Lv Hong-Juan, Li Yong-Peng, Xue Ying-Ying, Jiang Yu-Cheng, Li Shu-Ni, Hu Man-Cheng, Zhai Quan-Guo
Key Laboratory of Macromolecular Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an, Shaanxi 710062, People's Republic of China.
Inorg Chem. 2020 Apr 6;59(7):4825-4834. doi: 10.1021/acs.inorgchem.0c00115. Epub 2020 Mar 18.
The separation of a mixture of CH and CO is a great challenge due to their similar molecular sizes and shapes. Al-based metal-organic frameworks (Al-MOFs) have great promise for gas separation applications due to their light weight, high stability, and low cost. However, the cultivation of suitable Al-MOF single crystals is extremely difficult and has limited their explorations up to now. Since In, Ga, and Al are all 3p-block metal elements, a systematic application of the periodic law to investigate 3p-MOFs will undoubtedly help in the understanding and development of worthy Al-MOF materials. Herein, we report the design of a robust 3p metal-organic framework platform (SNNU-150) and the systematic regulation of CH/CO separation by open 3p-block metal sites. X-ray single-crystal diffraction analysis reveals that SNNU-150 is a 3,6-connected 3D framework consisting of [MO(COO)] trinuclear secondary building units (SBUs) and tritopic nitrilotribenzoate (NTB) linkers. Small {MO(COO)} tetrahedral cages and extra-large {MO(COO)} polyhedral cages connect with each other to generate a hierarchically porous architecture. These 3p-MOFs present very high water, thermal, and chemical stability, especially for SNNU-150-Al, which can maintain its framework at 85 °C in water for 24 h and in a room-temperature environment for more than 30 days. IAST calculations, breakthrough experiments, and GCMC simulations all show that SNNU-150 MOFs have top-level CH/CO separation performance and follow the order Al-MOF > Ga-MOF > In-MOF.
由于CH和CO的分子大小和形状相似，分离它们的混合物是一项巨大挑战。基于铝的金属有机框架（Al-MOFs）因其重量轻、稳定性高和成本低，在气体分离应用方面具有巨大潜力。然而，培养合适的Al-MOF单晶极其困难，到目前为止限制了它们的探索。由于铟、镓和铝都是3p族金属元素，系统应用周期律来研究3p-MOFs无疑将有助于理解和开发有价值的Al-MOF材料。在此，我们报告了一个稳健的3p金属有机框架平台（SNNU-150）的设计以及通过开放的3p族金属位点对CH/CO分离的系统调控。X射线单晶衍射分析表明，SNNU-150是一个由[MO(COO)]三核二级构筑单元（SBUs）和三齿氨三苯甲酸酯（NTB）连接体组成的3,6连接三维框架。小的{MO(COO)}四面体笼和超大的{MO(COO)}多面体笼相互连接，形成分级多孔结构。这些3p-MOFs具有非常高的水稳定性、热稳定性和化学稳定性，特别是对于SNNU-150-Al，它可以在水中85°C下保持其框架24小时，在室温环境下保持30多天。IAST计算、突破实验和GCMC模拟均表明，SNNU-150 MOFs具有顶级的CH/CO分离性能，且遵循Al-MOF > Ga-MOF > In-MOF的顺序。
