INCLUSION COMPLEX OF 8-ANILINONAPHTHALENE-1-SULFONATE WITH BETA-CYCLODEXTRIN

The interaction of 8-anilinonaphthalene-1-sulfonate with beta-cyclodextrin was investigated in 0.1 M phosphate buffer at pH 7.4 by fluorescence spectrophotometry. Utilizing the fact that the fluorescence intensity of 8-anilinonaphthalene-1-sulfonate increased in the presence of beta-cyclodextrin, the thermodynamic parameters for the inclusion complex formation were determined as follows DELTA-G(0) = -2.52 kcal/mol at 25-degrees-c, DELTA-H(0) = -1.92 kcal/mol, and DELTA-S(0) = 2.1 eu. The driving forces for the inclusion complex formation were considered to be van der Waals-London dispersion force and hydrophobic interaction. Also, from the measurements of H-1 NMR spectra and from studying the Corey-Pauling-Koltun (CPK) model, the structure of the inclusion complex was discussed.