Spectroscopic and mechanistic insights into solvent mediated excited-state proton transfer and aggregation-induced emission: introduction of methyl group onto 2-(<i>o</i>-hydroxyphenyl)benzoxazole
Yu Li, Yuanyue Wang, Xiaoqing Feng, Yanying Zhao
Abstract
the ESIPT reaction in non-polar and weakly polar solvents. The emission bands of normal* (∼370 nm) and tautomer* (∼500 nm) forms were identified and assigned, based on fluorescence spectroscopy and quantum chemical theoretical calculations. Solvatochromism confirmed ESIPT reaction inhibition by solvent polarity and intermolecular hydrogen bonding. The intramolecular reversal in combination with time-dependent density functional theoretical calculations revealed an emission-strengthening mechanism of ESIPT, coupled with aggregation-induced emission (AIE) (in mixed water/methanol solvents). Thus, this strategy provides an insight into designing potential "ESIPT + AIE" fluorescent sensors.
Topics & Concepts
BenzoxazoleSolvatochromismStokes shiftPhotochemistryChemistryIntramolecular forceTautomerFluorescenceIntermolecular forceQuantum yieldHydrogen bondExcited stateSolventMoleculeStereochemistryOrganic chemistryPhysicsQuantum mechanicsNuclear physicsPhotochemistry and Electron Transfer StudiesLuminescence and Fluorescent MaterialsPorphyrin and Phthalocyanine Chemistry