Electrophilic behaviour of the co-ordinated nitrosyl cation: reactions of pentahalogenonitrosyliridate(1–)

Abstract

The complexes [Ir(X)₅NO]^–(X = Cl or Br) are attacked at the nitrosyl nitrogen atom by nucleophiles according to the equations: (i)[Ir(X)₅NO]^–+ 2OH^–⇌[Ir(X)₅NO₂]^3–+ H₂O; (ii)[Ir(X)₅NO]^–+ NH₂OH →[Ir(X)₅H₂O]^2–+ N₂O + H⁺; (iii)[Ir(X)₅NO]^–+ N₃^–+ H₂O →[Ir(X)₅H₂O]^2–+ N₂O + N₂; and (iv)[Ir(X)₅NO]^–+ 2NH₃→[Ir(X)₅NH₃]^2–+ N₂+ H₃O⁺. Hydrazine hydrate and [Ir(Br)₅NO]^– form [IrBr₃(N₂H₄)₃],0·5H₂O by an unknown route. Equilibrium constants for the reversible reaction with OH^– are compared with the analogous reactions of NO⁺ and [Fe(CN)₅NO]^2–.