Xenon/Krypton Separation on a Bromine Functionalized Benzimidazole-Linked Porous Covalent Organic Polymer

Xe nuclear magnetic resonance (NMR) spectroscopy provides direct insight into the adsorption behavior, revealing a bimodal pore environment in the brominated polymer during Xe adsorption, indicative of heterogeneous binding sites. Complementary computational modeling elucidates the synergistic interplay between stronger confinement effects in the smaller pores of the brominated framework and energetically favorable adsorption sites in close proximity to the bromine functionalities. This study introduces a distinct separation mechanism for Xe/Kr based on polarity-induced specific interactions rather than conventional size-shape exclusion, offering a rare and effective example of organic porous materials for noble gas separation. The findings highlight halogen functionalization as a powerful strategy for tuning noble gas adsorption energetics and selectivity in covalent organic polymers.