Premium
Spectroscopic Properties of Quercetin Derivatives,
Quercetin‐3‐ O ‐rhamnoside and Quercetin‐3‐ O ‐rutinoside, in
Hydro‐organic Mixed Solvents
Author(s) -
Liu HaiBo,
Yu Daun,
Shin Sung Chul,
Park HyoungRyun,
Park Jong Keun,
Bark KiMin
Publication year - 2009
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.2009.00550.x
Subject(s) - chemistry , excited state , intramolecular force , intermolecular force , molecule , fluorescence , hydrogen bond , solvatochromism , solvent , quercetin , photochemistry , analytical chemistry (journal) , stereochemistry , crystallography , organic chemistry , atomic physics , physics , antioxidant , quantum mechanics
The characteristic fluorescence properties of quercetin‐3‐ O ‐rhamnoside (QCRM) and quercetin‐3‐ O ‐rutinoside (QCRT) were studied in CH 3 OH–H 2 O and CH 3 CN–H 2 O mixed solvents. Although QCRM and QCRT are known as nonfluorescent molecules, significant fluorescence emissions were discovered at 360 nm in CH 3 OH and CH 3 CN when they were promoted to the second excited state. The emission band is broad and structureless and the intensity decreases quickly as the H 2 O composition in the solvent increases. When the amount of H 2 O exceeds 60% in both mixed solvents, this emission disappears due to the formation of the distorted excited state. This state will be formed due to the strong intermolecular hydrogen bonding between the polar groups of solute and H 2 O. As the composition of CH 3 OH or CH 3 CN in solvent becomes large, the number of molecules having several intramolecular hydrogen bonding increases. Some of these molecules will be changed to a fluorescent species during the decay process, after excitation. The theoretical calculation further supports these results. The change of the lifetimes, quantum yields, and radiative and nonradiative rate constants of molecules was also examined as a function of solvatochromic parameters for CH 3 OH–H 2 O and CH 3 CN–H 2 O.