• Journal of the Korean Chemical Society
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• v.20 no.4
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• pp.270-276
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• 1976

The absorption spectra and the dissociation constants of various sulfophthaleins have been measured in the presence of a cationic surfactant. In the presence of 2.0 ${\times}$ 10-3 M zephiramine and an ionic strength of 0.05 at 25${\pm}1^{\circ}C$ the absorption maxima of the basic forms are shifted to red by 6${\sim}$21 nm and their molar absorptivities are increased, while the absorption maxima of the yellow forms are shifted to blue by 4${\sim}$20 nm and their molar absorptivities are decreased. The decreases in pKa values are of the order of ranging -1.38${\sim}$0.37. The characteristic of the observed changes has been explained by the assumption that the dye molecule adsorbed on micellar surface forms a stable coplanar structure easily and then the conjugation in the dye molecule is elevated.

• Archives of Pharmacal Research
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• v.9 no.3
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• pp.139-144
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• 1986

The solubilization sites of aniline and its derivatives in micelles were investigated with fluorescence probe technique. The fluorescence probes employed in this study are 12-(9-anthroyl) stearic acid (AS) and 2-p-toluidinylnaphthalene-6-sulfonate (TNS) which are incorporated in the interior of the micelle and attaced to its surface, respectively. As these two probes were effectively quenched by aniline and its surface, respectively. As these two probes were effectively quenched by aniline and its derivatives, the modified Stern-Volmer relationship in micellar system could be applicable to estimate the partition coefficient, $K_{p}$ of the solubilizate between aqueous and micellar phase. Because $K_{p}$ derived by this method reflects the relative proximity of the fluorophore to the quencher, the ratio of $K_{p}$ in the surface area to that in the interior of the micelle is interpreted in terms of the relative location of the solubilizate in micellar aggregate. The results show that the solubilizates are not located in a definite position but distributed in the multiple-sites of the micelle. The solubilization sites of the solubilizates in the icelle are dependent on their structures. As the solubilizate has more numbers of N-substituents of aniline and more numbers, of carbon in the substituent, it tends to incorporate in the interior of the micelle more effectively.