Guo Zhen-Ji, Yu Jiamei, Zhang Yong-Zheng, Zhang Jian, Chen Ya, Wu Yufeng, Xie Lin-Hua, Li Jian-Rong
Institute of Circular Economy, Beijing University of Technology , Beijing 100124, P. R. China.
Beijing Key Laboratory for Green Catalysis and Separation and Department of Chemistry and Chemical Engineering, College of Environmental and Energy Engineering, Beijing University of Technology , Beijing 100124, P. R. China.
Inorg Chem. 2017 Feb 20;56(4):2188-2197. doi: 10.1021/acs.inorgchem.6b02840. Epub 2017 Feb 6.
Three new water-stable In(III)-based metal-organic frameworks, namely, [In(TTTA)(OH)(HO)]·(DMA) (BUT-70, DMA = N,N-dimethylacetamide), [In(TTTA)(CHO)] (BUT-70A), and [In(TTTA)(OH)] (BUT-70B), with rod-shaped secondary building units (SBUs) and an new acrylate-based ligand, (2E,2'E,2″E)-3,3',3″-(2,4,6-trimethylbenzene-1,3,5-triyl)-triacrylate (TTTA) were obtained and structurally characterized. BUT-70A and -70B were generated in a single-crystal to single-crystal transformation fashion from BUT-70 through guest exchange followed by their removal. The solvents used for guest exchange were methanol and dichloromethane, respectively. Single-crystal structure analyses show that the guest exchange and removal process is accompanied by the substitution of coordinated water molecules of In(III) centers with uncoordinated carboxylate O atoms of TTTA ligands. Moreover, hydroxyl groups bridging two In(III) centers are also replaced by methoxyl groups in the transformation from BUT-70 to -70A. Overall, three metal-organic frameworks (MOFs) are constructed by infinite chains consisting of corner-sharing InO(OR) (R = H or Me) octahedral entities, which are interconnected by TTTA ligands to form three-dimensional frameworks. Unlike most reported MOFs with infinite chains as SBUs, such as well-known MIL-53 and M-MOF-74, which have one-dimensional channels along the chain direction, the BUT-70 series contain two-dimensional intersecting channels. The Brunauer-Emmett-Teller surface area and pore volume of BUT-70A were estimated to be 460 m g and 0.18 cm g, respectively, which are obviously lower than those of BUT-70B (695 m g and 0.29 cm g). Gas adsorption experiments demonstrated that BUT-70A and -70B are able to selectively adsorb CH over CO and CH. At 1 atm and 298 K, BUT-70A uptakes 3.1 mmol g CH, which is 3.6 times that of the CO uptake and 7.2 times that of the CH uptake. Compared with BUT-70A, BUT-70B presents an even higher CH uptake of 3.9 mmol g at the same conditions, but slightly lower Ideal Adsorbed Solution Theory CH/CO and CH/CH selectivities.
合成了三种新型水稳定的基于铟（III）的金属有机框架材料，即[In(TTTA)(OH)(HO)]·(DMA) （BUT - 70，DMA = N,N - 二甲基乙酰胺）、[In(TTTA)(CHO)] （BUT - 70A）和[In(TTTA)(OH)] （BUT - 70B），它们具有棒状二级构筑单元（SBUs）以及一种新型丙烯酸酯基配体(2E,2'E,2″E)-3,3',3″-(2,4,6 - 三甲基苯 - 1,3,5 - 三基)-三丙烯酸酯（TTTA），并对其进行了结构表征。BUT - 70A和 - 70B是通过客体交换然后去除客体，以单晶到单晶转变的方式从BUT - 70生成的。用于客体交换的溶剂分别是甲醇和二氯甲烷。单晶结构分析表明，客体交换和去除过程伴随着TTTA配体未配位的羧酸根O原子取代In(III)中心的配位水分子。此外，在从BUT - 70到 - 70A的转变中，连接两个In(III)中心的羟基也被甲氧基取代。总体而言，三种金属有机框架（MOF）由由共角InO(OR)（R = H或Me）八面体实体组成的无限链构建而成，这些实体通过TTTA配体相互连接形成三维框架。与大多数报道的以无限链作为SBUs的MOF不同，例如著名的MIL - 53和M - MOF - 74，它们沿链方向具有一维通道，BUT - 70系列包含二维交叉通道。BUT - 70A的布鲁诺尔 - 埃米特 - 泰勒表面积和孔体积分别估计为460 m²/g和0.18 cm³/g，明显低于BUT - 70B（695 m²/g和0.29 cm³/g）。气体吸附实验表明，BUT - 70A和 - 70B能够选择性地吸附CH₄而非CO和CH₂。在1 atm和298 K下，BUT - 70A吸附3.1 mmol/g CH₄，是CO吸附量的3.6倍，CH₂吸附量的7.2倍。与BUT - 70A相比，BUT - 70B在相同条件下对CH₄的吸附量更高，为3.9 mmol/g，但理想吸附溶液理论CH₄/CO和CH₄/CH₂选择性略低。
