Nitrogen-rich metal-free salts: a new look at the 5-(trinitromethyl)tetrazolate anion as an energetic moiety

A series of energetic nitrogen-rich salts comprised of a 5-(trinitromethyl)tetrazolate anion and high-nitrogen cations was synthesized by simple and efficient chemical routes from readily available commercial reagents. These energetic materials were fully characterized by IR and multinuclear NMR ( 1 H, 13 C, 14 N) spectroscopy, elemental analysis, and differential scanning calorimetry (DSC). Additionally, the structure of an energetic salt containing the 3,6,7-triamino-7 H -[1,2,4]triazolo[4,3- b ][1,2,4]triazolium cation was confirmed by single-crystal X-ray diffraction. The synthesized compounds exhibit decent experimental densities (1.648-1.845 g cm −3 ) and positive enthalpies of formation (up to 725.5 kJ mol −1 ) and, as a result, superior detonation performance (detonation velocities 8.2-9.2 km s −1 and detonation pressures 28.5-37.8 GPa), which is comparable to or even exceeding those of commonly used booster explosive PETN. On the other hand, high mechanical sensitivity of several novel 5-(trinitromethyl)tetrazolate salts along with their high combined nitrogen-oxygen content (>81%) and excellent detonation performance render them environmentally friendly alternatives to lead-based primary explosives. Promising high-nitrogen and eco-friendly energetic salts with excellent detonation performance based on a 5-(trinitromethyl)tetrazolate core were prepared.