The effect of a pendant amine in phosphine ligand on the structure and electrochemical property of diiron dithiolate complexes

Abstract

In order to explore the effect of a pendant amine on a phosphine ligand on the structure and electrochemical properties of diiron dithiolate complexes, this work reports the crystallographic and electrocatalytic comparisons of three diiron monophosphine complexes Fe2(μ-pdt)(CO)5{Ph2P(NHR)} [pdt = propanedithiolate (SCH2CH2CH2S); R = para-methoxycarbonylphenyl (C6H4CO2Me-p) (1), para-methoxyphenyl (C6H4OMe-p) (2) and phenyl (Ph) (3)] with a pendant amine and one reference analogue Fe2(μ-pdt)(CO)5{Ph2P(CH2Ph)} (4). While the new complex 4 has been characterized by elemental analysis and various spectroscopic techniques, the molecular structures of 3 and 4 were further determined by X-ray crystallography. In addition, the electrochemical properties of 1–4 were studied in acetonitrile (MeCN) in the absence and presence of acetic acid (HOAc) as a mild proton source using cyclic voltammetry (CV). This may demonstrate that they are found to be active electrocatalysts for proton reduction to hydrogen (H2).