THE THERMODYNAMICS OF THE BINDING OF BENZENE TO BETA-CYCLODEXTRIN IN AQUEOUS-SOLUTION

The apparent enthalpies, entropies and Gibbs energies for the binding of benzene to beta-cyclodextrin in aqueous solution have been determin ed at 291.15, 298.15 and 308.15 K by microcalorimetry. The calorimetri c data are consistent with a binding model that assumes formation of b oth 1:1 and 2:1 (benzene:beta-cyclodextrin) adducts. The apparent chan ge in heat capacity for the 1:1 binding, calculated from the temperatu re derivative of the enthalpy changes, indicates that the hydrophobic effect is the driving force for formation and stability of this comple x.