Phosphine-containing Diiron Propane-1,2-dithiolate Derivatives: Synthesis, Spectroscopy, X-ray Crystal Structures, and Electrochemistry

Abstract

Biomimics for the active site of [FeFe]-hydrogenases, have been synthesized and characterized. Treatment of [Fe2(CO)6{μ-SCH2CH(CH3)S}] (1) and phosphine ligands tris(2-furyl)phosphine, tri(m-tolyl)phosphine, bis(diphenylphosphino)methane (dppm), or 1,2-bis(diphenylphosphino)benzene (dppbz) with Me3NO·2H2O as the decarbonylation agent afforded the corresponding phosphine-containing derivatives [Fe2(CO)5(L){μ-SCH2CH(CH3)S}] (L = P(2-C4H3O)3, 2; P(3-C6H4CH3)3, 3; Ph2PCH2PPh2, 4) and [Fe2(CO)4{κ2-(Ph2P)2(1,2-C6H4)}{μ-SCH2CH(CH3)S}] (5) in moderate to good yields. The new complexes 2‒5 have been structurally characterized by elemental analysis, IR, NMR spectroscopy, and further confirmed by X-ray diffraction analysis. The electrochemistry of complexes 2‒5 have been investigated by cyclic voltammetry, showing that they can catalyze the reduction of protons to H2 in the presence of HOAc.