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Two novel sodium-pentazolate frameworks (namely, MPF-3 and MPF-4) were achieved by adding simple additives. MPF-3 exhibits an aesthetic three-dimensional (3D) framework with the zeolitic MTN topology, featuring Na28N80 and Na20N60 nanocages. In MPF-4, two left-handed helical chains construct enclosed homochiral channels filled with dimethyl sulfone molecules, which constitute a zeolite-like UNJ topology. Importantly, the preparation of these two compounds provides an effective experimental means to explore the unique symmetrical structure and multiple coordination modes of pentazolium anion and demonstrates that it is possible to regulate the crystal structure through appropriate additives.

Pentazole (HN5) has been actively pursued due to its intriguing aesthetic structure and potential applications as ultrahigh energetic materials. It is generally accepted that cyclo-N5– is a highly ...

Using a facile and cost-effective method, nine bicyclic 1,2,3-triazine 2-oxides were synthesized from o-aminocyanide substrates through an unusual nitration cyclization. The reaction mechanism was studied experimentally and theoretically. Moreover, nine 1,2,3-triazine 3-oxides were also obtained in good yields.

A novel H2O2 adduct of ammonium cyclopentazolate, NH4N5·½H2O2, was readily synthesized by a simple and effective method. This adduct, as determined by single-crystal X-ray diffraction, has a cyclo-N5− anion, an ammonium ion and ½H2O2 molecule in the asymmetric unit. In this structure, H2O2 molecules are incorporated into the crystal lattices of NH4N5, forming an interesting three-dimensional (3D) network structure in which cyclo-N5− ions are stacked layer by layer and NH4+ ions are intercalated into the layers and connected the layers through hydrogen bonds. This novel solvate, NH4N5·½H2O2, has a high oxygen balance (−22.86% based on CO2), high calculated detonation velocity and pressure (8938 m s−1 and 26.37 GPa) and an impressive specific impulse (259.97 s) much higher than that of anhydrous NH4N5. Moreover, the combustion products of this solvate mainly include nontoxic N2, H2 and H2O. This simple and effective strategy of combining NH4N5 with H2O2 is highly desirable for future studies on the development of disruptive energetic materials.

A series of fused-ring energetic materials, i.e., 3,6-dinitro-1,4-di(1H-tetrazol-5-yl)-pyrazolo[4,3-c]pyrazole (DNTPP, compound 2) and its ionic derivatives (compounds 3-8), were designed and synthesized in this study. The molecular structures of compounds 2, 3, 6, 7·2H2O, and 8 were confirmed using single-crystal X-ray diffraction. Their physicochemical and energetic properties, such as density, thermal stability, heat of formation, sensitivity, and detonation properties (e.g., detonation velocity and detonation pressure), were also evaluated. The results indicate that DNTPP and most of its ionic derivatives are extremely thermally stable and insensitive toward mechanical stimuli. In particular, the thermal decomposition temperature of compound 3 is up to 329 °C, while compounds 7 and 8 are very insensitive (impact sensitivity: >20 J; friction sensitivity: >360 N). Compounds 2, 3, and 6 possess good comprehensive properties, including excellent thermal stability, remarkable low sensitivities, and favorable detonation performance. These features show that DNTPP and its ionic derivatives have considerable promise as thermally stable and insensitive energetic materials.

Sulfur compounds in fuel oils are a major source of environmental pollution, and the ultra-deep desulfurization of fuels has become an urgent task. Adsorptive desulfurization (ADS) is a competitive method with low energy consumption and mild reaction conditions compared with conventional hydrodesulfurization, and ADS is considered to be one of the most promising alternative technologies for achieving deep desulfurization. Currently, as a new member of porous material family, metal organic frameworks (MOFs) have shown promising characteristics for ADS application. The remarkable desulfurization ability of MOFs and its composites have been demonstrated by researchers, the highest adsorption value can reach 825 mg-S/g. In this review, we introduce research on and applications of MOFs and their composites for ADS presently, and present an overview of the desulfurization capacity of MOFs. Additionally, the factors affecting the desulfurization performance and the main desulfurization mechanisms are described and discussed.

