Structure-Reactivity-Spectra Correlations for Substituted Benzenesulfonamides

Abstract

The infrared absorption bands of the S=O and N-H stretching vibrations as well as the natural abundance 13 C and the 17 O NMR chemical shifts were measured for fifteen substituted benzenesulfonamides in CDCl 3 and acetone-d 6 . For the unsubstituted compound the natural abundance 33 S NMR chemical shift was also measured in acetone-d 6 PM3 charge densities and bond orders were calculated for the completely optimised geometry. Mutual correlations are reported between the wave numbers of the asymmetric SO 2 stretching vibration, the arithmetic means of symmetric and asymmetric NH 2 stretching vibrations, Hammett or + substituent constants, dissociation constants, 1 H, 13 C, 15 N and 17 O NMR chemical shifts as well as the PM3 S=O and N-H bond orders and hydrogen, nitrogen and oxygen atom charge densities. The results of the correlation analysis showed that the factors determining the electronic structure and controlling the dissociation equilibria, the IR and NMR spectral properties of substituted benzenesulfonamides must be the same.