A TRICHLORO-BRIDGED DIRUTHENIUM (II,III) COMPLEX - PREPARATION, PROPERTIES AND X-RAY STRUCTURE OF TRI(-MU-CHLORO) DICHLOROCARBONYLTRIS (TRIPHENYLPHOSPHINE)DIRUTHENIUM(II,III)

The triply chloro-bridged binuclear complex [Ru2Cl5(CO)(PPh(3))(3)].CH2Cl2, (PPh(3) = triphenylphosphine), M(r)=1279.23, prepared from the precursor compound [RuCl3(PPh(3))(2)DMA].DMA (DMA =N,N'-dimethylacelamide) and crystallizes in the monoclinic space group P2(1)/c. The structure was solved from 6994 independent reflections for which I > 3 sigma(I) by Patterson and difference Fourier techniques and refined to a final R = 0.042. The complex is formed by two Ru atoms bridged through three chloride anions. One Ru atom is further coordinated to two non-bridging Cl atoms and a triphenylphosphine ligand, whereas the other is bonded to two PPh(3) ligands and a carbon monoxide molecule. The presence of Ru-III was confirmed by EPR data. The absence of an intervalence charge-transfer transition (IT) in the near-infrared spectrum suggests that the binuclear complex is of a localized valence type. The IR spectrum shows a v(Co) band at 1964 cm(-1) and V-Ru.Cl bands at 328, 280 cm(-1), corresponding to chlorides at terminal positions and 250, 225 cm(-1) for the bridged ones. Two redox processes, Ru-II/Ru-II (E(1/2) = -0.29 V)<-- Ru-II/Ru-III --> (E(1/2) = 1.19 V) Ru-III/Ru-III, were observed by cyclic voltammetry.