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采用MP2和密度泛函M06-2X方法,在6-31++G(d,p)基组水平上对烯丙基类不对称醚异构化反应机理进行了计算研究.揭示了其可能的反应途径,预测了互变异构吉布斯自由能,活化能等性质.计算结果表明,在没有金催化剂的条件下,尽管有醇溶剂时异构化活化能垒有所降低,异构化反应依然不容易进行.相反,存在金催化剂并且有醇溶剂情况下,烯丙基类不对称醚异构化反应活化自由能大大降低,仅为7.5 kcal/mol.通过比较有无醇溶剂和金催化剂对异构化的影响,揭示了金烯烃络合和醇分子参与反应以质子转移的异构化反应机理,很好解释了实验中观察的现象.计算结果还表明:醇分子不仅参与反应提供质子转移,它还能与醚竞争金催化剂络合,因此在高浓度醇条件下会抑制异构化反应进行.
The mechanism of isomerization of allylic ethers was studied on the 6-31 ++ G (d, p) basis set using MP2 and density functional theory M06-2X. The possible mechanism Reaction pathways to predict the Gibbs free energy, activation energy and other properties of the tautomerism.Results show that in the absence of gold catalyst, despite the decrease of isomerization activation energy barrier with alcohol solvent, isomerization The reaction is still not easy to proceed.On the contrary, in the presence of a gold catalyst and an alcohol solvent, the free activation energy of the allylic asymmetric ether isomerization reaction is greatly reduced to only 7.5 kcal / mol. The effect of catalyst on isomerization was revealed by the isomerization reaction mechanism of gold olefin complexation and proton transfer reaction of alcohol molecules, and the phenomena observed in the experiment are well explained. The calculation results also show that alcohol molecules not only participate in the reaction, Proton transfer, it can compete with the ether gold complex catalyst, so in high concentrations of alcohol will inhibit the isomerization reaction.