Title: 

"Redox frustrated molecules as high-energy-density, switchable energetic materials"

Abstract:

New advances in energetic materials (EM) technology (i.e., explosives, propellants, incendiaries, pyrotechnics) are needed for defense, civilian, and space exploration applications. A major challenge in advancement of this technology is the achievement of higher-energy-density materials that bridge the gap between chemical and thermonuclear materials, but which is blockaded by the CHNO ceiling for energy density (the hypothesis that we have reached—or are near reaching—the maximum theoretical energy density achievable in organic chemical EM’s). A second major challenge in EM technology is the balance between safety and performance. Often, the most reliably performing energetic materials are also sensitive (i.e., to impact, friction, electrostatic discharge), rendering them unsafe for large-scale preparation, storage, and transport. Conversely, the safest materials often suffer from poorer performance or reliability. One common approach toward achievement of new high-energy-density materials over the past 20 years is to target polymeric or oligomeric nitrogen species. The first part of my seminar will focus on the metal-ligand chemistry of the redox-non-innocent tetrazene ligand (RN=N-N=NR) with manganese explored by our group, with an emphasis on electronic structure characterization, and with a side-quest into a surprising rearrangement of an aromatic azide. The second part of my seminar will focus on what we have termed “redox-frustrated energetic materials” which include the use of unusual atoms in energetic materials, such as transition metals and halogens in targeting higher-energy-density materials. In these studies, we have serendipitously discovered explosive molecular magnets that show potential for magnetically switchable sensitivity. Our initial findings and future directions in this area will be described.