过去一个世纪以来, 探索合成含有五唑阴离子( cyclo -N5−)的聚氮化合物吸引了科学家们的极大兴趣. 本论文报道了一例基于异质双金属的五唑骨架, [LiNa(N5)2(H2O)4]·H2O( 1 ), 并对其结构和热性质进行了表征. 单晶X射线衍射表明化合物 1 具有三维超分子结构, 其中相邻的{Li(H2O)2(N5)5}三聚体之间通过O–H···N氢键作用形成左手型和右手型螺旋链结构. 化合物 1 在室温条件下具有良好的热稳定性, 五唑环在106.1°C开始分解. 本研究对于探索五唑阴离子的配位化学以及相关聚氮材料提供了新思路.

A novel family of hydrophobic triaminocyclopropenium cation based ionic liquids have been synthesized, and their structures and physicochemical properties characterized by NMR and IR spectroscopy, elemental analysis, differential scanning calorimetry, and hypergolic tests. The experimental results showed that all of these ionic liquids exhibited the expected hypergolic reactivity with the oxidizer white fuming nitric acid. Among them, the hypergolic ionic liquid based on the cyanoimidazolylborohydride anion showed excellent integrated properties, including high decomposition temperature (194 °C), high density (0.95 g cm-3 ), moderate viscosity (44 MPa s), ultrafast ignition delay time (6 ms), and high specific impulse (301.9 s); this demonstrates its potential as an environmentally friendly alternative to toxic hydrazine derivatives.

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 (Na20 N60 and Na24 N60 ) 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.

Nowadays, sulfur compounds in fuel oils are the main source of environmental pollution and ultra-deep desulfurization of fuel oils has become a top priority. Many porous materials such as activated carbon and metal–organic frameworks (MOFs) have attracted attention in the field of adsorption desulfurization in recent years. A series of novel MOF/hydroxylated graphene hybrid materials were successfully designed and synthesized with different ratios for application in the field of ADS. The hydroxylated graphene (HG) was found dispersed not just on the surface but also inserted in the MOF crystals in what we call a nut-like structure. It was found that the introduction of a small amount (

In this work, bicyclic fused [1,2,4]triazolo[4,3-b]pyridazine was used to construct new low-sensitivity high-energy materials. Two exemplary compounds, 6,7-diamino-3,8-dinitro- [1,2,4]triazolo[4,3-b]pyridazine (1) and 7-amino-6-azido-3,8-dinitro-[1,2,4]triazolo[4,3-b]pyridazine (2), were synthesized and characterized. The properties of the energetic materials, including their detonation velocities (Dv: 8994 m·s−1 for 1, 8819 m·s−1 for 2) and detonation pressures (P: 34.1 GPa for 1, 32.4 GPa for 2) were evaluated based on their densities (ρ: 1.93 g·cm−3 for 1, 1.84 g·cm−3 for 2) and heats of formation (ΔHf: 348 kJ·mol−1 for 1, 684 kJ·mol−1 for 2). Their impact and friction sensitivities were measured to be 20 J and > 360 N for 1 and 18 J and 360 N for 2. The onset decomposition temperatures of 1 and 2 were 234 °C and 217 °C, respectively; therefore, both compounds were highly energetic materials with low sensitivities and good thermostability.

Hypergolic ionic liquids (HILs) are considered as a promising alternative of toxic hydrazine derivatives in the field of liquid bipropellants. The anionic structure plays an important role in determining the hypergolic performance of HILs. Nevertheless, the structure–activity relationship between the cationic structure and ignition properties is still unclear. In this study, the aromaticity, electrostatic potentials (ESPs), natural bond orbital (NBO) analysis, and molecular orbital gap of 25 ionic liquids based on dicyanamide anion were studied to gain more insight into the correlation between cationic structure and hypergolic properties. For the HILs based on the same type of cation with different substituents, better aromaticity leads to better thermal stability of HILs. For the HILs with different types of cations, when the ESPs distribution is relatively concentrated around a certain value, the thermal stability of HILs is relatively higher. The second-order perturbation energy (E(2)) would be responsible for ignition delay (ID) time. The larger the E(2), the more stable the system, and the longer the ID time of HILs. It is also proved for the first time that the energy gap between the HOMO of cations and LUMO of HNO3 could not be used as a method to determine whether this cation-based IL is hypergolic. All these results can be fully justified with experimental data and have important theoretical instructive significance in the design of new high-performance HILs.

