Phosphine-substituted diiron 1,2-dithiolate complexes as the models for the active site of [FeFe]-hydrogenases

Abstract

In this article, five diiron 1,2-dithiolate complexes containing phosphine ligands are reported. Treatment of complex [Fe2(CO)6(μ-SCH2CH2S)] (1) with the phosphine ligands tris(4-methylphenyl)phosphine, tris(4-methoxyphenyl)phosphine, tris(3-chlorophenyl)phosphine, tris(3-methylphenyl)phosphine, or 2-(diphenylphosphino)biphenyl in the presence of Me3NO·2H2O as the decarbonylating agent afforded the target products [Fe2(CO)5(L)(μ-SCH2CH2S)] [L = P(4-C6H4CH3)3, 2; P(4-C6H4OCH3)3, 3; P(3-C6H4Cl)3, 4; P(3-C6H4CH3)3, 5; Ph2P(2-C6H4Ph), 6] in 80–93% yields. Complexes 2–6 have been characterized by elemental analysis, spectroscopy, and X-ray crystallography. Additionally, the electrochemical properties were studied by cyclic voltammetry.