A Cage-Interconnected Metal-Organic Framework with Tailored Apertures for Efficient C2H6/C2H4 Separation under Humid Conditions

Metal-Organic Frameworks (MOFs) with open metal sites (OMSs) have been shown to preferentially adsorb unsaturated hydro-carbons such as C2H4 due to the formation of π-complexation. However, the adsorption capacity and selectivity might well be dampened under humid conditions because OMSs could be easily poisoned in the presence of water vapor. C2H6-selective adsor-bents with less hydrophilic environments, on the other hand, not only could effectively minimize the impact of humidity on separa-tion capacity; they could also directly produce high-purity C2H4 from C2H6/C2H4 mixtures. Here, we report a C2H6-selective MOF (JNU-2) underlying a rare xae topology. Its cage-like cavities are interconnected through apertures with a limiting diameter of ca. 3.7 A, which is in the domain of kinetic diameters of C2H4 and C2H6 molecules. Molecular modeling studies suggest the four oxy-gen atoms on aperture are poised to preferentially interact with C2H6 through multiple C–H···O hydrogen bonding, rendering JNU-2 an enhan...