CAREER:Developing Novel Nuclear Magnetic Resonance Contrast and Sensitivity Enhancement Mechanisms for Materials and Reactions Studies

加州大学圣巴巴拉分校的Song-I Han在实验物理化学项目的支持下，开发了核磁共振（NMR）的新型对比机制，通过对选定的流体分子进行靶向信号增强来突出材料和过程的分子特异性功能。两种不同的方法来实现非平衡核自旋极化将追求和发展，提出机制，以获得不同类型的对比。一种方法，利用固体基质中插入的或天然的不成对电子进行核磁共振信号调制，以前没有被证明过。在研究工作中，(1)广泛使用的奥弗豪瑟效应将扩展到更广泛的核和分子范围，(2)将更好地理解材料中原子核与未配对电子之间的相互作用，(3)将在原位获得多孔材料中分子的流动分散，吸收和反应性-难以研究的性质，(4)将阐明多相催化剂中活性位点的位置。理论努力，仪器开发利用新兴的，高功率，微波技术和跨学科知识的整合将被用来满足研究目标。在这个项目中开发的新型对比和更高灵敏度的核磁共振将允许利用目前难以获得的分子-材料相互作用。在化学反应、生物功能、药物输送和石油研究等广泛领域，直接追踪小分子在多孔介质中的运输和吸收的能力是非常重要的。教育项目计划包括为本科生和高中生组织基于磁共振的研讨会和实地研究，这将使他们有机会动手学习磁场，以及如何使用核磁共振来了解环境中的常见材料。

Song-I Han of the University of California-Santa Barbara is supported by the Experimental Physical Chemistry Program to develop novel contrast mechanisms for nuclear magnetic resonance (NMR) that highlight molecule-specific functions of materials and processes by targeted signal enhancement of selected fluid molecules. Two different approaches for achieving non-equilibrium nuclear spin polarization will be pursued and developed, presenting mechanisms to obtain different types of contrast. One approach, utilizing inserted or natural unpaired electrons in solid matrices for NMR signal modulation, has not been demonstrated previously. In the research effort, (1) the widely used Overhauser effect will be extended to a broader range of nuclei and molecules, (2) a better understanding of the interactions between nuclei and unpaired electrons in materials will be achieved, (3) flow dispersion, absorption and reactivity of molecules in porous materials -- difficult properties to study-- will be accessed in situ, and (4) light will be shed on the whereabouts of active sites in heterogeneous catalysts. Theoretical efforts, instrumentation development utilizing emerging, high-power, microwave technology and the integration of interdisciplinary knowledge will be employed to meet the research aims.Novel contrast and higher sensitivity NMR as developed in this project will allow the exploitation of molecule-material interactions that are currently difficult to access. The developing capability to trace directly the transport and absorption of small molecules into porous media in situ is highly significant in a broad range of areas such as chemical reaction, biological function, drug delivery, and petroleum research. The educational project plan includes the organization of magnetic resonance based workshops and field studies for undergraduate and high school students that will give them the opportunity for hands-on learning about magnetic fields and how NMR can be used to learn about common materials in the environment.