Exploitation of flexibility, responsivity and chemical selectivity in switchable pillared layer MOFs for specific gas adsorption and separation – a first-principles approach

利用可切换柱状层 MOF 的灵活性、响应性和化学选择性进行特定气体吸附和分离——第一原理方法

• 批准号: 323221727
• 负责人: Professor Dr. Thomas Heine
• 金额: --
• 依托单位: Professur für Theoretische Chemie
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/323221727?language=en
• 关键词: Exploitation; flexibility; responsivity; chemical; selectivity

Switchable pillared layer metal-organic frameworks offer high selectivity towards adsorbed gas species. This selectivity can even be enhanced if in addition the flexibility, which is offered by DUT-8, is exploited, as demonstrated for the example of CH4 vs. CO2 adsorption by Kaskel and Brunner (S2, P1). Here, we will explore how flexibility and selectivity can be synergistically combined. The potential to tailor linkers, pillars and metal centers offers a rich diversity of materials that can undergo both significant structural changes, resulting in different pore volumes, and subtle rearrangements of the constituent building blocks, which can enable particular geometries with specific interactions towards target molecules. The interplay between flexibility and linker functionality is still rather unexplored to date. Four key questions will be tackled by T1: First, we aim to understand the role of the adsorbate (QP4) and of the long-range ordering (QP3) on the flexibility of DUT-8(M), M=Ni, Cu, Co, Zn. This will be carried out in close collaboration with S2, where structural data will be obtained, and with T2, supporting T1 with force field calculations of large super cells. Here, we will also develop a numerical model that allows to estimate the flexibility of DUT-8 depending on the thermodynamic conditions and the type of adsorbate gas species (QP1). Second, we will investigate the responsivity of DUT-8(M) towards binary gas mixtures (QP4, QF1), in particular for gases imposing significant differences in responsivity of the MOF. Third, in order to guide synthesis in S2, we will investigate if and how building block variation, including functionalization, will affect the flexibility of DUT-8 and expanded DUT-128 derivatives (QP1, QF1). Finally, we will elucidate the specific structure of adsorbed molecules with specific groups and understand their interaction with the framework (QF2). In collaboration with P1, NMR spectroscopy of various nuclei will guide us to understand the specific adsorbate-MOF interactions. For the lattice geometry, we will support P2, which uses EPR techniques to follow the hinge dynamics of the MOFs either by spin probes in the mixed metal paddle-wheels of the framework or by adsorbed spin-carrying probe molecules in the pore (QP2).

可切换的柱撑层金属有机框架提供对吸附的气体物种的高选择性。如果另外利用DUT-8提供的灵活性，甚至可以增强这种选择性，如Kaskel和Brunner（S2，P1）对CH 4与CO2吸附的示例所示。在这里，我们将探讨如何灵活性和选择性可以协同结合。定制连接体、柱和金属中心的潜力提供了丰富多样的材料，这些材料可以经历显著的结构变化，导致不同的孔体积，以及组成构件的细微重排，这可以实现具有与靶分子的特定相互作用的特定几何形状。灵活性和连接器功能之间的相互作用迄今为止仍然是相当未开发的。T1将解决四个关键问题：首先，我们的目标是了解吸附质（QP 4）和长程有序（QP 3）对DUT-8（M）（M=Ni，Cu，Co，Zn）柔性的作用。这将与S2密切合作，获得结构数据，并与T2合作，通过大型超级细胞的力场计算支持T1。在这里，我们还将开发一个数值模型，允许估计DUT-8的灵活性取决于热力学条件和吸附物气体种类（QP 1）的类型。其次，我们将研究DUT-8（M）对二元气体混合物（QP 4，QF 1）的响应度，特别是对MOF响应度有显著差异的气体。第三，为了指导S2中的合成，我们将研究构建块变化（包括官能化）是否以及如何影响DUT-8和扩展DUT-128衍生物（QP 1，QF 1）的灵活性。最后，我们将阐明具有特定基团的吸附分子的特定结构，并了解它们与框架（QF 2）的相互作用。与P1合作，各种核的NMR光谱将指导我们了解特定的吸附物-MOF相互作用。对于晶格几何形状，我们将支持P2，它使用EPR技术通过框架的混合金属桨轮中的自旋探针或通过孔中吸附的自旋携带探针分子（QP 2）来跟踪MOF的铰链动力学。