Understanding solvent polarity dependent excited state behavior and ESIPT mechanism for 2-benzo[b]thiphen-3-yl-3-hydroxy-6-methoxy-chroman-4-one compound

Abstract

In view of potential applications in microbial protein tissues, the novel benzothiophene-substituted chromenone 2-benzo[b]thiphen-3-yl-3-hydroxy-6-methoxy-chroman-4-one (CHBT) compound is explored theoretically. Insights into photo-induced hydrogen bonding changes and charge redistribution in solvents with different polarities, we confirm the intramolecular hydrogen bond of CHBT is strengthened. It is worth mentioning excited state hydrogen bonding strengthening phenomenon is more pronounced in nonpolar solvents. Photo-induced increased electronic densities around acceptor attract proton with promoting excited state intramolecular proton transfer (ESIPT) reaction. Exploring potential energy curves and transition state (TS) energy profiles, we clarify the ultrafast ESIPT behavior of CHBT is easier in nonpolar solvents.