The Ingenious Synthesis of a Nitro-Free Insensitive High-Energy Material Featuring Face-to-Face and Edge-to-Face π-Interactions

Abstract

Density, detonation property, and sensitivity may be the most valued features when evaluating an energetic material. By reasoning structure–property relationships, a nitro-free planar energetic material with high nitrogen and oxygen content, 7-hydroxy-difurazano[3,4- b :3′,4′- f ]furoxano[3″,4″- d ]azepine ( 4 ), was synthesized using a unique and facile approach. The structure was fully characterized by IR and NMR spectra, elemental analysis, differential scanning calorimetry (DSC), and single-crystal X-ray diffraction. The expected properties of 4 , including a high density of 1.92 g cm −3 , high detonation velocity of 8,875 m s −1 , and low mechanical sensitivities (impact sensitivity, 21 J and friction sensitivity, >360 N), confirm our strategy. Interestingly, the single-crystal structures of 4 reveal expected face-to-face and edge-to-face π-interactions in the crystal stacking. The remarkable differences in crystal stacking of 4 provide unequivocal evidence that face-to-face π-π interactions contribute significantly to closer assembly and higher density.

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

“…By incorporating energy-rich functional groups (-NO 2 , -NHNO 2 , -ONO 2 , etc.) into furazan backbones, a large number of energetic materials with excellent detonation properties were successfully developed (Tang et al, 2016;Liu et al, 2018;Zhai et al, 2019;Zhang et al, 2019). Meanwhile, it is noteworthy that an inevitable and inherent contradiction existed SCHEME 1 | (A-C) Electrostatic potential of compounds 6 and 8 [B3LYP/6-31+G** 0.001 electron/b3 isosurface, energy values −0.03 to +0.03 H].…”

Bionic inspired multifunctional modular energetic materials: an exploration of new generation of application-oriented energetic materials

“…5k, the wide green region isosurface between the parallel furazan rings in model B implies face-to-face p-p interactions caused by p-p stacking, which contribute to the efficient packing (density) and insensitivity. [48][49][50] To obtain a better understanding of the relationship between intermolecular interactions and their physical characteristics, the associated Hirshfeld surfaces analysis and two-dimensional ngerprints were employed. 45,46,51,52 In model A, the strong O/H interaction (2.256 Å, 34.0%) integrates two "side-by-side" monomers into a close binary monomer (Fig.…”

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

“…From a practical standpoint, cyanofurazan/furoxan has been regarded as one of the most important energetic intermediates for the synthesis of nitrogen-rich energetic compounds comprising furazan and furoxan structures, and these key cyanofurazan/furoxan structures mainly include 3-amino-4-cyanofurazan, 4-amino-3-cyanofuroxan, 3,4-dicyanofurazan, and 3,4-dicyanofuroxan. From a synthetic standpoint, cyano groups in cyanofurazan/furoxan structures enjoy a high degree of transformational diversity and can be further transformed into other heterocyclic five-membered rings such as furoxan, isofurazan, tetrazole, and isoxazole, leading to a series of linear or fused frameworks of nitrogen-rich energetic compounds ( Qu et al, 2016 ; Pagoria et al, 2017 ; Wu et al, 2017 ; Zhai et al, 2019a ; Johnson et al, 2020 ). The cyano groups could also be easily turned to highly powerful explosophoric groups of dinitromethyl, trinitromethyl, and fluorodinitromethyl groups ( Gu et al, 2018 ).…”