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Skeletal Rearrangement of a C2 Unit on a Triruthenium Cluster. Synthesis of μ-Ethylidene, μ3-Ethylidyne, and μ3-Vinylidene Complexes by the Reaction of {Cp*Ru(μ-H)}33-H)2 with Acetylene

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journal contribution
posted on 29.10.2002, 00:00 by Toshiro Takao, Toshifumi Takemori, Makoto Moriya, Hiroharu Suzuki
Reaction of the triruthenium pentahydride complex {Cp*Ru(μ-H)}33-H)2 (1; Cp* = η5-C5Me5) with acetylene was investigated, in which the μ3-ethylidene−μ32(∥)-ethyne complex {Cp*Ru(μ-H)}3(μ-CMeH){μ32(∥)-CHCH} (2) was produced via formation of the intermediary bis(μ-vinyl) complex {Cp*Ru(μ-H)}3(μ-η12-CHCH2)2 (3). An α-C−H bond of the μ-ethylidene ligand of 2 underwent oxidative addition upon thermolysis to yield the μ3-ethylidyne−μ32(∥)-ethyne complex (Cp*Ru)3(μ-H)23-CCH3){μ32(∥)-CHCH} (5), which showed fluxional behavior of both the μ3-ethyne and the hydride ligands. Further C−H bond cleavage of the μ3-ethylidyne ligand, affording the μ-vinylidene−μ32(∥)-ethyne complex (Cp*Ru)3(μ-H)(μ3-CCH2){μ32(∥)-CHCH} (6), was also investigated. Treatment of 5 with an excess amount of acetylene resulted in C−C bond formation at the Ru3 core, and the μ3-ethylidyne−μ33-diruthenaallyl complex (Cp*Ru)33131-C(H)C(H)CCH3}(μ3-CCH3)(μ-H) (7) was obtained. The molecular structures of 5 and 7 were determined by single-crystal X-ray diffraction studies.