Studies on the synthesis and properties of nitramino compounds based on tetrazine backbones

In this paper, a series of novel energetic compounds based on the backbone of the tetrazine-triazole structure were successfully synthesized. N,N'-((1,2,4,5-Tetrazine-3,6-diyl)bis(1,2-dihydro-3H-1,2,4-triazole-5-yl-3-ylidene))dinitramino (4) was prepared by the nitration of 5,5'-(1,4-dihydro-1,2,4,5-tetrazine-3,6-diyl)bis(1H-1,2,4-triazol-3-amine) (3) with 100% nitric acid and its energetic salts (6-14) were also prepared. All the compounds were fully characterized. The structures of 4 and 5 were further confirmed by single crystal X-ray diffraction analysis. The results show that these compounds have high heats of formation ranging from 2.09 to 3.95 kJ g^-1, good detonation pressures and detonation velocities and acceptable sensitivities. Among them, compound 4, with low sensitivities (IS: 20 J and FS: 270 N) and excellent detonation properties (v_D = 9100 m s^-1; P = 34.1 GPa) shows potential for application in the field of highly energetic and insensitive explosives. The hydroxylammonium salt (7) exhibits promising energetic properties, which, in some cases, are superior to those of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX).