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In this work, we designed and synthesized a series of novel triazolopyridine fused-ring compounds with alternating nitro and amine groups. Three compounds showed remarkable thermal stability at 256, 310, and 294 °C, respectively, and a low mechanical sensitivity [impact sensitivity (IS) = 40 J, friction sensitivity (FS) = 324 N; IS = 35 J, FS = 240 N; and IS > 40 J, FS = 324 N, respectively]. Significantly, two of these compounds exhibited a better detonation performance [detonation velocity (D) = 8200 and 8335 m s–1 , Detonation pressure (P) = 25.6 and 27.2 GPa, respectively] than the widely used heat-resistant explosive hexanitrostilbene (HNS; D = 7612 m s–1 , P = 24.3 GPa). Additionally, a nitramine derivative displayed a detonation performance (D = 8569 m s–1 , P = 31.3 GPa) similar to that of the high-energy explosive RDX. The superior properties of the materials were further confirmed by X-ray diffraction analysis and by several theoretical calculations (ESP, LOL–π, Hirshfeld surfaces, RDG, and NCI analyses). These results indicated that the three compounds might be potential candidates for use as heat-resistant energetic materials. [ABSTRACT FROM AUTHOR]

With the increase in the demand for high‐performance composite explosives, the search for advanced energetic melt‐castable compounds has attracted increasing attention in the field of energetic materials. Herein, two new energetic materials with nitromethyl and azidomethyl substituents (1‐(nitromethyl)‐3,4‐dinitro‐1H‐pyrazole (NMDNP) and 1‐(azidomethyl)‐3,4‐dinitro‐1H‐pyrazole (AMDNP) were prepared by the substituent modification of a potential melt‐castable molecule ((3,4‐dinitro‐1H‐pyrazol‐1‐yl) methyl nitrate, MC‐4), respectively. NMDNP exhibited a suitable melting point (90 °C), good thermal stability (Td: 185 °C) and excellent detonation performance (8484 m s−1) and impact sensitivity (25 J), thereby demonstrating promise as an energetic melt‐castable material. Simultaneously, compared with the nitrato‐methyl and azidomethyl substituents, the nitromethyl substituent exhibited greater advantages in regulating performance. [ABSTRACT FROM AUTHOR]

N,N-Dimethyl-3,5-dinitro-1H-pyrazol-4-amine was prepared by the reaction of 4-chloro-3,5-dinitropyrazole and DMF at 100°C for 4 h. Based on this compound, four new energetic derivatives, i.e., N,N,1-trimethyl-3,5-dinitro-1H-pyrazol-4-amine, 1,1'-methanediylbis- (N,N-dimethyl-3,5-dinitro-1H-pyrazol-4-amine), 1,1'-ethane-1,2-diylbis(N,N-dimethyl-3,5-dinitro-1H-pyrazol-4-amine), and 1,1'-propane- 1,3-diylbis(N,N-dimethyl-3,5-dinitro-1H-pyrazol-4-amine), were prepared through nucleophilic reactions. The structures of the compounds were confirmed by single crystal X-ray diffraction. One of the synthesized compounds has promising melting point and thermal stability and can be considered as potential melt-castable explosive. [ABSTRACT FROM AUTHOR]

Energetic isomers often exhibit different properties. To understand the effect of arrangement and connection of isomers on energetic properties and sensitivity, in this study, we designed and synthesized a series of oxadiazole nitramine compounds including N-(5-(5-(nitramino)-1,3,4-oxadiazol-2-yl)-1,2,4-oxadiazol-3-yl)nitramide (NOON) and its ionic derivatives. NOON exhibits comparable performance (D = 8888 m s−1, P = 34.1 GPa) to highly explosive RDX. A comparative study of detonation properties, sensitivity, and thermal stability of the three oxadiazole nitramine isomers (NOON, ICM-101, and DNBO) is carried out. The results show that due to the proton transformation, strong intramolecular hydrogen bonding interaction, and formation of six-membered ring conformation, the 2-nitramino-1,3,4-oxadiazole building block exhibits better detonation properties and higher thermal stability than its isomer 2-nitramino-1,2,4-oxadiazole. [ABSTRACT FROM AUTHOR]

New derivatization reactions of 1,1-diamino-2,2-dinitroethylene (FOX-7) are explored, which afford three cyclic triazinane-based energetic compounds 1, 2 and 3 featuring the FOX-7 backbone. Their structures were characterized by X-ray single crystal diffraction analysis. Among them, compound 1 shows a high detonation performance (vD: 8899 m s−1, P: 35.83 GPa) comparable to that of FOX-7. Compound 2 exhibits a good detonation performance (vD: 8332 m s−1, P: 26.47 GPa) and good thermal stability (Td = 188 °C), which is superior to that of most FOX-7-derived energetic compounds. Both of them inherit the low-sensitivity characteristic of FOX-7 because of strong inter- and intra-molecular hydrogen bonds. The presented derivatization reaction has contributed to the ever-expanding chemistry of FOX-7. [ABSTRACT FROM AUTHOR]

