Elimination of the Hydrogen Bonding Effect on the Solvatochromism of 3-Hydroxyflavones

摘要: We address the important, frequently discussed, and still unresolved question of role solute−solvent hydrogen bonding in modulating excited-state intramolecular proton transfer (ESIPT) reaction 3-hydroxyflavone (3HF) derivatives, which provides a dramatic variation relative intensities normal (N*) phototautomer (T*) emissive species. synthesized new 3HF derivative, 5,6-benzo-4‘-diethylamino-3-hydroxyflavone (BFE), additional benzene ring protects 4-carbonyl from H-bonding with protic solvents but allows bond 3-hydroxyl group, is pathway ESIPT, to be maintained. The absorption fluorescence properties BFE its parent analogue 4‘-diethylamino-3-hydroxyflavone (FE) were studied set 20 representative solvents. In aprotic media, these dyes spectra show similar solvatochromism, whereas differences are observed, demonstrate that for t...