Bis-3,5-Diamino-1,2,4-Triazolyl-1,2,4,5-Tetrazine: From Insensitive High Energy Density Materials to Small Molecule Organic Semiconductors

Abstract

Besides the well-known pyrotechnic applications of insensitive high energy compounds such as s-tetrazine, they are promising materials for relevant applications (e.g., electrochemical energy storage, photocatalysis). Bis-3,5-diamino-1,2,4-triazolyl-1,2,4,5-tetrazine (BDTT) is a nitrogen-rich conjugated heterocyclic compound (nitrogen ≈ 71 wt %), inert to ignition and mechanical stimuli and thermally stable up to 370 °C. The solvent-free crystalline structure of this high energy density compound (named IEF-12 for IMDEA energy framework) is reported here for the first time using the high resolution powder X-ray diffraction (PXRD) and 1H, 13C, and 15N solid state nuclear magnetic resonance (NMR) spectroscopy. We demonstrate that IEF-12 has features of a small molecule organic semiconductor, namely, lamellar π-stacked crystal packing in the solid state, a low energy optical bandgap Egopt = 2.27 eV, and a relatively high value of dielectric constant εr = 4.86. Overall, we demonstrated on IEF-12 that insensitive high energy density materials (HEDM) may open an avenue for nonclassically structured organic semiconductors, paving the way for optoelectronic and photovoltaic applications.