Synthesis, characterization and electrochemistry of phenyl-functionalized diiron propanedithiolate complexes

A dinuclear [2Fe2S] mimic, [μ-(SCH2)2CHC6H5]Fe2(CO)6 (1), of the active site of FeFe-hydrogenases has been synthesized from the reaction of 2-phenyl-1,3-propanedithiol with Fe3(CO)12. Displacement one or two carbonyls of complex 1 with triphenylphosphine (PPh3) or bis(diphenylphosphino)methane (dppm) yielded [μ-(SCH2)2CHC6H5]Fe2(CO)5(PPh3) (2), [μ-(SCH2)2CHC6H5]Fe2(CO)5(κ-dppm) (3) and [μ-(SCH2)2CHC6H5]Fe2(CO)4(μ-dppm) (4). Complexes 1–4 have been fully characterized by elemental analysis, mass spectrometry, IR, 1H, 13C and 31P NMR spectroscopic techniques, and unequivocally determined by single crystal X-ray diffraction analysis. The phenyl groups are attached directly to the bridgehead–C atoms of the propanedithiolate bridge via equatorial bonds in chair conformation six-membered rings. The electrochemical behavior of 1–4 and the reduction of the proton of CF3COOH to hydrogen, catalyzed by 1 and 3, were investigated by cyclic voltammetry.

The phenyl-functionalized diiron propanedithiolate complex [μ-(SCH2)2CHC6H5]Fe2(CO)6 (1) and its carbonyl substitution derivatives [μ-(SCH2)2CHC6H5]Fe2(CO)5(PPh3) (2), [μ-(SCH2)2CHC6H5]Fe2(CO)5(κ-dppm) (3) and [μ-(SCH2)2CHC6H5]Fe2(CO)4(μ-dppm) (4) have been synthesized.Figure optionsDownload as PowerPoint slide