Reaction of [M(CO)4(η2-C2H2)] (M=Fe, Os) with [(η5-C5H5)(CO)2WCC6H5]; unexpected substitution of acetylene, formation and molecular structure of [MW(μ-CC6H5)(CO)6(η5-C5H5)]

摘要: Abstract Reaction of [M(CO)4(η2-C2H2)] (M=Fe, Os) with [(η5-C5H5)(CO)2WCC6H5] affords the heterobimetallic complexes [MW(μ-CC6H5)(CO)6(η5-C5H5)] 1; Os, 2). This is contrary to usual substitution reactions former compounds, which proceed by loss CO and not that acetylene ligand. The IR NMR signatures compounds are in accord their formulation this has been corroborated single crystal X-ray crystallography. Each compound contains a d8 M(CO)4 fragment. geometry Group 8 metal trigonal bipyramidal (tbp) tungsten-carbyne unit, acting as two-electron pseudo-alkyne ligand, occupying an in-plane equatorial position. In solution fluxional. At room temperature, local scrambling at iron averages all four terminal carbonyl ligands, whereas process slower for osmium results only broadened axial resonances 13C-NMR spectrum. Intermetallic exchange observed on time scale. Plausible scenarios formation 1 2 outlined.