Excellent separation performance in a mesoporous MOF induced by 1D rhombic channels and bare nitrogen-donor sites

Abstract Metal-organic frameworks with open active sites and appropriate pore size show great application promises in gas storage and separation due to their structural characteristics and functionality can be adjusted and controlled. Based on a benzimidazole and carboxylate decorated new MOF, [Cd(PCA)2]n, (YAU-1, HPCA=(2-(pyrid-4′-yl)-benzimidazole-5- carboxylic acid) has been gained under solvent-thermal conditions. Each dinuclear [Cd2] unit are linked through PCA− ligands to obtain a 2D layer structure, and the 2D structure is further connected by PCA− ligands to form the 3D framework of YAU-1. Remarkably, the un-coordinated benzimidazole and pyridine groups of PCA− ligand not only provide the 1D channels with exposed N atoms to create a mesoporous environment but also stabilizes 3D framework by π⋯π stacking. Taking advantage of these structural characteristics, YAU-1 shows different adsorption capacity for CO2, C2H2, C2H4 and CH4, and remarkable separation effect of C2H2/CH4, C2H4/CH4 and CO2/CH4. The research on the configuration-effect relationship of YAU-1 provides a promising methods to design and construction materials with high gas uptake and separation performance.