Pseudo Jahn-Teller effect in oxepin, azepin, and their halogen substituted derivatives
- Authors: Ilkhani A.R.1
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Affiliations:
- Department of Chemistry, Yazd Branch
- Issue: Vol 91, No 9 (2017)
- Pages: 1743-1751
- Section: Structure of Matter and Quantum Chemistry
- URL: https://journals.rcsi.science/0036-0244/article/view/169698
- DOI: https://doi.org/10.1134/S0036024417090035
- ID: 169698
Cite item
Abstract
Oxepin and azepin are heterocyclic compounds with a seven-membered ring, which are present in the main skeleton of many anti-depressive drugs. Planar configuration instability due to the pseudo Jahn-Teller effect (PJTE) in oxepin, azepin and six their halogen substituted derivatives were investigated as an original PJTE study. Optimization and the following frequency calculations in these two series illuminated that all of these eight compounds were unstable in high-symmetry planar (with C2v symmetry) configuration and their structures were puckered to lower Cs symmetry stable geometry. Moreover, the vibronic coupling interaction between 1A1 ground and the first 1B1 excited states via (1A1 + 1A1’ + 1B1) ⊗ b1 and (1A1 + 1B1 + 1A1’) ⊗ b1 PJTE problems were the reasons for the symmetry breaking phenomenon and non-planarity of the seven-member ring in those series. Finally, numerical fitting of the adiabatic potential energy surface (APES) cross-sections along the b1 puckering coordination was employed to estimate the vibronic coupling constants of PJTE problems for all the considered compounds.
About the authors
Ali Reza Ilkhani
Department of Chemistry, Yazd Branch
Author for correspondence.
Email: ilkhaniali@iauyazd.ac.ir
Iran, Islamic Republic of, Yazd