Reactions involving transition metals. Part X. Reactions of the complexes α- and β-[L3RhHX2](L = tertiary phosphine or arsine, X = Cl or Br)

Abstract

The reactions of the complexes α- and β[L_nRhHX₂](n= 2 or 3; L = tertiary phosphine or arsine; X = Cl or Br) with acidic, basic, oxidising, and reducing reagents have been investigated. The α-isomers are inert to acids (except nitric acid) but are rapidly dehydrohalogenated by bases. With weak bases, equilibria are established, the positions of which show that stability to dehydrohalogenation increases in the series L = Ph₂RP < PhR₂P < R₃P, R = Et < Me (n= 3) and L = Ph₃P < Ph₃ As < Ph₃Sb (n= 2). The β-isomers react similarly with bases and give trihalogeno-complexes with hydrogen halides. With sulphur dioxide both isomers are reduced and.form the SO₂ complexes [L₃RhXSO₂]·HX (X = Cl or Br). Both isomers also react with nitric acid to give [L₂ RhX₂NO₃].