Reactions of OsH2(η2-CH2 =CHEt) (CO) (PiPr3) 2 with unsaturated organic molecules

Article abstract of DOI:10.1016/S0022-328X(97)00399-9

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.