image: The chiral capillary column coated with three-dimensional chiral crown ether covalent organic frameworks (CCOFs) performs electrochromatographic separation of racemic chiral compounds.
Credit: ©Science China Press
This study is led by professor Yong Cui (School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, China). The authors demonstrate that incorporating chiral crown ethers into stable covalent organic frameworks (COFs) enable efficient and stable separations of racemates by CEC.
The two 3D CCOFs were synthesized by polycondensation of a chiral 1,1’-binaphyl-20-crown-6-derived dialdehyde and tetraamines with diisopropyl substituents. Both feature a 11-fold interpenetrated diamond framework, characterized by tubular open channels decorated with chiral crown ethers serving as enantioselective recognition and binding sites. These frameworks demonstrate excellent stability in water, acid, and base, thanks to the presence of bulky iso-propyl groups that shield the dynamic imine linkages. Moreover, the precisely defined COF channels enhanced the accessibility of the enclosed crown ethers to the analytes while providing strong protection against harsh environments, rendering them suitable for CSPs in CEC separations.
The CCOFs can effectively separate some important enantiomers, including ketones, epoxides, and alkaline substances, when utilized as coatings on chiral columns, particularly facilitating the chiral separation of drugs. This study advances the application of COFs in electrochromatographic separations, expanding the scope of porous materials design and engineering to create COFs with targeted enantioselective properties.
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See the article:
Construction of chiral crown ethers into robust covalent organic frameworks for electrochromatographic enantioseparation
https://doi.org/10.1093/nsr/nwae256
Journal
National Science Review