Theoretical Studies On The Reaction Mechanism Of Tautomerization Of 5-Substitued-1,2,3-Triazoles

Molecular structures of 1,2,3-triazoles and C5-(-F,-Cl,-Br;-CHO,-CFO,-CHS, -CFS; -OH,-SH; -COOH) substitued-triazole tautomers were calculated by the B3- LYP method at the 6-311++G** level both in the gaseous and aqueous phases with full geometry optimization. The geometrical and electronic structure of the tautomers of 1,2,3-triazoles and C5-substitued-triazole and their transition states were obtained. The influence of the different substituents and solvent effect on the geometrical structure,energy,charge and activated energy were discussed. The reaction mechanism of tautomers of 1,2,3-triazoles and C5-substitued-triazole were also studied. There are two reaction pathways: (a) intermolecular proton transfer; (b) water-assisted intermolecular transfer. The calculated results showed that process (b) has lower activation energies than (a).