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Owing to its simple preparation and high oxygen content, nitroformate [−C(NO2)3, NF] is an extremely attractive oxidant component for propellants and explosives. However, the poor thermostability of NF-based derivatives has been an unconquerable barrier for more than 150 years, thus hindering its application. In this study, the first example of a nitrogen-rich hydrogen-bonded organic framework (HOF-NF) is designed and constructed through self-assembly in energetic materials, in which NF anions are trapped in pores of the resulting framework via the dual force of ionic and hydrogen bonds from the strengthened framework. These factors lead to the decomposition temperature of the resulting HOF-NF moiety being 200 °C, which exceeds the challenge of thermal stability over 180 °C for the first time among NF-based compounds. A large number of NF-based compounds with high stabilities and excellent properties can be designed and synthesized on the basis of this work. Nitroformate is an attractive oxidant compound in propellants and explosives but its poor thermostability prevents it from application. Here, the authors demonstrate that incorporation of nitroformate in a hydrogen-bonded organic framework increases the thermostability of nitroformate. [ABSTRACT FROM AUTHOR]

5-(4-Azidofurazan-3-yl)-1-hydroxytetrazole (4) and its ammonium (4a), hydroxylammonium (4b), and hydrazinium (4c) salts were synthesized. Each compound was characterized by X-ray single crystal structure diffraction, infrared (IR), and 1H and 13C NMR spectroscopy, elemental analyses, thermal stability, and sensitivity to external stimulants. Crystal structures and packing coefficients were analyzed and compared with respect to π–π stacking and hydrogen bonding. Due to the presence of lattice water in compound 4, the impact sensitivity (IS = 15 J) and friction sensitivity (FS = 120 N) are notably lower than those of the anhydrous material (IS = 3 J, FS = 20 N), which could act as a primary explosive. In this way, the primary explosive could be synthesized, transported, and stored more safely than traditional primary explosives. The detonation properties determined by EXPLO 6.02 software show that among the four compounds, 4b has superior detonation velocity (Vd = 9201 m s−1) and pressure (P = 36.0 GPa) values which are comparable to those of HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine). The impact sensitivity (10 J) is less-sensitive than HMX (7.5 J), which suggests compound 4b as a potential alternative to HMX. [ABSTRACT FROM AUTHOR]

An analogue-oriented synthetic route for the formulation of furazan-functionalized 5-nitroimino-1,2,4-triazoles has been explored. The process was found to be straightforward, high yielding, and highly efficient, and scalable. Nine compounds were synthesized and the physicochemical and energetic properties, including density, thermal stability, and sensitivity, were investigated, as well as the energetic performance (e.g., detonation velocities and detonation pressures) as evaluated by using EXPLO5 code. Among the new materials, compounds 4- 6 and 11 possess high densities, acceptable sensitivities, and good detonation performances, and thereby demonstrate the potential applications as new secondary explosives. [ABSTRACT FROM AUTHOR]

A new class of N,N′-ethylene-bridged bis(nitropyrazoles) was synthesized and fully characterized. The highly efficient formation of the N,N′-ethylene bridge was accomplished using dibromoethane and ammonium or potassium pyrazolate. Further functional-group transformations of diaminobis(pyrazole) and dichlorobis(pyrazole) gave rise to diversified derivatives, including dinitramino-, diazido- and hexanitrobis(pyrazole). Single-crystal X-ray diffractions were obtained for hexanitro and diazido derivatives to illustrate the structural characteristics. Heats of formation and detonation performance were calculated by using Gaussian 03 and EXPLO5 v6.01 programs, respectively. Because of the different functionalized groups, the impact and friction sensitivities of these new compounds range from insensitive to sensitive. Among them, the hexanitro derivative displays the most promising overall energetic properties (density ( ρ)=1.84 g cm−3; decomposition temperature ( Td)=250 °C; detonation pressure ( P)=34.1 GPa; detonation velocity ( vD)=8759 m s−1; impact sensitivity (IS)=25 J; friction sensitivity (FS)=160 N), which is competitive with those of 1,3,5-trinitrotriazacyclohexane ( ρ=1.80 g cm−3; Td=205 °C; P=35.0 GPa; vD=8762 m s−1; IS=7 J; FS=120 N). [ABSTRACT FROM AUTHOR]

