Reactions of dodecacarbonyl-triangulo-triosmium with alkenes and benzene; fluxional behaviour of µ3-(ethan-1-yl-2-ylidyne)-di-µ-hydrido-triangulo-tris(tricarbonylosmium)(3Os–Os)

Abstract

Ethylene on reaction with Os₃(CO)₁₂ heated under reflux in octane undergoes 1,1-elimination of H₂ to give the ethan-1-yl-2-ylidyne complex [H₂Os₃(CH₂C)(CO)₉], (I), whereas cyclopentene and benzene undergo 1,2-elimination of H₂ to give corresponding cyclopenta-1,2-diylidene and cyclohexa-3,5-dien-1,2-diylidene complexes (II) and (III). Kinetic data are given for intramolecular exchange of the –CH₂C hydrogen atoms of complex (I) which is faster than hydride exchange, and mechanisms for these processes are discussed. Diphenyl(o-vinyl-phenyl) phosphine (dpvp) reacts with Os₃(CO)₁₂ to give the complex [H₂Os₃(Ph₂P·C₆H₄·C₂H)(CO)₈], (IV), which is related to the derivatives above.