New materials based upon molecular chemistry are the focus of our group's research activities. We strive toward the preparation and characterization of new materials with fascinating magnetic, electrical, and optical properties. At present, our major effort is to prepare magnets based on molecular/ organic/ polymeric chemistry. We have demonstrated that systems comprising radical cations and anions such as those with alternating chain structures, may exhibit ferromagnetic coupling and in some cases are bulk (3-D) ferromagnets. The tetracyanoethylene (TCNE) radical anion salt of decamethylferrocene is a magnet with a Tc of 4.8 K. Furthermore, on a mole basis they are significantly stronger magnets than iron metal.
This led us to react bis(benzene)vanadium with TCNE, and an exciting new magnet with an unexpected Tc above room temperature was prepared. We have also identified a new class of molecule-based magnets based on Mn(porphyrin)(TCNE) and exciting new materials with unexpected magnetic properties are evolving. We are studying the intradimer bonding that occurs for π-[TCNE]22- that has a 2.9 Å intradimer separation, and an unusual 2-electron 4-carbon atom bond. This bonding arrangement gives rise to an additional CN as well as a new CC vibrations. Related dimers are being studied.
Our multidisciplinary research targets projects aimed to understand the structure-function relationship to ultimately enable the preparation of stable, technologically useful, high-Tc molecule-based and/or polymeric magnets.
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Film of V[TCNE]x- Room Temperature Sticking to a Magnet. |
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[TCNE]22- Structure with 2e-/4c CC Bond. |