Synthesis of 5-Nitrotetrazolates by the Direct Oxidation of 5-Aminotetrazole in a Single-Pot Synthesis without Isolation of Explosive Intermediates

Chemistry of 2,5-diaminotetrazole

1,5-Diaminotetrazole is one of the most prominent high-nitrogen tetrazole compounds described in the literature. Interestingly the isomer 2,5-diaminotetrazole is nearly undescribed due to its challenging synthetic routes. 2,5-Diaminotetrazol (1) was successfully synthesized via amination of 5-aminotetrazole followed by various purification steps to separate it from isomeric 1,5-diaminotetrazole. In addition to the extensive characterization of 2,5-DAT further derivates by protonation, methylation and amination of the tetrazole ring were synthesized and characterized. The resulting tri-functionalized, ionic tetrazolium derivatives were combined with energetic anions (nitrate, perchlorate, azide, 5,5'-bistetrazole-1,1'-diolate (BTO^2-)) to adjust and tune the properties of each compound. All compounds were intensively characterized including IR and multinuclear NMR spectroscopy, thermal analysis through DTA, X-ray diffraction and sensitivity testing. The purity was verified by CHNO elemental analysis and the energetic properties were calculated using the EXPLO5 code and the calculated enthalpy of formation (CBS-4M).

1,3,4,5-Tetraamino-1,2,4-triazolium Cation: An Energetic Moiety

The amination of 3,4,5-triamino-1,2,4-triazole with O-tosylhydroxylamine yielded the nitrogen-rich 1,3,4,5-tetraamino-1,2,4-triazolium cation as its tosylate salt. Subsequent metathesis reactions produced energetic salts with various energetic anions, including perchlorate, nitrate, nitrotetrazolate, and bistetrazolate diolate. All energetic salts possess relatively high heats of formation, thermal sensitivities, and detonation velocities and pressures. The prepared energetic salts were characterized chemically using single-crystal X-ray crystallography, elemental analysis, and ¹H NMR, ¹³C NMR, and IR spectroscopy and energetically by measuring their thermal, impact, and friction sensitivities. ¹⁵N NMR was carried out on the tosylate salt. Energetic performances were determined by a combined experimental-computational method using calculated heats of formation and experimental crystal densities.

Methyl sydnone imine and its energetic salts

First investigation of this new energetic cation, which may greatly expand the range of possible energetic salts available.