Nitrogen Centered Radicals

在这个由化学部化学结构、动力学机制B计划资助的项目中，内布拉斯加大学林肯分校化学系的Andrzej Rajca教授研究了与新型磁性材料和光学技术相关的稳定有机聚自由基。 利用稳定的有机多自由基，可以开发出在可穿戴电子产品中有应用的轻质、柔软的有机磁体。 稳定的有机多自由基还可以帮助开发用于磁共振成像的造影剂，其广泛用于医学诊断。 这一跨学科研究项目有能力为各级科学家提供最高水平的培训和教育，包括目前在科学领域代表性不足的科学家。该项目的具体目标是高自旋氮（氨基）为中心的二，三和多自由基，螺旋折叠的高自旋碳为中心的多自由基，螺旋和双螺旋低聚噻吩为基础的自由基。高自旋胺基自由基源自基于增环、交叉共轭结构的分子设计，该结构促进电子自旋密度离域到铁磁耦合器中。 预期这些自由基在室温下具有长半衰期，这将允许隔离和/或热鲁棒性，从而允许在真空下升华以制备薄膜。基于螺旋和双螺旋寡聚噻吩的自由基是有趣的新型分子，具有手性π系统和顺磁性的组合。与螺旋或双螺旋π系统相关的顺磁性可以由于手性和离域电子自旋的组合而呈现独特的性质，为开发具有固有强手性性质的新型顺磁性材料提供了一条途径，这可能有助于发现新的有机磁光材料和器件。拟议的自由基正在通过现代有机合成方法制备，并通过电子自旋共振光谱学、超导量子干涉装置磁力测定法以及计算来表征。

In this project funded by the Chemical Structure, Dynamic & Mechanism B Program of the Chemistry Division, Professor Andrzej Rajca of the Department of Chemistry at the University of Nebraska-Lincoln investigates stable organic polyradicals that are relevant to novel magnetic materials and optical technology. With stable organic polyradicals, lightweight, soft organic magnets, which have applications in wearable electronics, can be developed. Stable organic polyradicals can also assist the development of contrast agents for magnetic resonance imaging, which is widely used in medical diagnosis. This interdisciplinary research project is well positioned to provide the highest level of the training and education of scientists at all levels, including those currently underrepresented in science. The specific objectives of this project are high-spin nitrogen (aminyl) centered di-, tri- and polyradicals, helically folded high-spin carbon-centered polyradicals, helical and double helical oligothiophene-based radicals. The high-spin aminyl radicals derive from a molecular design based upon annelated, cross-conjugated structures that facilitate delocalization of electron spin density into the ferromagnetic coupler. These radicals are expected to possess a long half-life at room temperature that would permit isolation and/or thermal robustness permitting sublimation under vacuum to prepare thin films. The helical and double helical oligothiophene-based radicals are intriguing novel molecules with a combination of chiral pi-systems and paramagnetism. Paramagnetism associated with helical or double helical pi-system may render unique properties due to the combination of chirality and delocalized electronic spin, providing an avenue for development of novel paramagnetic materials with inherently strong chiral properties that could facilitate discovery of new organic magneto-optic materials and devices. The proposed radicals are being prepared by modern organic synthetic methodologies and characterized by electron spin resonance spectroscopy, superconducting quantum interference device magnetometry, as well as computations.