Reaction of the diyne complex [Os3(μ-CO)(CO)9{μ3-η2-Me3SiCCCtriple bond; length of mdashCSiMe3}] with phosphines and phosphites: Characterization of monophosphine substituted clusters [Os3(μ-CO)(CO)8(PR3){μ3-η2-Me3SiCCCtriple bond; length of mdashCSiMe3}]

The reactions of [Os3(μ-CO)(CO)9{μ3-η2-Me3SiCCCtriple bond; length of mdashCSiMe3}] with phosphorus donor ligands (PPh3, PEt3, P(OEt)3, PHPh2 and a diphosphine; Ph2PCH2PPh2 (dppm)) afford carbonyl mono-substitution products [Os3(μ-CO)(CO)8(L){μ3-η2-Me3SiC2C2SiMe3}] even in the case of the bidentate phosphine dppm. All the complexes have been characterized by IR and multinuclear NMR spectroscopy and for 2 (L = PPh3), 3 (L = PEt3), 4 (L = P(OEt)3) and 5 (L = η1-dppm) the structures have been confirmed by single-crystal X-ray analysis. The structural analyses show that in all four clusters the substitution has occurred at one of osmium equatorial sites that is σ-bonded to the μ3-η2-alkyne.