Thermodynamic Study on the Effects of β-Cyclodextrin Inclusion with Anilinonaphthalenesulfonates

Thermodynamic parameters and stoichiometries for the binding of anilinonaphthalenesulfonates to β-cyclodextrin are obtained from steady-state fluorescence intensity and an-isotropy measurements. Specifically, formation constant, enthalpy, and entropy values are obtained for complexes of β-cyclodextrin with eight different substrate molecules at five different temperatures and six different pH values, and their associated errors are given. We propose an explanation of the relative magnitudes of the values obtained with regard to the geometry of the substrate and the importance of the various noncovalent interactions responsible for the complexation.