Octahedral chromium(III) complexes in dipolar aprotic solvents. V. Isomerisation and anation reaction of trans-[CrCl(DMSO)(en) 2] 2+, and cis and trans-[Cr(DMSO) 2(en) 2] 3+ in anhydrous dimethyl sulphoxide

Abstract

The isomerisation and anation reactions of complexes of the type trans-[CrCl(DMSO)(en) 2] 2+ and cis and trans-[Cr(DMSO) 2(en) 2] 3+ have been studied in dimethyl sulphoxide (DMSO) over a wide range of chloride concentration and temperature. This work supplements an earlier study 1 of the reactions of cis and trans-[CrCl 2(en) 2] + in DMSO. Following the isolation of the trans-[CrCl(DMSO)(en) 2](ClO 4) 2 complex a reappraisal of the previously suggested mechanism for the reactions of trans-[CrCl 2(en) 2] + has been made. The kinetics were interpreted in items of a dissociative mechanism with the characteristic effects of ion association. For trans-[CrCl(DMSO)(en) 2] 2+ in the presence of chloride ion loss of ethylenediamine dominated the kinetics. However no significant loss of ethylenediamine was detected in any of the other reactions.