N-Acetimidamide functionalized 5-aminotetrazole: a precursor to thermally stable and insensitive nitrogen-rich energetic materials.

A novel nitrogen-rich cationic precursor (compound 2) was designed and synthesized by linking an acetimidamide moiety to 5-aminotetrazole. In contrast to conventional 5-aminotetrazole-derived energetic compounds, which typically form energetic salts with strong acids (e.g., nitric and perchloric acids), compound 2 readily pairs with both strong acids and a range of nitrogen- and oxygen-rich weak acids. This strategy enabled the synthesis of a series of high-performance nitrogen-rich ionic energetic materials (4-11). All the compounds were fully characterized by NMR spectroscopy, IR spectroscopy, and elemental analysis, while the structures of energetic salts 2, 4, and 11 were further confirmed by single-crystal X-ray diffraction. Among all the synthesized compounds, energetic salt 10 (ρ = 1.83 g cm-3; Dv = 9165 m s-1; P = 32.3 GPa) exhibited exceptionally high-performance properties and outperformed the conventionally used energetic compounds RDX and HMX. Notably, most of the synthesized salts displayed higher energetic performance than the salts derived from the corresponding energetic acids and previously reported 5-aminotetrazole-based cations. Additionally, they exhibited a marked improvement in overall stability (thermal and physical) compared to their parent energetic acids. Computational analyses, including Hirshfeld surface analysis, 2D fingerprint plot, noncovalent interaction (NCI), reduced density gradient (RDG), and electrostatic potential (ESP) studies, were also conducted to establish correlations between the molecular structures and properties of energetic salts 4 and 11.