Thermodynamics of binding of guest molecules to α- and β-cyclodextrins

Abstract

Values of ΔG, ΔH, and ΔS are reported for the interaction of eighteen molecules and ions with α-cyclodextrin and of four molecules with β-cyclodextrin. The conclusions of this study are (1) the cyclodextrin–ClO₄^– complex has been shown to bind a cation, (2)α- and β-cyclodextrin have equilibrium constants for binding the same guest that are similar but the enthalpy and entropy changes are quite different in some cases, and (3) changes in ΔH are largely compensated for by changes in ΔS and it is suggested that this effect is due principally to the nature of the solvent, i.e. water.