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.