Series of AzTO-Based Energetic Materials: Effect of Different π–π Stacking Modes on Their Thermal Stability and Sensitivity

π-Stacking
is common in materials, but different π–π
stacking modes remarkably affect the properties and performances of
materials. In particular, weak interactions, π-stacking and
hydrogen bonding, often have a great impact on the stability and sensitivity
of high-energetic compounds. Therefore, several of energetic materials
based on 1,1′-dihydroxyazotetrazole (1) with a
nearly flat structure, such as the salts of aminoguanidine (2), 1,3-diaminoguanidine (3), imidazole (4), pyrazole (5) and triaminoguanidine (6), and a cocrystal of 2-methylimidazole (7),
were designed and synthesized. Based on single-crystal diffraction
data, thermal decomposition behaviors, and the mechanical sensitivity
test, the compounds of 4, 5, and 7 with face-to-face π–π stacking display outstanding
thermal stability and insensitivity.