Understanding Surface-Mediated Hyperpolarization of Water and other Neat Liquids from Parahydrogen

在这个由化学部门化学测量和成像项目资助的项目中，佛罗里达大学和爱荷华州立大学的Clifford R Bowers教授和Wenyu Huang教授及其团队试图理解SWAMP效应（地面水被对氢磁化），这是最近发现的一种现象，可以显著提高水介质中磁共振分子分析的灵敏度-这是一个关键的挑战，例如，医学磁共振成像（MRI）。SWAMP效应可以为某些类型的MRI提供一种廉价、便携、持续产生的“超磁化”水来源，为通常使用的昂贵、高维护方法提供了一种替代方案。因此，SWAMP效应可以为偏远或贫困地区的医疗诊断MRI提供便利。通过与佛罗里达大学的几个项目协调，这些概念被用于向高中生进行拓展演讲。美国大学预科教育培训中心（CPET）。在爱荷华州立大学，相关的拓展活动包括科学展览和本科生和高中生参与适当的研究活动。这个项目的灵感来自于最近发现的液态水、甲醇和乙醇的表面介导质子超极化，这是通过包裹在介孔二氧化硅中的Pt3Sn金属间纳米颗粒（iNPs）的异相催化（Pt3Sn@mSiO2）得到的。在理论指导下，系统地研究了催化剂性质（如表面结构、组成、粒径、包封壳终止）和反应条件（温度、磁场、溶剂组成（化学和同位素））的结构/活性相关性。催化剂性质的变化是基于公认的多相催化原理，包括d带中心和组成原子的电负性性质。本项目的目标是：(1)了解支持SWAMP效应的机制，(2)利用机理理解开发新的催化剂以提高SWAMP过程的效率，(3)探索各种纯净液体和溶液上核磁共振信号增强的普遍性，以及(4)研究潜在的应用。研究和推广计划是由一个跨学科的化学家团队进行的。一位是催化剂材料专家（黄文宇，爱荷华州立大学），一位是核磁共振波谱学家（Russ Bowers，佛罗里达大学），一位是计算化学家（Graeme Henkelman，德克萨斯大学奥斯汀分校）。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。

In this project funded by the Chemical Measurements and Imaging program of the Chemistry Division, Professors Clifford R Bowers and Wenyu Huang and their groups at the University of Florida and Iowa State University seek to understand the SWAMP effect (surface waters are magnetized by parahydrogen), a recently discovered phenomenon which could significantly increase the sensitivity of molecular analysis by magnetic resonance in aqueous media - a key challenge for improving, for example, medical magnetic resonance imaging (MRI). The SWAMP effect could provide an inexpensive, portable, and continuously generated source of "hyper-magnetized" water needed for some types of MRI, offering an alternative to the expensive, high-maintenance approaches normally used. Hence, the SWAMP effect could facilitate medical diagnostic MRI in remote or impoverished areas. The concepts are adapted for outreach presentations to high school students through coordination with several programs in the University of Florida?s Center for Precollegiate Education and Training (CPET). At Iowa State, related outreach activities include science shows and involvement of undergraduates and high school students in suitable research activities.This project is inspired by the recent discovery of surface-mediated proton hyperpolarization of liquid water, methanol, and ethanol by heterogeneous catalysis over Pt3Sn intermetallic nanoparticles (iNPs) sheathed in mesoporous silica (Pt3Sn@mSiO2). Guided by theory, structure/activity correlations are systematically studied as a function of the catalyst properties (e.g. surface structure, composition, particle sizes, encapsulation shell termination) and reaction conditions (temperature, magnetic field, solvent composition (chemical and isotopic)). Variation of catalyst properties is based on well-established principles of heterogeneous catalysis involving the d-band center and electronegativity properties of the constituent atoms. The goals of this project are to (1) understand the mechanism underpinning the SWAMP effect, (2) use the mechanistic understanding to develop new catalysts to increase the efficiency of the SWAMP process, (3) explore the generality of the NMR signal enhancement on a variety of neat liquids and solutions, and (4) investigate potential applications. The research and outreach plans are being carried out by an interdisciplinary team of chemists ? a catalyst materials specialist (Wenyu Huang, Iowa State University), an NMR spectroscopist (Russ Bowers, University of Florida), and a computational chemist (Graeme Henkelman, University of Texas, Austin).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.