TEMPERATURE EFFECTS ON THE SOLUBILIZATION BEHAVIOR OF SOME 3H-INDOLESIN WATER AND MICROHETEROGENEOUS MEDIA

The solubilization behavior of 3,3-dimethyi-2-phenyl-3H-indole (I) and its substituted derivative 2-[p-(dimethylamino)phenyl]3,3-dimethyl-3H -indole (II) was studied in sodium dodecylsulfate (SDS) and cetyltrime thylammonium bromide (CTAB) aqueous micelles and dioctadecyldimethylam monium bromide (DODAB) surfactant vesicles. The site of solubilization of both probes in the micelles and vesicles was highly polar but mode rately viscous, e.g. the interface. The effect of temperature on the f luorescence quantum yield of both molecules indicated that the gel to liquid crystalline phase transition temperature of DODAB was 309 K (36 degrees C). Molecule II, below the phase transition temperature, is l ocked in a site where rotation of the phenyl moiety is order limited, whereas molecule I occupies a site which is exclusively viscosity cont rolled. Molecule I may penetrate deeper into the hydrophobic region of DODAB above the phase transition temperature.