Photons, radicals, bubbles, and beer: using EPR spectroscopy to understand the universe
Photons, radicals, bubbles, and beer: using EPR spectroscopy to understand the universe
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光子、自由基、气泡和啤酒：利用 EPR 光谱来了解宇宙
DOI：
10.1117/12.2652953
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Forbes, Malcolm
中科院分区：
文献类型：
--
作者：
Forbes, Malcolm
我们的实验室对均匀和非均匀介质中自由基的结构，反应性和动力学有着长期的兴趣。在本报告中，稳态和时间分辨（CW）电子顺磁共振光谱（SSEPR和TREPR）的基本原理进行了解释，并概述了它们在理解自由基的物理和化学行为中的用途。将介绍的例子包括使用稳定的氮氧化合物自旋探针来研究建筑涂料的干燥和固化，以及在分子水平上探测结构化（非牛顿）流体的物理性质。涉及自由基的化学反应性可以直接使用TREPR进行研究，例如在研究啤酒的光冲击风味（所谓的“臭臭”）的机制中。也可以使用自旋捕获技术研究反应性。将提出两种不同的捕获方法：硝酮可用于确认生物相容性聚合物引发剂的作用机制，受阻胺与单线态氧的反应可用于量化受限介质中此类反应的动力学和拓扑结构。最后，EPR光谱的应用，研究在液体溶液中的聚合物链动力学的两个方面：1）丙烯酸类聚合物的主链自由基研究作为聚合物的结构和温度的函数，和2）在丙烯酸类聚合物的长程自由基-三重态对相互作用。
Our laboratory has a long-standing interest in the structure, reactivity, and dynamics of free radicals in both homogeneous and heterogeneous media. In this presentation, the basic tenets of steady-state and time-resolved (CW) electron paramagnetic resonance spectroscopy (SSEPR and TREPR) are explained, and their use in understanding the physical and chemical behavior of free radicals is outlined. Examples to be presented include the use of stable nitroxide spin probes to investigate the drying and curing of architectural coatings, and to probe the physical properties of structured (non- Newtonian) fluids at the molecular level. Chemical reactivity involving free radicals can be studied directly using TREPR, for example in the study of the mechanism for the light-struck flavor (so-called “skunking”) of beer. Reactivity can also be investigated using spin trapping techniques. Two different trapping methods will be presented: nitrones can be used to confirm the mechanism of action of biocompatible polymer initiators, and the reaction of hindered amines with singlet oxygen can be used to quantify the kinetics and topology of such reactions in confined media. Finally, the application of EPR spectroscopy to study two aspects of polymer chain dynamics in liquid solution will be presented: 1) main chain radicals of acrylic polymers studied as a function of polymer structure and temperature, and 2) long-range radical-triplet state pair interactions in acrylic polymers.