论文部分内容阅读
Quantum chemical ab initio method has been used to study the cycloaddition reaction between singlet oxygen and imidazole theoretically. The intermediate product, an endoper-oxide, of which the structure has not yet been found experimentally was optimized by using energy gradient method. The transition state (TS) structure of this reaction was also located on the potential energy surface and characterized. From the structural features of the TS, e.g. the transition vector of the imaginary vibration mode, as well as the interaction of orbitals, it is realized that this cycloaddition is a synchronous concerted reaction. The activation barriers calculated are 69.5 kJ·mol (forward reaction) and 140.4 kJ·mol-1 (backward reaction) respectively (6-31G results).
Quantum chemical ab initio method has been used to study the cycloaddition reaction between singlet oxygen and imidazole theoretically. The intermediate product, an endoper-oxide, of which the structure has not yet been found experimentally was optimized by using energy gradient method. The transition state (TS) structure of this reaction was also located on the potential energy surface and characterized. From the structural features of the TS, eg the transition vector of the imaginary vibration mode, as well as the interaction of orbitals, it is realized that this cycloaddition The activation barriers calculated are 69.5 kJ · mol (forward reaction) and 140.4 kJ · mol-1 (backward reaction) respectively (6-31G results).