Hydrogen bonding dynamics of cyclodextrin- water solutions by depolarized light scattering

Depolarized light scattering measurements performed on aqueous solutions of ?-cyclodextrin are used for investigating the hydration properties of this natural cyclic oligosaccharide, which iswell known for its ability to form inclusion complexeswith a large variety of guest hydrophobic molecules. The spectral analysis allows the characterization of the solvent relaxation process assigned to hydration water, which is found to be seven to eight times slower than the bulk. As a structural information, the number of water molecules involved in the hydration process is also estimated at about 46. These results are a key step for understanding the role played by water in determining the properties of different forms of cyclodextrins and their derivatives, in turn related to complexation ability of thesemacrocycles.