Diiron ethanedithiolate complexes with acetate ester: Synthesis, characterization and electrochemical properties

Abstract

Five diiron ethanedithiolate complexes bearing acetate ester have been prepared and characterized. Esterification of complex [{μ-SCH2CH(CH2OH)S}Fe2(CO)6] (1) with acetic acid in the presence of N,N′-dicyclohexylcarbodiimide and 4-dimethylaminopyridine gave the acetate ester [{μ-SCH2CH(CH2O2CCH3)S}Fe2(CO)6] (2) in 94% yield. Further treatment of complex 2 with a monophosphine ligand triphenylphosphine, tricyclohexylphosphine, tris(2-methoxyphenyl)phosphine or tris(4-tolyl)phosphine in the presence of Me3NO·2H2O resulted in the formation of the corresponding monophosphine-substituted diiron derivatives [{μ-SCH2CH(CH2O2CCH3)S}Fe2(CO)5L] (L = PPh3, 3; PCy3, 4; P(C6H4OCH3-2)3, 5; P(C6H4CH3-4)3, 6) (Cy = cyclohexyl) in 69–87% yields. The complexes 2–6 were characterized by elemental analysis and spectroscopy, together with X-ray crystallography. Furthermore, the electrochemical properties were investigated by cyclic voltammetry.