The stabilities of Meisenheimer complexes. Part 25. Kinetic studies of the reaction of 1,3,5-trinitrobenzene with aliphatic amines in dimethyl sulphoxide

Abstract

Kinetic studies by stopped-flow spectrophotometry are reported for the reactions of 1,3,5-trinitrobenzene with n-butylamine, benzylamine, isopropylamine, or piperidine in dimethyl sulphoxide. These reactions lead to the formation of anionic σ-adducts via zwitterionic intermediates and it is shown that proton-transfer may be kinetically significant. Reduction below the values expected for diffusion-control in the values of rate constants for proton-transfer between the zwitterions and amines is attributed to a steric effects which is more pronounced in the reaction involving piperidine than in the reactions of primary amines.