New mononitrosyl derivatives of iron, ruthenium and osmium

Hydride nitrosyl complexes [MH(NO)L4][PF6]2 1 [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]PF6 2 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+. © Copyright 1992 by the Royal Society of Chemistry.