Abstract—The 1H, 13C and 15N chemical shifts of benzotriazole and its adducts with acetone have been measured. Using dynamic 13C NMR
spectroscopy in the þ30/2908C range, the barrier to prototropy in benzotriazole has been determined (10.8 kcal mol21 at 294 K). The thermodynamic parameters corresponding to the equilibria between benzotriazole and its two acetone adducts have been measured. GIAO
calculations (B3LYP/6-311þþGpp) have been carried out on 1H-benzotriazole tautomer: they provide a sound basis for signal assignment of all the nuclei. q 2002 Elsevier Science Ltd. All rights reserved.