Enhanced Chiral Recognition Abilities of Cyclodextrin Covalent Organic Frameworks via Chiral/Achiral Functional Modification

beta-Cyclodextrin covalent organic frameworks (beta-CD COFs) show great potential in enantioseparation due to their uniformly distributed chiral recognition sites and good chemical stability. The hydroxyl and amino groups of beta-CD COFs enable facile post-modification to introduce the desired functionality into the frameworks. In this study, we perform post-modification of beta-CD COFBPDA with 1,4-butane sultone and [(3R,4R)-4-acetyloxy-2,5-dioxooxolan-3-yl] acetate to construct two kinds of novel functional beta-CD COFs. The capillary columns prepared with these two functional beta-CD COFs separated chiral dihydropyridines and fluoroquinolones with excellent selectivity and repeatability in capillary electrochromatography, while beta-CD COF BPDA -modified capillary columns did not present the chiral recognition ability for these drugs. The mechanism of chiral recognition and the enhanced enantioselectivity of functional beta-CD COFs were further demonstrated by molecular docking simulation. The divergent chiral separation performances of beta-CD COFs suggest that the introduction of functional groups enables the modification of beta-CD COF properties and tuning of its chiral recognition abilities for the diversity of enantioseparation.