Chromium(III) complexes in dipolar aprotic solvents. VI. The anation of Hexa(dimethyl sulphoxide)chromium(III) [Cr(Me₂SO)₆]³⁺ in dimethyl sulphoxide

Abstract

The anation reactions:                      Cr(Me₂SO)₆³⁺ + X^- → CrX(Me₂SO)₅²⁺ + Me₂SO have been studied in detail for X- = N₃^- and SCN^- as a function of concentration, temperature and ionic strength in both conditions of X^- in excess over Cr(Me₂SO)₆³⁺, and Cr(Me₂SO)₆³⁺ in excess over X^-, where greater certainty exists concerning the nature of the solution species. The reactions are interpreted as dissociative interchange reactions in which anation is a probable result of dissociation only when the anion occupies a position in the first solvation sphere of the complex.     Less complete results are presented for the less tractable anation of Cr(Me₂SO)₆³⁺ by Cl^- in Me₂SO, and the analogous reaction of Cr(HCONMe₂)₆³⁺ by Cl^- in dimethylformamide.