Thermostable Insensitive Energetic Materials Based on a Triazolopyridine Fused Framework with Alternating Nitro and Amine Groups

In this work, we designed and synthesized a series of novel triazolopyridine fused-ring compounds with alternating nitro and amine groups. Three compounds showed remarkable thermal stability at 256, 310, and 294 °C, respectively, and a low mechanical sensitivity [impact sensitivity (IS) = 40 J, friction sensitivity (FS) = 324 N; IS = 35 J, FS = 240 N; and IS > 40 J, FS = 324 N, respectively]. Significantly, two of these compounds exhibited a better detonation performance [detonation velocity (D) = 8200 and 8335 m s -1, Detonation pressure (P) = 25.6 and 27.2 GPa, respectively] than the widely used heat-resistant explosive hexanitrostilbene (HNS; D = 7612 m s -1, P = 24.3 GPa). Additionally, a nitramine derivative displayed a detonation performance (D = 8569 m s -1, P = 31.3 GPa) similar to that of the high-energy explosive RDX. The superior properties of the materials were further confirmed by X-ray diffraction analysis and by several theoretical calculations (ESP, LOL-π, Hirshfeld surfaces, RDG, and NCI analyses). These results indicated that the three compounds might be potential candidates for use as heat-resistant energetic materials.