Formation of Osmium-Allylphosphinomethanide Complexes by Coupling of an Isopropenyldiisopropylphosphine and Monosubstituted Allenes

Complex [Os­(η5-C5H5)­{κ3-P,C,C-PiPr2[C­(Me)CH2]}­(MeCN)]­PF6 (1) reacts with cyclohexylallene and ethyl carboxylate allene to give the allylphosphinomethanide derivatives [Os­(η5-C5H5)­{κ5-P,Ca,Cb,Cc,Cd-PiPr2[Ca(Me)­CH2Cb(CcH2)­CdHR]}]­PF6 (R = Cy (2), CO2Et (3)). In fluorobenzene at 95 °C, complexes 2 and 3 evolve into the corresponding γ-allyl-α-alkenyldiisopropylphosphine compounds [OsH­(η5-C5H5)­{κ4-P,Ca,Cb,Cc-PiPr2[C­(CH2)­CH2Ca(CbH2)­CcHR]}]­PF6 (R = Cy (4), CO2Et (5)). Complexes 2 and 4 have been characterized by X-ray diffraction analysis.