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

The compound solution as a mixture of two slowly interconverting isomers. It is decarbonylated by treatment with Me₃NO·2H₂O to yield two new products Ru₆(CO)₁₃(μ-PMe₂)(μ₃-η³-Me₂PC₆H₄)(μ₆-C) (2) and Ru₆(CO)₁₄(PMe₂Ph)(μ-η²-MePhPCH₂)(μ₆-C)(μ-H) (3). Compound 2 is also obtained from 1 by thermal decarbonylation at 127 °C together with two additional compounds: Ru₆(CO)₁₄(μ-PMe₂)(μ-η²-MePhPCH₂) (μ₆-C) (4) and Ru₆(CO)₁₂(μ-PMe₂)₂(μ₃-η²-C₆H₄)(μ₆-C) (5). Compound 2 reacts reversibly with CO to form the CO adduct Ru₆(CO)₁₄ (μ-ηPMe₂)(μ-η²-Me₂PC₆H₄)(μ₆-C) (6). The structures of compounds 1-6 were established crystallographically. All contain octahedral Ru 6 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 η³-Me₂PC₆H₄ ligand formed by ortho-metallation of the phenyl ring of the second PMe₂Ph ligand. Compound 3 contains a bridging η²-MePhPCH₂ ligand formed by metallation of one of the methyl groups of a PMe₂Ph ligand. Compound 4 contains a bridging PMe₂ and a bridging η²-MePhPCH₂ ligand. Compound 5 contains two bridging PMe₂ ligands and a bridging (μ₃-η²-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 η²-Me₂PC₆H₄ ligand formed by ortho-metallation of the phenyl ring of one of the PMe₂Ph ligands.