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

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 (VD = 8760–8981 m s−1), detonation heat (Qv = 7551 kJ kg−1) and explosive power (A = 1712 kJ g−1) than RDX, a decomposition temperature (Td = 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.