Kinetics of aromatic nucleophilic substitution by toluene-p-thiolate in dimethylformamide. Effect of solvent on Hammett-type correlations

The kinetics of the reaction of some 4-substituted 2-nitrochlorobenzenes with toluene-p-thiolate in dimethylformamide have been measured at temperatures from -39.7 to 71.9\ub0C. Correlation of rates by Hammett-type equations gives, using the best set of \u3c3 values, \u3c1 = +6.65 at 10\ub0C. The dependence of the \u3c1 value on the solvent is discussed. A comparison of these reactions with those of Ar2C=CHCl and of ArC 61CCl with the same nucleophile-solvent system shows that the substituent effects are markedly attenuated by the interposition of C=C or C 61C bonds