Computational Insights into Excited State Intramolecular Double Proton Transfer Behavior Associated with Atomic Electronegativity for Bis(2′-benzothiazolyl)hydroquinone

Inspired by the distinguished regulated photochemical and photophysical properties of 2-(2′-hydroxyphenyl)benzazole derivatives, in this work, novel bis(2′-benzothiazolyl)hydroquinone (BBTHQ) fluorophore is explored, looking at its photo-induced behaviors associated with different substituted atomic electronegativities, i.e., BBTHQ-SO, BBTHQ-SS BBTHQ-Se compounds. From structural changes, infrared (IR) vibrational variations simulated core-valence bifurcation (CVB) indexes for dual hydrogen bonds three BBTHQ we see that low electronegativity could be conducive to enhancing bonding effects S1 state. Particularly, O4-H5⋯N6 BBTHQ-SO O1-H2⋯N3 BBTHQ-SSe strengthened more intensive state, respectively. Looking into charge recombination induced photoexcitation, confirm a favorable ESDPT trend deriving from reorganization regions. By constructing potential energy surfaces (PESs) along paths compounds, not only unveil stepwise behaviors, but also present an electronegativity-regulated mechanism.