Ligand Circuit Concept for Developing Gas Separation Materials from Pore-Space-Partitioned Metal-Organic Frameworks

Isoreticular chemistry is among the most powerful strategies for designing novel materials with optimizable pore geometry and properties. Of great significance to the further advance of isoreticular chemistry is the development of broadly applicable new concepts capable of guiding and systematizing the ligand-family expansion as well as establishing correlations between dissimilar and seemingly uncorrelated ligands for better predictive synthetic design and more insightful structure and property analysis. Here ligand circuit concept is proposed and its use has been demonstrated for the synthesis of a family of highly stable, high-performance pore-space-partitioned materials based on an acyclic ligand, trans, trans-muconic acid. This work represents a key step toward developing highly porous and highly stable pore-space-partitioned materials from acyclic ligands. The new materials exhibit excellent sorption properties such as high uptake capacity for CO₂ (81.3 cm³ g^-1) and C₂H₂ (165.4 cm³ g^-1) by CPM-7.3a-NiV. CPM-7.3a-CoV shows C₂H₆-selective C₂H₆/C₂H₄ separation properties and its high uptakes for C₂H₄ (134.0 cm³ g^-1) and C₂H₆ (148.0 cm³ g^-1) at 1 bar and 298 K contribute to the separation potential of 1.35 mmol g^-1. The multi-cycle breakthrough experiment confirms the promising separation performance for C₂H₂/CO₂.