摘要
采用密度泛函B3LYP方法,在6-31+G(d,p)基组水平上对二苯甲酰甲烷质子转移引起的酮式-烯醇式互变异构反应机理进行了计算研究,获得了零点能、总能量、吉布斯自由能及质子转移过程的反应焓、活化能、活化吉布斯自由能和速率常数等参数.3种非质子溶剂中的优化和频率计算采用Onsager模型进行计算.计算结果表明,不论在气相还是3种溶剂中,二苯甲酰甲烷的烯醇式较酮式稳定,烯醇式向酮式气相转变需要较高的活化能垒,在不同极性的溶剂中,随着溶剂介电常数的增大,异构化反应活化能垒减小,反应速率常数增大.
The tautomerization reaction mechanisms of keto-enol resulted from proton transfer were investigated using DFT-B3LYP method with 6 31＋G（d,p） basis set. Zero point energies, total energies, Gibbs free energies, reaction enthalpies, activation energies, activation Gibbs free energies and the rate constants of tautomerization reaction were obtained. The calculations in three solvents were carried out using Onsager model. The results show that the enol form of dibenzoylmethane is more stable than the keto form either in the gas phase or the three solvents. The activation energy barriers are much high from the enol form to the keto form tautomerism. In the different polar solvents, the more large are the dielectric constants, the more small are the activation energy barriers and the more large are the rate constants.
出处
《分子科学学报》
CAS
CSCD
北大核心
2013年第1期62-66,共5页
Journal of Molecular Science
基金
西安市科技计划项目
西安文理学院科研创新基金专项项目(CXY1134WL13)
陕西省教育厅专项科研基金资助项目(11JK0581)
陕西省分析化学省级重点学科基金支持项目
关键词
二苯甲酰甲烷
互变异构
质子转移
溶剂效应
活化能垒
dibenzoylmethane
tautomerization
proton transfer
solvent effect
activation energy barrier
作者简介
联系人简介：任宏江（1979-），男，讲师，主要从事生物分子异构化反应的量子化学研究．E—mail：renhongjiang2008@126．com
