Post-synthetic modification of metal–organic frameworks for chiral gas chromatography

Abstract

Chiral metal–organic frameworks (MOFs) show great potential in chiral catalysis and separation. However, their application is still hindered by the limited availability of chiral MOFs and chiral recognition centers due to the great challenges for direct synthesis of chiral MOFs with designed chiral recognition sites. Here we report a post-synthesis approach for the facile preparation of chiral MOFs for chiral gas chromatography. Five chiral MOFs with an identical parent framework but different chiral recognition sites were synthesized via grafting various chiral recognition sites of ligands onto MIL-101–NH₂. The chiral MOF-coated capillary columns gave good resolution for the separation of diverse racemates with superior separation to the commercial chiral capillary columns. The results reveal that the post-synthesis approach is convenient to fabricate target chiral MOFs with pre-designed functions with the ability to avoid blind synthesis of chiral MOFs via direct synthesis and to facilitate the evolution of chiral stationary phases in chiral chromatography.