Medium effects on the initial and the transition states upon the solvolysis of trans‐dichlorobis(N‐methyl‐ethylenediamine)cobalt(III) complex in water‐mixed solvents

Abstract

AbstractThe kinetics of solvolysis of trans‐dichlorobis(N‐methylethylenediamine)cobalt(III) complex have been investigated in aqua‐organic solvent media (0–60% (v/v) cosolvent) at 25 ≤ t°C ≤ 60, using n‐propanol and tert‐butyl alcohol as cosolvents. The first‐order rate constant increased nonlinearly with the reciprocal of the dielectric constant Ds−1, and xorg, reflecting the individuality of the cosolvents and thereby suggesting that the relative stabilities of the transition state and initial state were governed by the preferential solvation effect. The thermodynamic parameters (ΔH≠ and ΔS≠) were sensitive to the structural changes in the bulk solvent phase. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 34: 495–499, 2002