Recent advances of chiral covalent organic frameworks for enantiomer separation

Chiral covalent organic frameworks (CCOFs) are an emerging class of crystalline porous materials, that possess excellent physical and chemical properties, such as large specific surface area, tunable pore size, abundant chiral recognition sites, and so on. Owing to their unique advantages, CCOFs have shown great potential in diverse fields, especially in enantiomer separation, arousing broad interest. This review summarizes the preparations of CCOFs and their applications in enantiomer separation from 2019 to the present. We focus on the synthetic strategies for CCOFs, including post-synthesis modification (PSM), direct synthesis, chiral induction and other innovative methods, to inspire the feasible design of CCOFs. Furthermore, the applications of CCOFs in chromatography, membrane and adsorption separation of enantiomers have been reviewed. However, there also exist some challenges on the construction of CCOFs to improve selectivity and universality for enantiomer separation, which have been pointed out.