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采用密度泛函B3LYP/6-311G(d,p)方法和分子内质子迁移及水助质子迁移2种途径,计算苦参碱酮式与烯醇式互变异构反应,得到各异构体和过渡态的结构及变化过程中的活化能、反应焓、活化吉布斯自由能等性质。结果表明:苦参碱结构中有3个椅式和1个近扭船式六元环。无论是孤立分子还是一水合物,其酮式是最稳定结构。水助质子迁移可以大大降低反应活化能,其氢键起重要作用。得到了非平面四元环及六元环的过渡态,其碳原子杂化方式均为sp~3。
The ketal and enol tautomerism of matrine was calculated using density functional B3LYP / 6-311G (d, p) method and intramolecular proton transfer and hydropic proton transfer. The isomers And the transition state of the structure and process of change in the activation energy, reaction enthalpy, activation Gibbs free energy and other properties. The results show that there are three chairs and one nearly torsional six-membered ring in matrine structure. Either isolated molecules or monohydrate, the ketones are the most stable structure. Hydrotropic proton migration can greatly reduce the activation energy, its hydrogen bonding plays an important role. The transition states of non-planar four-membered ring and six-membered ring were obtained, and the carbon atom hybridization modes were all sp ~ 3.