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Mechanistic Investigations on the Photoisomerization Reactions of Five-Membered Ring Heterocyclic Molecules Containing Sulfur and Selenium Atoms

[Image: see text] The restricted active space self-consistent field method in the 26-electron/27-orbital active space and the 6-311(d) basis set has been used to investigate the mechanisms of the photochemical isomerization reactions concerning the model systems of 1,2,3-thiadiazole and 1,2,3-selena...

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Detalles Bibliográficos
Autor principal: Su, Ming-Der
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2018
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6641236/
https://www.ncbi.nlm.nih.gov/pubmed/31458599
http://dx.doi.org/10.1021/acsomega.8b00016
Descripción
Sumario:[Image: see text] The restricted active space self-consistent field method in the 26-electron/27-orbital active space and the 6-311(d) basis set has been used to investigate the mechanisms of the photochemical isomerization reactions concerning the model systems of 1,2,3-thiadiazole and 1,2,3-selenadiazole. The computational works suggest that the preferred reaction paths for both 1,2,3-thiadiazole and 1,2,3-selenadiazole are as follows: reactant → Franck–Condon region → conical intersection → intermediate → transition states → photoproducts. As a result, the structures of the conical intersections, which play a decisive role in these photoisomerization reactions, are obtained. In particular, the present theoretical evidences demonstrate that the potential energy surfaces for the formation of 1,3-diradicals are quite flat. This may explain why their experimental detections are so difficult.