From the sensitive primary explosive ICM-103 to insensitive heat-resistant energetic materials through a local azide-to-amino structural modification strategy

With the increasing demand for deep mineral resources and rapid development of space exploration, the search for advanced heat-resistant energetic compounds have attracted increasing attention in the field of energetic materials. In this study, we designed and prepared two new fused aromatic nitrogen heterocyclic compounds of 4-amino-5-nitro-7H-pyrazolo[3,4-d][1,2,3]triazine-2-oxide (PTO) and 4-amino-7-methyl-5-nitro-7H-pyrazolo[3,4-d][1,2,3]triazine-2-oxide (MPTO) by a local structural modification on a highly sensitive initiating explosive (ICM-103). This minor structural adjustment endows PTO and MPTO with totally different properties in contrast to the starting material (ICM-103). The decomposition temperatures of PTO and MPTO reached 365.0 °C and 347.7 °C, respectively, around 200 °C higher than that (160.3 °C) of ICM-103. Moreover, PTO and MPTO also exhibit good detonation velocity (8528 m s⁻¹ and 8102 m s⁻¹, respectively) and low impact sensitivity (20 J and 18 J, respectively). The comprehensive performances of PTO and MPTO are superior to the widely used heat-resistant energetic materials HNS (T_d: 318 °C, D_v: 7612 m s⁻¹, IS: 5 J) and PYX (T_d: 360 °C, D_v: 7757 m s⁻¹, IS: 10 J), demonstrating their important applied potentiality as novel heat-resistant energetic materials.