Thermodynamics of binding between α- and β-cyclodextrins and some p-nitro-aniline derivatives:: reconsidering the enthalpy-entropy compensation effect

The thermodynamics of binding between native alpha- and beta-cyclodextrin towards several p-nitro-aniline derivatives was examined, in order to gain further insights about the occurrence of different interaction modes for the two hosts. Valuable information was achieved regarding the `expanded hydrophobic sphere' of alpha-cyclodextrin. Furthermore, very interesting and unexpected aspects of the behavior of beta-cyclodextrin were enlightened, such as the crucial role played by hydrogen bond interactions. Experimental data were examined under the perspective of the `enthalpyentropy compensation effect', and some ideas about this topic are discussed. (C) 2004 Elsevier Ltd. All rights reserved.