UV-induced proton transfer in 3-amino-1,2,4-triazole

UV-induced proton transfer between two tautomeric forms of 3-amino-1,2,4-triazole (1-AT, 2-AT) was followed by FUR spectroscopy coupled with matrix isolation technique. The 1-AT -> 2-AT photo transformation was observed upon the 248 nm irradiation. State-averaged CASSCF(8,8)/6-311 ++G (2d,2p) approach was applied to study mechanism of the observed phototautomerization. The obtained results indicate that the S1/S0 conical intersection (Cl) plays a crucial role in the mechanism under study. It was shown that the 1-AT(S1)-> CI -> 1-AT(S0)/2-AT(S0) path was responsible for the experimentally observed photo-induced tautomerization process. (C) 2016 Elsevier B.V. All rights reserved.