Electrocatalytic properties of diiron ethanedithiolate complexes containing benzoate ester

Abstract

Six diiron ethanedithiolate complexes containing benzoate ester have been synthesized and characterized. Treatment of the starting material [{μ‐SCH2CH(CH2OH)S}Fe2(CO)6] (1) with benzoic acid in the presence of N,N′‐dicyclohexylcarbodiimide and 4‐dimethylaminopyridine afforded the benzoate ester‐containing complex [{μ‐SCH2CH(CH2O2CPh)S}Fe2(CO)6] (2) in 97% yield. Carbonyl substitution of complex 2 with a monophosphine ligand, such as triphenylphosphine, tris(2‐methoxyphenyl)phosphine, tris(4‐fluorophenyl)phosphine, isopropyldiphenylphosphine or cyclohexyldiphenylphosphine, in the presence of Me3NO⋅2H2O gave the derivatives [{μ‐SCH2CH(CH2O2CPh)S}Fe2(CO)5L] (L = PPh3, 3; P(C6H4OCH3‐2)3, 4; P(C6H4F‐4)3, 5; Ph2PCH(CH3)2, 6; Ph2PC6H11, 7) in 66–95% yields. Complexes 2–7 were characterized using elemental analysis, spectroscopy and X‐ray diffraction analysis. In addition, these complexes can catalyze the reduction of protons to H2 in the presence of weak acid HOAc under electrochemical conditions.