ELECTROCHEMICAL-BEHAVIOR AND X-RAY CRYSTAL-STRUCTURE OF THE UNUSUAL DIMERIC RUTHENIUM(CYCLOOCTADIENE) COMPLEX, NITRILE)BIS(ETA(4)-CYCLOOCTADIENE)-DIRUTHENIUM(II)

A novel Ru(II)(COD) dimer containing triply-bridging chloride ligands has been prepared and its crystal structure determined. The metal atom s each contain axial COD ligands and are separated by a distance of 3. 251 angstrom. Both transition metals possess octahedral coordination g eometries. One contains a coordinated molecule of acetonitrile and the other contains an axial halide ligand. Electrochemical investigations show that the complex undergoes two one-electron oxidations that sati sfy the criteria for a fully reversible diffusion controlled process. An improved method of preparing this dimeric Ru(II) cycloolefin comple x is also presented. The crystals are monoclinic, space group C2/c, a = 21.258(6), b = 7.179(2), c = 27.068(7) angstrom, beta = 93.18(2)-deg rees, V = 4124(2) angstrom-3. Convergence to conventional R values of R = 0.0368 and R(w) = 0.0394 with a goodness-of-fit of 0.95 was obtain ed for 226 variable parameters and 2710 reflections with I > 0sigma(I) .