A Stable Zr-Based Metal–Organic Framework with Specific Molecule Traps for Reverse C2H6/C2H4 Separation

C₂H₄ separation from C₂H₆/C₂H₄ binary mixtures is still a great challenge; however, most metal–organic frameworks (MOFs) with high C₂H₆/C₂H₄ selective performance often exhibit low C₂H₆ adsorption. Herein, a stable MOF based on UiO-68 type (UiO-68-A) was selected, and single-crystal X-ray crystallography data were obtained in this work. Owing to the large cavities and specific anthracene ring traps, UiO-68-A demonstrated high C₂H₆ adsorption ability and good reverse C₂H₆/C₂H₄ selectivity. Gas adsorption behavior calculations evidenced that multiaromatic surfaces and [Zr₆(μ₃-O)₄(μ₃-OH)₄(−COO^–)₁₂] clusters provided more C–H···π and C–H···O interactions compared to C₂H₄. In addition, the central anthracene rings formed a molecule trap to provide more and stronger C–H···H–C interactions with C₂H₆, which further enhanced the affinity toward C₂H₆ and led to the reverse selective performance for C₂H₆/C₂H₄. This work synergized the adsorption ability and separation capacity, which supplied a balance of C₂H₆ adsorption and C₂H₄ purification.