A Series of Isoreticular, Highly Stable, Porous Zirconium Oxide Based Metal-Organic Frameworks
A Series of Isoreticular, Highly Stable, Porous Zirconium Oxide Based Metal-Organic Frameworks
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DOI：
10.1002/anie.201204806
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发表时间：
2012-01-01
影响因子：
16.6
通讯作者：
Serre, Christian
中科院分区：
文献类型：
--
作者：
Guillerm, V.;Ragon, F.;Serre, Christian
金属-有机框架（mof）是一种混合多孔固体，近年来在气体分离/储存、催化、传感器、包裹体和药物输送等潜在应用领域引起了人们的极大兴趣。[1-5]然而，这类材料的化学和机械稳定性仍然令人担忧。大多数mof的水热稳定性差，显然限制了它们在实际分离过程中的应用具有更高稳定性的mof也需要用于液相催化应用，例如从水裂解中产生氢气Willis等人进行了一项系统的研究，表明对于给定的连接剂，增加金属的电荷通常会导致所得到的MOF的水热稳定性增强。[6a]迄今为止，基于聚羧酸盐和四价金属的多孔mof仍然很少，只有少数这种固体可以被氮分子接触到。[8-10]其中，对苯二甲酸钛（IV） MIL-125 （MIL代表拉瓦锡研究所的材料）[10]和对苯二甲酸锆UiO-66 (Zr)（UiO代表奥斯陆大学）[9]都具有三维微孔立方孔系统，由于其相对较高的稳定性和较大的可达孔体积而引起人们的兴趣。例如，UiO-66 （Zr）在空气中高达4508C时是稳定的，并且通过在脱羟基和羟化版本之间可逆切换，在水吸附/脱吸循环中保持不变[9,11]，并且在机械刺激下具有优异的稳定性近年来，利用功能化或扩展的二羧酸盐连接剂获得了一系列UiO结构的衍生物其他人报道了使用抑制剂来控制这些uio的结晶过程，而我们中的一些人已经确定，通过使用预定义的氧簇作为二级构建单元（SBU），可以在低温下制备UiO-66 （Zr）类似物这些最新的结果表明，四价金属基羧酸mof的化学性质是“可接近的”，尽管合成条件和结构确定是与极性溶剂中M4+离子的高反应性有关的挑战。本文报道了以ZrCl4与1,4 - h2bdc（1,4 -苯二羧酸）、2,6 - h2ndc（2,6 -萘二羧酸）、4,4 ' -H2BPDC（4,4 ' -联苯二羧酸）和H2Cl2 ABDC（3,3 ' -二氯- 4,4 ' -偶氮苯二羧酸）反应为溶剂热法制备新型多孔二羧酸锆mof。本文分离并表征了一系列新的多孔二羧酸锆固体MIL-140A ~ MIL-140D，通式为[ZrO (O2CR-CO2)](R= C6H4（MIL-140A）、C10H6 (B)、C12H8 (C)、C12N2H6Cl2 (D))，并将其性能与多晶型UiO-66及其上部类似物（即具有相同结构类型但具有较长有机间隔的固体）进行了比较。利用x射线粉末衍射（XRPD）数据或基于密度泛函理论（DFT）几何优化的计算辅助策略来求解晶体结构。MIL-140固体在空间群（SG） C2/c (No. 15)（MIL-140A和c）或Cc (No. 9)（MIL-140B和D；支持信息，表S3）中结晶。这些固体都具有相同的c参数（ca. 7.8），与复合氧化锆链的无机亚基一致，沿着c轴取向（图1），通过二羧酸盐连接剂连接到其他六个链。这将沿着c轴划定三角形通道。锆原子呈现出3个μ3-O氧原子和4个μ3-O氧原子的7配位模式。
Metal–organic frameworks (MOFs) are hybrid porous solids that have recently attracted great interest for potential applications including gas separation/storage, catalysis, sensors, inclusion, and drug delivery.[1–5] However, there are still concerns about the chemical and mechanical stabilities of this class of materials. The poor hydrothermal stability of most MOFs is clearly a limitation for their use in real separation processes.[6] MOFs with enhanced stability are also required for liquid-phase catalysis applications, such as the production of hydrogen from water splitting.[7] Willis et al. have performed a systematic study showing that for a given linker, increasing the charge of the metal usually leads to an enhancement of the hydrothermal stability of the resulting MOF.[6a] To date, porous MOFs based on polycarboxylate and tetravalent metals are still scarce with only a few such solids being accessible to nitrogen molecules.[8–10] Among them, the titanium (IV) terephthalate MIL-125 (MIL stands for Materials from Institut Lavoisier)[10] and the zirconium terephthalate UiO-66 (Zr)(UiO for University of Oslo),[9] which both have a 3D microporous cubic pore system, are of interest because of their relatively high stability combined with large accessible pore volumes. For instance, UiO-66 (Zr) is stable up to 4508C under air and remains unaltered upon water adsorption/desorption cycles by switching reversibly between dehydroxylated and hydroxylated versions,[9, 11] and has an exceptional stability under mechanical stimulus.[9] Recently, a series of derivatives of the UiO structure has been obtained using either functionalized or extended dicarboxylate linkers.[12] Others have reported the use of inhibitors to control the crystallization process of these UiOs [13] while some of us have established that by using pre-defined oxo clusters as secondary building units (SBU), UiO-66 (Zr) analogues can be prepared at low temperature.[14] These recent results show that the chemistry of tetravalent-metal-based carboxylate MOFs is “accessible”, although the synthesis conditions and the structure determination are challenges related to the very high reactivity of M4+ ions in the presence of polar solvents. We report herein the solvothermal synthesis of new porous zirconium dicarboxylate MOFs based on the reactions of ZrCl4 with 1, 4-H2BDC (1, 4-benzenedicarboxylic acid), 2, 6-H2NDC (2, 6-naphthalenedicarboxylic acid), 4, 4’-H2BPDC (4, 4’-biphenyldicarboxylic acid), and H2Cl2 ABDC (3, 3’-dichloro-4, 4’-azobenzenedicarboxylic acid). A whole new series of porous zirconium dicarboxylate solids, denoted MIL-140A to MIL-140D, with a general formula [ZrO (O2CR-CO2)](R= C6H4(MIL-140A), C10H6 (B), C12H8 (C), C12N2H6Cl2 (D)) has been isolated and characterized, and their properties compared with those of the polymorphs UiO-66 and its upper analogues (that is, solids of the same structure type but with longer organic spacers). The crystal structures have been either solved using X-ray powder diffraction (XRPD) data or through a computational assisted strategy based on density functional theory (DFT) geometry optimizations. The MIL-140 solids crystallize in the space group (SG) C2/c (No. 15)(MIL-140A and C) or Cc (No. 9)(MIL-140B and D; Supporting Information, Table S3). These solids all have the same c parameter (ca. 7.8), consistent with the inorganic subunit of complex zirconium oxide chains, oriented along the c axis (Figure 1), connected to six other chains through the dicarboxylate linkers. This delimits triangular channels along the c axis. The zirconium atoms exhibit a seven coordination mode with three μ3-O oxygen atoms and four oxygen atoms from …