Quasi-Discrete Channels of Porous Coordination Polymers for Selective Multiscenario CO₂ Recognition

Selective recognition of carbon dioxide (CO₂) 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 CO₂ recognition and separation. CID-PNA features corrugated channels composed of aromatic cavities connected by narrow windows, forming π-rich, nonpolar pockets that preferentially capture CO₂ over C₂H₂, CH₄, and N₂. Specifically, CID-PNA achieves excellent CO₂/C₂H₂, CO₂/CH₄, and CO₂/N₂ selectivity (5.1, 14.8, and 117.7, respectively), a moderate CO₂ adsorption enthalpy of 33.2 kJ mol^-1, rapid adsorption-desorption kinetics with cycling completed within minutes at room temperature, and a high CO₂/H₂O 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 C₂H₂ (>99.5%), CH₄ (>99.9%), and N₂ (>99.9%) from the corresponding CO₂-containing mixtures, even under wet-hot flue gas conditions. In situ crystallography, spectroscopy, and theoretical calculations reveal that selective CO₂ 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 CO₂ separation across diverse gas mixtures.