Spectroscopic properties of quercetin-3-O-rhamnoside and quercetin-3-O-rutinoside in aerosol-OT reverse micelles

Abstract

The anomalous spectroscopic properties of quercetin-3-O-rhamnoside (QCRM) and quercetin-3-O-rutinoside (QCRT) in AOT reverse micelle were studied. The excited state intramolecular proton transfer (ESIPT) occurs through the strong hydrogen bond between the -OH at position 5 and the carbonyl oxygen. Because the ESIPT can only happens in the S1 state and the Franck-Condon factor involved in the S2 → S1 internal conversion is small, the S2 → So emission alone appears. Because the molecular planarity is improved at the interior of the micelle, the excited state intramolecular charge transfer in the S1 state is extended, and the excited state is more tolerable for any quenching effects in the micelle. Therefore, an S1 → So emission was newly discovered under this micelle microenvironment. For the S2 → So emission, the quantum yields increase but the quantum yield of the S1 → So emission approximately decreases as the water concentration in the micelle increases. Copyright © 2005 KCSNET.