Heterometallic clusters in homogeneous catalysis. Hydrogenation of diphenylacetylene and isomerization of cis-stilbene in the presence of , , , , and related compounds. Identification of organometallic complexes and a discussion of...

Article abstract of DOI:10.1016/0022-328X(93)80080-U

The clusters (M=Ru or Fe), , , and (M=Ru, M'=Fe or Ru) have been tested as homogeneous catalysts for the hydrogenation of C2 Ph2 and isomerization of cis-stilbene.The effect of the cluster stoichiometry, of dihydrogen and of the substrate/cluster ratio have been evaluated.There is evidence of competition between dihydrogen, which favours the formation of catalytically active hydrides or "metal fragments", and C2Ph2, which favours metal-fragment condensation to give alkyne-substituted clusters; with the exception of , these derivatives are stable by-products and react slowly with dihydrogen, giving only small amounts of hydrogenation products.The alkyne-substituted derivatives found in the hydrogenation solutions are the reported products of the reactions of iron, ruthenium or iron-ruthenium carbonyl clusters with C2Ph2 under dinitrogen; however, there are differences in the yields.Moreover, in the reactions of or , a new derivative was obtained; this was characterized spectroscopically as a third isomer of .