960222-16-6Relevant academic research and scientific papers
Reaction of a heterobimetallic polyhydrido cluster, [Cp*Ru(μ-H) 4OsCp*] (Cp* = η5-C5Me 5), with diphenylacetylene. Regioselective C-H bond activation at the osmium center
Shima, Takanori,Ichikawa, Toshiaki,Suzuki, Hiroharu
, p. 6329 - 6337 (2007)
The reactivity of a heterobimetallic polyhydrido complex [Cp*Ru(μ-H)4OsCp*] (1) toward diphenylacetylene is studied to elucidate the roles of each metal atom in the substrate activation step. The reaction of 1 with an equivalent of diphenylacetylene exclusively produces a η2-frans-stilbene complex [Cp*Ru(μ-H) 2(μ-trans-PhHC=CHPh)OsCp*] (8), in which trans-stilbene is coordinated to the osmium metal by way of the η2-cis-stilbene complex [Cp*Ru(μ-H)2(μ-cis-PhHC=CHPh)OsCp*] (10). Treatment of 1 with an excess amount of diphenylacetylene yields [Cp*Ru(μ-H)(μ-η1:n2-cis-PhC=CHPh)(trans- PhHC= C HPh)OsCp*] (11) via complex 8. Intermediacy of 8 in the formation of 11 is confirmed by the reaction of 8 with diphenylacetylene. Thermolysis of 11 in C6D6 at 50 °C generates a μ-perpendicularly coordinated diphenylacetylene complex [Cp*Ru(μ-H)2(μ- η2:η2-PhCCPh)OsCp*] (12) and a benzo-osmacyclopentadiene complex [Cp*Os(μ-PhC=CH-C6H 4-)H2RuCp*] (13) together with trans-stilbene. Complex 8 is converted into 13 even in the absence of added diphenylacetylene. Upon heating of 8 in THF, 13 is formed as a result of the C(sp2)-H bond cleavage and subsequent intramolecular activation of the C(ortho)-H bond at the osmium center. The molecular structures of [(C5Me 4Et)Ru(μ-H)2(μ-trans-PhHC=CHPh)OsCp*] (80′, [(C5Me4Et)Ru(μ-H)(μ-η1: η2-cis-PhC=CHPh)(oros-Ph HC=CHPh)OsCp*] (11′), 12, [Cp*Os(μ-PhC= CH-C 6H4-)H2Ru(C5Me4Et)] (13′), and [Cp*Os(μ-PhC=CH-C6H4-)H 2OsCp*] (15) are determined by X-ray studies.
