New reticular chemistry of pillared rare-earth kgd supermolecular building layer frameworks with ethane-trapping property

The industrial demand for ethylene is increasing, efficient purification of ethylene from ethane is of significant importance but challenging. Pillar-layered metal-organic frameworks (MOFs) have aroused extensive attention due to their application potential in gas separation, storage and catalysis, etc. Herein, five pillar-layered rare-earth (RE)-MOFs based on rare kgd supermolecular building layers (SBLs) were successfully prepared under solvothermal conditions by means of Tb(NO3)(3)center dot 6H(2)O as the metal source, single tritopic H3NTB (4,4 ',4 ''-nitrilotribenzoic acid) or mixed H3NTB, with a series of ditopic ligands with distinct length as the bridge linkers. Single crystal structure analyses show that three types of pillar-layered RE-MOFs were isolated due to the difference of pillars between the exclusive kgd SBLs, i.e., trk, zma and tpk topological networks. The N-2 isotherms exhibit that the first four MOFs feature microporous characteristics. Furthermore, the single component of C2H6, C2H4, C2H2 and CO2 sorption isotherms show that the four materials exhibit reverse C2H6/C2H4 separation as well as C2H2-selective adsorption for a C2H2/CO2 mixture. Among them, Tb-NTB-1,4-NDC displays the best separation potential as revealed by ideal adsorption solution theory and dynamic column breakthrough experiments.