Hydrogen-Free Explosive of <i>N</i>-Azo-Bridged 1,2,4-Triazole: A Novel Nitrogen-Chain-Extended Compound with Exceptional Energy Performance

The design of high-energy-density materials (HEDMs) and the investigation of energy limits have consistently represented a focal point and a significant challenge in research. This study prepared a hydrogen-free compound, <b>BLG-102</b>, with high nitrogen content (66.6%) using an energetic block design based on a long nitrogen chain (N6). <b>BLG-102</b> has a high crystal density of 1.85 g·cm^-3, with a measured crystal density of 1.82 g·cm^-3. It also achieves zero oxygen balance (based on CO), excellent enthalpy of formation, and good conjugate planarity and aromaticity. <b>BLG-102</b> demonstrates exceptional detonation performance with a high detonation velocity (<i>V</i>_D = 9311 m·s^-1) and detonation pressure (<i>P</i> = 38.5 GPa). These values are superior to the well-known energetic compound RDX (<i>V</i>_D = 8991 m·s^-1, <i>P</i> = 35.2 GPa), and are comparable to HMX (<i>V</i>_D = 9144 m·s^-1, <i>P</i> = 39.2 GPa). Nevertheless, BLG-102 exhibits slightly higher but acceptable sensitivity (IS = 5 J, FS = 54 N). BLG-102 demonstrates remarkable capabilities in laser initiation. Notably, a 10 mg charge of BLG-102 can effectively detonate 20 mg of RDX, producing a pore diameter of 11.44 mm in the lead plate (2 mm thick). The integrated design approach using the block design concept─combining nitro, azide, and long nitrogen chain structures with a 1,2,4-triazole framework─significantly enhances the energy performance of 1,2,4-triazole compounds. It breaks through the energy limit of already known 1,2,4-triazole-based compounds and provides a new idea for the design and synthesis of HEDMs with high performance.