Synthesis and characterization of a molecular electrocatalyst based on an iron(III) complex supported by an amine-bis(phenolate) ligand for proton or water reduction

Abstract

Reaction of FeCl3 with N,N-bis[methyl(2-hydroxy-3-tert-butyl-5-methoxyphenyl)]-N′N′-dimethylethylenediamine (H2L) produces an iron(III) complex [LFeCl] 1, which has been characterized by X-ray crystallography. Electrochemical studies show that 1 can electrocatalyze hydrogen evolution, both from acetic acid with a turnover frequency (TOF) of 11 mol of hydrogen per mole of pre-catalyst per hour at an overpotential of 470 mV (in DMF), and from water with a TOF of 205 mol of hydrogen per mole of pre-catalyst per hour at an overpotential of 987.6 mV (in buffer, pH 7.0).