Mechanism of octahedral substitutions in non-aqueous media. Part V. Rates of replacement reactions in cis-chloroaquo-, trans-dichloro-, and trans-chloronitro-bis(ethylenediamine)cobalt(III) ions in methanol

Abstract

The rates of anation of cis-chloroaquo-complex ion by chloride, bromide, and nitrite have been studied at low reagent concentrations. The replacement rates of chloride by thiocyanate and nitrite, respectively, in trans-chloronitro-complex ion, and the replacement of chloride by thiocyanate in trans-dichloro-complex ion in methanolic solutions have also been studied at low concentrations. The kinetic results can be explained in terms of ion-associations. The corresponding ion-association constants, the rate constants for the rearrangement of the ion-aggregates and for the reactions of the free ions have been determined. The differences in the kinetic behaviour between chloronitro-complex ion on the one hand, and dichloro- and chloroaquo-complex ions, respectively, on the other are discussed.