The reaction of [OsHCl(CO)(PPri3)2] (1) with cyclopentadiene in refluxing methanol affords the novel cyclopentadienylosmium(II) complex [OsH(η5-C5H5)(CO)-(PPri3)] (2). Reaction of 2 with CCl4 in pentane gives the chloro complex [Os(η5-C5H5)Cl(CO)(PPri3)] (3). The protonation of 2 with HBF4‚Et2O leads to the transdihydridoosmium(IV) complex [OsH2(η5-C5H5)(CO)(PPri3)]-BF (4). Treatment of the chloro complex 3 with AgBF4 followed by the terminal alkyne phenylacetylene or 1-ethynyl-1-cyclohexanol gives the stable vinylidene [Os-(η5-C5H5){dCdC(H)Ph}(CO)(PPri3)]BF4 (5) or vinylvinylidene [Os(η5-C5H5) {dCdC(H)CdCH(CH2)3CH2}(CO)-(PPri3)]BF4 (6), respectively.

We thank the DGICYT (Project PB-92-0092, Programa de Promocion General del Conocimiento) and the EU (European Union) (Project: Selective Processes and Catalysis Involving Small Molecules) for financial support.

Peer reviewed