Construction of a series of insensitive energetic materials starting from the condensation reaction of 3-amino-4-cyanofurazan

Abstract

Multicyclic compounds containing a 1,2,5-oxadiazole core exhibit high density and excellent thermal stability due to their 3,4-substitution arrangement, which facilitates attaining a planar conformation. In this work, a series of new compounds (2–5) that consist of 1,2,5-oxadiazoles bonded to other heterocycles or modifiable groups via stable C–C bonds are synthesized through condensation reactions of 3-amino-4-cyanofurazan. Then their 14 energetic derivatives were developed. The synthesis methods and chemistry involved in the production of these novel energetic materials have been explained. The new compounds were investigated through IR, NMR (¹H and ¹³C) spectroscopy, elemental analysis, and single-crystal X-ray diffraction studies. The thermal decomposition temperatures of the samples were determined using thermogravimetry and differential scanning calorimetry and found to range from 136 °C to 345 °C (onset). Furthermore, the results of impact and friction testing showed that these compounds exhibited greater insensitivity compared to FOX-12. Detonation properties, densities, and heats of formation were determined through the EXPLO5 v6.05.04 program, a gas pycnometer, and the Born–Haber energy cycle, respectively. The combination of good detonation properties, enhanced thermal stabilities, and low sensitivities indicates that certain compounds (8, 9, 12, 14, and 16) could be promising contenders for insensitive energetic uses. Interestingly 6-(1H-tetrazol-5-yl)-[1,2,5]oxadiazolo[3,4-b]pyridine-5,7-diamine (7) displays fluorescence, making it a promising option for usage as an energetic filler or in the production of energetic materials to facilitate easy detection.