STRUCTURAL STUDIES ON RUTHENIUM CARBONYL HYDRIDES .16. ISOMERISM IN 47-ELECTRON AND 48-ELECTRON (METHYLIDYNE)TRIRUTHENIUM CLUSTERS - CRYSTAL-STRUCTURES OF (MU-H)3RU3(MU-3-COME)(CO)6(MU-3-(PPH2CH2)3CME) AND (MU-H)3RU3(MU-3-COME)(CO)7(MU-2-(PPH2)3CH).1.25CH2CL2

Ligand substitution on (mu-H)3Ru3(mu-3-COMe)(CO)9 has been used to prepare the clusters (mu-H)3Ru3(mu-3-COMe)(CO)6{mu-3-(PPh2CH2)3CMe} and (mu-H)3Ru3(mu-3-COMe)(CO)7{mu-2-(PPh2)3CH}. The complex (mu-H)3Ru3(mu-3-COMe)(CO)6{mu-3-(PPh2CH2)3CMe} crystallizes in the centrosymmetric triclinic space group P1BAR with a = 10.053 (2) angstrom, b = 12.920 (3) angstrom, c = 19.185 (4) angstrom, alpha = 87.23 (2)-degrees, beta = 75.80 (2)-degrees, gamma = 77.62 (2)-degrees, V = 2359.6 (9) angstrom 3, and Z = 2. The molecule has approximate C3 symmetry, with the mu-3-COMe group and the mu-3-MeC(CH2PPh2)3 ligand capping opposite faces of the planar triruthenium core; the P-donor atoms thus are all in axial sites. Electrochemical and chemical oxidation of (mu-H)3Ru3(mu-3-COMe)(CO)6{mu-3(PPh2CH2)3CMe} forms the corresponding 47-electron radical cation, characterized by EPR spectroscopy. The complex (mu-H)3Ru3(mu-3-COMe)(CO)7{mu-2-(PPh2)3CH} crystallizes from CH2Cl2 in the centrosymmetric monoclinic space group P2(1)/n with a = 21.653 (6) angstrom, b = 19.078 (4) angstrom, c = 25.238 (8) angstrom, beta = 106.63 (3)-degrees, V = 9989 (5) angstrom 3, and Z = 8. The crystallographic asymmetric unit contains 2 triruthenium cluster molecules and 2.5 CH2Cl2 molecules. The (PPh2)3CH ligand behaves only as a bidentate bridging ligand and spans adjacent equatorial sites on two ruthenium atoms.