<i>In Situ</i> Preparation of Hydrophilic Chiral Covalent Organic Framework Membranes for Enantioseparation of Drugs

The trend of integrating chirality into stable membrane systems for large-scale preparation provides new opportunities in this field. However, the contradiction between the chiral recognition ability and the permeability of the membrane limits its development. The traditional membrane production method produces chiral membranes with several disadvantages, including weak mechanical properties, low load, uneven distribution of chiral selectors, a discontinuous membrane structure, and low selectivity. To improve the membrane's overall performance, the <i>in situ</i> growing process may regulate the membrane's thickness and guarantee its continuity. Therefore, in this study, a novel chiral membrane was prepared by <i>in situ</i> growth of chiral covalent organic frameworks (CCOFs) by using a commercial nylon membrane as the supporting base at room temperature. Among them, the [NALC]_<i>X</i>-TAPB-DVA COFs synthesized by us, as a novel form of CCOF, equip the membrane with good hydrophilicity and chiral recognition capacity, providing an effective solution to the problem of mutual limitations between selectivity and permeability. Under optimal preparation conditions, the obtained CCOF membrane exhibited excellent stability and achieved effective separation of mandelic acid, naproxen, ibuprofen, and warfarin. In addition, theoretical calculations revealed the reasons for the differences in separation performance of various chiral drugs. The difference in the type and quantity of interaction forces between substrates and chiral selectors is the basis for achieving separation. In summary, this study proposes a strategy for the preparation of chiral separation membranes, providing valuable insights for advancing research on chiral recognition and separation processes.