Dual-Mechanism Synergy in Chiral Conjugated Microporous Polymer Membranes for Enhanced Enantioselective Permeability

Chiral membrane separation, an emerging enantiomer separation technology featuring low-energy consumption, high efficiency, and environmental sustainability, faces a significant challenge in simultaneously enhancing enantioselectivity and permeability. Herein, chiral conjugated microporous polymer composite membranes (CCMP-SiO₂) via surface-initiated Sonogashira-Hagihara coupling reaction, enabling exceptional chiral resolution properties is developed. The membrane exhibits excellent chemical stability and thermostability, achieving the highest enantiomer permeability (3.3 × 10^-8 m² h^-1) among the chiral membranes with enantioselectivity exceeding 99% ee (99.7% ee in this study) for the separation of D,L-phenylalanine (D,L-Phe) racemic mixture. The 3D conjugated frameworks of chiral conjugated microporous polymer (CCMP) provide both mechanical stability and porous transport channels, collectively enhancing permeability. In addition, strategic incorporation of amide and aromatic functionalities into chiral recognition sites, synergistically enhances enantioselectivity and permeability through stereoselective recognition and non-stereoselective interactions. Density functional theory (DFT) and non-covalent interaction (NCI) analysis reveal dual-mechanism synergy for enhanced enantioselective permeability of CCMP-SiO₂ membranes. Notably, the membrane demonstrates retarded transport behavior, enabling precise enantiomer separation. This work establishes a dual-objective synergistic strategy for concurrent optimization of enantioselectivity and permeability, providing a generalizable platform for rational design of chiral membranes.