水环境下甲硫氨酸混合体系手性转换反应物的电子激发特性

用密度泛函理论(DFT)中的B3LYP方法, 在6-311+G(2df)基组水平上优化气相条件下甲硫氨酸(Met)分子的几何构型, 并在PBE0/def2-TZVPP下, 用含时密度泛函理论(TDDFT)方法计算得到隐式溶剂甲醇下Met与H₂O分子以1∶1和1∶2混合体系手性转换反应物的分子轨道(MO)特征及空穴-电子分布等值面图, 并用图解对比分析电子激发特性. 结果表明： 三者定性分析结果基本一致, 其中S-Met-CH₃OH与S-Met-CH₃OH+1H₂O和S-Met-CH₃OH+2H₂O的激发态S9定性结果不一致, S-Met-CH₃OH+2H₂O与S-Met-CH₃OH+1H₂O的激发态S7定性结果不一致； 水链对S-Met-CH₃OH分子体系的电子激发特性有一定影响.

Electronic Excitation Characteristics of Chiral Conversion Reactants of Methionine Mixed System in Water Environment

Using B3LYP method of density functional theory (DFT), the geometry of methionine (Met) was optimized under the gas phase condition at the level of 6-311+G(2df) basis set, and under the PBE0/def2-TZVPP, using the method of time-dependent density functional theory (TDDFT), we obtained the molecular orbital (MO) characteristics, and hole-electron distribution isosurface maps of the chiral conversion reactants of Met and H₂O molecules with 1∶1,1∶2 mixed system in the implicit methanol solvent,  compared and analyszed electronic excitation characteristics with diagrams. The results show that the three qualitative analysis results are basically consistent, and the qualitative results of excitaed state S9 of S-Met-CH₃OH are inconsistent with those of S-Met-CH₃OH+1H₂O and S-Met-CH₃OH+2H₂O, the qualitative results of excited state S7 of S-Met-CH₃OH+2H₂O and S-Met-CH₃OH+1H₂O are inconsistent, and the water chain has a certain effect on the electronic excitation characteristics of S-Met-CH₃OH molecular system.