Application of NMR spectroscopy for the investigation of structure-mobility relations in nanoporous host-guest systems in concerted action with IR Micro-Imaging

在项目KA 953/20- 1，2的过程中，重点关注基于仪器和系统的工作，为新的显微成像方法（用红外和干涉显微镜测量瞬态浓度分布）奠定了基础。它们为探索纳米多孔主客体体系的分子动力学提供了一种新的途径。具有脉冲场梯度的NMR扩散法（PFG NMR）构成另一种显微方法，其以双重方式互补。首先，它是在平衡条件下应用的，其次，在温度和压力的变化（从而客体负载）中，可以覆盖更宽的范围（此外，这种变化是用更少的实验努力实现的）。PFG NMR和显微成像的协同应用所提供的潜力将有目的地用于本项目，以加深我们对纳米多孔材料分子动力学的了解。该提案与C的申请同时提交。Chmelik在“用于探索纳米多孔材料中的扩散和反应的显微成像”上。只有通过协调使用这两种技术，才能成功地解决所提出的问题。除了在特定领域使用PFG NMR的技术和仪器开发外，（包括温度、压力和观测时间在当前极限以上的变化），工作将围绕以下三个主题展开：（一）自扩散的综合测量（PFG NMR，本项目）和运输扩散（显微成像）为平衡和非平衡条件下运输现象的相互关系的调查建立了前所未有的选择。这是当前空间约束下介观分子系统研究的基本问题之一，也是第一个课题研究的重点。(ii)第二，我们将研究和利用PFG NMR的选择来研究主客体相互作用对主体结构和客体动力学的影响。这特别包括在宽范围内的温度变化的选项，其中预期特性的剧烈变化。为了理解这些过程，甚至可能仅仅是为了检测这些过程，一个特别大的变化是必不可少的。(iii)虽然在第二个主题中考虑的主-客体相互作用被发现引起一种全新类型的滞后现象，但在介孔材料中的吸附滞后是已知的，因为超过100年。然而，这种现象的起源和内在机制决定其时间依赖性仍然是一个有争议的讨论话题。通过PFG NMR和显微成像对这些系统的内在动力学的联合应用所获得的信息，我们希望在我们研究计划的第三个主题中，提供迄今为止无法获得的实验证据。

With the focus on instrument-based and methodical work, in the course of the project KA 953/20-1,2, the background was set for new micro-imaging methods (measurement of transient concentration profiles with IR and interference microscopy). They provide a new approach to the exploration of molecular dynamics in nanoporous host-guest systems. NMR diffusometry with pulsed field gradients (PFG NMR) constitutes another microscopic method, which is complementary in a double fashion. First, it is applied under equilibrium conditions and, second, in the variation of temperature and pressure (and thereby of the guest loading) a much wider range can be covered (moreover, the variation is achieved with much less experimental effort). The potential offered by the concerted application of PFG NMR and Micro-Imaging shall be purposefully employed in this project to deepen our knowledge on molecular dynamics in nanoporous materials. The proposal is submitted in parallel with the application of C. Chmelik on "Micro-Imaging for the exploration of diffusion and reaction in nanoporous materials". A successful approach of the posed questions will be achieved only by the concerted use of both techniques. Besides technical and instrument-based developments for the use of PFG NMR in the particular fields (including the variation of temperature, pressure and observation time above the current limits), the work will be centered on the following three topics: (i) The combined measurement of self-diffusion (PFG NMR, this project) and transport diffusion (Micro-Imaging) establishes unprecedented options for the investigation of the interrelation of transport phenomena under equilibrium and non-equilibrium conditions. This is one of the fundamental questions of current research in the investigation of mesoscopic molecular systems under spatial confinement, which shall be in the focus of the studies within the first topic. (ii) We are, second, going to examine and to exploit the options of PFG NMR to study the impact of host-guest interactions on host structure and guest dynamics. This includes, in particular, the option of temperature variation over a wide range, in which drastic changes in the characteristics are expected. For the understanding of these processes and, possibly, even for their mere detection, a particular wide variation is essential. (iii) While the host-guest interactions considered in the second topic was found to give rise to a completely new type of hysteresis phenomena sorption hysteresis in mesoporous materials is known since over 100 years. However, the origin of this phenomenon and the intrinsic mechanisms determining its time dependence are still a topic of controversial discussion. With the information obtained by the combined application of PFG NMR and Micro-Imaging on the intrinsic dynamics of such systems we hope to contribute, within a third topic of our research plan, with so far inaccessible experimental evidence.