New mononitrosyl derivatives of iron, ruthenium and osmium

Abstract

Hydride nitrosyl complexes [MH(NO)L₄][PF₆]₂1[M = Ru or Os; L = P(OEt)₂Ph] were prepared by allowing [MH(η²-H₂)L₄]BF₄ to react with NO⁺PF₆^– at –80 °C in CH₂Cl₂. Five-co-ordinate [Fe(NO)L₄]PF₆2 was obtained from the same reaction in the case of iron. Deprotonation of cations [MH(NO)L₄]²⁺1 with NEt₃ or OH^– led to the formation of new mononitrosyl cations [M(NO)L₄]⁺2(M = Ru or Os). All 2 react with HBF₄·Et₂O to give [MH(NO)L₄]²⁺ derivatives, according to the equilibrium [MH(NO)L₄]²⁺⇄[M(NO)L₄]⁺. Characterization of nitrosyls 1 and 2 by infrared, ¹H and ³¹P NMR spectra is reported. The reaction of [M(NO)L₄]⁺2(M = Fe, Ru or Os) with isocyanides and CO was examined and led to the synthesis of [M(NO)(CNR)₂L₂]⁺(M = Fe), [M(CNR)₄L₂]²⁺(M = Ru or Os), and [M(NO)(CO)₂L₂]⁺(M = Fe or Ru) derivatives (R = 4-MeC₆H₄ or 4-MeOC₆H₄). The [M(NO)L₄]PF₆ complexes are also oxidized by bromine to produce [RuBr₂(NO)L₃]⁺ and [OsBr(NO)L₄]²⁺.