Development and Application of Size and Charge Resolved NMR

尺寸和电荷分辨核磁共振的开发与应用

• 批准号: 9903723
• 负责人: Charles Johnson
• 金额: $ 45.2万
• 依托单位: University of North Carolina at Chapel Hill
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-07-15 至 2003-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9903723&HistoricalAwards=false
• 关键词: Development; Application; Size; Charge; Resolved

Charles Johnson of the University of North Carolina at Chapel Hill is supported by the Experimental Physical Chemistry Program to continue the development of diffusion ordered and mobility ordered NMR methods for the resolution of molecules on the basis of molecular size and charge. A major effort will be directed toward implementing toroid cavity detectors (TCDs) for high resolution NMR combined with imaging of diffusion and flow. Experiments and computer simulations will be used to investigate manifestations of static field inhomogeneities, off-resonance effects, incomplete relaxation, and radiation damping that are unique to TCD images and line shapes. Both traditional and TCD methods will be focused on two collaborative applications: (1) studies of interactions of specially designed surface active polymers in liquid and supercritical carbon dioxide, and (2) studies of recently synthesized isolable, water soluble gold clusters protected by monolayers of tiopronin. The first set of experiments is motivated by the growing importance of liquid/supercritical carbon dioxide as a solvent system for polymerization reactions resulting from the environmentally driven needed to phase out chlorofluorocarbons, to avoid emission of volatile organic compounds, and to reduce aqueous waste streams. The second set of experiments provides a testing ground for electrophoretic NMR methods as well as the opportunity to model electrokinetic properties of particles in which core radius, layer thickness of ligands, and degree of polydispersity can be varied. This project involves the development of novel experiments using nuclear magnetic resonance spectroscopy, and the application of these new techniques to significant chemical problems. Environmentally benign carbon dioxide is growing in importance as a solvent for polymer synthesis and cleaning processes, and outcomes from this project will enhance the understanding needed for effective practical use of liquid and supercritical carbon dioxide. Gold clusters protected by monolayers of organic compounds have potential applications in nanoscale electronic devices, chemical sensors, and biosensors, and the present studies will provide insights into the properties of these cluster systems.

北卡罗来纳大学教堂山分校的查尔斯·约翰逊 (Charles Johnson) 在实验物理化学计划的支持下，继续开发扩散有序和迁移率有序 NMR 方法，用于根据分子大小和电荷来解析分子。 主要工作将是实施环形腔探测器 (TCD)，以实现高分辨率 NMR 与扩散和流动成像相结合。 实验和计算机模拟将用于研究 TCD 图像和线形状特有的静态场不均匀性、偏共振效应、不完全弛豫和辐射阻尼的表现。 传统方法和 TCD 方法都将侧重于两个协作应用：（1）研究专门设计的表面活性聚合物在液体和超临界二氧化碳中的相互作用，以及（2）研究最近合成的由单层保护的可分离的水溶性金簇。硫普罗宁。第一组实验的动机是液体/超临界二氧化碳作为聚合反应的溶剂系统越来越重要，这是由于环境驱动需要逐步淘汰氯氟烃，以避免挥发性有机化合物的排放，并减少含水废物流。 第二组实验为电泳核磁共振方法提供了试验场，并为颗粒的动电性质建模提供了机会，其中核半径、配体的层厚度和多分散度可以变化。 该项目涉及使用核磁共振波谱进行新颖实验的开发，以及将这些新技术应用于重大化学问题。 环境友好的二氧化碳作为聚合物合成和清洁过程的溶剂越来越重要，该项目的成果将增强人们对液体和超临界二氧化碳的有效实际使用所需的理解。 由单层有机化合物保护的金簇在纳米级电子器件、化学传感器和生物传感器中具有潜在的应用，目前的研究将为这些簇系统的特性提供深入的见解。