Diazido nitro pyrazoles: unlocking high-performance primary explosives with binder capabilities

Abstract

Metal-free, highly efficient diazido-nitro-pyrazole-based primary explosives were synthesized and fully characterized using various spectroscopic techniques, including multinuclear NMR (¹H, ¹³C, ¹⁵N), infrared spectroscopy (IR), high-resolution mass spectrometry (HRMS), elemental analysis (EA), and thermal studies (TGA-DSC). Additionally, the structure of 3,5-diazido-4-nitro-1H-pyrazole (2) was confirmed by single-crystal X-ray diffraction (SC-XRD). Both the compounds (2 and 3) exhibit high densities (1.75 and 1.79 g cm⁻³), acceptable thermal decomposition temperatures (T_d: 119 °C and 159 °C), and impressive detonation parameters (VOD = 8203, 7743 m s⁻¹; DP = 27.08, 20.61 GPa). They also demonstrate excellent impact (2.5 J) and friction sensitivities (5 N and 30 N, respectively). Furthermore, both compounds exhibit a low minimum primary charge (MPC) requirement and respond positively to the hot needle test. These balanced multifunctional properties, combined with excellent synthetic feasibility, make these compounds strong candidates for applications requiring high initiation efficiency and enhanced safety.