CH and PC bond activations of PMe2Ph ligands by an octahedral Ru6 cluster

The compound Ru-6(CO)(15)(PMe2Ph)(2)(mu(6)-C) (1) was obtained from the reaction of Ru-6(CO)(17)(mu(6)-C) with PMe2-Ph. Compound 1 exists in solution as a mixture of two slowly interconverting isomers. It is decarbonylated by treatment with Me3NO.2H(2)O to yield two new products Ru-6(CO)(13)(mu-PMe2)(mu(3)-eta(3)-Me2PC6H4)(mu(6)-C) (2) and Ru-6(CO)(14)(PMe2Ph)(mu-eta(2)-MePhPCH2)(mu(6)-C)(mu-H) (3). Compound 2 is also obtained from I by thermal decarbonylation at 127 degreesC together with two additional compounds: Ru-6(CO)(14)(mu-PMe2)(mu-eta(2)-MePhPCH2)(mu(6)-C) (4) and Ru-6(CO)(12)(mu-PMe2)(2)(mu(3)-eta(2)-C6H4)(mu(6)-C) (5). Compound 2 reacts reversibly with CO to form the CO adduct Ru-6(CO)(14)(mu-PMe2)(mu-eta(2)-Me2PC6H4)(mu(6)-C) (6). The structures of compounds 1-6 were established crystallographically. All contain octahedral RU6 Clusters with a carbido ligand in the center. Except for 1, all contain phosphine ligands in various stages of degradation. Compound 2 contains one bridging PMe2 ligand formed by loss of a phenyl ring from a PMe2Ph ligand and a bridging eta(3)-Me2PC6H4 ligand formed by ortho-metallation of the phenyl ring of the second PMe2Ph ligand. Compound 3 contains a bridging eta(2)-MePhPCH2 ligand formed by metallation of one of the methyl groups of a PMe2Ph ligand. Compound 4 contains a bridging PMe2 and a bridging eta(2)-MePhPCH2 ligand. Compound 5 contains two bridging PMe2 ligands and a bridging (mu(3)-eta(2)-C6H4) benzyne ligand fromed by cleavage of a phenyl ring from one of the PMe2Ph ligands. Compound 6 contains one bridging PMe2 ligand and a bridging eta(2)-MePC6H4 ligand formed by ortho-metallation of the phenyl ring of one of the PMe2Ph ligands. (C) 2002 Elsevier Science BY. All rights reserved.