摘要
采用密度泛函理论(DFT)方法和极化连续介质模型(PCM),在B3LYP/6-311++G**水平上对五味子丙素的一个立体异构体的基态几何构型进行了优化;以优化得到的稳定构型为基础,采用含时密度泛函理论(TD-DFT)方法,在相同基组水平进行了电子圆二色谱(ECD)研究,根据计算获得的电子跃迁吸收波长(λ)和电子旋转强度(R)拟合得到了理论ECD谱。理论研究发现:甲醇溶液中,2个苯环之间扭曲形成的二面角∠C(2)-C(1)-C(8)-C(7)约为64°;计算获得的理论ECD谱吸收峰略红移,各谱带形状与实验谱吻合较好。通过对相关跃迁性质的分析发现,理论ECD谱的吸收峰1主要由自于HOMO-2→LUMO和HOMO-2→LUMO+1的电子跃迁贡献;吸收峰2的吸收主要由HOMO→LUMO的电子跃迁贡献。这些结论对深入理解五味子丙素异构体的电子结构和手征光学性质具有一定的科学意义。
One isomer of Schisandrin C was optimized using density functional theory （DFT） at the B3LYP/6-311＋＋G^＊＊ level. Based on the optimized results, the absorption wavelength （2） and rotational strengths （R） was calculated using time-dependent density functional theory （TD-DFT） with the same functional and basis set. In these calculations, solvent effects of CH3OH were included using the polarized continuum model （PCM）. The dihedral angle between two benzene rings is 64° in CH3OH. The theoretical electronic cireular dichroism （ECD） spectrum was fitted using the SpecDis 1.50 software. Comparing with the experimental date, the calculated absorption peaks exhibits red shitl and calculated ECD spectrum is in good agreement with experimental one. Detailed analyses of the dominant transitions reveal that the peak 1 is dominated by the HOMO-2→LUMO and HOMO-2→LUMO＋1 charge transfer, and peak 2 is dominated by the charge transfer transition from HOMO to LUMO. These findings provide a deep insight into the electronic structures and chiroptical properties of the Schisandrin C.
出处
《计算机与应用化学》
CAS
CSCD
北大核心
2014年第9期1150-1152,共3页
Computers and Applied Chemistry
基金
重庆市教委科学技术研究项目(KJ120307)
