Isomeric structures of benzimidazole, benzoxazole, and benzothiazole derivatives, their electronic properties and transformations

The optimized structures of all isomers of HBI, HBO, HBT, HPyBI, HPyBO, and HPyBT compounds were obtained using the potential energy surface method at the B3LYP/6-311++G(d,p) level of theory. Four isomers and three transition states of their transformations for each compound of HBO, HBT, HPyBO, and HPyBT and two isomers and one transition state for each HBI and HPyBI compounds were found. Energetics, thermodynamic properties, rate constants, and equilibrium constants of their transformations were determined.