A Useful Access to the Chemistry of the Indenyl-Osmium-Triisopropylphosphine Moiety

Complex OsH3Cl(PiPr3)2 (1) reacts with indenyllithium to give OsH(η5-C9H7)(PiPr3)2 (2), which affords (3) by treatment with methyl trifluoromethanesulfonate. In acetonitrile, complex 3 evolves to an equilibrium mixture of the acetonitrile adducts [Os(η5-C9H7)(NCCH3)-(PiPr3)2]OTf (4) and [Os(η5-C9H7)(NCCH3)2(PiPr3)]OTf (5). The addition of 2,5-norbornadiene (NBD) to this mixture leads to [Os(η5-C9H7)(η4-NBD)(PiPr3)]OTf (6). Complex 2 also reacts with I2 and HBF4, to give [OsHI(η5-C9H7)(PiPr3)2]I (7) and [OsH2(η5-C9H7)(PiPr3)2]BF4 (8), respectively.