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Three-Centre Oxidative Addition of Phosphorus Ylides to Ru3(CO)12 Phosphorus ylides undergo oxidative addition to Ru3(CO)12 to yield a wide range of Ru3 clusters with triply bridging organic ligands derived from the ylides. Ph3PCH2 forms HRu3(CO)9(μ31-Ph3P — CH — CO) (1) containing a phosphonio enolate. Ph3PCH — CHO yields a product mixture containing the phosphonio enolate-bridged cluster and its PPh3 derivative 6, the phosphoniomethylidyne-bridged compound H2Ru3(CO)9(μ31-C — PPh3) (5), and the ketenylidene-bridged compound H2Ru3(CO)8(PPh3)(μ31-C — CO) (7). Thermal treatment converts the phosphonio enolate ligand (in 1) into the phosphoniomethylidyne ligand (in 5), and the latter into the ketenylidene ligand (in 7). With Ph3PCH — C(O)Me and Ru3(CO)12ortho1-metalated Ru3 derivatives 10, 11 of the phosphonio ketone R3P — C — C(O)Me are produced, and likewise with Ph3PCH — COOEt the ortho1-metalated derivative 12 of the phosphonio ester R3P — C — CO2Et. Me3PCH — COOtBu is oxidatively added to form HRu3(CO)9(μ31-Me3P — C — COOtBu) (13) bearing a phosphonio ester ligand. — The crystal structures of 6 and 13 are reported. The sequence of Ru3 clusters and the bonding modes of the μ3 ligands can be related to the surface reactions during Fischer-Tropsch catalysis. |
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