Doi:10.1016/S0040-4020(02)01157-2

An experimental (NMR) and theoretical (GIAO) study of the tautomerism of benzotriazole in solution

The ¹H, ¹³C and ¹⁵N chemical shifts of benzotriazole and its adducts with acetone have been measured. Using dynamic ¹³C NMR spectroscopy in the +30/−90°C range, the barrier to prototropy in benzotriazole has been determined (10.8 kcal mol⁻¹ at 294 K). The thermodynamic parameters corresponding to the equilibria between benzotriazole and its two acetone adducts have been measured. GIAO calculations (B3LYP/6-311++G^∗∗) have been carried out on 1H-benzotriazole tautomer: they provide a sound basis for signal assignment of all the nuclei.