PHENANTHRENE AND TRIPHENYLENE AS FLUORESCENCE PROBES FOR MICELLAR SYSTEMS

The solvent intensification effect on the forbidden S1 half arrow right over half arrow left S0 transitions of phenanthrene and triphenylene has been studied. Both compounds show a remarkable enhancement of the origin bands on going from a nonpolar to a polar solvent. The investigation on solute-solvent interactions causing such effects has revealed that two factors are responsible for the anomalous intensity enhancement of the origin bands: bulk solvent polarity and a specific solute-solvent interaction. The sensitivity of the origin band intensity to solvent polarity, together with the fluorescence lifetime, has been applied to the detection of critical micelle concentration (cmc) of surfactants. The results indicate the potential utility of the probes for characterizing micellar systems.