Electrochemistry of iron and ruthenium flyover bridge complexes

Article abstract of DOI:10.1021/om00092a008

The redox chemistry of dimetallacycloheptadiene (flyover bridge) complexes M₂(CO)₆[C(R)=C(R′)COC(R″)=(R?)] (M = Fe or Ru) has been investigated by electrochemical and spectroscopic techniques. For the Fe₂(CO)₆[(PhC₂Ph)₂CO] derivative the bulk of the data indicates a sequence of electrochemical events involving the formation of the monoanion and its decomposition to solvated [Fe(CO)₃]^- and Fe(CO)₃[(PhC₂Ph)₂CO] fragments, which are able to recombine together on electrochemical or chemical reoxidation giving back the parent complex. Electron paramagnetic resonance features of electroreduced solutions of ¹³CO-enriched sample of Fe₂(CO)₆[(PhC₂Ph)₂CO] and its monophosphine derivative Fe₂(CO)₅(PPh)₃[(PhC₂Ph) ₂CO] lend support to the proposed mechanism. The influence of the dienone substituents, R, as well as the effect of the replacement of group V (15) donor ligands for CO on the trend of the electrode potentials is discussed.