The triazole moiety with a high heat of formation and a high nitrogen content has been investigated for decades in combination with other nitrogen-rich heterocyclic rings in the field of energetic materials. A novel strategy for the construction of both thermally stable and mechanically insensitive energetic materials using a multi-aminotriazole system is now described. Using this methodology, two series of energetic materials were created on the basis of a duo of triazoles, 5-amino-3-(3,4-diamino-1,2,4-triazol-5-yl)-1H-1,2,4-triazole (TT), and a trio of triazoles, 4,5-di­(3,4-diamino-1,2,4-triazol-5-yl)-2H-1,2,3-triazole (TTT). Their nitrogen-rich salts were also synthesized. Compound TT exhibits an excellent onset decomposition temperature (T d = 341 °C), which is superior to that of the conventional heat-resistant explosive hexanitrostilbene (HNS) (T d = 318 °C). The nitrogen-rich salt 4,5-di­(3,4-diamino-1,2,4-triazol-5-yl)-2H-1,2,3-triazolium 3,4,5-trinitropyrazol-1-ide (TTT-1) exhibits both remarkable detonation properties and low sensitivities (D v = 8715 m s–1; P = 32.6 GPa; IS > 40 J; FS > 360 N), which are superior to those of the traditional explosive LLM-105 (D v = 8639 m s–1; P = 31.7 GPa; IS = 20 J; FS = 360 N). Therefore, this methodology of building a multi-aminotriazole system could effectively assist in the design of thermally stable and mechanically insensitive energetic materials in future exploration.

For an energetic molecule with a definite elemental composition, the substituent type and position are the most important factors to influence its detonation performance and mechanical sensitivities. In this work, two pairs of FOX-7-like energetic isomers based on (2 and HTz-FOX; 5 and 6) were synthesized and characterized. Through positional isomerization, advanced high-performance insensitive explosives were obtained. Compounds 2 and 5 with an amino group adjacent to the electron-withdrawing side of the ethene bridge show both higher thermal stability and lower mechanical sensitivities (2: T d = 258 °C, impact sensitivity (IS) = 25 J, and friction sensitivity (FS) = 300 N; 5: T d = 264 °C, IS = 30 J, and FS = 320 N). In addition, 2 shows ultrahigh detonation performance (D v = 9224 m s–1 and P = 31.1 GPa). These promising physicochemical properties are comparable to those of HMX (D v = 9193 m s–1, P = 37.8 GPa, T d = 275 °C, IS = 7.4 J, and FS = 120 N), which suggests that 2 may be a promising energetic material in future applications.

No abstract

Exploring derivatives of FOX-7 to improve the thermal stability has been an important project in the field of energetic materials. Creating vicinal nitro/amino arrangement and planar structure are the most common strategies used to improve the thermal stability of energetic materials. In this research, a carbonyl substituted vicinal nitro/amino pyrimidine (4) with planar structure was synthesized. It showed ultrahigh thermal stability with the onset decomposition temperature of 328 °C, which is higher than the commonly used heat-resistant explosive hexanitrosilbene (HNS) (T d = 322 °C). 4 also exhibited extremely low mechanical sensitivities, compared to these of HNS, which further guaranteed its application as an HNS replacement.

Lead-free, eco-friendly primary explosive which can replace lead azide (LA) has been a long-lasting challenge. Hereby, a new candidate copper(I) 5-(2,2-diamino-1nitrovinyl)tetrazolate (CTX) was synthesized through a mild metathesis reaction by bridging nitrogen-rich heterocycles with Cu(I) centers. The structure was characterized with IR spectrum, NMR spectrum, X-ray diffraction, and elemental analysis. The linear reinforced structure and condensed packing pattern of CTX lead to its high density (2.16 g cm À 3 ) and low sensitivities (IS = 10 J, FS > 120 N). It also exhibits a remarkably high thermal stability (340 °C), which to our knowledge, is the highest one known for the energetic coordination polymers (ECPs). The initiation capability test reveals CTX has high priming ability comparable to LA. The combined properties and performances contribute to its future prospects as a promising green primary explosive.