Introducing Azide into Fully Nitrated Systems: Charge Mutations toward Advanced Initiators

Over the past century, the continuous search for advanced initiators has been a major challenge in the field of high-energy-density materials. In this study, we revealed a new strategy for constructing initiators by inducing intramolecular charge mutations, achieved by introducing a strongly charge-positive azide group into highly charge-negative fully nitrated systems. Two azide functionalized fully nitrated compounds─3-nitro-5-azide-1-trinitromethyl-1H-1,2,4-triazole (ATT) and 3-nitro-6-azide-1-trinitromethyl-1H-[1,2,4]triazolo[3,2-c][1,2,4]triazole (FTT with α and β polymorphs)─were designed and synthesized. Among these, β-FTT demonstrated a record density of 1.967 g/cm³ and detonation velocity of 9587 m/s, outperforming all previously reported organic azide compounds. Moreover, the initiation capability of β-FTT was assessed through its notably low minimum primary charge (MPC) of 30 mg, which exceeded those of representative organic initiators such as DDNP (MPC: 70 mg) and ICM-103 (MPC: 60 mg), establishing it as one of the most efficient organic initiators available. Mechanistic investigations demonstrated that charge mutations enhanced the initiating performance when compared to typical initiators and fully nitrated systems. Furthermore, high-density β-FTT demonstrated superior initiating ability relative to low-density α-FTT, challenging traditional notions regarding initiators─that density does not correlate with initiating ability. This study provides new insights into advanced initiators while emphasizing the influence of molecular charge on energy output performance.