Xu Xiaohui, Li Shenhui, Liu Qi, Liu Zhiyu, Yan Wei, Zhao Ligong, Zhang Wenhao, Zhang Liang, Deng Feng, Cong Hengjiang, Deng Hexiang
State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan , Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences , Wuhan 430071 , China.
ACS Appl Mater Interfaces. 2019 Jan 9;11(1):973-981. doi: 10.1021/acsami.8b19211. Epub 2018 Dec 21.
We report the introduction of π-interaction sites into a series of chemically robust metal-organic frameworks (MOFs), MOF-526, -527, and -528, with progressively increased pore size, 1.9-3.7 nm, and the inclusion and release of large organic molecules in water. The mesopores in these MOFs lead to fast adsorption kinetics, whereas the π-interaction between isolated porphyrin units in the MOF backbone and polycyclic structure of the organic guests provides excellent reversibility. Specifically, seven large organic dyes were quantitatively captured by the porphyrin units of these MOFs in a 2:1 molar ratio, exhibiting unprecedented kinetics for MOFs [e.g., 4.54 × 10 L/mol for rhodamine B] at an extremely low concentration (10 ppm) in water. Rotational-echo double-resonance NMR experiments revealed that the distance between the guest molecules and porphyrin units in MOFs was in the range from 3.24 to 3.37 Å, confirming the specific π-interaction. Repetitive and reversible dynamics was achieved in these MOFs for 10 complete inclusion-release cycles without any decay in performance, which is ideally suited for the removal and recycle of large polycyclic organic molecules from water. The performance of MOF-526 rivals that of state-of-the-art carbon and polymers.
我们报道了将π相互作用位点引入一系列化学性质稳定的金属有机框架（MOF）中，即MOF - 526、- 527和- 528，其孔径逐渐增大，为1.9 - 3.7纳米，并且实现了大有机分子在水中的包合与释放。这些MOF中的介孔导致快速的吸附动力学，而MOF骨架中孤立的卟啉单元与有机客体的多环结构之间的π相互作用提供了出色的可逆性。具体而言，七种大有机染料以2:1的摩尔比被这些MOF的卟啉单元定量捕获，在水中极低浓度（10 ppm）下展现出MOF前所未有的动力学[例如，罗丹明B为4.54×10 L/mol]。旋转回波双共振核磁共振实验表明，MOF中客体分子与卟啉单元之间的距离在3.24至3.37 Å范围内，证实了特定的π相互作用。这些MOF实现了10个完整的包合 - 释放循环的重复且可逆动力学，性能无任何衰减，这非常适合从水中去除和回收大型多环有机分子。MOF - 526的性能可与最先进的碳材料和聚合物相媲美。
