Metal-Organic Frameworks with Internal Urea-Functionalized Dicarboxylate Linkers for SO2 and NH3 Adsorption
Metal-Organic Frameworks with Internal Urea-Functionalized Dicarboxylate Linkers for SO2 and NH3 Adsorption
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DOI：
10.1021/acsami.7b10884
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发表时间：
2017-10-25
影响因子：
9.5
通讯作者：
Janiak, Christoph
中科院分区：
文献类型：
--
作者：
Glomb, Sebastian;Woschko, Dennis;Janiak, Christoph
在4，4 '-联苯二羧酸的中心引入脲RNHCONHR基团作为七元二氮杂环，得到脲官能化的二羧酸酯连接基（L12），由此可以获得四种锌金属有机框架（MOF），具有{Zn-4（mu（4）-O）（O2 C-）（6）} SBU和IRMOF-9拓扑结构（化合物[Zn-4（μ 4-O）（L1）（3）]，1，来自二甲基甲酰胺，DMF）或二维网络中的{Zn-2（O2 C-）（4）}桨轮SBU（化合物[Zn-2（L1）（2）（DEF）2中心点2.5DEF]，2，来自二乙基甲酰胺，DEF）。用4，4 '-联吡啶（bipy）或1，2-双（4-吡啶基）乙烷（bpe）柱撑2的二维网络得到具有菱形畸变pcu-a拓扑结构的三维骨架（分别为[Zn-2（L1）（2）（bipy）]，3和[Zn-2（L1）（2）（bpe）]，4）。3D-框架1、3和4是2倍互穿的，具有类似于50%的溶剂可及体积，尽管具有明显的动态多孔特性，使得在77 K下不发生N-2吸附，而在77 K下的H-2（高达类似于1重量%）和在293 K下的CO2（类似于5重量%）在这些柔性MOF中被大的双氢树脂吸附。脲官能化的MOF 3在293 K、1巴下表现出10.9 mmol g（-1）（41重量%）的SO2吸收，这似乎是迄今为止观察到的最高值。化合物3和4分别吸附14.3mmol g（-1）（20wt%）和17.8mmol g（-1）（23wt%）NH3，这在所报道的值的顶部。这些高吸收值可追溯到尿素功能及其与吸附剂的氢键相互作用。气体吸收能力遵循的框架，结合从吸附等温线拟合的孔径大小和亲和常数的特定孔隙率。
Introduction of a urea RNHCONHR group as a seven-membered diazepine ring at the center of 4,4 '-biphenyl-dicarboxylic acid leads to a urea-functionalized dicarboxylate linker (L12) from which four zinc metalorganic frameworks (MOFs) could be obtained, having a {Zn-4(mu(4)-O)(O2C-)(6)} SBU and IRMOF-9 topology (compound [Zn-4(mu 4-O)(L1)(3)], 1, from dimethylformamide, DMF) or a {Zn-2(O2C-)(4)} paddle-wheel SBU in a 2D-network (compound [Zn-2(L1)(2)(DEF)2 center dot 2.5DEF], 2, from diethylformamide, DEF). Pillaring of the 2D-network of 2 with 4,4 '-bipyridine (bipy) or 1,2-bis(4-pyridyl)ethane (bpe) gives 3D frameworks with rhombohedrally distorted pcu-a topologies ([Zn-2(L1)(2)(bipy)], 3 and [Zn-2(L1)(2)(bpe)], 4, respectively). The 3D-frameworks 1, 3, and 4 are 2-fold interpenetrated with similar to 50% solvent-accessible volume, albeit of apparently dynamic porous character, such that N-2 adsorption at 77 K does not occur, while H-2 at 77 K (up to similar to 1 wt %) and CO2 at 293 K (similar to 5 wt %) are adsorbed with large hystereses in these flexible MOFs. The urea-functionalized MOF 3 exhibits an uptake of 10.9 mmol g(-1) (41 wt %) of SO2 at 293 K, 1 bar, which appears to be the highest value observed so far. Compounds 3 and 4 adsorb 14.3 mmol g(-1) (20 wt %) and 17.8 mmol g(-1) (23 wt %) NH3, respectively, which is at the top of the reported values. These high uptake values are traced to the urea functionality and its hydrogen-bonding interactions to the adsorbents. The gas uptake capacities follow the specific porosity of the frameworks, in combination with pore aperture size and affinity constants from fits of the adsorption isotherms.