Molecular oxygen reduction catalyzed by a highly oxidative resistant complex of cobalt–hydrazone at the liquid/liquid interface

Abstract

A new complex of Co(III) using an oxidative stable hydrazone ligand, CoL, was synthesized and characterized by elemental analysis, spectroscopic methods and single crystal X-ray analysis where HL is bis-[(E)-N′-(phenyl(pyridin-2-yl)methylene)]carbohydrazide. X-ray analysis revealed that the complex is mononuclear and the coordination environment around the Co(III) core is trans-[CoN₄Cl₂]. The catalytic activity of the complex in the oxygen reduction reaction was investigated. The complex is a highly oxidative resistant cobalt-hydrazone which can efficiently catalyze the reduction of oxygen (O₂) by a weak electron donor ferrocene, (Fc), at the polarized water/1,2-dichloroethane (DCE) interface. Oxygen reduction is coupled with proton transfer from water to the organic phase to form hydrogen peroxide, which is extracted into the aqueous phase.