Energetic bi-diazole ‘transformers’ toward high-energy thermostable energetic compounds†

Seeking a fine balance between high performance and good stability remains a major challenge in designing advanced high-energy-density materials (HEDMs). In this work, a novel energetic molecule, namely 1,1-diamino-3,3′,5,5′-tetranitro-4,4′-bipyrazole (DATNBP-2), was designed and synthesized through backbone ‘transformation’. Though sharing the same elemental composition, compared to 4,4′,5,5′-tetranitro-1H,1′H-[2,2′-biimidazole]-1,1′-diamine (DATNBI) and 2,2′-diamino-4,4′,5,5′-tetranitro-3,3′-bipyrazole (DATNBP-1), not only did DATNBP-2 achieve a high room temperature measured density of 1.88 g cm⁻³, but also a higher thermal decomposition temperature of 305 °C, by far the highest decomposition temperature among the reported analogs. Furthermore, DATNBP-2 possesses a high detonation performance (D_v = 8951 m s⁻¹, P = 35.9 GPa) and mechanical insensitivity (IS = 40 J, FS > 360 N), outperforming to the traditional benchmark explosives cyclotrimethylnitramine (RDX) and hexanitrostilbene (HNS), rendering it a thermostability energetic material.