Synthesis, characterization and properties of halogen-substituted 1,1-diamino-2-nitro-2-(1-amino-1H-tetrazol-5-yl) ethene derivatives as energetic materials

Azo-bridged FOX-7 derivatives with ultra-high theoretical detonation performance were seen as potential high-performance energetic materials. So far, most of the researches were focused on the diverse oxidation reactions involving 1,1-diamino-2,2-dinitroethene (FOX-7) as a starting material, which usually results in undesirable products. In this paper, by replacing the starting substrate from FOX-7 to its analogous 1,1-diamino-2-nitro-2-(1-amino-1H-tetrazol-5-yl) ethene (1), three unexpected halogenated-substituted compounds (2-4) were obtained rather than the anticipated azo-bridged products. The crystal structures of 2-4 were fully determined by single-crystal X-ray diffraction. The reaction mechanism and physicochemical properties to them were deeply investigated. 4 shows good detonation performance (D_v = 7554 m/s, P = 24.3 GPa), which are superior to these of TNT (D_v = 6881 m/s, P = 19.5 GPa). The methodology may be helpful for the exploration of azo-bridged FOX-7 compounds in the future.