A novel fused-ring polynitro compound (5) and a cyclic compound featuring gem-dinitromethylene and nitroso groups (7) were synthesized from 1,1-diamino-2,2-dinitroethylene (FOX-7). Both compounds exhibit high density, decent thermal stability, high detonation performances, and low mechanical sensitivities. This newly developed derivatization strategy enriches the ever-expanding reactive chemistry of FOX-7. [ABSTRACT FROM AUTHOR]

Abstract: The experimental detection and synthesis of pentazole (HN5) and its anion (cyclo‐N5−) have been actively pursued for the past hundred years. The synthesis of an aesthetic three‐dimensional metal–pentazolate framework (denoted as MPF‐1) is presented. It consists of sodium ions and cyclo‐N5− anions in which the isolated cyclo‐N5− anions are preternaturally stabilized in this inorganic open framework featuring two types of nanocages (Na20N60 and Na24N60) through strong metal coordination bonds. The compound MPF‐1 is indefinitely stable at room temperature and exhibits high thermal stability relative to the reported cyclo‐N5− salts. This finding offers a new approach to create metal–pentazolate frameworks (MPFs) and enables the future exploration of interesting pentazole chemistry and also related functional materials. [ABSTRACT FROM AUTHOR]

Bis(4-nitraminofurazanyl-3-azoxy)azofurazan ( 1) and ten of its energetic salts were prepared and fully characterized. Computational analysis based on isochemical shielding surface and trigger bond dissociation enthalpy provide a better understanding of the thermal stabilities for nitramine-furazans. These energetic compounds exhibit good densities, high heats of formation, and excellent detonation velocity and pressure. Some representative compounds, for example, 1 ( vD: 9541 m s−1; P: 40.5 GPa), and 4 ( vD: 9256 m s−1; P: 38.0 GPa) exhibit excellent detonation performances, which are comparable with current high explosives such as RDX ( vD: 8724 m s−1; P: 35.2 GPa) and HMX ( vD: 9059 m s−1; P: 39.2 GPa). [ABSTRACT FROM AUTHOR]

The development of hypergolic materials has aroused great interest since their significant application in bipropellant systems. In this work, five energetic complexes (1–5) were developed to demonstrate hypergolic performance with the green oxidizer hydrogen peroxide. The compounds were comprehensively characterized. The decomposition temperatures of these compounds were in the range from 228.8 to 295.5 °C. The highest thermal stability was observed in compound 5. The density of these compounds were in the range from 1.389 to 1.502 g∙cm−3 which was higher than most of the known hypergolic materials. Furthermore, the hypergolic performance of these materials were evaluated with 90% H 2 O 2 by an "oxidizer-to-fuel" standard droplet test. For the examined hypergolic combinations, the shortest ignition delay time was only 3 ms which was observed in compound 2. This ultra-short ignition delay time was shorter than that of most hypergolic combinations and attributed to synergy between different components in the energetic complexes. The copper ion metal center was the key promoting factor affecting hypergolic performance of the target compounds. The organic ligand acted as an energetic fuel while the NO 3 − counter ions further improved the hypergolic performance. Integrating these components into one complex and demonstrating their hypergolic performance with hydrogen peroxide as the oxidizer was successfully achieved. The hypergolic phenomenon observed in this work between energetic complexes and hydrogen peroxide may lead to a new approach for the development of green hybrid propulsion systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • An energetic molecule (NTTD) was obtained by one-step reaction with high yield. • NTTD can act as a heat-resistant and insensitive explosive. • The reaction has many advantages, which are conducive to large-scale preparation. • The derivatives of NTTD were synthesized through simple derivatization reactions. Low cost, high yield, good safety, and simple synthesis process are the problems that must be solved in the engineering preparation of energetic compounds, even beyond the pursuit of high energy level to some extent. In this work, a novel 5,6-fused energetic molecule 2-nitro-[1,2,4]triazolo[1,5- a ][1,3,5] triazine-5,7-diamine (NTTD) was designed and easily obtained. By the introduction of oxidants (HNO 3 and HClO 4) and high-energy groups (–NHNO 2), the derivatives of NTTD were prepared, some of which exhibited good comprehensive properties. Importantly, NTTD features excellent thermostability and low mechanical sensitivities. The whole preparation process has advantages of simple operation, short time, cheap and simple reagents, good repeatability, and high yield, which are conducive to large-scale preparation, indicating that NTTD can be a potential candidate of heat-resistant and insensitive explosives. [ABSTRACT FROM AUTHOR]