 ] 2+ and [VO(phen) 2 ] 2+ (where, bipy = 2,2'-bipyridine and phen = 1,10-phenanthroline) have been examined in DMSO and DMF with 0.1 M TBAP using cyclic voltammetry at a Pt working electrode. It is found that [VO(bipy) 2 ] 2+ and [VO(phen) 2 ] 2+ complexes are irreversibly oxidized (V0 2+/3+ ) with anodic peak potential, E pa1 ≃ 1,10 V vs SCE at 200 mV s -1 . The initial reduction of these complexes in DMSO and DMF media revealed two irreversible cathodic peaks with E pc1 = -0.96 to -1.13 V and E pc2 = -1.17 to -1.30 V vs SCE. It should be mentioned that dependence of I pa1 or I pc1 on v 1/2 is linear without any intercept. This suggests that the redox processes a 1 and c 1 are diffusion controlled. It is also observed that the oxidation of bipy complex is easier while reduction is difficult in comparison to phen complex in a given medium.