The 1-butene ligand of the dihydrido complex OsH2(η2-CH2=CHEt)(CO)(PiPr3)2 (1) can be readily displaced by cyclopentadiene to yield OsH2(η2-C5H6)(CO)(PiPr3)2 (2). Complex 1 selectively hydrogenates the carbon−carbon triple bond of 2-methyl-1-hexen-3-yne to give the methylhexadiene derivative Os{η4-CH2=C(CH3)(CH=CHCH2CH3}(CO)(PiPr3)2 (3). Treatment of 1 with phenylacetylene in a 1:10 molar ratio leads to the diphenylbutenynyl complex Os(C2Ph){η3-C(C≡CPh)=CHPh}(CO)(PiPr3)2 (5a) containing the carbonyl ligand trans disposed to the carbon−carbon triple bond of the butenynyl unit. In benzene-d6 at 60°C, 5a affords a new isomer 5b, where the carbonyl group is disposed trans to the OsC= carbon atom of the diphenylbutenynyl ligand. Isomer 5a reacts with HBF4 · H2O to give Os(CH2Ph)(FBF3)(CO)2(PiPr3)2 (6), which by reaction with NaCl yields Os(CH2Ph)Cl(CO)2(PiPr3)2 (7). The reactions of 1 with dicyclohexyl-carbodiimide, phenylisocyanate, phenylisothiocyanate and methylisothiocyanate lead to the corresponding insertion products OsH{κ2-N(Cy)CHN(Cy)}(CO)(PiPr3)2 (8), OsH {κ2-N(Ph)CHO}(CO)(PiPr3)2 (9) OsH{κ2-N(Ph)CHS}(CO)(PiPr3)2 (10) and OsH{κ2-N(CH3)CHS}(CO)(PiPr3)2 (11). Complex 1 also reacts with benzophenone imine, in this case the reaction product is OsH{NH=C(Ph)C6H4} (Co)(PiPr3)2 (12). The protonation of 12 with HBF4 · OEt2 gives the five-coordinate complex [OsH(CO)(NH=CPh2)(PiPr3)2]BF4 (13). which by reaction with carbon monoxide and trimethylphosphite affords [OsH(CO)2(NH=CPh2)(PiPr3)2]BF4 (14) and [OsH(CO)(NH=CPh2){P(OMe)3}PiPr3)2]BF4 (15), respectively.

We thank the DGlCYT (Project PB95-0806, Programa de Promocion General del Conocimiento) for financial support.

Peer reviewed