Abstract：
Promising advances in adsorption technology can lead to energy-efficient solutions in industrial sectors. This work presents precise molecular sieving of xylene isomers in the polymer-metal-oragnic framework (polyMOF), a hybrid porous material derived from the parent isoreticular MOF-1 (IRMOF-1). PolyMOFs are synthesized by polymeric ligands bridged by evenly spaced alkyl chains, showing reduced pore sizes and enhanced stabilities compared to its parent material due to tethered polymer bridge within the pores while maintaining the original rigid crystal lattice. However, the exact configuration of the ligands within the crystals remain unclear, posing hurdles to predicting the adsorption performances of the polyMOFs. This work reveals that the unique pore structure of polyIRMOF-1-7a can discriminate xylene isomers with sub-angstrom size differences, leading to highly selective adsorption of p-xylene over other isomers and alkylbenzenes in complex liquid mixtures (αpX/OM = 15 and αpX/OME = 9). The structural details of the polyIRMOF-1-7a are elucidated through computational studies, suggesting a plausible configuration of alkyl chains within the polyMOF crystal, which enable a record-high p-xylene selectivity and stability in liquid hydrocarbon. With this unprecedented molecular selectivity in MOFs, \"polymer-MOF\" hybridization is expected to meet rigorous requirements for high-standard molecular sieving through precisely tunable and highly stable pores.
摘要：
吸附技术的有希望的进步可以为工业部门带来节能解决方案。这项工作提出了聚合物-金属-有机骨架（polyMOF）中二甲苯异构体的精确分子筛，衍生自母体等网状MOF-1(IRMOF-1)的混合多孔材料。PolyMOFs是由均匀间隔的烷基链桥连的聚合配体合成的，由于孔内的束缚聚合物桥同时保持原始刚性晶格,显示与其母体材料相比减小的孔径和增强的稳定性。然而,晶体中配体的确切构型仍不清楚，对预测polyMOFs的吸附性能构成障碍。这项工作表明，聚IRMOF-1-7a的独特孔结构可以区分具有亚埃尺寸差异的二甲苯异构体，导致对二甲苯相对于复杂液体混合物中的其他异构体和烷基苯的高选择性吸附（αpX/OM=15和αpX/OME=9）。通过计算研究阐明了polyIRMOF-1-7a的结构细节，表明在polyMOF晶体中烷基链的合理构型，这使得在液态烃中具有创纪录的高对二甲苯选择性和稳定性。在MOFs中这种前所未有的分子选择性，“聚合物-MOF”杂交有望通过精确可调和高度稳定的孔满足高标准分子筛分的严格要求。
