Catenane molecular crystals with fine-tunable pore size

Fine-tuning the aperture size of porous materials is pivotal for the selective uptake and separation of chemicals with similar molecular dimensions and physicochemical properties. However, achieving a family of porous crystals in which the aperture size can be tuned at the subangstrom (subÅ) level without altering the internal pore surface compositions remains a challenging task3. Here we show a series of porous molecular crystals of [2]catenanes whose constituent macrocycle sizes can be systematically adjusted. The [2]catenanes underwent isoreticular crystallization to afford one-dimensional (1D) channels, and the aperture sizes of these channels can be tuned at the subÅ level without altering the chemical composition of the channel surfaces. We have demonstrated that such fine-tuning significantly modulates the adsorption capabilities of the porous crystals toward various hydrocarbons and gaseous molecules, highlighting their potential in the recovery and separation of industrial chemicals.