Collaborative Research: Continuous-Flow Hyperpolarization of Liquids Utilizing Parahydrogen and Heterogeneous Catalysis

在化学系(CHE)化学测量和成像(CMI)计划的支持下，以及另外两个CHE计划--化学结构、动力学和机制-A(CSDM-A)和化学催化(CAT)以及分子和细胞生物科学部(MCB)的分子生物物理组的部分共同资助下，佛罗里达大学的Clifford R.Bowers教授和爱荷华州立大学的黄文宇教授寻求开发新的仪器和方案来提高核磁共振(NMR)谱的灵敏度。这是表征化学结构的组成和结构的重要方法，也是磁共振成像的基础--磁共振成像是医学诊断的主要工具。该团队正在开发连续流动方法和先进的金属间纳米颗粒催化剂，以努力将核磁共振光谱的灵敏度提高1万倍以上。这项研究将通过佛罗里达大学的大学前教育和培训中心(CPET)和几个NSF本科生研究经验(REU)项目，为高中生和本科生提供研究经验。在爱荷华州的艾姆斯，外展活动还包括科学表演以及本科生和高中生参与研究活动和结合项目概念的演示。核磁共振(核磁共振)依赖于分子中核自旋能级(即自旋极化)之间的总体差异。在传统的核磁共振中，自旋极化是通过将样品置于高静态磁场中来诱导的。然而，即使在最高可用磁场下，环境温度附近的热平衡自旋极化也不大于约0.01%，因此核磁共振跃迁强度本质上是弱的。基于对氢的超极化可以提供一种可靠且经济高效的方法，该方法可扩展，并与在极化接近100%的流体中快速且连续地生产分子相兼容。对于由仲氢生产超极化液体，多相催化具有关键的优点：固体催化剂可以提供一致的活性(在适当的条件下)，催化剂材料可以很容易地从溶解的超极化产物中分离出来。从对氢和非均相催化到溶液状态超极化的进展需要清楚地了解分子解离后的催化机理和对氢自旋动力学。利用连续流动非均相催化的对氢增强极化的发展将有助于对氢化反应和非氢化过程中超极化的基本机制和自旋动力学的基础研究，例如表面介导的对氢超极化。这一奖项反映了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。

With support from the Chemical Measurement and Imaging (CMI) Program in the Division of Chemistry (CHE), and partial co-funding from two other CHE programs, Chemical Structures, Dynamics, and Mechanisms - A (CSDM-A) , and Chemical Catalysis (CAT) and also from the Molecular Biophysics Cluster in the Molecular and Cellular Biosciences (MCB) Division, Professors Clifford R. Bowers at the University of Florida and Wenyu Huang at Iowa State University seek to develop new instrumentation and protocols for enhancing the sensitivity of nuclear magnetic resonance (NMR) spectroscopy, an important method for characterizing the composition and structure of chemical structures and the foundation of magnetic resonance imaging – a major tool for medical diagnostics. The team is developing continuous-flow methods and advanced intermetallic nanoparticle catalysts in efforts to improve the sensitivity of NMR spectroscopy by more than a factor of 10,000. The research will provide research experiences for high school and undergraduate students coordinated through the Center for Pre-collegiate Education and Training (CPET) at the University of Florida and several NSF Research Experiences for Undergraduates (REU) programs. In Ames, Iowa, outreach activities additionally include science shows and involvement of undergraduates and high school students in research activities and demonstrations incorporating project concepts.Nuclear Magnetic Resonance (NMR) relies on population differences among nuclear spin energy levels (i.e. spin polarization) in a molecule. In conventional NMR, spin polarization is induced by placing the sample in a high static magnetic field. However, even at the highest available magnetic fields, thermal equilibrium spin polarizations near ambient temperature are no greater than about 0.01%, and hence the NMR transition intensities are inherently weak. Parahydrogen-based hyperpolarization can provide a robust and cost-effective method that is scalable and compatible with rapid and continuous production of molecules in fluids with polarizations approaching 100%. For production of hyperpolarized liquids from parahydrogen, heterogeneous catalysis offers key benefits: the solid catalysts can provide consistent activity (under appropriate conditions) and the catalyst material can be easily separated from dissolved hyperpolarization products. Advancement of solution-state hyperpolarization from parahydrogen and heterogeneous catalysis requires a clear understanding of the catalytic mechanism and parahydrogen spin dynamics after dissociation of the molecule. The development of parahydrogen-enhanced polarization by continuous-flow heterogeneous catalysis will facilitate fundamental studies of the underlying mechanisms and spin dynamics of hyperpolarization from hydrogenation reactions as well as non-hydrogenative processes such as surface-mediated hyperpolarization from parahydrogen.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.