Highly Selective Separation of C₃H₈ and C₂H₂ from CH₄ within Two Water-Stable Zn₅ Cluster-Based Metal–Organic Frameworks

Adopting the mixed ligands approach, two water-stable Zn5 cluster-based MOFs, [Zn10(TZ)12(TADIPA)2(DMF)4]·DMF·6H2O (JLU-MOF66) and [Zn10(TZ)12(TPTA)2(DMA)2]·2DMA·4H2O (JLU-MOF67), have been constructed (H4TADIPA = 5,5′-(1H-1,2,4-triazole-3,5-diyl)diisophthalic acid, H4TPTA = [1,1′:3′,1″-terphenyl]-3,3″,5,5″-tetracarboxylic acid, and HTZ = 1H-[1,2,3]triazole). Both compounds with [Zn5(TZ)6] clusters exhibit extraordinary stability (pH = 2–11) and selectivity of C3H8/CH4 (308 for JLU-MOF66, and 287 for JLU-MOF67). Compared to JLU-MOF67, JLU-MOF66 with functional groups exhibits higher CO2 and C2H2 uptake capacity and excellent selective separation for C2H2/CH4 (86, 1:1). Such high separation and chemical stability render them as promising materials for industrial applications.