Switchable compound for safer explosives

Abstract

Bomb-detonator materials must strike a balance between maintaining stability and triggering spectacular self-destruction. Chemists now report a material with a fully reversible switching mechanism that could offer more control over initiating an explosion and might be used to build safer detonation devices (J. Am Chem. Soc. 2020, DOI: 10.1021/jacs.9b13835). Thuy-Ai D. Nguyen of Los Alamos National Laboratory and colleagues synthesized a spin-crossover complex called [Fe(Htrz)3]n[ClO4]2n, in which iron is nestled between energetic nitrogen-rich rings common to explosives and an oxidizing counterion of perchlorate, a typical component of fireworks. This complex changes from a low-spin to a high-spin electronic state in response to increased temperature. To test the impact sensitivity of the material, the researchers dropped weights on it inside an anvil cell at various temperatures. They found that the complex exploded under less force in the high-spin state, at 60 °C, compared with the low-spin state, at 2...