Hydrogen-Bonded Organic Nanochannels Capturing Carbon Monoxide Under Ambient Conditions

The development of efficient materials for carbon monoxide (CO) storage and separation is essential because of their critical role in syngas-related chemical processes. Hydroquinone-based organic clathrates provide tunable hydrogen-bonded cages that can stably capture small gas molecules under ambient conditions. CO-loaded hydroquinone (CO–HQ) clathrates were synthesized via a simple gas-phase reaction, exhibiting a gas storage capacity of 2.12 mmol g–1 and cage occupancy of 0.7. Combined synchrotron X-ray diffraction and Rietveld refinement revealed that CO molecules were localized near the cage center with an orientation parallel to the channel axis. Temperature-dependent Raman and solid-state 13C nuclear magnetic resonance spectroscopy demonstrated that CO guest release occurred through hydrogen-bonded hexagonal windows without structural alterations of the host lattice. Molecular dynamics simulations revealed the amorphous-to-ordered transition of CO–HQ clathrates, confirming the cooperative framework reconstruction driven by CO guest trapping. The comprehensive structural and dynamic characterization of the CO–HQ clathrate conducted in this study is expected to present significant potential for advancing industrial-scale CO management technologies. Furthermore, the hydrogen-bonded organic nanochannel structure of CO–HQ clathrates is expected to provide an ambient-stable solid-state platform, enabling the safe handling and efficient utilization of CO, a key feedstock in syngas production and various chemical syntheses.