Functionalization of Macroporous Organic Polymer Monolith Based on Succinimide Ester Reactivity for Chiral Capillary Chromatography: A Cyclodextrin Click Approach

Macroporous cross-linked organic polymer based on N-acryloxysuccinimide (NAS) and ethylene dimethacrylate (EDMA) was prepared inside 75 mu m id fused silica capillary as a functionalizable monolithic stationary phase for chromatographic applications. Succinimide groups on the monolith surface provide reactive sites able to react readily through standard electrophile-nucleophile chemistry. Propargylamine was used to prepare alkyne functionalized poly(NAS-co-EDMA). Onto this azido-reactive polymer surface was grafted beta-cyclodextrin (CD) via a triazole ring utilizing the copper(I)-catalyzed 1,3-dipolar cyclo-addition reaction. Chemical characterization was performed in situ after each synthetic step by means of Raman spectroscopy. Good enantio-separations of flavanone enantiomers, chosen as test chiral compound, were achieved under reversed phase conditions by both capillary electrochromatography and nano-liquid chromatography (nano-LC) techniques. These results demonstrate the potentiality and usefulness of click chemistry in the preparation of beta-CD containing chiral organic polymer monolith.