Kinetics and Mechanism of Substitution of Chloride Ion in trans-[Co(en)2Cl2]+ by Organic Bases in Dimethyl Acetamide Solution

The kinetics of substitution of chloride ion in trans-dichlorobis(ethylenediamine) cobalt(III) cation by five organic bases (diethylamine, triethylamine, benzylamine, t-butylamine and n-propylamine) in dimethylacetamide (DMA) at ionic strength of 0.80 M NaClO4 is reported. The activation parameters for the second-order path lie on a good isokinetic line. The linear plots of kobs vs. [B], the large negative values of ΔS2 ‡ and the span of k2 values signify an associative mechanism