A Non‐Heme Iron Photocatalyst for Light‐Driven Aerobic Oxidation of Methanol

Abstract

Non-heme (L)Fe^III and (L)Fe^III -O-Fe^III (L) complexes (L=1,1-di(pyridin-2-yl)-N,N-bis(pyridin-2-ylmethyl)ethan-1-amine) underwent reduction under irradiation to the Fe^II state with concomitant oxidation of methanol to methanal, without the need for a secondary photosensitizer. Spectroscopic and DFT studies support a mechanism in which irradiation results in charge-transfer excitation of a Fe^III -μ-O-Fe^III complex to generate [(L)Fe^IV =O]²⁺ (observed transiently during irradiation in acetonitrile), and an equivalent of (L)Fe^II . Under aerobic conditions, irradiation accelerates reoxidation from the Fe^II to the Fe^III state with O₂ , thus closing the cycle of methanol oxidation to methanal.