Redox characteristics of manganese and cobalt complexes obtained from pyridine N-oxide

Manganese and cobalt complexes, using pyridine N-oxide as ligand, have been synthesized, and their cyclic and square-wave voltammetric measurements have been carried out. The results reveal that the complexes exhibit different voltammetric pattern, which suggests that the redox processes are most probably metal-centered. In both complexes, extra redox activity is observed once the potential exceeds certain value of the voltage. The observation of an oxidation wave in manganese complex at +0.75 V vs. Ag/AgCl or +0.95 V vs. NHE strongly suggests that this complex can bring about oxidation of water and can, thus, serve as a synthetic analogue of water oxidizing complex (WOC) of PS II. Copyright (C) 2000 Elsevier Science S.A.