New pyrazole energetic materials and their energetic salts: combining the dinitromethyl group with nitropyrazole

Abstract

In this work, a series of pyrazole-derived energetic compounds were successfully synthesized. These energetic compounds were fully characterized by NMR spectroscopy, IR spectroscopy, and elemental analysis. The structures of compounds 5, 6, 7 and 7a were determined by single crystal X-ray diffraction. The physicochemical and energetic properties of all synthesized energetic compounds, including density, thermal stability and energetic performance, were investigated. The structure–property relationship was illustrated using two-dimensional fingerprint plots based on Hirshfeld surfaces, NCI plots and ESP of 7 and 7a. Among these energetic compounds, the hydroxylammonium salt 7b exhibited satisfactory calculated detonation performance (8700 m s⁻¹), which was comparable to the commonly used highly explosive RDX (8748 m s⁻¹). The potassium salt 5 was tested for its detonation ability by detonating RDX. The result indicates that compound 5 could be used as a potential green primary explosive.