Elaborating and regulating ESIPT associated with solvent polarity for the novel 2-(benzo[d]thiazol-2-yl)-4-(9H-diphenylamino-9-yl)phenol fluorophore

In light of the potential applications as full-colour organic emitting materials crossing the entire visible spectra, the novel diphenylamino submitted 2-(2'-hydroxyphenyl) benzothiazole derivative 2-(benzo[d]thiazol-2-yl)-4-(9H-diphenylamino-9-yl)phenol (pPhOH) is explored in this work about its excited state behaviours. Solvent-polarity-related photo-induced hydrogen bonding effects of pPhOH indicate nonpolar aprotic solvents largely enhance S1-state hydrogen bonding interactions. Charge reorganisation stemming from photoexcitation and polarity-dependent energy gap between HOMO and LUMO orbitals further reveals the excited state intramolecular proton transfer (ESIPT) tendency. Insights into potential energy curves (PECs) along ESIPT paths in solvents with different polarities and electronic spectral behaviours of pPhOH as well as its proton-transfer tautomer pPhOH-T, we present solvent polarity could harness the excited state behaviours for pPhOH system.