Proton-Coupled Electron Transfer Between Metal-Bound Ligands and Organic Radicals

摘要

Transition metal complexes that have an affinity for an electron and a proton can abstract a hydrogen atom - a proton and an electron - from organic substrates.For instance,the deprotonated iron(III) tris(bi-imidazoline) complex [Fe(Hbim)(H_2bim)_2]~(2+) (1) reacts with dihydroanthracene to give anthracene and the iron(Il) complex [Fe(H_2bim)_3]~(2+) (2; see equation below).Mechanistic studies indicate that this reaction proceeds by one-step proton-coupled electron transfer (hydrogen atom transfer),rather than by stepwise pathways of electron transfer followed by proton transfer or vise versa.