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

Abstract

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, BLG-102, with high nitrogen content (66.6%) using an energetic block design based on a long nitrogen chain (N6). BLG-102 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. BLG-102 demonstrates exceptional detonation performance with a high detonation velocity (V_D = 9311 m·s^–1) and detonation pressure (P = 38.5 GPa). These values are superior to the well-known energetic compound RDX (V_D = 8991 m·s^–1, P = 35.2 GPa), and are comparable to HMX (V_D = 9144 m·s^–1, P = 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.