Chitosan Derivatives Bearing Pendant Cyclodextrin Cavities: Synthesis and Inclusion Performance

A new synthetic route to β-cyclodextrin-linked chitosan was developed. This was based on the preparation of a monosubstituted β-cyclodextrin (β-CD) derivative possessing a reducing sugar on the primary face followed by its reductive amination. The CD−polysaccharide was fully characterized in terms of chemical integrity and purity by high-resolution NMR and light scattering. The formation of inclusion complexes was investigated by NMR spectroscopy using tert -butylbenzoic acid and (+)-catechin as model guests. Inclusion properties of the grafted β-CDs were shown to be similar to those of native β-CD in terms of complex geometry and affinity constant. These results confirm that the pendant β-cyclodextrin preserves its conformation and its complexing characteristics.