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采用3种不同泛函(B3LYP,BP86,PBE1PBE)在6-31G*和6-311+G*基组下,计算有机材料1-吡啶-3-[4-(苯基偶氮)苯基]-三氮烯(PYPAPT)不同结构上三氮异构化的途径有2种可能:(a)分子内质子迁移,(b)水助质子迁移,因此获得它们的互变异构过程活化能、活化吉布斯自由能和质子转移反应的速率常数等性质。采用PCM法研究反应体系的溶剂化效应。证明孤立分子和一水合物最稳定的异构体相同都为M11,计算结果也与实验值符合得很好,溶剂化效应对异构化能垒的影响较大。最稳定的异构体分子内质子转移的速控步骤的活化能为170.48kJ/mol,速率常数为3.86×10-15s-1;当水分子参与反应以双质子转移机理异构化时,活化能显著降低,有利于三氮异构化,其最稳定异构体的速控步骤的活化能为47.41kJ/mol,速率常数为9.73×104s-1。计算结果还表明,氢键作用在增大PYPAPT一水合物相对稳定性、降低质子转移异构化反应活化能等方面起着重要作用。
The organic materials 1-pyridine-3- [4- (phenylazo) phenyl] -2-methyl-1-propenoic acid were calculated using three different functionalities (B3LYP, BP86, PBE1PBE) - Triazene (PYPAPT) There are two possibilities for the triazine isomerization on different structures: (a) intramolecular proton migration, (b) water-assisted proton migration and hence their tautomerism activation energies, Activated Gibbs free energy and proton transfer reaction rate constants and other properties. The solvating effect of the reaction system was studied by PCM method. It is proved that the most stable isomers of isolated molecules and monohydrate are all M11, and the calculated results agree well with the experimental ones. The solvation effect has a great influence on the isomerization barrier. The most stable isomer intramolecular proton transfer rate-controlling step has an activation energy of 170.48 kJ / mol and a rate constant of 3.86 × 10-15 s-1. When the water molecule is involved in isomerization by the double proton transfer mechanism, Can be significantly reduced in favor of tri-isomerization. The activation energy of the most stable isomer-controlled step is 47.41 kJ / mol and the rate constant is 9.73 × 10 4 s -1. The calculated results also show that hydrogen bonding plays an important role in increasing the relative stability of PYPAPT monohydrate and reducing the activation energy of proton transfer isomerization reaction.