Energetic furazan-triazole with high thermal stability and low sensitivity: facile synthesis, crystal structures and energetic properties
The crystal stacking has significant implications for the properties of energetic materials, especially molecular stability. A series of furazan-triazole energetic compounds with diverse crystal stacking were synthesized through a facile procedure. All new compounds were characterized by NMR spectroscopy, IR spectroscopy, elemental analysis, and differential scanning calorimetry (DSC). Single crystal X-ray analysis indicated that compounds 2a and 2c show face-to-face stacking while compounds 3 and 3a exhibit wavelike stacking as a result of planar furazan-triazole skeleton . Furthermore, on the basis of single-crystal data, noncovalent interactions were analyzed to comprehensively study their structure-property relationships. The compound 2b are highly stable, including a decomposition temperature of 324 °C, an impact sensitivity of > 40J, and friction sensitivity of > 360J, and thereby demonstrate the potential applications as a heat-resistant and insensitive explosive. Whereas 3b with its superior detonation velocity (9114 m s-1) and pressure (35.8 GPa) and favorable stability (Td = 226 °C, IS = 20 J, FS = 280 N), exhibits performances superior to those of RDX. This work put insights on the combination of molecular design and crystal stacking for generating new energetic materials.