Solvent effects on the kinetics of aquation of ?-chloro(diethylenetriamine) (ethylenediamine)cobalt(III) ion in mixed aqueous solvents

Abstract

Solvent effects on the kinetics of aquation of [Co(dien)(en)Cl]2+ have been investigated within the temperature range (40–60°C) in acetone-water and ethanol-water media of varying solvent compositions up to 60% by weight of the organic solvent component. The variation of the activation paremeters (ΔG#, Δh#, and ΔS#) with the mole fraction of the organic solvent component was analyzed and discussed. The isokinetic plots were linear in both solvent systems and revealed the existence of compensation effect due to a strong solute-solvent interactions. The correlation of log k with the ionizing power (Y) was found to be linear in both solvent mixtures. Morever, the correlation of log k with D−1 was linear in case of ethanol-water medium while in case of acetone-water it was nonlinear. © John Wiley & Sons, Inc. Int J Chem Kinet 29: 431–436, 1997.