Regulation of Structural Flexibility and C₂H₆ Selectivity of Interpenetrated Isoreticular Metal-Organic Frameworks

Interpenetrated pillar-layered metal-organic frameworks (MOFs), distinguished by their readily tunable pore architectures and functionalities, hold particular promise for separating molecules with similar physicochemical characteristics. Here, we report two isoreticular interpenetrated pillar-layered MOFs, designated as M-PTTB-BPY (M = Zn, Co). They exhibit the same connectivity with slightly different linker distortion. This subtle difference leads to their notably different structural flexibilities and pore geometries, which influences the gas adsorption behaviors. Both structures exhibit favored adsorption of C₂H₆ over C₂H₄ with structure-regulated adsorption capacity and selectivity. Their separation capabilities have been fully validated through column breakthrough measurements and the underlying selective adsorption mechanism uncovered by DFT calculations.