4-Amino-1,2,3-triazine 2-oxide: a promising structural unit for the design and synthesis of novel energetic materials with good thermal stability and low impact sensitivity

Abstract

A new [6,6]-fused ring energetic molecule, 4-amino-6,8-dinitrobenzo[d][1,2,3]triazine 2-oxide (1), was designed and synthesised using 4-amino-1,2,3-triazine 2-oxide as the basic skeleton unit. Subsequently, an amino group was incorporated into the corresponding position of compound 1via a vicarious nucleophilic substitution (VNS) reaction, resulting in the formation of 4,5-diamino-6,8-dinitrobenzo[d][1,2,3]triazine 2-oxide (2). Despite the introduction of adjacent C–NO₂/C–NH₂ blocks into the molecular structure of compound 2, which is generally accepted to contribute to the increase in the thermal decomposition temperature of energetic molecules, the results of thermal analysis demonstrated that the thermal decomposition temperature of compound 2 (T_d = 285 °C) was lower than that of its precursor (T_d = 311 °C). This suggested that the incorporation of adjacent C–NO₂/C–NH₂ blocks into the molecular structure did not inevitably lead to the formation of novel energetic molecules with enhanced thermal decomposition temperatures. To elucidate the mechanism behind this phenomenon, the structures of compounds 1 and 2 were subjected to detailed analysis using X-ray diffraction and quantum chemical calculations. Both 1 and 2 displayed high resistance to mechanical impact and were prepared using straightforward methods. The aforementioned results suggested that both 1 and 2 can be employed as heat-resistant, insensitive energetic materials.