Insight into the structural and energetic features of substituted triazolofurazans

Abstract

A comparative study of experimentally established structures, stability and energetic performance of ammonium and hydrazinium salts of 4H-[1,2,3]triazolo[4,5-c][1,2,5]oxadiazole (triazolofurazan, TF) as well as its N-oxide and N-nitroimide was performed. The aim of this study was to reveal the structure–property relationships of heterocyclic systems by the example of triazolofurazan derivatives. It was shown that the introduction of N-oxide oxygen into position 5 of the TF anion led to a small loss in enthalpy of formation (4 kcal mol⁻¹) while the introduction of the N–NO₂ (N-nitroimido) group in the same position added a significant amount of energy into the molecule (36 kcal mol⁻¹). Both substituents improved the oxygen balance and increased the density (0.065–0.22 g cm⁻³) of the final salts; however, only N-oxide enhanced the thermal stability by ca. 35–45 °C, while N-nitroimide either remained unchanged or decreased the heat resistance compared to unsubstituted analogues.