A simple route for syntheses of trihalide-bridged carbonyl diruthenium(II,III) complexes: Crystal and molecular structure of ttt-[(RuCl2)-Cl-II(CO)(2)(PPh3)(2)], [(CO)(AsPh3)(2)RuII(mu-Cl-3)(RuCl2)-Cl-III(AsPh3)] and [(CO)(PPh3)(2)Ru-II(mu-Br-3)(RuBr2)-Br-III(PPh3)], spectroscopies, electrochemistry and properties

The triply halide-bridged binuclear complexes [Ru2Cl5(CO)(AsPh3)(3)](AsPh3 = triphenylarsine), [Ru2Cl5(CO)(PPh3)(2)(AsPh3)] (PPh3 = triphenylphosphine ), [Ru2Cl5(CO)(AsPh3)(2)(PPh3)], [Ru-2 Br-5(CO)(PPh3)(3)], [Ru2Cl5(CO)(P{p- tol}(3))(2)(PPh3)] (P{p-tol}(3) = tri-p- tolylphosphine) and [Ru-2 Br2Cl3(P Ph3)(2)(AsPh3)] were prepared from the precursor compounds ttt-[RuX2(CO)(2) (P)(2)] (X = Cl or Br) and [RuY3(P ')(2)S].S (Y = Cl or Br; P = PPh3, AsPh3 or P{p- tol}(3) and P ' = AsPh3 or PPh3; S = DMA or MeOH, where DMA = N,N ' -dimethylacetamide). The molecular structures of the binuclear complexes [Ru2Cl5(CO)(AsPh3)(3)] (P2(1/c)), [Ru2Br5(CO)(PPh3)(3)] (P2(I/c)) and ttt-[ RuCl2(CO)(2)(PPh3)(2)] (Pl) were determined by X-ray diffraction methods. T he complexes are always formed by two Ru atoms bridged through three halide anions, two of which are X type (from the Ru-II precursor) and the other i s Y type (from the ruthenium(III) precursor) confirming our previously sugg ested mechanism for obtaining this class of complexes. The Ru-II atom is al so coordinated to a carbon monoxide molecule and two P ligands from the ttt -starting isomer whereas the Ru-III atom is bonded to two non-bridging Y ha lides and one P ' molecule. The presence of Ru-III was confirmed by EPR dat a, a technique that was also useful to suggest the symmetry of the complexe s. The absence of intervalence charge transfer transitions (IT) in the near infrared spectrum confirm that the binuclear complexes have localized vale nce. The IR spectra of the complexes show upsilon (CO) bands close to 1970 cm(-1) and upsilon (Ru-Cl) or upsilon (Ru-Br) bands at about 230-380 cm(-1) corresponding to halides at terminal or bridged positions. Two widely sepa rated redox processes, Ru-II/Ru-II<-- Ru-II/Ru-III--> Ru-III/ Ru-III, were observed by cyclic voltammetry and differential pulse voltammetry.