Nuclear magnetic resonance and X-ray diffraction studies on some substituted benzenesulphonamides

Abstract

Solid-state ¹³C c.p.-m.a.s. and solution ¹³C, ¹⁵N, and ¹⁷O n.m.r. spectra were measured for toluene-p-sulphonamide, N-methyltoluene-p-sulphonamide, NN-dimethyltoluene-p-sulphonamide, p-chlorobenzenesulphonamide, and NN-dimethyl-p-chlorobenzenesulphonamide. The ¹³C c.p.-m.a.s. n.m.r. resonance lines of the carbon atoms bonded to nitrogen show characteristic line broadening with slightly asymmetric doublet patterns. Some differences are evident in the ¹³C shielding of the carbon atoms between the solid-state and solution-state spectra. In the solution spectra the ¹⁵N and ¹⁷O chemical shifts increase in conformity with the polarity order of the amides. The n.m.r. relaxation times of the methyl groups of the compounds were measured as well. The crystal structures of N-methyltoluene-p-sulphonamide and NN-dimethyltoluene-p-sulphonamide were determined by single-crystal X-ray diffraction technique and refined to final R values of 0.056 and 0.044, respectively. Except for some barely significant differences, the bond lengths and angles are similar in the two compounds. The most striking difference is the value of the C–C–S–N torsion angle.