Inclusion Complex of 8-Anilinonaphthalene-1-sulfonate with β-Cyclodextrin

Abstract

The interaction of 8-anilinonaphthalene-1-sulfonate with β-cyclodextrin was investigated in 0.1M phosphate buffer at pH 7.4 by fluorescence spectrophotometry. Utilizing the fact that the fluorescence intensity of 8-anilinonaphthalene-1-sulfonate increases in the presence of β-cyclodextrin, the thermodynamic parameters for the inclusion complex formation were determined as follows: ∆G° = −2.52 kcal/mol at 25 °C, ∆H° = −1.92 kcal/mol, and ∆S° = 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 1H NMR spectra and from studying the Corey–Pauling–Koltun (CPK) model, the structure of the inclusion complex was discussed.