Chen Fengli, Bai Dongjie, Wang Yao, He Minghui, Gao Xiaoxia, He Yabing
Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China.
Dalton Trans. 2018 Jan 15;47(3):716-725. doi: 10.1039/c7dt04087c.
The combination of an angular diisophthalate ligand, 5,5'-(naphthyl-2,7-yl)diisophthalate (HL), and copper ions under different solvothermal conditions afforded two polymorphous metal-organic frameworks (ZJNU-77 and ZJNU-78) with the same framework composition of [Cu(L)(HO)], providing a platform to investigate the relationship between MOF polymorphism and gas adsorption properties. As determined by single-crystal X-ray diffraction, ZJNU-77 and ZJNU-78 exhibited three-dimensional networks crystallizing in different space groups. Their structural differences were mainly manifested by the ligand's conformation, the level of framework interpenetration and the network's topology. Interestingly, gas adsorption studies showed that the two compounds after desolvation displayed comparable gas adsorption properties with respect to CH, CO and CH, despite their different surface areas and pore volumes. The CH, CO, and CH uptake capacities at 298 K and 1 atm are 120.2, 78.1, and 18.4 cm (STP) g for ZJNU-77, and 122.0, 82.0, and 18.9 cm (STP) g for ZJNU-78, respectively. The IAST adsorption selectivities for the equimolar CH/CH and CO/CH mixtures are 28.6 and 5.7 for ZJNU-77, and 28.4 and 5.9 for ZJNU-78 at 298 K and 1 atm. These results indicate that besides the surface area, the pore size also plays a crucial role in gas adsorption. This work not only represents an intriguing example of MOF polymorphism achieved by controlling solvothermal conditions, but also provides an insight into the correlation between MOF polymorphism and gas adsorption properties.
在不同溶剂热条件下，角型间苯二甲酸酯配体5,5'-(萘-2,7-基)间苯二甲酸酯（HL）与铜离子相结合，得到了两种具有相同骨架组成[Cu(L)(H₂O)]的多晶型金属有机骨架材料（ZJNU - 77和ZJNU - 78），为研究金属有机骨架材料的多晶型与气体吸附性能之间的关系提供了一个平台。通过单晶X射线衍射确定，ZJNU - 77和ZJNU - 78呈现出在不同空间群中结晶的三维网络结构。它们的结构差异主要体现在配体的构象、骨架互穿程度和网络拓扑结构上。有趣的是，气体吸附研究表明，尽管这两种化合物的表面积和孔体积不同，但脱溶剂后它们对CH₄、CO₂和C₂H₂表现出相当的气体吸附性能。在298 K和1 atm下，ZJNU - 77对CH₄、CO₂和C₂H₂的吸附容量分别为120.2、78.1和18.4 cm³(STP) g⁻¹，ZJNU - 78分别为122.0、82.0和18.9 cm³(STP) g⁻¹。在298 K和1 atm下，对于等摩尔的CH₄/C₂H₂和CO₂/C₂H₂混合物，ZJNU - 77的IAST吸附选择性分别为28.6和5.7，ZJNU - 78分别为28.4和5.9。这些结果表明，除了表面积外，孔径在气体吸附中也起着至关重要的作用。这项工作不仅代表了通过控制溶剂热条件实现金属有机骨架材料多晶型的一个有趣例子，还为深入了解金属有机骨架材料的多晶型与气体吸附性能之间的相关性提供了思路。
