Chemical and Spectroscopic Studies of Organic Radical Cations

新泽西州立大学罗格斯大学化学系的Heinz D.Roth教授在有机化学和高分子化学计划的支持下，对有机自由基阳离子进行了化学和光谱研究。有机自由基阳离子是在一系列介质中通过光诱导电子转移和化学氧化产生的，包括流体溶液、冷冻玻璃和固体载体(沸石)。光谱技术，包括光谱学、电子顺磁共振和化学诱导的动态核极化，使得研究这些自由基阳离子的结构成为可能。通过实验和理论相结合的方法，罗斯教授探索了自由基阳离子反应的区域化学，重点是环应变、共轭程度和空间位阻作为区域选择性的决定因素。还讨论了与三重自由基对的反应有关的问题，包括双自由基的形成，从垂直的自由基阳离子产生双自由基或三重态，形成垂直的三重态，以及通过三重离子对的耦合产生扩展的双自由基。许多化学反应通过一系列的化学步骤进行，每个步骤都会产生一种活性中间物种，再进行进一步的反应，最终得到最终的反应产物。化学反应中的中间体经常表现出不寻常的化学和结构特征，并且通常带有正电荷(‘阳离子’)或负电荷或单电子(‘自由基’)。在有机和高分子化学项目的支持下，新泽西州立大学罗格斯大学化学系的Heinz D.Roth教授研究了同时包含正电荷和未配对电子的活性中间体的形成、结构和反应性。通过应用各种物理和化学技术，并辅之以计算研究，罗斯教授阐明了这些“自由基阳离子”的化学本质，有助于我们对化学反应如何发生的基础知识。

Professor Heinz D. Roth, of the Department of Chemistry at Rutgers, the State University of New Jersey, carries out chemical and spectroscopic studies of organic radical cations with the support of the Organic and Macromolecular Chemistry Program. Organic radical cations are generated by photo-induced electron transfer and by chemical oxidation in a range of media, including fluid solutions, frozen glasses, and solid supports (zeolites). Spectroscopic techniques, including optical spectroscopy, electron paramagnetic resonance, and chemically induced dynamic nuclear polarization, permit the study of the structures of these radical cations. Through a combination of experimental and theoretical techniques, Professor Roth explores the regiochemistry of radical cation reactions, focusing on ring strain, extent of conjugation, and steric hindrance as determinants of regioselectivity. Also explored are issues relating to the reactions of triplet radical pairs, including biradical formation, generation of biradicals or triplet states from `vertical` radical cations, formation of perpendicular triplet states, and generation of extended biradicals by coupling of triplet ion pairs. Many chemical reactions proceed via a sequence of chemical steps, each producing a reactive intermediate species which undergoes further reaction, ultimately leading to the final reaction product. The intermediates in chemical reactions often display unusual chemical and structural features, and often bear a positive charge (`cations`) or negative charge or a lone electron (`radicals`). With the support of the Organic and Macromolecular Chemistry Program, Professor Heinz D. Roth, of the Department of Chemistry at Rutgers, the State University of New Jersey, studies the formation, structure, and reactivity of reactive intermediates containing both a positive charge and an unpaired electron. Through the application of a variety of physical and chemical techniques, complemented by calculational studies, Professor Roth elucidates the chemical nature of these `radical cations,` contributing to our fundamental knowledge of how chemical reactions occur.