Synthesis, Spectral Characterization, and Solvent Effects on the Electro- and Photo-Reduction of Co(III) Complexes

Abstract

Six new Co(III) complexes of the type cis-β-[Co(dmen)2(4-R-Py)Cl]Cl2 (where dmen = NN′-dimethylethylenediamine, R = H, Me, Et, t-Bu, COMe, and CN) have been synthesized and characterized by elemental analysis, UV-Vis, FT-IR, 1H NMR, TGA, and differential pulse voltammetric (DPV) techniques. Further, the effect of solvent and structure on the electro- and photo- reduction of these Co(III) complexes have been studied in propan-2-ol/water and 1,4-dioxane/water binary mixtures. The redox potential (E1/2) and the photo-reduction quantum yield (ΦCo(II)) data were correlated with solvent and structural parameters with an aim to shed some light on the mechanism of these reactions. Correlation of E1/2 and ΦCo(II) with solvent parameters indicated that the reactivity is influenced largely by dipolarity/polarizability of the medium.