Basicity of nitrogen-sulphur(VI) compounds. Part 2. Protonation equilibria of N-arylsulphamates using ultraviolet and nuclear magnetic resonance methods
Abstract
The eouilibrium ArN(R)SO3–+ H+⇌ ArN[graphic omitted]RSO3– was examined using seven arylsulphamates and one mixed alkylarylsulphamate, i.e. N-methyl-N-phenylsulphamate. H0 Values at half protonation, (H0)½, have been calculated, together with Bunnett and Olsen pKBH+ values, from ionization data obtained from u.v. spectra. N.m.r. downfield shifts generally in deuteriosulphuric acid have been used for four of the compounds to obtain protonation data from which (H0)½ values have been calculated. The agreement between the (H0)½ values obtained by the two methods is generally good. Some recent Russian data agrees well with the Bunnett and Olsen pKBH+ values. N-Protonation to give a zwitterion rather than O-protonation to give ArNHSO3H is favoured.