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将密度泛函理论应用于卟吩内氢迁移反应机理的理论研究,计算反式卟吩trans-PH2和顺式卟吩cis-PH2的结构参数、总能量、电子密度和振动频率等参数。计算发现trans-PH2比cis-PH2的能量低29．13 kJ／mol(接近实验数据25．0 kJ／mol)。振动分析表明中间态TS-PH2只有一个虚频,而中间态SS-PH2有两个虚频,可以判定TS-PH2是分步反应机理的过渡态,而且同步反应历程比分步反应历程需要更大的活化能,因此可得出卟吩内氢迁移反应采用分步反应历程的结论。此研究表明,密度泛函理论的计算结果与实验数据能够较好地相吻合,能直观地表述卟吩内氢迁移反应的机理,从理论上解释了该反应采用分步反应机理。
Density functional theory was applied to theoretical study on the mechanism of intramolecular hydrogen migration in porphine. The structural parameters, total energy, electron density and vibrational frequency of trans-PH2 and cis-PH2 were calculated. The calculated trans-PH2 was found to be 29.13 kJ / mol lower than that of cis-PH2 (close to the experimental data of 25.0 kJ / mol). Vibration analysis shows that the intermediate state TS-PH2 has only one imaginary frequency, while the intermediate state SS-PH2 has two imaginary frequencies. It can be concluded that TS-PH2 is a transition state of the stepwise reaction mechanism, and the synchronization reaction process requires more steps than the step reaction process Of the activation energy, it can be drawn within the transition of porphine hydrogen reaction using the conclusion of the step-by-step reaction process. This study shows that the calculated results of density functional theory can be in good agreement with the experimental data, and the mechanism of intramolecular hydrazine migration can be described intuitively. It is theoretically explained that the reaction mechanism is stepwise.