Microporous Cyclen-Based Octacarboxylate Hydrogen-Bonded Organic Framework Exhibiting Selective Gas Adsorption

A microporous hydrogen-bonded organic framework (HOF) was successfully prepared by a cyclen-based octacarboxylate ligand H8tacnip-Zn. The obtained three-dimensional structure presents a periodic double-layer unit that stacks to form a one-dimensional channel that buttresses discrete cavities (∼5.6 × 5.6 Å2). From the single crystal structure, the macrocycle-bound metal ion was proven to greatly enhance the rigidity of the cyclen-based ligand while adjusting the direction of the carboxyl groups. The indelible porosity of degassed HOF was elucidated by CO2 sorption and selective gas adsorption. This work provides facile access to construct more porous HOFs based on a cyclen unit.