High-energy density materials represent a significant class of advanced materials and have been the focus of energetic materials community. The main challenge in this field is to design and synthesize energetic compounds with a highest possible density and a maximum possible chemical stability. Here we show an energetic compound, [2,2′-bi(1,3,4-oxadiazole)]-5,5′-dinitramide, is synthesized through a two-step reaction from commercially available reagents. It exhibits a surprisingly high density (1.99 g cm−3 at 298 K), poor solubility in water and most organic solvents, decent thermal stability, a positive heat of formation and excellent detonation properties. The solid-state structural features of the synthesized compound are also investigated via X-ray diffraction and several theoretical techniques. The energetic and sensitivity properties of the explosive compound are similar to those of 2, 4, 6, 8, 10, 12-(hexanitrohexaaza)cyclododecane (CL-20), and the developed compound shows a great promise for potential applications as a high-energy density material., High energy density materials are of interest, but density is the limiting factor for many organic compounds. Here the authors show the formation of a high density energetic compound from a two-step reaction between commercially available compounds that exhibit good heat thermal stability and detonation properties.

Hypergolic ionic liquids (HILs) as potential replacements for hydrazine derivatives have attracted increasing interest over the last decade. Previous studies on HILs are mostly concentrated on the anionic innovations of ionic liquids to shorten the ignition delay (ID) time, but few attentions have been paid to the cationic modifications and their structure-property relationships. In this work, we presented a new strategy of cationic functionalization by introducing the energetic nitrato group into the cationic units of HILs. Interestingly, the introduction of oxygen-rich nitrato groups into the cationic structure has obviously improved the combustion performance of HILs with larger flame diameters and duration times. The density-specific impulse (ρIsp) of these novel HILs are all above 279.0 s*g*cm-3, which are much higher than that of UDMH (215.7 s*g*cm-3). In addition, the densities of these HILs are in range of 1.22-1.39 g*cm-3, which is much higher than that of UDMH (0.79 g*cm-3), showing their higher loading capacity than hydrazine-derived fuels in propellant tank. This promising strategy of introducing nitrato group into the cationic structures has provided a new platform for developing high-performing HILs with improved combustion properties.

In this study, a series of high-energy-density materials (1·2H2O–9) based on N-(3-nitro-1-(trinitromethyl)-1,2,4-triazol-5-yl)nitramide were synthesized and structurally characterized using 1H NMR, 13C NMR, IR spectroscopy, elemental analysis, and single-crystal X-ray diffraction. The crystal results demonstrated that potassium 3-nitro-5-(nitroimino)-1-(trinitromethyl)-1,2,4-triazolate hydrate (2·H2O) exhibits an infinite two-dimensional (2D) metal–organic framework (MOF) containing the coordination group NO2 and metal cation K+. Additionally, this 2D MOF exhibited a high oxygen content (46.41%) and a positive oxygen balance (14.77%). Heats of formation and the detonation properties of the newly prepared compounds were calculated using the Gaussian 09 and EXPLO 5 programs, respectively. Energetic evaluation indicated that these compounds demonstrate good detonation performances, all of which outperform traditional primary explosives mercury fulminate, lead azide, 2-diazo-4,6-dinitrophenol, and in some cases, even exceed the performance of high explosive RDX. Therefore, the high detonation parameters of the compounds enable these potential primary explosives to trigger the whole detonation easily. Furthermore, several attractive properties, such as an excellent density (2.00 g cm−3), an impact sensitivity of 2 J, a friction sensitivity of 32 N, and a low amount of toxic detonation products, make 2·H2O an eco-friendly primary explosive.

A series of C–N linked bistetrazolate nitramino compounds, i.e., 1-(2H-tetrazol-5-yl)-5-nitraminotetrazole (2) and its energetic salts (3–8), were successfully prepared from readily available 5-aminotetrazole. All new energetic compounds were fully characterized by IR and NMR spectra and elemental analysis, and six of them (1, 3–7) were further determined by single-crystal X-ray diffraction analysis. The nitrogen contents of these energetic bistetrazolate compounds, ranging from 59.3% (3) to 74.8% (7), are much higher than those of the commonly used high explosives such as RDX (N: 37.8%), HMX (N: 37.8%) and CL-20 (N: 38.3%). And theoretical calculations by using the Gaussian 09 program package demonstrate that compounds 1–8 have high positive heats of formation, of which the heats of formation of ammonium salt 4 (3.60 kJ g−1), aminonitroguanidinium 5 (3.11 kJ g−1) and dihydrazinium salt 7 (3.25 kJ g−1) are approximately eight times higher than those of RDX (0.39 kJ g−1) and HMX (0.39 kJ g−1), and four times higher than that of CL-20 (0.83 kJ g−1). The high nitrogen contents and high heats of formation have endowed these energetic compounds with prominent detonation performance. It is noteworthy that compound 7 exhibits an excellent calculated detonation velocity of 9822 m s−1 superior to that of CL-20 (9730 m s−1), while the impact and friction sensitivities of 7 (IS = 8 J, FS = 192 N) are comparable to those of HMX (IS = 7 J, FS = 112 N). The good detonation properties with moderate sensitivities demonstrate that compound 7 is a promising candidate for application as a high-performance energetic material.

