Kinetics and Mechanism of Nucleophilic Substitution in SnR2Cl2 · 2DMSO by Chloride Ions in Micellar Microenvironment

Abstract

Abstract The kinetics of nucleophilic substitution of dimethylsulfoxide by chloride ion in bis-dimethyl sulfoxide dimethyltin(IV) dichloride and bis-dimethyl sulfoxide diphenyltin(IV) dichloride in micellar microenvironment (1.0 × 10–2 M SDS in aqueous solution of ethanol (1:1, v/v) has been studied conductometrically. The reactions have been carried out at 25°C. Substitution follows first order path with respect to chloride ion concentration. A millimolar solution of the complexes in ethanolic solution of 1.0 × 10–2 M SDS shows an increase in conductance with time due to solvation of the molecule. Sn(CH3)2Cl2 · 2 DMSO shows high conductance as compared to Sn(C6H5)2Cl2 · 2 DMSO. In the presence of the nucleophilic reagents, C6H5COCl and CH3COCl there is a greater enhancement in conductance due to substitution of DMSO by chloride ion. The data of rate constant for solvation (KS) and for nucleophilic substitution (K1 and K2) have been calculated. It was found that the solvation is a slower process compared to the substitution by chloride ions i.e., K1, K2 > Ks. A possible mechanism has been suggested.