Cyclopentadienyl-ruthenium and -osmium chemistry. Part 18. Oxidative addition and nitrosylation reactions: crystal structure of [Os-(NO)(PMe3)2(η-C5H5)][PF6]2

Abstract

Reaction of [MX(PR₃)₂(η-C₅H₅)](M = Ru, X = Cl; M = Os, X = Br; R = Me or Ph) with HPF₆ gives the metal(IV) complexes [MH(X)(PR₃)₂(η-C₅H₅)][PF₆], and with Cl₂–[NH₄][PF₆] gives [RuCl₂(PMe₃)₂(η-C₅H₅)]-[PF₆]. Reaction with [NO][PF₆] gives the dications [M(NO)(PR₃)₂(η-C₅H₅)]²⁺, which have unusually high ν(NO) frequencies (1 850–1 875 cm^–1). The crystal structure of [Os(NO)(PMe₃)₂(η-C₅H₅)][PF₆]₂ has been determined by single-crystal X-ray methods at 295 K and refined by least squares to a residual of 0.044 for 2 038 ‘observed’ reflections. Crystals are orthorhombic, space group Pbca, with a= 21.680(6), b= 16.606(4), c= 12.772(5)Å, and Z= 8. The Os–N–O system is linear, Os–N 1.75(1), N–O 1.17(2)Å being indicative of the OsN⁺O moiety; Os–P lengths are 2.367(4) and 2.364(4)Å and Os–C 2.23(2)–2.29(2)Å.