An unusual reaction of 1,1-diamino-2-nitro-2-(1H-triazol-5-yl)ethene and hydrazine: The synthesis of a dihydrotetrazine bridged energetic compound

The exploration of energetic derivatives of 1,1-diamino-2,2-dinitroethylene (FOX-7) is a feasible strategy for attaining high-performance energetic materials. Of all the extant types of energetic derivatives, hydrazino-substituted FOX-7 derivatives have received the most extensive attention because of their excellent detonation performance. However, the applications of these derivatives are restricted by their relatively high mechanical sensitivities. In this study, the exploration of the reaction between 1,1-diamino-2-nitro-2-(1H-triazol-5-yl)ethene (Tri-FOX) and hydrazine monohydrate resulted in the development of an unexpected dihydrotetrazine bridged energetic compound: 3,6-bis((E)-hydrazono(1H-1,2,4-triazol-5-yl)methyl)-1,4-dihydro-1,2,4,5-tetrazine (BHDT). BHDT exhibits high onset decomposition temperature (Td ​= ​240 ​°C), low impact sensitivity (IS ​= ​30 ​J), and low friction sensitivity (FS ​= ​270 ​N). These features are more advantageous than those of H-FOX (Td ​= ​125 ​°C, IS ​= ​6 ​J) and HTz-FOX (Td ​= ​237 ​°C, IS ​= ​10 ​J, FS ​= ​240 ​N). Reaction of 1,1-diamino-2-nitro-2-(1H-triazol-5-yl)ethene (Tri-FOX) and hydrazine monohydrate led to the formation of an unusual dihydrotetrazine bridged energetic compound, which exhibits good thermal stability (Td ​= ​240 ​°C) and low mechanical sensitivities (IS ​= ​30 ​J, FS ​= ​300 ​N). [Display omitted]