Host–Host Interactions Enhanced the Structural Rigidity in a 6-Fold Interpenetrated Diamondoid Metal–Organic Framework Exhibiting C₂H₂/C₂H₄ Separation

Abstract

Multi-interpenetrated metal−organic frameworks (MOFs) have exhibited excellent performance in selective adsorption due to the variable post-interspersed flexibility, but the design and control remain challenging. Herein, two anthracene-based ligands, 4,4′-(anthracene-9,10diyl)dibenzoic acid (H 2 L1) and 9,10-di(pyridin-4-yl)anthracene (L2), are used to construct a new three-dimensional 6-fold interpenetrated MOF [Zn(L1)(L2)] n (NBU-X1), which exhibits multiple C−H•••π interactions that enhance the structural rigidity, thereby entangling with a C 2 H 2 /C 2 H 4 separation performance. In this material, the incorporation of abundant anthracene rings within the framework not only partitions and restricts the pore window size to a quasi-double pore but also stabilizes it through host−host interactions. The structural stability upon heating or guest displacement/removal has been investigated by single-crystal X-ray diffraction and in situ variabletemperature powder X-ray diffraction, in contrast to the extreme flexibility of most multiinterpenetrated MOFs. The performance of purifying C 2 H 4 from C 2 H 2 /C 2 H 4 mixtures has been proved by dynamic breakthrough tests.