Diferrocenyltriphosphines 1: Five-coordinate ruthenium complexes

Article abstract of DOI:10.1016/S0022-328X(98)00505-1

The ligand bis-1-(1′-diphenylphosphinoferrocenyl)phenylphosphine, triphosfer, reacts with dichlorotris-triphenylphosphineruthenium(II) to give the complex [(triphosfer)RuCl₂], (17), in almost quantitative yield. This complex reacts with CO at ambient temperature to afford [(triphosfer)Ru(CO)Cl₂]. Three related complexes, [{(η-R₂PC₅H₄)Fe-μ²-(η-C₅H₄P(R′)η-C₅H₄)Fe(η-C₅H₄R₂)}RuCl₂], R,R′=Ph, iPr (18-20), exhibit identical chemical properties. Reaction of complexes 17-20 with excess PMe₂Ph results in the deligation of the ferrocene ligand. The electrochemistry shows that while the diferrocenyltriphosphine ligands undergo a single two-electron oxidation, irreversible in character, complexes (17-19) exhibit two separated one-electron oxidations having features of chemical reversibility. This data suggests that while within the ligands no electronic communication exists between the two ferrocene subunits, complexation with RuCl₂ allows communication between the two ferrocenes. The single crystal X-ray structure of [(triphosfer)RuCl₂] has been determined.