HIGH-NUCLEARITY PHOSPHINIDENE CLUSTERS - SYNTHESIS, CHARACTERIZATION, AND REACTIVITY OF 2 W2RU4 CLUSTERS WITH A MU(4)-ETA(2)-CO LIGAND

[[abstract]]Thermolysis of the heterometallic phosphinidene cluster Cp*WRu2(CO)8(mu-H)(mu3-PPh) (2) in refluxing toluene solution gave two W2Ru4 clusters (4 and 5) via elimination of one H-2 and four CO molecules. Complexes 4 and 5 are isomers, which adopt a square-pyramidal WRu4 core skeleton with a pendant W atom bridging a Ru-Ru edge, on which the unusual mu4-eta2-CO ligand is associated with the butterfly W2Ru2 array; one mu4-PPh ligand occupies a WRu3 square face in both isomers, while a second mu3-PPh ligand caps a Ru3 face in 4 and a WRu2 face in 5. In refluxing toluene solution 4 and 5 began to equilibrate via a process involving mu3-PPh migration. When a solution of 4 was treated with dihydrogen, cluster degradation occurred to regenerate a small amount of 2 and tetranuclear Cp*WRu3(CO)10(mu3-PPh)(mu3-H)(3). Similarly,compound 4 reacts with carbon monoxide at 4 atm to produce the homometallic phosphinidene compounds Ru3(CO)9(mu3-PPh)2 (6) and Ru4(CO)11(mu4-PPh)2 (7) in moderate yield. Crystal data for 4: space group P2(1)/n; a = 12.174(4), b = 17.427(5), c = 22.773(6) angstrom; beta = 100.21(2)degrees; Z = 4; 5016 observed reflections; R = 0.034. Crystal data for 5: space group C2/c; a = 45.527(5), b = 10.201(1), c = 21.906(9) angstrom, beta = 93.90(3)degrees; Z = 8; 5448 observed reflections; R = 0.033.[[fileno]]2010302010111[[department]]化學