Structure of silylated sulphonamides; a silicon-29 nuclear magnetic resonance investigation

Abstract

The structures of eighteen silylsulphonamides have been determined by ²⁹Si n.m.r. The chemical shifts of the compounds were compared with those of model compounds. The N-silyl tautomer was the only isomer observed, except in cases were strongly electron-withdrawing groups (e.g. Cl, NMe₂) were attached to nitrogen; in such cases the O-silyl tautomer dominates. The results have been rationalised in terms of effect of substituents on the S–N π-bonds order. An estimate of the hitherto unmeasured SN molar bond enthalpy as 325 kJ mol ^–1 was obtained.