Synthesis and electrochemistry of phenyl-functionalized diiron propanedithiolate complexes with bidentate phosphine ligands

Carbonyl substitution reactions of [mu-(SCH2)(2)CHC6H5]Fe-2(CO)(6) with bidentate phosphine ligands, cis-1,2-bis(diphenylphosphine)ethylene (cis-dppv) and N,N-bis(diphenylphosphine)propylamine [(Ph2P)(2)N-Pr-n], yielded an asymmetrically substituted chelated complex [(mu-SCH2)(2)CHC6H5]Fe-2(CO)(4)(k (2)-dppv) and a symmetrically substituted bridging complex [(mu-SCH2)(2)CHC6H5]Fe-2(CO)(4)[mu-(PPh2)(2)N-Pr-n] under different reaction conditions. Both complexes were fully characterized by spectroscopic methods and by X-ray crystallography. Their electrochemical behaviors were observed by cyclic voltammetry, and the catalytic electrochemical reduction of protons from acetic or trifluoroacetic acid to give dihydrogen mediated by complex [(mu-SCH2)(2)CHC6H5]Fe-2(CO)(4)(k (2)-dppv) was investigated.