Electronic Structure and Circular Dichroism of Natural Alboatisins Isolated from Aerial Parts of Isodon Albopilosus: DFT and TDDFT Study
- Received Date: 2015-03-19
- Alboatisin, Optical activity, Density functional theory, Circular dichroism, Cotton effect
Abstract: The stable conformations of a series of bioactive molecules, (?)-alboatisins A?C, are identified via Monte Carlo searching with the MMFF94 molecular mechanics force field. Then, the optical rotation (OR) values, vibrational circular dichroism (VCD), and electronic circular dichroism (ECD) spectra were calculated using the gradient-corrected density functional theory method. The vibrational and transition modes of molecular chirality were explored in terms of their microscopic origin. The calculated specific rotations are in agreement with the experimental values. From the OR analysis, it was concluded that optical rotation values areregulated by hydroxyl substitution. Vibrations occurring on the chiral skeleton may cause strong absorption in VCD spectra; VCD spectra are thus the spectral response to deformation vibrations on the chiral carbon skeleton. The lowest-energy negative Cotton effect is caused by σ→π* transition. Frontier molecular orbital analysis showed that strong ECD absorptions are produced when the dominant transition on the chiral skeleton is asymmetric; ECD spectra show the result of transitions lacking asymmetry on the chiral skeleton.
|Citation:||Gao-zhang Gou, Bo Zhou, Ling Shi, Shao-ming Chi, Xian-lan Chen, Wei Liu. Electronic Structure and Circular Dichroism of Natural Alboatisins Isolated from Aerial Parts of Isodon Albopilosus: DFT and TDDFT Study[J]. Chinese Journal of Chemical Physics , 2015, 28(6): 695-702. doi: 10.1063/1674-0068/28/cjcp1503045|