An Interpenetrated Pillar-Layered Metal-Organic Framework with Novel Clusters: Reversible Structural Transformation and Selective Gate-Opening Adsorption

Abstract

A new metal–organic framework (MOF), [Co3(tzba)2(bpy)3(F)2]·DMF·C2H5OH·2H2O (1), has been constructed by solvothermal reaction of Co(NO3)2 with 4-(1H-Tetrazol-5-yl) benzoic acid (H2tzba) and 4,4′-bipyridine (bpy) mixed ligands. 1 shows an interpenetrated three-dimensional (3D) pillar-layered framework with the novel trinuclear [Co3(CN4)2(F2)] clusters. The π···π interactions existing among three bpy give rise to an uncommon tripillar in the framework. The framework reveals a reversible dynamic flexibility related to the solvent molecules. Meanwhile, the adsorption of CO2 exhibits an interesting gate opening–closing phenomenon which features the S-shaped isotherms with dramatic hysteretic desorption. The selective adsorption of CO2 over CH4 as well as the adsorption mechanism for CO2 were also discussed deeply.