Quasi-Discrete Channels of Porous Coordination Polymers for Selective Multiscenario CO ₂ Recognition

Selective recognition of carbon dioxide (CO 2 ) from mixtures containing many similar species is crucial for industrial energy and environmental applications, yet it remains elusive. Herein, we report an interdigitated coordination polymer (CID-PNA) that leverages quasi-discrete channels for multiscenario CO 2 recognition and separation. CID-PNA features corrugated channels composed of aromatic cavities connected by narrow windows, forming π-rich, nonpolar pockets that preferentially capture CO 2 over C 2 H 2, CH 4, and N 2 . Specifically, CID-PNA achieves excellent CO 2 /C 2 H 2, CO 2 /CH 4, and CO 2 /N 2 selectivity (5.1, 14.8, and 117.7, respectively), a moderate CO 2 adsorption enthalpy of 33.2 kJ mol –1, rapid adsorption–desorption kinetics with cycling completed within minutes at room temperature, and a high CO 2 /H 2 O uptake ratio (3.24) that far exceeds those of benchmark materials (e.g., CALF-20, ALF, and Zeolite-13X). Breakthrough experiments demonstrate that CID-PNA enables one-step purification of high-purity C 2 H 2 (>99.5%), CH 4 (>99.9%), and N 2 (>99.9%) from the corresponding CO 2 -containing mixtures, even under wet-hot flue gas conditions. In situ crystallography, spectroscopy, and theoretical calculations reveal that selective CO 2 binding originates from cooperative C═O···H and π···π interactions within confined aromatic pockets. Overall, the quasi-discrete aromatic channels in CID-PNA integrate strong recognition, rapid transport, and energy-efficient regeneration, offering a general design motif for selective CO 2 separation across diverse gas mixtures.