Excited state proton transfer and solvent relaxation of a 3-hydroxyflavone probe in lipid bilayers.

摘要: The photophysics of a ratiometric fluorescent probe, N-[[4′-N,N-diethylamino-3-hydroxy-6-flavonyl]methyl]-N-methyl-N-(3-sulfopropyl)-1-dodecanaminium, inner salt (F2N12S), incorporated into phospholipid unilamellar vesicles is presented. reconstructed time-resolved emission spectra (TRES) unravels unique feature in the this probe. TRES exhibit signatures both an excited-state intramolecular proton transfer (ESIPT) and dynamic Stokes shift associated with solvent relaxation lipid bilayer. ESIPT fast, being characterized by risetime ∼30−40 ps that provides equilibrium to be established between excited normal (N*) tautomer (T*) on time scale 100 ps. On other hand, displays bimodal decay kinetics average ∼1 ns. observed slow dynamics likely embodies response nonspecific dipolar solvation coupled formation probe−water H-bonds as well relocati...