A Family of Energetic Materials Based on 1,2,4-Oxadiazole and 1,2,5-Oxadiazole Backbones With Low Insensitivity and Good Detonation Performance

Abstract

Design and synthesis of new compounds with both high detonation performances and good safety properties have always been a formidable task in the field of energetic materials. By introducing -ONO 2 and -NHNO 2 moieties into 1,2,4-oxadiazole-and 1,2,5-oxadiazole-based backbones, a new family of energetic materials, including ammonium 3-nitramino-4-(5-hydroxymethyl-1,2,4-oxadiazol-3-yl)-furazan (4), 3,3 ′ -bis[5-nitroxymethyl-1,2,4-oxadiazol-3-yl]-4,4 ′azofuroxan (6), [3-(4-nitroamino-1,2,5-oxadiazol-3-yl)-1,2,4-oxadiazol-5-yl]-methylene nitrate (8), and its energetic ionic salts (10-12), were synthesized and fully characterized. The energetic and physical properties of the materials were investigated through theoretical calculations and experimental determination. The results show that the oxadiazole-based compounds exhibit high enthalpy of formations, good detonation performances, and extraordinary insensitivities. In particular, the hydrazinium salt (11) shows the best energetic properties (11: d =1.821 g cm −3 ; P = 35.1 GPa, v D = 8,822 m s −1 , IS = 40 J, FS > 360 N). The ESP and Hirshfeld surface analysis indicated that a large number of hydrogen bonds as well as π-π stacking interactions within molecules might be the key reason for their low sensitivities and high energy-density levels.

Tetrazole Azasydnone (C2N7O2H) And Its Salts: High‐Performing Zwitterionic Energetic Materials Containing A Unique Explosophore

“…This has the advantage of increasing oxygen balance and setting up polarized bonds allowing high densities. While this strategy has been very welle xplored in the 2-carbon5 -membered heterocycles with oxadiazole-based energetic materials, [31][32][33][34] introducing an oxygen to a5 -membered 1-carbon heterocycle is less explored as an energetic backbone. ( Figure 2)…”

Synthesis of Energetic 7-Nitro-3,5-dihydro-4H-pyrazolo[4,3-d][1,2,3]triazin-4-one Based on a Novel Hofmann-Type Rearrangement

“…As has been proved in the insensitive structures of TATB and LLM-105, strong hydrogen bonds can significantly reduce the “hot spots” in a crystal [ 21 , 22 , 23 , 24 ]. There are seven types of intermolecular hydrogen bonds (N4-H2…N4’’ (3.0100 Å, 143.2°), O4-H4B...O3 (2.8837(4)Å, 162.9°), N3-H1…O5 (2.6453 Å, 170.0°), N4’-H2’…N2 (3.0100 Å, 143.2°), O5’-H5A’…O1 (2.9985 Å, 170.7°), O4-H4A’…N6 (2.8907 Å, 165.1°) and O5-H5A...O4 (2.7407(7)Å, 178.2°)), which explained the excellent insensitive performances of NPTO [ 25 , 26 ]. ( Figure 3 ).…”

Synthetic Strategies Toward Nitrogen-Rich Energetic Compounds Via the Reaction Characteristics of Cyanofurazan/Furoxan

“…Although the formation enthalpy of isofurazan (1,2,4-oxadiazole and 1,3,4-oxadiazole) is lower than that of furazan, its stabilities toward external stimuli are much higher ( Xue et al, 2019 ). Therefore, the introduction of isofurazans as desensitizing moieties to high-energy energetic compounds to form conjugate systems was an important strategy for the design and synthesis of low sensitivity and high-energy materials ( Xue et al, 2020 ).…”