Reactions of metal complexes in solution. Part II. The effect of chloride ion on the rate of the acid-catalysed aquation of trans-dinitrotetramminecobalt(III) nitrate

TLDR: In this paper, the acid-catalysed aquation of trans-dinitrotetramminecobalt(III) nitrate has been studied in the presence of chloride ions over a temperature range 25-40° at an ionic strength of 2·5M.

Abstract: The acid-catalysed aquation of trans-dinitrotetramminecobalt(III) nitrate has been studied in the presence of chloride ions over a temperature range 25–40° at an ionic strength of 2·5M. In the acid range [H+]= 0·1–1·5M at [Cl–]= 2·0M, the increase in the rate may be interpreted in terms of the reactions of the ion-pairs [Co(NH3)4(NO2)2]+Cl–, [Co(NH3)4(NO2)(NO2H)]2+Cl–, and [Co(NH3)4(NO2H)2]3+Cl–. Rate constants for each reaction have been obtained and thermodynamic parameters derived. The results are consistent with a reaction scheme involving a solvent-assisted dissociative mechanism.