Unconventional modulation of fluorescence anisotropy of 3-hydroxyflavone in cationic micelles

Abstract

Atypical trend for the fluorescence anisotropy of an excited state intramolecular proton transfer (ESIPT) prone molecular system, namely, 3-hydroxyflavone (3HF) has been reported in the aqueous cationic micellar media. Contrary to the conventional rising trend of fluorescence anisotropy for fluorophores with the addition of the micellar environments, 3HF exhibits a decreasing trend in the fluorescence anisotropy in cationic micelles. Disruption of the intermolecular hydrogen bond induced solvated structure involving 3HF and the water molecules is assigned to be responsible for this unusual modulation of the fluorescence anisotropy in the micellar microenvironments. As micelles mimic the bio-membranes, this unconventional behavior of the fluorescence anisotropy of 3HF is significant to understand the intricacies of solvation and thereby action of bioactive ESIPT prone flavonoid molecules in bio or biomimicking environments.