Synthetic Routes to a Triazole and Tetrazole with Trinitroalkyl Substitution at Nitrogen

Boosting the Energetic Performance of Trinitromethyl-1,2,4-oxadiazole Moiety by Increasing Nitrogen-Oxygen in the Bridge

The trinitromethyl moiety is a useful group for the design and development of novel energetic compounds with high nitrogen and oxygen content. In this work, by using an improved nitration method, the dinitromethyl precursor was successfully nitrated to the trinitromethyl product (2), and its structure was thoroughly characterized by FTIR, NMR, elemental analysis, differential scanning calorimetry, and single-crystal X-ray diffraction. Compound 2 has a high density (1.897 g cm⁻³), high heat of formation (984.8 kJ mmol⁻¹), and a high detonation performance (D: 9351 m s⁻¹, P: 37.46 GPa) that may find useful applications in the field of high energy density materials.

1,2-Bis(5-(trinitromethyl)-1,2,4-oxadiazol-3-yl)diazene: a water stable, high-performing green oxidizer

Trinitromethane moieties are very important for the design and development of high performing dense green oxidizers. The novel oxidizer 1,2-bis(5-(trinitromethyl)-1,2,4-oxadiazol-3-yl)diazene, 14 is stable in water in contrast to 1,2,4-oxadiazoles with other electron withdrawing substituents at the C5-position. Compound 14 is a CNO-based oxidizer with positive oxygen balance (+6.9%), moderate thermostability, and mechanical insensitivity that may find useful applications in the field of green rocket propallant.

Nitratoethyl-5H-tetrazoles: improving the oxygen balance through application of organic nitrates in energetic coordination compounds

1- and 2-Nitratoethyl-5H-tetrazole (1-NET and 2-NET) were prepared through nitration of the respective alkyl alcohol using 100% nitric acid. A mixture of 1- and 2-hydroxyethyl-5H-tetrazole was obtained after alkylation of 1,5H-tetrazole. Also, a one-pot synthesis of 1-hydroxyethyl-5H-tetrazole was developed enabling the selective preparation of 1-NET. Both organic nitrates were characterized by ¹H, ¹³C, and ¹H-¹⁵N HMBC NMR spectroscopy. In addition, calculations using the Hirshfeld method and the EXPLO5 code were performed. Principally, 20 energetic coordination compounds involving the d-metals Mn, Cu, Zn, and Ag, each structurally characterized by low temperature single crystal X-ray diffraction, were prepared based on 1-NET and 2-NET. Of these complexes, 18 were obtained as pure bulk materials, and therefore, characterized for impact, friction, and ball drop impact sensitivity, as well as electrostatic discharge and thermal stability using differential thermal analysis. Hot plate and hot needle tests were performed mostly showing strong deflagrations making the complexes candidates for green combustion catalysts. Furthermore, successful PETN initiation experiments were carried out for several complexes and all ECCs were investigated by laser ignition experiments.

A new oxygen-rich energetic salt dihydrazine tetranitroethide: a promising explosive alternative with high density and good performance

A novel high-energy salt with good oxygen balance, dihydrazine tetranitroethide (5), has been synthesized and characterized by FT-IR spectroscopy, NMR spectroscopy, elemental analysis, and X-ray single crystal diffraction. Compound 5 exhibits high crystal density (1.81 g cm-3) and impressive detonation velocity (9508 m s-1) and detonation pressure (37.9 GPa), showing potential applications as a high performance explosive and a promising additive of propellants.