Multipurpose Energetic Materials by Shuffling Nitro Groups on a 3,3′-Bipyrazole Moiety

A family of 3,3′-bipyrazole-based energetic compounds having C-NO₂/N-NO₂ functionalities was synthesized by using various nitrating conditions. These nitro derivatives of bipyrazole are significantly more dense and energetic compared to the corresponding nitropyrazole analogues while maintaining the desired thermal stability and sensitivity. Depending on the number and nature of energetic nitro groups (C-NO₂/N-NO₂), different classes of energetic materials, such as green primary explosives, high-performance secondary explosives and heat-resistant explosives, were obtained. All the compounds were thoroughly characterized by IR, NMR [¹H, ¹³C{¹H}, ¹⁵N], elemental analysis, and differential scanning calorimetry (DSC). Four were also structurally characterized with single-crystal X-ray diffraction studies. Heats of formation and detonation performance were calculated using Gaussian 03 and EXPLO5 v6.01 programs, respectively.