Nitrogen Centered Radicals

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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.