The Effects of Pressure, Temperature and Solvent Composition on Solvolysis of trans-[Co(N-eten)2Cl2]+ in Water-t-butyl Alcohol Mixture

摘要

Rates of solvolysis of trans-[Co(N-eten)2Cl2]+ have been investigated using spectrophotometric method at various pressures and temperatures in the mixtures of water with the t-butyl alcohol which possesses a high structure inducing capacity in water. The values of ツV× obtained from pressure effect on the rate constants were 2.55… 5.83 cm3mol-1. These values were discussed in terms of dissociative mechanism. Extrema found in the variation of ツH× and ツS× with solvent composition correlated with extrema in the variation of the physical properties of the mixtures. The logarithms of rate constants correlated linearly with both Grunwald-Winstein parameter and the reciprocal of dielectric constant (Ds-1). The gradient, m of Grunwald-Winstein plot for the trans-[Co(N-eten)2Cl2]+ was 0.09, which is significantly lower than those for the other cobalt (ゲ)-dichloro complexes. It was suggested that the reaction is an Id mechanism with long extension of Co-Cl bond in the transition state, as found for the C-Cl bond in the transition state for the solvolysis of t-butyl chloride.