Multi-Modular Design of Stable Pore-Space-Partitioned Metal-Organic Frameworks for Gas Separation Applications

Pore space partition (PSP) is an effective materials design method for developing high-performance small-pore materials for storage and separation of gas molecules. The continued success of PSP depends on broad availability and judicious choice of pore-partition ligands and better understanding of each structural module on stability and sorption properties. Here, by using substructural bioisosteric strategy (sub-BIS), a dramatic expansion of pore-partitioned materials is targeted by using ditopic dipyridyl ligands with non-aromatic cores or extenders, as well as by expanding heterometallic clusters to uncommon nickel-vanadium and nickel-indium clusters rarely known before in porous materials. The dual-module iterative refinement of pore-partition ligands and trimers leads to remarkable enhancement of chemical stability and porosity. Here a family of 23 pore-partitioned materials synthesized from five pore-partition ligands and seven types of trimeric clusters is reported. New materials with such compositionally and structurally diverse framework modules reveal key factors that dictate stability, porosity, and gas separation properties. Among these, materials based on heterometallic vanadium-nickel trimeric clusters give rise to the highest long-term hydrolytic stability and remarkable uptake capacity for CO₂ , C₂ H₂ /C₂ H₄ /C₂ H₆ , and C₃ H₆ /C₃ H₈ hydrocarbon gases. The breakthrough experiment shows the potential application of new materials for separating gas mixtures such as C₂ H₂ /CO₂ .