Strategy for Balance\nEnergy and Safety: Salt Formation\nof Nitrogen-Rich Bicyclic Compounds Based on 1,2,4-Triazole

Nitrogen-rich heterocycles with high energy are ideal\nunits for\nthe design of energetic materials. An improved one-step reaction was\ncarried out to obtain (tetrazolyl)-1,2,4-triazole <b>2</b> and\n(1,3,4-oxadiazolyl)-1,2,4-triazole <b>7</b>. A series of energetic\nsalts <b>3</b>–<b>5</b> and <b>9</b>–<b>11</b> were synthesized by treating <b>2</b> and <b>7</b> with the corresponding bases and acids, respectively. Single-crystal\nX-ray diffraction, elemental analysis, NMR spectroscopy, IR spectroscopy,\nsynchronous thermal analysis, and a laser ignition system were used\nto characterize these synthesized compounds. All energetic salts expressed\ngood stability (<i>T</i><sub>d</sub> > 150 °C) and\nhigh nitrogen and oxygen content (N + O > 73.7%). Especially, hydrazinium\nsalt <b>4</b> and dinitramide salt <b>11</b> exhibited\ngood detonation velocities with the values of 9243 m s<sup>–1</sup> and 8226 m s<sup>–1</sup>, respectively, which were higher\nthan those of traditional insensitive explosive TATB (<i>D</i> = 8179 m s<sup>–1</sup>). Especially, <b>4</b> showed\nthe best combustion performance. Salt formation contributes a simple\nand safe method to balance energy and safety in the field of energetic\nmaterials.