Chitosan derivatives bearing pendant cyclodextrin cavities:: Synthesis and inclusion performance

A new synthetic route to beta -cyclodextrin-linked chitosan was developed. This was based on the preparation of a monosubstituted beta -cyclodextrin (beta -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 beta -CDs were shown to be similar to those of native beta -CD in terms of complex geometry and affinity constant. These results confirm that the pendant beta -cyclodextrin preserves its conformation and its complexing characteristics.