Effects of substituted chalcogen atoms on excited state reaction for 1-(benzo[d]thiazol-2-yl)-6-substituted-naphthalen-2-ol derivatives

AbstractInspired by the brilliant photophysical properties of novel organic molecules containing chalcogenide substitution, in this work, effects of atomic electronegativity of chalcogen (O, S and Se) on hydrogen bond interactions and proton transfer (PT) reaction are focused. We present the characteristic CN-BTN is the main objective to explore the influence of atomic electronegativity on the hydrogen bond interaction and excited state intramolecular proton transfer (ESIPT) behaviour by photoexcitation. By comparing the structural changes and infrared (IR) vibrational spectra of the CN-BTN derivatives (CN-BTN-O, CN-BTN-S and CN-BTN-Se) fluorophores in S0 and S1 states, combined with the preliminary detection of hydrogen bond interaction by core-valence bifurcation (CVB) index, we can conclude that hydrogen bond is strengthened in S1 state, which is favourable for the occurrence of ESIPT reaction. The charge recombination behaviour of hydrogen bond induced by photoexcitation also further illustrates this point. Via constructing potential energy curves (PECs) based on restrictive optimisation and searching transition state (TS) configuration, we finally clarify the ESIPT mechanism for CN-BTN derivatives. Specially, we confirm change of atomic electronegativity has a regulatory effect on the ESIPT behaviour of CN-BTN derivatives, that is, the lower the atomic electronegativity is more conducive to the ESIPT reaction.KEYWORDS: Hydrogen bondexcited state proton transferatomic electronegativitycharge transferpotential energy surface Disclosure statementNo potential conflict of interest was reported by the author(s).Data availability statementData are available on request from the corresponding author.Additional informationFundingThis work was supported by the National Natural Science Foundation (No. 11904082), and the Fundamental Research Funds for the Central Universities (No. 2022MS120).