A series of hypergolic ionic liquids (HILs) based on the cyano (1H-1,2,3-triazole-1-yl) dihydroborate anion were synthesized by introducing the {BH2-CN} moiety into the 1,2,3-triazole anion. This introduction allowed us to improve the self-ignition property and decrease the viscosity of ionic fuels. The synthesized series of HILs exhibited wide liquid operating ranges (>220 °C), high densities (>1 g cm−3), low viscosities (as low as 22.48 cP), and ignition delay (ID) times as short as 5 ms by using white fuming nitric acid (WFNA) as the oxidizer. Furthermore, these HILs can be ignited upon contact with a 90 wt% H2O2 oxidizer in the presence of iodine.

Currently, toxic and volatile hydrazine derivatives are still the main fuel choices for liquid bipropellants, especially in some traditional rocket propulsion systems. Therefore, the search for safer hypergolic fuels as replacements for hydrazine derivatives has been one of the most challenging tasks. In this study, six imidazolylidene-borane compounds with zwitterionic structure have been synthesized and characterized, and their hypergolic reactivity has been studied. As expected, these compounds exhibited fast spontaneous combustion upon contact with white fuming nitric acid (WFNA). Among them, compound 5 showed excellent integrated properties including wide liquid operating range (-70-160 °C), superior loading density (0.99 g cm(-3) ), ultrafast ignition delay times with WFNA (15 ms), and high specific impulse (303.5 s), suggesting promising application potential as safer hypergolic fuels in liquid bipropellant formulations.

A family of hydride-rich bis(borano)hypophosphite-based ionic liquids was developed, which showed good water stability at room temperature and unexpected hypergolic reactivity with oxidizers. These ionic fluids have exhibited the shortest ignition delay times so far, demonstrating their application potential as hypergolic fuels or additives in liquid bipropellants.

The yolk-shell structured Ni/Co-based MOFs were first synthesized via one-step hydrothermal method without any template, followed by the pyrolysis treatment to prepare the multilayer core-shells NiCo2O4/NiO structure spheres. The growth mechanism of the Co/Ni-MOF and multilayer core-shells NiCo2O4/NiO microsphere can be explained by the Ostwald ripening and heterogeneous contraction effect, respectively. The obtained multilayer NiCo2O4/NiO microspheres displayed unique three-layer structure with an average diameter of 1–2 μm by TEM. Due to the compositional and structural benefits, the obtained multilayer NiCo2O4/NiO structure spheres exhibited high specific capacitance of 726 F·g−1 at the current density of 1 A·g−1 and a good cycling stability of 91.4% retention over 5000 cycles. In addition, an asymmetric supercapacitor (ASC) based on multilayer NiCo2O4/NiO microspheres and active carbon was fabricated and shown a high energy density of 22.1 Wh·kg−1 at a power density of 4518.6 W·kg−1. These superior electrochemical properties indicated that the multilayer NiCo2O4/NiO microsphere was a promising electroactive candidate for high-performance supercapacitors.

Over the past few decades, toxic and highly volatile hydrazine derivatives have been the main fuel choices for liquid bipropellants, especially in traditional hypergolic rocket engines. The search for new hypergolic fuels as replacements for hydrazine derivatives is of great interest to researchers. In this study, a series of N-alkylimidazole borane compounds has been synthesized and characterized. Interestingly, these compounds display promising applications as potential hypergolic fuels owing to their excellent physiochemical properties including low melting points, high thermal stability, low viscosities, and unique hypergolic reactivity. Compared with popular hypergolic ionic liquids, the cost-effective and scaling-up advantages of these materials highlight their promising potential as high-performance fuels in liquid bipropellant formulations.