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

A dinuclear [2Fe2S] mimic, [mu-(SCH2)(2)CHC6H5]Fe-2(CO)6 (1), of the active site of FeFe-hydrogenases has been synthesized from the reaction of 2-phenyl-1,3-propanedithiol with Fe-3(CO)(12). Displacement one or two carbonyls of complex I with triphenylphosphine (PPh3) or bis(diphenylphosphino)methane (dppm) yielded [mu-(SCH2)(2)CHC6H5]Fe-2(CO)(5)(PPh3) (2), [mu-(SCH2)(2)CHC6H5]Fe-2(CO)(5)(kappa-dPPm) (3) and [mu-(SCH2)(2)CHC6H5]Fe-2(CO)(4)(mu-dPPm) (4). Complexes 1-4 have been fully characterized by elemental analysis, mass spectrometry, IR, H-1, C-13 and P-31 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. (C) 2013 Elsevier Ltd. All rights reserved.