Polynitro-substituted bispyrazoles: a new family of high-performance energetic materials

Abstract

New polynitro-substituted bispyrazoles were synthesised and fully characterised in this study. Ammonium 4-(4′-amino-3′,5′-dinitro-1′-pyrazol)-3,5-dinitropyrazole (3), 4-(4′-amino-3′,5′-dinitro-1′-pyrazol)-1-amino-3,5-initropyrazole (6), diaminoguanidinium 4-(4′-amino-3′,5′-dinitro-1′-pyrazol)-3,5-dinitropyrazole (9), and 3,4,5-triamino-1,2,4-triazolium 4-(4′-amino-3′,5′-dinitro-1′-pyrazol)-3,5-dinitropyrazole (12) were further confirmed using single-crystal X-ray diffraction. The compounds exhibited excellent thermal stabilities, insensitivities and high detonation performance. The measured LC₅₀ of the compounds suggested that their toxicities were lower than that of TNT and that for compound 3 even lower than that of TATB. Compound 5 demonstrates unprecedented overall performance: higher detonation velocity (V_D = 8760–8981 m s⁻¹), detonation heat (Q_v = 7551 kJ kg⁻¹) and explosive power (A = 1712 kJ g⁻¹) than RDX, a decomposition temperature (T_d = 297 °C) higher than that of HMX, and much lower toxicity (LC₅₀ = 7 μg mL⁻¹) than that of TNT, ranking it in a new generation of heat resistant, less sensitive and low environmental impact high energetic materials.