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

在这个由化学系化学测量和成像计划资助的项目中，佛罗里达大学和爱荷华州立大学的Clifford R Bowers教授和Winyu Huang教授及其团队试图了解沼泽效应(地表水被仲氢磁化)，这是最近发现的一种现象，可以显著提高通过水介质中的磁共振进行分子分析的灵敏度，这是改进例如医学磁共振成像(MRI)的关键挑战。沼泽效应可以为某些类型的核磁共振成像提供一种廉价、便携、连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，沼泽效应可以促进偏远或贫困地区的医学诊断MRI。通过与佛罗里达大学S大学学前教育与培训中心(CPET)的几个项目协调，这些概念被调整为面向高中生的外展演示。在爱荷华州立大学，相关的外展活动包括科学表演和本科生和高中生参与适当的研究活动。该项目的灵感来自于最近发现的表面介导的液态水、甲醇和乙醇的质子超极化，这种超极化是通过包覆在介孔二氧化硅(Pt3Sn@mSiO)中的Pt3Sn金属间纳米颗粒(INPS)上的非均相催化来实现的。在理论的指导下，系统地研究了催化剂性质(如表面结构、组成、颗粒大小、包覆壳终止)和反应条件(温度、磁场、溶剂组成(化学和同位素))的结构/活性关联。催化剂性能的变化是基于多相催化的公认原则，涉及组成原子的d带中心和电负性属性。该项目的目标是(1)了解沼泽效应的机理，(2)利用对机理的了解来开发新的催化剂，以提高沼泽过程的效率，(3)探索在各种纯净液体和溶液中增强核磁共振信号的共性，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吗？一位催化剂材料专家(爱荷华州立大学的黄文宇)、一位核磁共振光谱仪(Russ Bowers，佛罗里达大学)和一位计算化学家(Graeme Henkelman，德克萨斯大学，奥斯汀)。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.