An interesting 1,4,2,5-dioxadiazine-furazan system: structural modification by incorporating versatile functionalities

Abstract

Herein, the 1,4,2,5-dioxadiazine ring is combined with two furazan rings. Interestingly, the structure of the 1,4,2,5-dioxadiazine-furazan system can be modified by incorporating versatile functionalities. The N-trinitroethylamino functionalization derivatives and energetic salts based on 3,6-bis(4-amino-1,2,5-oxadiazol-3-yl)-1,4,2,5-dioxadiazine are investigated. Derivatives of these functionalities are synthesized and fully characterized via multinuclear NMR spectroscopy, IR spectroscopy, and elemental analysis. The structures of compounds 1–7 are further confirmed by single-crystal X-ray diffraction. Compounds 1–12 have moderate thermal stabilities (143–177 °C, except 2 (114 °C), and 3 (88 °C)) and exhibit acceptable sensitivities (IS 3.52–16.3 J and FS 100–240 N). Based on the measured densities (1.73–1.95 g cm⁻³) and heats of formation (573.5–2065.4 kJ mol⁻¹), the detonation velocities (D 8519–9563 m s⁻¹) and pressures (P 29.3–43.3 GPa) are calculated. Among them, the trinitroethylamino derivative 1 and ammonium salt of 3,6-bis(4-nitroamino-1,2,5-oxadiazol-3-yl)-1,4,2,5-dioxadiazine 5 show a layered assembly of the 1,4,2,5-dioxadiazine-furazan system. These two compounds show good thermal stabilities (1, 154 °C and 5, 177 °C) and relatively low sensitivities (1, 16.3 J and 5, 13.4 J). These properties indicate that the layer assembly structure is helpful to improve the thermal stabilities and result in low sensitivities for the corresponding compounds.