In this study, we have successfully synthesized the click cluster of beta-cyclodextrin (beta-CD) and NH2-terminated poly(amido amine) (PAMAM) dendrons via efficient Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC). The highly water-soluble click cluster, namely CDG2H, was carefully characterized by various analytical tools to confirm the structure and product purity. H-1 NMR further resolved the degree of protonation at different pH, suggesting that a tetracationic peripheral attached to the primary face of beta-CD at physiological condition. This polycationic character allows CDG2H to effectively bind with anionic targets through a synergistic effect combining host-guest and electrostatic interactions. The UV-visible absorption and fluorescence spectroscopic analyses both indicated that CDG2H has relatively higher binding affinity toward anionic binaphthyl model compounds than unmodified beta-CD. In addition, because of the optically active cyclodextrin core, CDG2H still revealed significant chiral discrimination for enantiomeric binaphthyl pairs. (C) 2013 Elsevier Ltd. All rights reserved.
