Mechanism of octahedral substitutions in non-aqueous media. Part III. Rates of replacement reactions in trans-chloronitro- and dichlorobis(ethylenediamine)cobalt(III) ion in methanol and ethanol

Abstract

The rate of replacement of chloride by thiocyanate in trans- and cis-chloronitrobis(ethylenediamine)cobalt(III) ions in methanol and ethanol, respectively, is acid-independent, while the rate of analogous replacements in the trans-dichloro-complex ion decreases with increasing acid concentration until a limiting value is reached. The rate of replacement of chloride by azide in the trans-chloronitro-complex in methanol is independent of the azide concentration. The ratio of the rates of replacement of chloride in the trans-chloronitro-complex ion by thiocyanate in methanol and ethanol is one half of the analogous ratio in the dichloro-complex ion. The effect of the acid and of the solvent suggests that the replacement reactions of the chloronitro- and the dichloro-complex ions do not follow an identical mechanism.