print pageprinter friendly
Reports: UR452071-UR4: Hydrogen-Bonding Control of Solvatochromism and Non-Radiative Decay in the Fluorescence of PRODAN Derivatives

Christopher J. Abelt, PhD, College of William and Mary

The effects of H-bonding on the fluorescence of PRODAN and derivatives have been the subject of two publications acknowledging PRF support.  In one paper the preferential solvation of the following two derivatives was examined in binary mixtures of toluene and methanol, ethanol and isopropanol.  A three-step preferential solvation model was developed to model the data.  The photophysical parameters extracted from the model showed that alcohol-induced quenching involves two H-bonds and that that the quenching shows an energy-gap dependence.

In the other paper the fluorophores below were act as dual-polarity and H-bonding sensors in their binding with human serum albumin (HSA).  When HSA is unfolded with sodium dodecyl sulfate, the polarity experience by the sensors initially decreases, then increases.  With the right-hand probe, a significant increase in the local H-bonding was sensed indicating that the carbonyl group was being exposed to bulk solvent during denaturation.

Syntheses of the three model compounds incorporating one H-bond is complete.  Fluorescence studies show that the intramolecular H-bond does not itself lead to quenching, but leads to greater quenching with a single external alcohol.  The intramolecular H-bond also inhibits the intersystem crossing to the triplet state in nonpolar solvents.