Synthesis of β-cyclodextrin and poly(amido amine) dendron click cluster and its synergistic binding property

In this study, we have successfully synthesized the click cluster of β-cyclodextrin (β-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. 1H NMR further resolved the degree of protonation at different pH, suggesting that a tetracationic peripheral attached to the primary face of β-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 β-CD. In addition, because of the optically active cyclodextrin core, CDG2H still revealed significant chiral discrimination for enantiomeric binaphthyl pairs.

Synergistic binding property combining host-guest and electrostatic interactions between β-cyclodextrin/PAMAM dendron click cluster and binaphthyl compound.