Magnetic Resonance Studies of Molecular Structure and Dynamics

核磁共振波谱（NMR）和磁共振成像（MRI）是密切相关的技术，它们通过检测核“条形磁铁”在强磁场存在下对射频波的响应来揭示分子的结构和组成。该研究将利用现代核磁共振和核磁共振技术，为结构化学、材料科学和植物科学中的重要问题提供见解。我们的研究和研究生培训方法包括基础方面和更多的应用方面。本提案中概述的基础研究的目标是更好地理解在核磁共振实验中测量的参数与分子结构之间的关系。我们将利用固体材料的核磁共振研究为人们提供了表征所观察到的磁屏蔽的取向依赖性的机会，而不仅仅是它们的平均值。例如，固态（SS） H-1 NMR将用于更好地表征在催化无机和有机金属化学中起核心作用的过渡金属氢化物和二氢配合物的氢磁屏蔽。应用范围从利用SS核磁共振研究森林地表样品中存在的分子及其与森林健康的关系，到建立富集对氢的装置，从而利用超极化核磁共振研究重要有机金属反应的机理。我们将继续利用位于渥太华的国家固体超高场核磁共振设施，探索核磁共振在研究“困难”的四极核方面的潜力，这些核由于接受性差而很少被探索（例如，具有挑战性的同位素，如与生物相关的as -75和在有机金属化学中非常重要的Ir-193）。我们将继续探索微核磁共振成像的应用，这在研究和学生培训中已经被证明是重要的。

Nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) are closely related techniques which reveal molecular structure and composition by detecting the response of nuclear "bar magnets" to radiofrequency waves in the presence of a strong applied magnetic field. The proposed research will use modern NMR and MRI techniques to provide insights into important problems in structural chemistry, materials science and plant science. Our approach to research and graduate student training consists of fundamental aspects as well as more applied ones. The goal of the fundamental research outlined in this proposal is to gain a better understanding of the relationship between the parameters that one measures in an NMR experiment and molecular structure. We will take advantage of the fact that NMR studies of solid materials provide one with an opportunity to characterize the orientation dependence of the observed magnetic shielding, rather than just their average values. For example, solid-state (SS) H-1 NMR will be used to better characterize hydrogen magnetic shielding of transition metal hydrides and dihydrogen complexes that play a central role in catalytic inorganic and organometallic chemistry. The applied aspects range from using SS NMR to investigate the molecules present in forest floor samples and their relationship to forest health to building an apparatus to produce enriched para-hydrogen so that we can use hyperpolarized NMR to study the mechanism of important organometallic reactions. We will continue to take advantage of the National Ultrahigh-Field NMR Facility for Solids in Ottawa to explore the potential of NMR in studying "difficult" quadrupolar nuclei that have been little explored because of their poor receptivities (e.g., challenging isotopes, such as As-75, that are biologically relevant and Ir-193 that is very important in organometallic chemistry). We will continue exploring applications of micro-MRI which has proven important for research and student training.