Synthesis of hydride and alkyl compounds containing the Cp*Os(eta(3)-allyl) fragment. Crystal structures of Cp*Os(eta(3)-C8H13)Br-2 and [Cp*Os(eta(3)-C4H7)Me(H2O)][BF4]

Treatment of Gp*(2)Os(2)B(r)4 with 3-bromo-2-methylpropene or 1,3-cycloacta diene affords the 2-methylpropenyl and cyclooctenyl products Cp*Os(eta(3)-C 4H7)Br-2 and Cp*Os(eta(3)-C8H13)Br-2, respectively. The monoalkyl complexes Cp*Os(eta(3)-C4H7)MeBr and Cp*Os(eta(3)-C4H7)(CH2SiMe3)-Br can be generate d by treating Cp*Os(eta(3)-C4H7)Br-2 with MgMe2 or LiCE2SiMe3. The dimethyl complex Cp*Os(eta(3)-C4H7)Me-2 can be synthesized from CP*Os(eta(3)-C(4)H7 ())Br(2) by addition of methyllithium. In contrast, addition of ethyllithiu m to Cp*Os(eta(3)-C4H7)Br-2 yields the ethylene complex Cp*Os(eta(3)-C4H7)( eta(2)-C2H4) and a small amount of Cp*Os(eta(3)-C4H7)H-2. The latter dihydr ide can be synthesized in better yield by treating CP*Os(eta(3)-C4H7)Br-2 W ith LiAlH4. When the dimethyl complex Cp*Os(eta(3)-C4H7)Me-2 is protonated with HBF4 in the presence of H2O, the aqua complex [Cp*Os(eta(3)-C4H7)Me(H2 O)][BF4] is formed.