Synthetic, spectroscopic and electrochemical characterisation of mixed-metal acetylide complexes

Article abstract of DOI:10.1016/S0022-328X(98)00816-X

Terminal metal acetylide complexes trans-[(dppm)₂(Cl)Os(-CC-R-CC-H)] (dppm=Ph₂PCH₂PPh₂, R=-p-C₆H₄- (1), -p-C₆H₄-C₆H₄-p- (2)) and trans-[(Et₃P)₂(Ph)Pt(CC-p-C₆H₄-CCH)] (3) have been synthesised by the application of established synthetic routes. Acetylide bridged mixed-metal complexes trans-[(dppm)₂(Cl)Os-CC-p-C₆H ₄-CC-Ru(Cl)(dppm)₂] (4), trans-[(Et₃P)₂(Ph)Pt-CC-p-C₆H ₄-CC-Ru(Cl)(dppm)₂] (5), trans-[(Et₃P)₂(Ph)Pt-CC-p-C₆H ₄-CC-Ru(Ph₃P)₂(η⁵-C ₅H₅)] (6) and trans-[(Et₃P)₂(Ph)Pt-CC-p-C₆H ₄-CC-Ru(Ph₃P)₂(η⁵-C ₅H₄-CH₃)] (7) have been formed by the reaction of 1, 2 and 3 with the appropriate metal chlorides. Complex 6 is less soluble in common organic solvents than the other complexes but this insolubility has been overcome by introducing a methylcyclopentadienyl group on the ruthenium centre to form complex 7. Complexes 1, 2, 4, 6 and 7 have shown reversible redox chemistry and in the di-metallic complexes, intramolecular electronic communication has been investigated by cyclic voltammetry. The shift in the lowest energy band in the UV-vis spectra of the mixed-metal complexes 4, 5, 6 and 7 is largely dependent on the various metal fragments.