Trapping of a 12-valence-electron osmium intermediate

The hydride-dikydrogen complex [OsH(η2-H2) {κ3N,C,C-CH2=CH-o-C5H4N} (PiPr3)2] BF4 (1) is a >functional equivalent> of the 12-valence-electron monohydride cation >[OsH(PiPr3)2]+>, which is trapped by aromatic solvents, such as toluene, benzene, and fluorobenzene to form the arene derivatives [OsH(η6-C6H5R) (PiPr3)2] BF4 (R = CH3 (2), H (3), F (4)). This >functionalequivalent> can be also generated by protonation of the hexahydride OsH6-(PiPr 3)2 (5) with 1 equiv of HBF4 and subsequent release of three hydrogen molecules. The monohydride is also trapped by S. The protonation of the latter with 0.5 equiv of HBF4 yields the heptahydride dimer [{OsH2(PiPr3) 2}2(μ-H)3] BF4 (6), which does not undergo exchange of bridging and terminal hydrides. © 2009 American Chemical Society.Financial support from the MICINN of Spain (project numbers CTQ2008-00810 and Consolider Ingenio 2010 CSD2007-00006) and the Diputación General de Aragón (E35) is acknowledged. K.G. thanks the Spanish MEC for a grant.Peer Reviewe