Reactivity of Ph2P(Se)CH2C6H4CH2P(Se)Ph2 with [M3(CO)12] (M = Ru or Fe).: Synthesis and characterization of the new carbene cluster [Ru3(μ3-Se)(μ3-H)(μ3-PPh2)(CO)6(μ2-CHC6H4CH2PPh2)]

The reactions of [M-3(CO)(12)] (M = Ru or Fe) with 1,2 bis[(diphenylphosphino)methyl]benzene diselenide (dpmbSe(2)) in hot toluene afford a variety of phosphine-substituted selenido carbonyl clusters. They belong to the following three families: (i) 50-electron clusters with a M3Se2 core (2, 3, 5-7), (ii) 48-electron clusters with a M3Se core (1, 8), (iii) 34-electron clusters with a M2Se2 core (4). All these species derive from the P=Se bond cleavage. Cluster 1, which contains a hydrido, a phosphido, and a carbene ligand, is produced by multiple fragmentation of the diphosphine. This fragmentation appears related to the presence of the selenido ligand on the cluster, as the reaction of [Ru-3(CO)(12)] with dpmb (not selenized) produces only carbonyl substitution by the phosphine to give [Ru-3(CO)(10)(mu-dpmb)] (9). All the clusters synthesized have been characterized by spectroscopic techniques, and in some cases fluxional behavior has been detected in solution by NMR analysis. The structures of 1, 2, and 7-9 have been determined by X-ray diffraction methods.