Pseudo Jahn-Teller effects and optical activities of negatively curved hydrocarbons

23rd International Symposium on the Jahn-Teller Effect

Hatanaka, M.^1

Graduate School of Engineering, Tokyo Denki University, 5 Senju-Asahi-cho, Adachi-ku, Tokyo

120-8551, Japan^1

关键词: Curved structure;    Fundamental studies;    Optical rotatory dispersion;    Optically Active;    Potential surfaces;    Vibrational modes;    Vibronic coupling constants;    Vibronic interactions;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/833/1/012011/pdf
DOI  :  10.1088/1742-6596/833/1/012011

来源: IOP

【 摘 要 】

As a fundamental study on energetics of negatively curved structures, puckering energetics of [n]circulene is studied in view of vibronic interactions. In [7]circulene, the D7hgeometry is subject to pseudo Jahn-Teller effect (PJT) and unstable with respect to the E1″, E2″, and E3″ vibrational modes. It is distorted into Csor C2geometries to form valleys of the potential surface ca. 9 kcal/mol below the D7hgeometry. The C2structure is slightly stable than Csone, which is consistent with experiments. The resultant C2geometry is optically active, and the CD (circular dichroism) and ORD (optical rotatory dispersion) spectra are well simulated. This type of optical activities is interesting in that they should be proportional to the PJT-distortion. PJT-induced optical activity in [2m+1]circulenes should be mainly originated from vibronic coupling constants in the initial and final states, which leads to helical rule characteristic of C2molecules.