Chiral Metal–Organic Framework with Temperature-Dependent Homochirality for Chiral Discrimination

Chiral metal-organic frameworks (CMOFs) have attracted considerable attention in chiral discrimination and separation. In this work, a simple CMOF is synthesized through a facile one-pot method by using Zn(II), tetra(4-carboxyphenyl)-porphyrin (TCPP), and d-phenylalanine methyl ester (d-Phe-OMe) as metal ion, organic ligand, and chiral source, respectively. Interestingly, the CMOFs synthesized at different temperatures (25 and 160 °C) display quite different morphologies and diametrically opposite chirality due to the different interaction modes between TCPP and d-Phe-OMe at 25 and 160 °C. Next, the CMOFs synthesized at 25 and 160 °C are utilized for the chiral discrimination of the isomers of tryptophan (Trp), resulting in exactly the reverse effect. The developed CMOF-based chiral sensors also exhibit excellent reproducibility, suggesting their great potential for chiral analysis.