High Spin Organic Molecules and Materials

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This award is made in the Organic Dynamics Program in the Chemistry Division in support of the research of Dr. Dennis Dougherty at the California Institute of Technology. The research will continue Dougherty's efforts on the design, synthesis, and characterization of model spin- coupled and di- and tri-radicals based on complex heterocycles and/or radical ions where the spin-containing moieties are connected by a ferromagnetic coupling unit which ensures that any two or more spins linked through it will experience high spin ferromagnetic coupling rather than low spin antiferromagnetic coupling. Meta-phenylene will be the primary coupling unit. Radical systems which have high spin ground states and a large energy gap to low spin excited states will be candidates for assembly into highly cross linked organic networks with controlled topologies to ensure favorable magnetic coupling. Strategies for building extended networks will involve synthesizing closed shell polymers or networks, fully characterizing them, and then introducing spins by a chemical or electrochemical doping procedure. Magnetic properties will be characterized by variable temperature SQUID magnetometry and electron paramagnetic resonance measurements. This highly interdisciplinary research addresses fundamental issues of spin-spin interactions in simple model polyradical systems and how they can be applied to extended bulk organic magnets. Critical to the success of the project will be band gap engineering which will assure high spin ground states at ambient conditions. Magnetic materials are ubiquitous in modern technology. Organic magnets will find potential applications in light weight motors and information storage systems.