Theoretical insights into solvent-polarity-associated excited state behaviors for a novel 2-hydroxy-1-naphthaldehyde-triphenylamine (TPHY) fluorophore: A TDDFT study

Inspired by the profound allure of the exquisitely regulated characteristics exhibited by 2-hydroxy-1-naphthaldehyde-triphenylamine (TPHY) and its derivatives in the realms of photochemistry and photophysics, our current endeavor primarily revolves around delving into the intricacies of photo-induced excited state reactions for TPHY fluorophores within solvents boasting varying degrees of polarity. Our simulations, resulting from variations in geometry and vertical excitation charge reorganization, unveil solvent polarity-dependent hydrogen bonding interactions and charge recombination induced by photoexcitation that can significantly enhance the excited state intramolecular proton transfer (ESIPT) reaction for TPHY chemosensor. By constructing potential energy surfaces (PESs), we reveal that the single ESIPT reaction of TPHY occurs concurrently with alternative dual intramolecular hydrogen bonds (O1-H2<middle dot><middle dot><middle dot>N3 and O4-H5<middle dot><middle dot><middle dot>N6). We sincerely hope that the regulation of solvent polarity on excited state behaviors may pave the way for the development of innovative luminescent materials.