Very-High-Spin Organic Polyradicals and Chiral Alpha-Conjugated Systems

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This research focuses on the development of new synthetic methodologies for the synthesis of novel mesoscopic molecular architectures that serve as scaffolds for very-high-spin polyradicals, and the experimental and computational characterization of the polyradicals. The principles of fractal geometry will be applied to achieve connectivities differing from those obtainable with the current dendritic approach. MNDO, EHT and MM3 molecular calculations of the electronic structure of these, and mesoscopic systems possessing chiral pi-conjugated systems, will be correlated with measurements of the magnetic and electronic properties of the two- and three-dimensional polyradicals to achieve spin-coupled organic magnets with high Curie temperatures. Graduate and postdoctoral students carrying out the experiments will be trained in the synthesis of molecules of mesoscopic dimensions, and the experimental and theoretical characterization of their electronic properties. With this award, the Organic and Macromolecular Chemistry Program and the Advanced Materials Program support the educational and research activities of Dr. Andrzej Rajca of the Chemistry Department at the University of Nebraska. Dr. Rajca will focus his research efforts on developing synthetic routes to relatively large molecules, referred to as mesoscopic molecules. These multi-dimensional molecules serve as scaffolds for a relatively large number of sites possessing an unpaired electron, and are key intermediates in the development of organic magnets. Dr. Rajca will correlate the magnetic properties of these mesoscopic molecules with theoretical analyses to achieve organic materials that exhibit room temperature magnetic properties. Dr. Rajca's educational activities involve training graduate and postdoctoral students in the synthetic methodology needed to achieve molecules of mesoscopic dimensions, and their experimental and theoretical characterization.