Competitive Acetylide C−C Bond Scission vs Formation of a Quadruply Bridging Carbonyl Ligand. X-ray Crystal Structures of the Two Pentanuclear Clusters Cp*3W3Ru2(μ4-C)(μ3-CPh)(CO)9 and Cp*3W3Ru2(μ3-CCBut)(CO)9
journal contributionposted on 29.04.1997, 00:00 by Pei-Chiun Su, Yun Chi, Chi-Jung Su, Shie-Ming Peng, Gene-Hsiang Lee
Reactions of Cp*WRu2(CCPh)(CO)8 (1a) with excess Cp*W(CO)3H, Cp* = C5Me5, affords a carbido−alkylidyne cluster Cp*3W3Ru2(μ4-C)(μ3-CPh)(CO)9 (5) alone with three byproducts, which are identified as hydride cluster Cp*WRu3(μ-H)3(CO)11 (2), vinylidene cluster Cp*2W2Ru2(CCHPh)(CO)9 (4), and a pentanuclear oxo−carbido cluster Cp*2W2(O)Ru3(μ5-C)(CO)11 (3). In contrast, the respective condensation using tert-butyl derivative Cp*WRu2(CCBut)(CO)8 (1b) gives an acetylide cluster Cp*3W3Ru2(μ3-CCBut)(CO)9 (6). The X-ray structural determinations of 5 and 6 reveals the existence of an edge-bridged tetrahedral core, in which the butterfly crater is occupied by a μ4-carbide in 5 or a quadruply bridging CO ligand in 6. A plausible mechanism leading to the formation of these two cluster compounds is also presented.