Insights from Nuclear Magnetic Resonance into Bonding Interactions in Solids

核磁共振(核磁共振)光谱学是研究各种形式物质的首选非破坏性分析方法。我们的研究计划集中在核磁共振波谱方法的开发和应用上，重点是提供对固体中结构和成键的见解。我们还应用计算化学来补充我们的实验结果。 我们的目标是在几个广受关注的领域做出新颖的创新贡献。需要解决的三个具体方向是： (I)用核磁共振参数统一描述非共价相互作用。我们将系统地探索广泛的非共价相互作用，目的是提供对成键环境和强度之间的关系以及观察到的核磁共振参数之间的统一理解。例如，在理解SN2亲核取代反应的背景下，最近强调了Tetrel键，其中碳等14族元素充当亲电体。我们将通过多核固体磁共振光谱制备和表征元素周期表中元素之间形成的非共价键中涉及的亲电性和亲核性。这项工作将为非共价键提供非常独特的实验见解，非共价键是材料、超分子化学和生物分子中结构、成键和反应的关键。 (Ii)通过核磁共振光谱学对金属-金属结合的新见解。我们将开发和应用多核和多维核磁共振方法来直接探测固体中金属-金属键的相互作用。长期以来，这一直是一个艰巨的挑战，因为许多感兴趣的金属同位素具有很强的四极性质。这项工作将为金属-金属键的性质提供新的见解，并将解决金属-有机骨架(MOF)中的金属-金属相互作用，这对催化和石化工业具有重要意义。这项工作具有很强的潜力，可以灵敏而独特地探测MOF中的对称性和吸附，并在不同学科中得到不同的应用。 (Iii)最后一个新颖的研究方向包括开发和应用仲氢流动系统来超极化固体中的低感受性核。这项高风险的工作有望将我们对成键相互作用的研究提升到一个新的水平，使其适用于对诸如表面或非均相催化剂上发现的那些“真实”样品的低成本研究。

Nuclear magnetic resonance (NMR) spectroscopy is the premier non-destructive analytical method for studying all forms of matter. Our research program is focussed on the development and application of NMR spectroscopic methods with an emphasis on providing insights into structure and bonding in solids. We also apply computational chemistry to complement our experimental results. We aim to make novel innovative contributions to several areas of broad interest. Three specific directions to be addressed are: (i) A unified description of non-covalent interactions in terms of NMR parameters. We will systematically explore a broad range of non-covalent interactions with the goal of providing a unified understanding of the relationship between the bonding environment and strength, and the observed NMR parameters. For example, the tetrel bond, in which group 14 elements such as carbon act as electrophiles, has recently been highlighted in the context of understanding the SN2 nucleophilic substitution reaction. We will prepare and characterize via multinuclear solid-state magnetic resonance spectroscopy the electrophiles and nucleophiles involved in non-covalent bonds formed between elements from across the periodic table. This work will provide highly unique experimental insights into non-covalent bonds which are key to structure, bonding, and reactivity in materials, supramolecular chemistry, and biomolecules. (ii) New insights into metal-metal bonding via NMR spectroscopy. We will develop and apply multinuclear and multidimensional NMR methods to directly probe metal-metal bonding interactions in solids. This has long represented a daunting challenge because of the strong quadrupolar nature of many metal isotopes of interest. This work will provide novel insight into the nature of metal-metal bonding and will also address metal-metal interactions in metal-organic frameworks (MOFs) of importance to catalysis and the petrochemical industry. This work has strong potential to lead to a sensitive and unique probe of symmetry and adsorption in MOFs, with diverse applications across disciplines. (iii) A final novel research direction consists of the development and application of a parahydrogen flow system to hyperpolarize low-receptivity nuclei in solids. This high-risk work promises to take our studies of bonding interactions to the next level, rendering them applicable to the low-cost study of ‘real’ samples such as those found on surfaces or in heterogeneous catalysts.