Solution-State High Field DNP on Large Volume Samples: Sensitivity-Enchanced NMR for the Organic Chemist

在化学系化学测量和成像（CMI）项目的支持下，Sungsool Wi博士和他在佛罗里达州立大学国家高磁场实验室（NHMFL）的团队正在设计新的方法来提高核磁共振（NMR）光谱的能力，这是表征有机分子结构和动力学的主要手段。正在寻求互补的创新途径，以大幅提高核磁共振灵敏度，并为更广泛的目标分子提供相应的低检测限。如果成功，这些方法将为许多不同科学和工业应用领域的分子表征提供新的机会，包括药物研究、人类和动物研究中的代谢物、天然产品、食品和聚合物添加剂以及天然原油中的小分子。开发的工具将提供给国家人口基金的当地和远程用户。该项目为参与的学生和博士后学员提供了宝贵的培训机会，包括暑期实习，为本科生提供实践经验。Wi团队已经确定了两种独立的，互补的方法来增强任意分子的核磁共振信号。一种依赖于使用低粘度超临界溶剂来实现基于overhauser的电子到核动态核极化（ODNP）。另一种方法依赖于双基中产生的迄今未知的弛豫过程，使两个j耦合电子在各种各样的场和相关时间内转移到一个核上。Wi小组将利用这些技术和概念上的突破，在含有稀有机分子的~100 μL溶液态样品上实现高场灵敏度增强的DNP光谱，目的是潜在地创造核磁共振的新范式。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Chemical Measurement and Imaging (CMI) Program in the Division of Chemistry, Dr. Sungsool Wi and his team at the National High Magnetic Field Laboratory (NHMFL) at Florida State University are devising new methods to advance the capabilities of nuclear magnetic resonance (NMR) spectroscopy – a leading means of characterizing the structure and dynamics of organic molecules. Complementary innovative paths are being pursued to substantially improve the NMR sensitivity and to provide correspondingly lower limits of detection for a wider range of target molecules. If successful, these methods would provide new opportunities for characterizing molecules in many different areas of scientific and industrial applications, including studies of pharmaceuticals, metabolites in human and animal studies, natural products, food and polymer additives, and small molecules in natural crude oil. Tools developed will be made available to local and remote users of NHMFL. This project provides valuable training opportunities to participating student and postdoctoral trainees, including summer internships offering hands-on experience for undergraduate students. The Wi team has identified two independent, complementary approaches to enhancing the NMR signals of arbitrary molecules. One relies on the use of low-viscosity supercritical solvents to enable electron-to-nucleus Overhauser-based dynamic nuclear polarization (ODNP). The other relies on hitherto unknown relaxation processes arising in biradicals to enable transfers from two J-coupled electrons to one nucleus over a wide variety of fields and correlation times. The Wi group will leverage these technological and conceptual breakthroughs to enable sensitivity-enhanced DNP spectroscopy at high fields on ~100 μL solution-state samples containing dilute organic molecules, with the aim of potentially creating a new paradigm in NMR.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.