Amino-nitramino functionalized triazolotriazines: a good balance between high energy and low sensitivity

Using a simple and efficient approach, a series of fused triazolo-triazine compounds, namely, 2,5-dinitramide-7-amino-[1,2,4]triazolo[1,5-a][1,3,5]triazine (2) and its energetic salts (4-9, 11-13), were prepared by nitration of 2,5,7-triamine [1,2,4]triazolo[1,5-a][1,3,5]triazine (1) with 100% nitric acid, followed by reacting with the corresponding bases. All new compounds were comprehensively characterized. Structures of 2 and 4 were further confirmed by single crystal X-ray diffraction. Based on the measured densities and calculated heats of formation (Gaussian 09), detonation pressures and velocities were evaluated by EXPLO5, falling in the range of 21.5-34.2 GPa and 7823-9313 m s-1, respectively. Notably, impact and friction tests show that these compounds are very insensitive (IS > 40 J; FS > 360 N). Moreover, two representative compounds 5 and 6 with high decomposition temperature (5: 194 °C; 6: 199 °C), excellent detonation properties (vD = 9313, 9088 m s-1; P = 33.9, 34.1 GPa) as well as rarely low sensitivities (IS > 40 J; FS > 360 N) are promising candidates as high-energy and insensitive explosives.