500 MHz Solid State NMR Spectrometer

500 MHz 固态核磁共振波谱仪

• 批准号: 524658450
• 金额: --
• 依托单位: Universität Stuttgart
• 依托单位国家: 德国
• 项目类别: Major Research Instrumentation
• 财政年份: 2023
• 资助国家: 德国
• 起止时间: 2022-12-31 至 无数据
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/524658450?language=en
• 关键词: 500; MHz; Solid; State; NMR

Characterization of organometallic and organocatalysts immobilized on surfaces is extremely challenging, owing in part to the complexity of the surfaces on which the catalysts are immobilized and in part to complications in the measurement techniques, which often require more advanced equipment than for solution-based samples. Solid-state NMR is one of the most important techniques for characterizing immobilized catalysts on solid surfaces, because it allows us to determine the chemical state of individual active sites, compared to the solution phase data of the model complexes, and also obtain more information about the structures and conformations of species on solid surfaces not available by traditional liquid state NMR. In particular, solid state NMR spectroscopy allows us to take advantage of intermolecular dipolar coupling, which in liquid state NMR is averaged out by molecular tumbling. Such dipolar coupling can be measured both qualitatively by correlation spectroscopies such as HETCOR, spin diffusion, and TRAPDOR experiments and quantitatively (to get interatomic distances) via methods such as REDOR, SEDOR, and POSTC7 spectroscopies. In the CRC 1333 at the University of Stuttgart, 24 principal investigators are collaborating on 19 research topics concerning the effects of confining immobilized organometallic and organocatalysts inside mesoporous supports. Confinement in the constrained geometries affects both the activity and selectivity of the catalytic reactions by forcing the active sites into new and more active/selective conformations not accessible outside of the mesopore environment. In order to fully understand these effects, high-quality solid-state NMR characterization of the active sites is essential. It is necessary to use 2D (and 1D) correlation spectroscopies to understand the secondary structures of the active sites in the pores. Specifically, we propose to use correlation methods to understand a) changes in conformational geometry, b) association of active sites with the pore wall, and c) close association of nearby active sites with each other. Such measurements are not possible with our current NMR capabilities at the University of Stuttgart. In this project, we propose the acquisition of a new four channel 500 MHz solid-state NMR spectrometer optimized for 2D correlation spectroscopies. With this spectrometer it will be possible to understand the secondary structures that form inside the pores and affect the catalytic activity and selectivity of our confined heterogenized active sites. Without such a spectrometer, we will never be fully able to understand why confinement affects the catalytic reactions studied in the CRC 1333.

固定在表面上的有机金属和有机催化剂的表征非常具有挑战性，部分原因是催化剂被固定的表面的复杂性，部分原因是测量技术中的并发症，通常需要比溶液基于溶液的样品更先进的表面。固态NMR是表征固体表面上固定化催化剂的最重要技术之一，因为它使我们能够确定单个活动位点的化学状态，与模型复合物的溶液相数据相比，还可以获得有关更多信息，并获得有关更多信息，并获得了有关更多信息。传统液态NMR无法获得的固体表面上物种的结构和构象。特别是，固态NMR光谱使我们能够利用分子间偶极耦合，在液态中，NMR通过分子滚动将其平均。可以通过相关光谱（例如HETCOR，自旋扩散和诱捕者实验）进行定性测量这种偶极耦合，并通过重新，沉积物和后C7光谱镜等方法进行定量（以获得原子间距离）。在Stuttgart大学的CRC 1333中，24名主要研究人员正在合作就介入中心支持内部限制固定的有机金属和有机催化剂的影响的19个研究主题。约束几何形状中的限制通过将活性位点迫使活性位点进入新的，更有效/选择性的构象，从而影响催化反应的活性和选择性。为了充分理解这些效果，活动位点的高质量固态NMR表征至关重要。有必要使用2D（和1D）相关光谱学了解孔中有源位点的二级结构。具体而言，我们建议使用相关方法理解a）构象几何的变化，b）活动位点与孔隙壁的关联，c）彼此之间附近的活性位点的密切关联。我们目前在斯图加特大学的NMR功能无法进行此类测量。在这个项目中，我们提出了针对2D相关光谱优化的新四个通道500 MHz固态NMR光谱仪的采集。使用该光谱仪，可以理解孔内形成的二级结构并影响我们密闭异质化活性位点的催化活性和选择性。没有这样的光谱仪，我们将永远无法完全理解为什么限制会影响CRC 1333中研究的催化反应。