N -Methylene-C Bridged 4-Azido-3,5-dinitropyrazole and N -Hydroxytetrazole: Metal-Free Primary Explosive and Powerful Secondary Explosives

Here, we investigate a potential metal-free primary explosive, 5-((4-azido-3,5-dinitro-1H-pyrazol-1-yl)methyl)-1H-tetrazol-1-ol (5), constructed by combining the 4-azido-3,5-dinitro-1H-pyrazol (AzDNP) framework with the N-hydroxytetrazole scaffold via N-methylene-C linkage. The primary explosive behavior of compound 5 was evaluated through preliminary combustion tests and by measuring its activation energy (Ea = 122.0 kJ mol–1), which falls within the typical range of conventional primary explosives. In addition, a series of high-performing secondary explosives (7–15) with fine-tuned energy and stability properties was also synthesized via salt formation. Energetic salts 6, 7, 9, and 10 showed energetic performance comparable to that of traditional explosive RDX.