Phenyl-functionalized diiron dithiolate complexes with one bidentate or two unidentate phosphine-containing ligands

Abstract

Treatment of diiron dithiolate complex, [(μ-SCH2)2CHC6H5]Fe2(CO)6 (A), with one equivalent of bidentate phosphine-containing ligand N,N-bis(diphenylphosphine)butanamine [(Ph2P)2N-Bu-n] in refluxing xylene afforded the diphosphine-bridged complex [(μ-SCH2)2CHC6H5]Fe2(CO)4[(μ-PPh2)2N-Bu-n] (1) in high yield, while reaction of A with two equivalents of triphenylphosphine (PPh3) in the presence of decarbonylating agent Me3NO yielded the disubstituted complex [(μ-SCH2)2CHC6H5]Fe2(CO)4(PPh3)2 (2) in low yield. Both complexes were characterized by spectroscopic methods and X-ray crystallography. In the solid state, two phosphines of (PPh2)2N-Bu-n bridge the two irons with cis basal-basal conformation, while PPh3 occupies an apical position of the square pyramidal geometries of each iron. The influence of coordination manner on the electrochemical properties of both complexes was investigated by cyclic voltammetry.