Reactivity of new osmium dihydrides with arenediazonium cations: preparation and properties of bis(aryldiazene) and mono(aryldiazenido) complexes. A comparison with analogous iron and ruthenium derivatives

Abstract

Hydride complexes [OsH₂L₄][L = P(OEt)₃ or PPh(OEt)₂] were prepared. Their reactions with arenediazonium cations led to the synthesis of [Os(RNNH)₂L₄][BPh₄]₂ and [OsH(RNNH)L₄]BPh₄(R = Ph, 4-MeC₆H₄, or 4-MeOC₆H₄) complexes which were characterized by ¹H and ³¹P n.m.r. data (with ¹⁵N isotopic substitution). The compounds [Os(4-MeC₆H₄NNH)(4-MeC₆H₄NC)L₄][BPh₄]₂ were also prepared. The reaction of the bis(aryldiazene) derivatives with NEt₃ led to new five-co-ordinate aryldiazenido complexes [Os(RN₂)L₄]BPh₄(R = Ph or 4-MeC₆H₄). Protonation of the diazenido compounds with CF₃CO₂H and HBF₄ gave the six-co-ordinate mono(diazene)[Os(CF₃CO₂)(RNNH)L₄]BPh₄ and the five-co-ordinate [Os(RNNH)L₄]BPh₄(R = 4-MeC₆H₄) derivatives, respectively. Infrared and ¹H and ³¹P n.m.r. data for these complexes are reported.