Search

gem-Dinitro methyl based high-energy-density material 5-(dinitromethylene)-4,5-dihydro-1H-1,2,4-triazole (2) and its hydroxylamine salt (4) were synthesized for the first time in a single step and characterized. Further, the structure of 2was confirmed by single-crystal X-ray diffraction (SCXRD) studies. Interestengly, both the compounds show excellent density (> 1.83 g cm-3), detonation velocity (> 8700 m s–1), pressure (> 30 GPa) and are insensitive toward mechanical stimuli such as impact and friction sensitivity. Considering their synthetic fesibility and balanced energetic performance, compounds 2and 4show future prospects as potential next-generation energetic materials for the replacenent of many presently used benchmark high energy density materials such as RDX, FOX-7 and highly insensitive H-FOX.

In this work, we have synthesized 3,5-dihydrazinyl-4-nitro-1H-pyrazole (2), 9-nitro-1H-pyrazolo[3,2-c:5,1-c′]bis([1,2,4]triazole)-3,6-diamine (3), and N–N-bonded N,N′-{[4,4′-bi(1,2,4-triazole)]-3,3′-diyl}dinitramide (5) and its stable nitrogen-rich energetic salts in one and two steps in quantitative yields from commercially available inexpensive starting material 4,6-dichloro-5-nitropyrimidine (1). Along with characterization via nuclear magnetic resonance, infrared, differential scanning calorimetry, and elemental analysis, the structures of 2and 4–8were confirmed by single-crystal X-ray diffraction. Interestingly, 5–8show excellent thermal stability (242, 221, 250, and 242 °C, respectively) compared to that of RDX (210 °C). Detonation velocities of 2, 4, 6, and 7range from 8992 to 9069 m s–1, which are better than that of RDX (8878 m s–1) and close to that of HMX (9221 m s–1). All of these compounds are insensitive to impact (10–35 J) and friction (360 N) sensitivity. These excellent energetic performances, stabilities, and synthetic feasibilities make compounds 2, 4, 6, and 7promising candidates as secondary explosives and potential replacements for the presently used benchmark explosives RDX and HMX.

Various energetic salts (3a–f) were obtained from 1,3,5-tris[(2H-tetrazol-5-yl)methyl]isocyanurate (3), while N2,N4,N6-tri(1H-tetrazol-5-yl)-1,3,5-triazine-2,4,6-triamine (5) and N,N′-{6-[(1H-tetrazol-5-yl)amino]-1,3,5-triazine-2,4-diyl}bis[N-(1H-tetrazol-5-yl)nitramide] (6) were obtained from cyanuric chloride via a simple, efficient two-step synthetic route from inexpensive starting materials. Compounds 3a–fand 6show excellent detonation properties (VOD = 7876–8832 m s–1, and DP = 20.73–30.0 GPa), a high nitrogen content (>62%), and high positive heats of formation (205.2–1888.9 kJ mol–1) with excellent thermostability and remarkable insensitivity.

A novel fused-ring compound, 5-azido-6-oxo-6,7-dihydro-[1,2,5]oxadiazolo[3,4-b]pyrazine 1-oxide (3a), was synthesized for the first time with simple two-step process and characterized using various spectroscopic techniques such NMR, IR, EA and HRMS. Two polymorphs (α-3aand β-3a) identified by SCXRD differ in crystal packing and noncovalent interactions, demonstrating high density, substantial heat of formation, and superior detonation properties with reduced mechanical sensitivity compared to TNT, TATB, and close to RDX, suggesting their potential as environmentally friendly high energy density materials.