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(NO 3 ) 3 ·6H 2 O as the metal source, single tritopic H 3 NTB (4,4′,4′′-nitrilotribenzoic acid) or mixed H 3 NTB, 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 C 2 H 6 , C 2 H 4 , C 2 H 2 and CO 2 sorption isotherms show that the four materials exhibit reverse C 2 H 6 /C 2 H 4 separation as well as C 2 H 2 -selective adsorption for a C 2 H 2 /CO 2 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.