选用五种密度泛函B3LYP、B3PW91、MPW1PW91、PBE1PBE、PBEPBE方法, 在6-311++G(2d, 2p)为基组的理论水平下对长春胺的分子结构进行优化以获取长春胺的几何平衡构型。计算并分析了长春胺的几何结构参数、红外吸收光谱、前线分子轨道、能隙和热力学参数。此外, 采用溴化钾压片法测定了长春胺的红外吸收光谱。结果表明: 五种密度泛函理论计算得到的长春胺分子构型与其X单晶衍射数据吻合, 且理论红外吸收光谱与实验研究结果一致, 五种理论水平下均具有150个振动模式, 前线轨道分析表明, 长春胺具有较强的得电子能力。该研究为长春胺的结构分析、光谱解析和定量构效关系探讨提供理论依据。

The molecular structure of vincamine was optimized by density functional theory(DFT) B3LYP, B3PW91, MPW1PW91, PBE1PBE, PBEPBE methods with 6-311++G(2d, 2p) basis set.The geometric parameters, infrared absorption spectrum, frontier molecular orbital, energy gap and thermodynamic parameters of vincamine were calculated and analyzed.In addition, the infrared absorption spectrum of vincamine was determined by pellet technique method.The results show that the molecular structure of vincamine is similar to that of X single crystal, and the theoretical infrared absorption spectrum is consistent with the experimental results.There are 150 vibration modes under the five theoretical levels.The frontier orbital theory analysis shows that the ability of the vincamine molecule to obtain electrons is strong.This study can provide a theoretical reference for the structural analysis, spectral analysis and quantitative structure-activity relationship of vincamine.