Kinetics and mechanism of nucleophilic substitution of acridine by chloride ion in octahedral tin(IV) complexes

Abstract

The nucleophilic substitution of acridine by chloride ion in SnCl₄L₂ and R₂SnCl₂L₂ (where R = Me, Bu, Ph, and L = acridine) carried out in acetonitrile at ambient temperature follows first order kinetics. A millimolar solution of the complexes in acetonitrile shows increase in conductance with time indicating solvation which is enhanced in the presence of SOCl₂, C₆H₅COCI and CH₃COC1 suggesting the replacement of acridine by chloride ion. The rate constants <em>k</em>₁<em>, k</em>₂ and the thermodynamic parameters (activation energy, entropy, and enthalpy) have been calculated. The nucleophilicity of these reagents has been found to be in the order : SOCl₂ > C₆H₅COCl > CH₃COCl.