Hydrogen-bonded ionic framework with ultrafine adaptive pores for selective gas adsorption

The development of hydrogen-bonded frameworks with both robust stability and adaptive functionality remains a significant challenge. Herein, we report a series of hydrogen-bonded ionic frameworks (HIFs) constructed via a supramolecular assemble strategy, utilizing bulky cationic Zn (II) coordination complexes and small inorganic anions. Directional charge-assisted hydrogen bonds effectively suppress closed-pack and yields robust architectures, with adaptive porosity under external stimuli owing to relatively weak interactions. Notably, HIF-23 exhibits a sophisticated guest-induced gate-opening effect, specifically triggered by the CO2 with quadrupole moment. Comprehensive DFT simulations and spectroscopic analyses reveal that the transition is driven by a localized conformational twisting of propane bridges and adaptive nature of the hydrogen-bonding network. The specific interaction with CO2 enables high CO2/CH4 and CO2/N2 selectivity, complemented by a substantial high-pressure CO2 capacity of 30.4 wt% at 50 bars. This work underscores the potential of the HIF platform for the precision engineering of stimuli-responsive materials tailored for energy-efficient carbon capture.