Assembly of a protein-mimetic helical metal–organic framework for enantioseparation

Abstract

The selective separation of racemic epoxides is crucial for pharmaceutical production, yet achieving high enantioselectivity remains challenging. Inspired by the inherent chirality and precise assembly of peptide helices in natural proteins, we constructed a chiral metal–organic framework (MOF) featuring one-dimensional (1D) helical nanochannels by using phenylalanine-derived dicarboxyl-functionalized chiral ligands with C₂ symmetry and backbone flexibility. In the chiral MOF, the nanochannel walls are decorated with dense and ordered phenylalanine residues, mimicking the sophisticated chiral microenvironments of protein channels. When employed as a chiral adsorbent, this protein-mimetic chiral MOF enables the enantioselective separation of a series of pharmacologically important epoxides, as well as 1-phenylethanol, phenylethanediol and sec-butylamine, achieving excellent enantiomeric excess (ee) values of up to 99.9%. Moreover, the chiral adsorbent can be readily recovered and reused over five cycles without significant loss of enantioselectivity, demonstrating its excellent recyclability. Control adsorption experiments and in-depth structural analyses reveal that the high enantioselectivity arises from the biomimetic chiral microenvironment within the helical nanochannels. This work provides a bioinspired design strategy for advanced chiral separation materials enabling targeted enantioseparations.