A mixture of an iron or a cobalt carboxylate and an isocyanide ligand catalyzed the hydrosilylation of alkenes with hydrosiloxanes with high efficiency (TON >10(3)) and high selectivity. The Fe catalyst showed excellent activity for hydrosilylation of styrene derivatives, whereas the Co catalyst was widely effective in reaction of alkenes. Both of them catalyzed the reaction with allylic ethers. Chemical modification and cross-linking of silicones were achieved by choosing the right catalyst and reaction conditions.

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Carbon-chain recombination, similar to that observed during the cracking of alkanes and in the Shell higher olefin process, is one of the most important reactions in the chemical industry. There has been a continuous demand for a process that can yield hydrocarbons of desired chain length. Recently, a method for converting lower alkanes into higher alkanes, which is referred to as alkane metathesis, has been reported. [1] Alkane metathesis has considerable scientific and industrial importance because it can convert gaseous hydrocarbons into liquid fuels. Such interconversion involves three catalytic reactions: activation of the alkane CÀH bond, olefin metathesis, and hydrogenation of the formed olefins. However, because of the cross-metathesis of the alkenes during the recombination process, the product will have a molecular weight distribution to some extent.Coupling reactions between two hydrocarbyl ligands placed on both faces of a trimetallic plane have often been seen in organometallic chemistry, [2] as has CÀC bond scission on a cluster.[3] These reactions have attracted considerable attention and are considered to be characteristic of cluster compounds. We have studied C À C bond formation on a triruthenium cluster by directing our attention to the roles of an MÀM bond.[4] Recently, we reported the synthesis of 2 using the coupling reaction of m 3 -benzyne and m 3 -vinylidene ligands separated by the Ru 3 plane of 1 (Scheme 1).[4c] In this reaction, the formation of the ruthenacyclopentadiene skeleton was accompanied by the rupture of a Ru À Ru bond. We also reported the scission of a CÀC bond in a ruthenacyclopentadiene skeleton in which a Ru 3 triangle was reconstructed.[4a] Such flexibility in a cluster skeleton would enable a novel recombination of hydrocarbons. Herein, we report an unprecedented selective interconversion of two C 5 fragments into C 8 and C 2 fragments on a triruthenium cluster.The thermolysis of 4, which was obtained by the sequential treatment of 3 with 1-pentene and 1-pentyne, [5] resulted in the quantitative formation of an equilibrated mixture of 5 a and 5 b (Scheme 2). At ambient temperature, the motion of the hydrido ligand was so rapid that the signals of 5 a and 5 b coalesced. For simplification, we denote this equilibrated mixture as 5.[6] The structures of 4 and 5 were determined by X-ray diffraction studies (Figure 1 and Figure 2, respectively).[7] These results clearly indicate that the m 3 -pentylidyne and m 3 -pentyne ligands in 4 were respectively transformed into the m 3 -ethylidyne and m 3 -octyne ligands in 5.This rearrangement required the migration of the C 3 fragment across the Ru 3 plane. In order to elucidate the mechanism, we monitored the reaction by means of NMR spectroscopy. Upon heating at 80 8C, formation of the m 3 -butylidyne-m 3 -hexyne complex 6 was observed (Path a in Scheme 3). For the formation of 6, a carbyne group must Scheme 1. CÀC bond formation in a trimetallic cluster accompanied by MÀM bond breaking. Cp* = pentamethylcyclopentadienyl. Sche...

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