International Research Fellowship Program: Hyperpolarized Solid State NMR Spectra of Materials and Catalysis Using Dynamic Nuclear Polarization

国际研究奖学金计划使美国科学家和工程师能够在国外进行9至24个月的研究。该计划的奖励为联合研究提供了机会，并利用独特或互补的设施、专业知识和国外的实验条件。该奖项将支持Leah B. Casabianca博士与Lucio Frydman博士在以色列魏茨曼研究所进行为期24个月的研究。核磁共振波谱无疑是测定化学体系和材料的结构和动力学的最通用和最有用的工具之一。没有其他技术能与这种光谱学所能提供的丰富的原子细节相比。然而，核磁共振波谱的最大缺点是灵敏度低。核磁共振将非常适合于催化有机体系、功能化表面或无机纳米管的结构研究？只要能克服它的敏感性问题。这项工作的目标是开发新的核磁共振技术，利用低温动态核极化（DNP）来表征静态固体中的超极化核。DNP在固体中金属核中的应用将通过脉冲序列的开发、极化转移到金属核的最佳超极化条件和用于低温环境的硬件来验证、优化和理解。这些方法将被用于检查催化剂和无机纳米管中的金属核。该项目的另一个目标是研究利用单壁碳纳米管（SWNTs）和纳米金刚石中存在的内源性顺磁杂质作为DNP极化剂的可行性，增强这些碳纳米材料中13C核的信号。催化剂在合成和工业化学以及日常生活中无处不在，无机纳米管由于其无毒的性质而具有独特的潜在应用，碳纳米材料的应用范围从膜和传感器到电池和纳米电子学。尽管这些领域的结构表征传统上由低分辨率技术主导，但灵敏度增强的核磁共振有可能允许这些和其他新兴先进材料的原子级表征。这项工作将推动超极化固体核磁共振领域的发展，并将对催化和材料科学等其他领域产生积极影响。正在开发的技术将允许表征传统上由于该方法固有的灵敏度限制而难以通过核磁共振研究的系统，从而通过增加该技术的适用性来推进核磁共振领域。此外，该项目将有助于理解一般的超极化过程。这项工作将通过含金属催化剂、无机纳米管、单壁碳纳米管和其他碳基纳米材料的潜在应用造福社会。这些材料的原子级结构特性将使这些系统在生物医学、电子、汽车和航空航天工业中的应用得以实现。

0965137CasabiancaThe International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twenty-four-month research fellowship by Dr. Leah B. Casabianca to work with Dr. Lucio Frydman at the Weizman Institute in Israel.Nuclear Magnetic Resonance (NMR) spectroscopy is undoubtedly one of the most versatile and useful tools for the determination of structure and dynamics in chemical systems and materials. No other technique compares in the wealth of atomistic detail that can become available from this kind of spectroscopy. The greatest disadvantage of NMR spectroscopy, however, is its low sensitivity. NMR would be ideally suited for structural studies of catalytic organic systems, functionalized surfaces, or inorganic nanotubes ? should only its sensitivity problems be surmounted. This goal of this work is the development of new NMR techniques exploiting cryogenic dynamic nuclear polarization (DNP) to characterize hyperpolarized nuclei in static solids. The application of DNP to metal nuclei in solids will be validated, optimized and understood through the development of pulse sequences, optimal hyperpolarization conditions for polarization transfer specifically to metal nuclei, and hardware for use in cryogenic environments. These approaches will then be used to examine metal nuclei in catalysts and inorganic nanotubes. A concomitant goal of this project is to examine the feasibility of using endogenous paramagnetic impurities present in single-walled carbon nanotubes (SWNTs) and nanodiamonds as polarizing agents for DNP, enhancing the signal of 13C nuclei in these carbon nanomaterials. Catalysts are ubiquitous in synthetic and industrial chemistry as well as in everyday life, inorganic nanotubes have unique potential applications due to their non-toxic nature, and carbon nanomaterials have applications ranging from membranes and sensors to batteries and nanoelectronics. Whereas structural characterization in these fields has traditionally been dominated by low-resolution techniques, sensitivity-enhanced NMR has the potential to allow atomic-level characterization of these and other emerging advanced materials. The proposed work will lead to advances in the field of hyperpolarized solid-state NMR, and will also have a positive impact on other fields including catalysis and materials science. The techniques being developed will allow the characterization of systems that have traditionally been difficult to study by NMR due to the inherent sensitivity limitations of this method, thus advancing the field of NMR by increasing the applicability of this technique. In addition, this project will contribute to the understanding of hyperpolarization processes in general. This work will benefit society through the potential applications of metal-containing catalysts, inorganic nanotubes, SWNTs, and other carbon-based nanomaterials. Atomic-level structural characterization of these materials will allow applications of these systems in the biomedical, electronics, automotive, and aerospace industries to be realized.