UTSA-74: A MOF-74 Isomer with Two Accessible Binding Sites per Metal Center for Highly Selective Gas Separation
UTSA-74: A MOF-74 Isomer with Two Accessible Binding Sites per Metal Center for Highly Selective Gas Separation
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UTSA-74：MOF-74 异构体，每个金属中心有两个可接近的结合位点，用于高选择性气体分离
DOI：
10.1021/jacs.6b02030
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发表时间：
2016-05-04
影响因子：
15
通讯作者：
Chen, Banglin
中科院分区：
文献类型：
--
作者：
Luo, Feng;Yan, Changsheng;Chen, Banglin
合成了一种新的金属-有机骨架锌-2(H2O)-(DOBDC)中心点0.5(H2O)(UTSA-74，H4DOBDC=2，5-二氧代-1，4-苯二甲酸)，并对其结构进行了表征。它具有一个新的四配位FGL拓扑结构，一维通道约为8.0A。与已建立的杆状堆积结构中的金属中心不同，UTSA-74中的两个双核次级建筑单元中有两个不同的锌离子中心，其中一个(锌)位于四面体中，另一个(锌)位于八面体配位几何中。活化后，锌离子上的两个轴向水分子可以被去除，生成每个锌离子有两个可达气体结合位的UTSA-74a。因此，UTSA-74a的乙炔含量中等偏高(145厘米(3)/厘米(3))，与锌-MOF-74相当。有趣的是，UTSA-74a中可访问的锌离子中心被二氧化碳分子桥联，而不是末端结合在Zn-MOF-74中，因此在室温和1bar的条件下，UTSA-74a吸附的二氧化碳(90 cm3/cm3)比Zn-MOF-74(146 cm3/cm3)小得多，这使得UTSA-74a是一种用于高选择性C2H2/CO2分离的优异的MOF材料。X射线晶体结构、气体吸附等温线、分子模拟以及模拟和实验的突破全面支持这一结果。
A new metal-organic framework Zn-2(H2O)-(dobdc)center dot 0.5(H2O) (UTSA-74, H4dobdc = 2,5-dioxido-1,4-benzenedicarboxylic acid), Zn-MOF-74/CPO-27-Zn isomer, has been synthesized and structurally characterized. It has a novel four coordinated fgl topology with one-dimensional channels of about 8.0 A. Unlike metal sites in the well established MOF-74 with a rod-packing structure in which each of them is in a five coordinate square pyramidal coordination geometry, there are two different Zn2+ sites within the binuclear secondary building units in UTSA-74 in which one of them (Znl) is in a tetrahedral while another (Zn2) in an octahedral coordination geometry. After activation, the two axial water molecules on Zn2 sites can be removed, generating UTSA-74a with two accessible gas binding sites per Zn2 ion. Accordingly, UTSA-74a takes up a moderately high and comparable amount of acetylene (145 cm(3)/cm(3)) to Zn-MOF-74. Interestingly, the accessible Zn2+ sites in UTSA-74a are bridged by carbon dioxide molecules instead of being terminally bound in Zn-MOF-74, so UTSA-74a adsorbs a much smaller amount of carbon dioxide (90 cm3/cm3) than Zn-MOF-74 (146 cm3/cm3) at room temperature and 1 bar,, leading to a superior MOF material for highly selective C2H2/CO2 separation. X-ray crystal structures, gas sorption isotherms, molecular modeling, and simulated and experimental breakthroughs comprehensively support this result.