A Microporous Mn(II) MOF Based on 5-(4H-1,2,4-triazol-4-yl) Isophthalic Acid for CO2/N2 Separation

Removal of carbon dioxide (CO₂) from a CO₂/N₂ mixture by utilizing CO₂-selective sorbents is important from the perspective of energy security and environmental sustainability. Herein, a microporous metal-organic framework (MOF) composed of manganese(II) and a bifunctional linker 5-(4H-1,2,4-triazol-4-yl)benzene-1,3-dicarboxylic acid (H₂L), [Mn(HL)₂] (1) is designed and synthesized using a hydrothermal method. Characterized by single-crystal X-ray diffraction (SCXRD), a microporous channel was found in the structure of compound 1 along the a-axis. Attributed to hydrogen-binding interactions between CO₂ molecules and N- and O-donor ligands in its microporous one-dimensional (1D) channel, compound 1 exhibits favorable adsorption of CO₂ over N₂. Further, verified by experimental breakthrough tests, the CO₂/N₂ mixture can be separated efficiently. This work provides potential guidance for designing CO₂-selective MOFs for CO₂/N₂ separation.