Transition-metal nitrosyl compounds. Part VIII. The preparation and properties of some cationic nitrosyl complexes of zerovalent ruthenium and osmium

Abstract

Cationic nitrosyl complexes of the type [M(CO)₂(NO)L₂]Y (M = Ru or Os; L = PPh₃ or PCy₃; Y = BPh₄ or PF₆) have been prepared and their properties are discussed. Carbonyl and phosphine substitutions led to isolation of the species [M(CO)(NO)L₃]⁺[M = Ru, L₃=(PPh₃)₃ or (PPh₃)dppe; M = Os, L₃=(PPh₃)₃, (PMePh₂)₃, (PPh₃)dppe, or (PPh₃)₂P(OMe)₃] and [M(NO)(dppe)₂]⁺(M = Ru or Os). The reaction of M(CO)(NO)(PPh₃)₂Cl with AgPF₆, in CH₂Cl₂/acetone followed by the addition of ligands (CO, PPh₃, or dppe) provides an alternate route to the cations [M(CO)₂NO(PPh₃)₂]⁺ and [M(CO)(NO)L₃]⁺. The cations [M(CO)₂(NO)L₂]⁺ are oxidized by chlorine to produce cis- M(CO)₂L₂Cl₂(M = Ru or Os) and M(NO)L₂Cl₃(M = Ru); they react with halide ion (X^–) to give M(CO)(NO)L₂X and with OMe^– to produce M(CO)(NO)L₂(CO₂Me)(M = Os, L = PPh₃). Reduction of [Os(CO)NO(PPh₃)₃]⁺ with BH₄^– yields the hydride OsH(CO)NO(PPh₃)₂. Possible structures for these complexes are discussed.