3,6-Dinitropyrazolo[4,3-c]pyrazole was prepared using an efficient modified process. With selected cations, ten nitrogen-rich energetic salts and three metal salts were synthesized in high yield based on the 3,6-dinitropyrazolo[4,3-c]pyrazolate anion. These compounds were fully characterized by IR and multinuclear NMR spectroscopies, as well as elemental analyses. The structures of the neutral compounds 4 and its salt 16 were confirmed by single-crystal X-ray diffraction showing extensive hydrogen-bonding interactions. The neutral pyrazole precursor and its salts are remarkably thermally stable. Based on the calculated heats of formation and measured densities, detonation pressures (22.5-35.4 GPa) and velocities (7948-9005 m s−1) were determined, and they compare favorably with those of TNT and RDX. Their impact and friction sensitivities range from 12 to >40 J and 80 to 360 N, respectively. These properties make them competitive as insensitive and thermally stable high-energy density materials. [ABSTRACT FROM AUTHOR]

The straightforward synthesis and energetic properties of a new class of energetic materials, 1,2,3-triazolo- [4,5- e]furazano[3,4- b]pyrazine 6-oxide and its energetic salts are described. They were characterized by IR and multinuclear NMR spectroscopy, elemental analysis, differential scanning calorimetry, and single-crystal X-ray diffraction are given. The X-ray structures show that in the title compound, the hydrogen atom is bonded to the nitrogen in the pyrazine ring; however, in the salts, the negative charge is associated with the triazole nitrogen. Heats of formation for all compounds were calculated with the G2 method and then combined with experimentally determined densities to obtain detonation pressures ( P) and velocities ( D) by using EXPLO5 program. These new materials exhibit good densities and thermal stabilities, high heats of formation, acceptable detonation properties, and are insensitive to impact. [ABSTRACT FROM AUTHOR]

1,3-Dichloro-2-nitro-2-azapropane is an excellent precursor to dense energetic functionalized dipyrazolyl- N-nitromethanamines. This new family of energetic compounds was fully characterized by using 1H, 13C, and 15N NMR and IR spectroscopy, differential scanning calorimetry, elemental analysis, and impact sensitivity tests. Additionally, single-crystal X-ray structuring was done for 3 and 5⋅CH3CN, which gave insight into structural characteristics. The experimentally determined densities of 2- 9 fall between 1.69 and 1.90 g cm−3. Heats of formation and detonation properties were calculated by using Gaussian 03 and EXPLO5 programs, respectively. The influence of different energetic moieties on the structural and energetic properties was established theoretically. [ABSTRACT FROM AUTHOR]

Fifteen iodo compounds and six iodyl compounds with an iodine content between 45.3 and 89.0 % were prepared. The mono, di, and triiodyl compounds were obtained from the corresponding iodo compound by employing Oxone. All the compounds were characterized by IR, 1H and 13C NMR, elemental analysis, and differential scanning calorimetry (DSC). The impact sensitivity was measured by using BAM (Bundesamt für Materialforschung) methodology. Based on the calculated heats of formation and experimental densities, the detonation properties and detonation products were predicted by employing Cheetah 6.0. A total percentage of iodine-containing species in wt % (I2, HI, and I in gas phase) ranged from 46.7 ( 21) to 88.94 % ( 11) was found in the detonation products. The high concentration and easy accessibility of iodine and/or iodine-containing species is very important in developing materials suitable as Agent Defeat Weapons (ADWs). [ABSTRACT FROM AUTHOR]

A family of 3,6-dinitropyrazolo[4,3-c]pyrazole-based energetic compounds was synthesized by using versatile N-functionalization strategies. Subsequently, nine ionic derivatives of the N, N′-(3,6-dinitropyrazolo[4,3-c]pyrazole-1,4-diyl)dinitramidate anion were prepared by acid-base reactions and fully characterized by infrared, multinuclear NMR spectra, and elemental analysis. The structures of four of these compounds were further confirmed by single-crystal X-ray diffraction. Based on their different physical and detonation properties, these compounds exhibit promising potential as modern energetic materials and can be variously classified as green primary explosives, high-performance secondary explosives, fuel-rich propellants, and propellant oxidizers. [ABSTRACT FROM AUTHOR]