A comparison of the H2 sorption capacities of isostructural metal-organic frameworks with and without accessible metal sites:: [{Zn2(abtc)(dMf)2}3] and [{Cu2(abtc)(dMf)2}3] versus [{Cu2(abtc)}3]
A comparison of the H2 sorption capacities of isostructural metal-organic frameworks with and without accessible metal sites:: [{Zn2(abtc)(dMf)2}3] and [{Cu2(abtc)(dMf)2}3] versus [{Cu2(abtc)}3]
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DOI：
10.1002/anie.200801488
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发表时间：
2008-01-01
影响因子：
16.6
通讯作者：
Suh, Myunghyun Paik
中科院分区：
文献类型：
--
作者：
Lee, Yong-Gon;Moon, Hoi Ri;Suh, Myunghyun Paik
各种金属有机框架（mof）已经被制备出来，以获得具有特定或多功能性质的材料。含有可容纳客体分子的自由空间的多孔mof特别令人感兴趣，因为它们可以应用于气体储存[1 - 4]和分离，[4-6]有机分子的选择性吸附和分离，[1,7]离子交换，[8]催化，[9]传感器技术，[1,10]以及金属纳米颗粒的制造具有特定几何形状的二次构建单元（Secondary building units, SBUs）通常被用于多孔mof的模块化构建，因为它们使分子结构的设计和预测变得简单和容易。特别是，M2+离子与合适的羧酸溶剂热反应形成的{M2-(CO2) 4}型桨轮簇被广泛用于多孔框架的构建。具有不同拓扑结构的三维多孔框架（Pt3O4、硼砂、NbO和PtS网）可以由桨轮型金属簇SBUs和三或四羧酸盐构建，[13-16]而柱状方形网格网络可以由桨轮簇SBUs和二羧酸盐在二胺配体存在下构建具有可达金属位（ams）的多孔mof应该比没有ams的mof具有更高的储氢能力[14,18]，尽管目前还没有足够的实验数据支持这一假设。为了确定AMSs对MOF中H2吸附的影响，应该比较相同框架中不存在和不存在AMSs的H2吸收量，或者两个独立的同构MOF中有和没有AMSs的H2吸收量。H2的吸收以前已经在几种不同的放气条件下进行了测量不幸的是，这些实验并不能清楚地证明ams的作用，因为每个阶段的确切公式和结构都不清楚。此外，即使在保留多孔框架结构的情况下成功地去除配位溶剂分子，金属离子有时也会将其配位几何形状转变为热力学上最稳定的形式，而不是保持结构
Various metal–organic frameworks (MOFs) have been prepared to obtain materials that show specific or multifunctional properties. Porous MOFs that contain free space where guest molecules can be accommodated are of particular interest because they can be applied in gas storage [1–4] and separation,[4–6] selective adsorption and separation of organic molecules,[1, 7] ion exchange,[8] catalysis,[9] sensor technology,[1, 10] and for the fabrication of metal nanoparticles.[11] Secondary building units (SBUs) with a specific geometry have often been employed [12] for the modular construction of porous MOFs as they make the design and prediction of molecular architectures simple and easy. In particular,{M2-(CO2) 4}-type paddlewheel clusters that can be formed from the solvothermal reaction of M2+ ions and the appropriate carboxylic acid are widely used for the construction of porous frameworks. Three-dimensional porous frameworks with various topologies (Pt3O4, boracites, NbO, and PtS nets) can be built from paddlewheel-type metal cluster SBUs and tri-or tetracarboxylates,[13–16] whereas pillared square-grid networks can be constructed from paddlewheel cluster SBUs and dicarboxylates in the presence of diamine ligands.[17] Porous MOFs with accessible metal sites (AMSs) should have a higher hydrogen storage capacity than those without AMSs,[14, 18] although there are not yet enough experimental data to support this assumption. To determine the effect of AMSs in a MOF on H2 adsorption, the H2 uptakes should be compared for the same framework in the absence and presence of AMSs, or for two independent isostructural MOFs with and without AMSs. H2 uptake has previously been measured under several different outgassing conditions.[13] Unfortunately, these experiments could not clearly demonstrate the effect of AMSs as the exact formula and structure at each stage were not known. Furthermore, even when coordinating solvent molecules are successfully removed with retention of the porous framework structure, the metal ion sometimes transforms its coordination geometry to the thermodynamically most stable form instead of keeping the