A promising perovskite primary explosive.

A primary explosive is an ideal chemical substance for performing ignition in military and commercial applications. For over 150 years, nearly all of the developed primary explosives have suffered from various issues, such as troublesome syntheses, high toxicity, poor stability or/and weak ignition performance. Now we report an interesting example of a primary explosive with double perovskite framework, {(C6H14N2)2[Na(NH4)(IO4)6]}n (DPPE-1), which was synthesized using a simple green one-pot method in an aqueous solution at room temperature. DPPE-1 is free of heavy metals, toxic organic components, and doesn't involve any explosive precursors. It exhibits good stability towards air, moisture, sunlight, and heat and has acceptable mechanical sensitivities. It affords ignition performance on par with the most powerful primary explosives reported to date. DPPE-1 promises to meet the challenges existing with current primary explosives, and this work could trigger more extensive applications of perovskite.

In situ synthesis of [Cu(BODN)·5H2O]n@nano-Al composite energetic films with tunable properties in pyro-MEMS.

Integrating energetic materials with microelectromechanical systems (MEMS) to achieve miniaturized integrated smart energetic microchips has broad application prospects in miniaturized aerospace systems and civil explosive systems. In this work, MEMS compatible [Cu(BODN)·5H2O]n arrays and [Cu(BODN)·5H2O]n@nano-Al composite energetic films were successfully fabricated on copper substrates by the in situ reaction method and drop-coating method. Single crystal X-ray diffraction, powder X-ray diffraction, scanning electron microscopy, infrared spectroscopy, differential thermal analyses, and pulsed laser ignition were employed to characterize the prepared samples. The results show that [Cu(BODN)·5H2O]n arrays formed by the coordination reaction between the Cu(OH)2 template and the BODN ligand exhibit a porous supramolecular structure with excellent thermal and energy properties. Their morphology and composition on a copper substrate can be effectively regulated by adjusting the reaction time and solution concentration. In addition, adjustable energetic properties of [Cu(BODN)·5H2O]n@nano-Al composite films can be achieved after the encapsulation of nano-Al. Their heat release, flame height and ignition duration can reach as much as 1987.5 J g-1, 13.2 mm, and 5900 µs, respectively, indicating that [Cu(BODN)·5H2O]n@nano-Al can be used as an excellent pyrotechnic agent in MEMS ignition chips. Overall, this work provides a reference for the integration and application of energetic materials in MEMS systems.

One Step Closer to an Ideal Insensitive Energetic Molecule: 3,5-Diamino-6-hydroxy-2-oxide-4-nitropyrimidone and its Derivatives.

Reaching the goal of developing an insensitive high-energy molecule (IHEM) is a major challenge. In this study, 3,5-diamino-6-hydroxy-2-oxide-4-nitropyrimidone (IHEM-1) was synthesized in one step from 2,4,6-triamino-5-nitropyrimidine-1,3-dioxide hydrate (ICM-102 hydrate). The density of compound IHEM-1 is 1.95 g cm-3 with a decomposition temperature of 271 °C. Its detonation velocity and pressure are 8660 m s-1 and 33.64 GPa, respectively, which are far superior to the detonation performance of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB), while its sensitivity is identical with that of TATB. In addition, four derivatives (1a, chloride; 1b, nitrate; 1c, perchlorate; and 1d, dinitramide) were prepared on the basis of the weak base site (N-O group) and show excellent energetic properties. By combining a series of advantages, including simple preparation, high yield, high density, very low solubility in aqueous solution, high thermostability, insensitivity, and excellent detonation performance, IHEM-1 approaches an ideal insensitive high-energy molecule. Compounds 1b-1d are also competitive as new high-energy-density materials.

Taming nitroformate through encapsulation with nitrogen-rich hydrogen-bonded organic frameworks.

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.

Rivaroxaban versus low-molecular weight heparin plus warfarin prevents portal vein system thrombosis after splenectomy and pericardial devascularization: A randomized clinical trial.

This study aimed to evaluate the safety and efficacy of rivaroxaban in preventing portal vein system thrombosis (PVST) in patients with liver cirrhosis after splenectomy and pericardial devascularization. 70 cirrhotic patients undergoing splenectomy and pericardial devascularization were randomly assigned to rivaroxaban treatment (n=35) or low-molecular weight heparin (LMWH) plus warfarin treatment (n=35) for 30 days in this randomized controlled trial. The primary endpoint is the PVST formation. Ultrasound doctors and radiologists were blinded to the randomization results. Both groups received routine outpatient inspection every month and were followed for one year. 17 patients (48.6 %) in rivaroxaban group developed PVST, compared with 27 patients (77.1 %) in LMWH plus warfarin group (P=0.025). The incidence of PVST during the first year postoperation was significantly lower in rivaroxaban group than in LMWH plus warfarin group (F=7.901, P=0.006). The intra-group comparisons versus baseline showed the liver function improved from POD 21 to POM 1, and coagulation function improved from POM 2, in rivaroxaban group. In contrast, the liver function improved from POM 1 to POM 2, and coagulation function improved from POM 4, in LMWH plus warfarin group. The prophylactic use of rivaroxaban significantly decreases the incidence of PVST after splenectomy and pericardial devascularization in cirrhotic patients compared to LMWH plus warfarin treatment. Besides, rivaroxaban treatment was safe and effective and associated with better liver and coagulation functions improvement than LMWH plus warfarin treatment.

5,6-Fused bicyclic tetrazolo-pyridazine energetic materials.

This study presents the synthesis of 5,6-fused bicyclic conjugated energetic compounds through a combined strategy of anchoring the catenated nitrogen-atom chain and introducing vicinal C-amino and C-nitro groups into a tetrazolo-pyridazine ring. Their crystal structures were confirmed by single crystal X-ray diffraction. Both compounds display good thermal stability, high energetic properties and low sensitivities as energetic materials.

Energetic Metal-Organic Frameworks Incorporating NH3OH+ for New High-Energy-Density Materials.

Energetic metal-organic frameworks (E-MOFs) have witnessed increasing development over the past several years. However, as a highly energetic cation, NH3OH+ has never been explored to construct transition-metal-based E-MOFs. Herein, we report the first examples of NH3OH+-containing E-MOFs with bis(tetrazole)methane (H2btm) as a ligand and copper and manganese as central metal ions, [(NH3OH)2(Cu(btm)2)]n and [(NH3OH)2(Mn(btm)2)]n. Crystal structure determinations reveal that both E-MOFs show two-dimensional layered structures. Experimental results suggest that they have high thermal decomposition temperatures (>200 °C). Among them, Cu-based E-MOFs possesses outstanding thermal stability (Tdec = 230.3 °C), which surpasses those of known NH3OH+-containing compounds. They also have high energy density; in particular, the Cu-based E-MOF affords a high heat of combustion (11447 kJ kg-1) and high heat of detonation (713.8 kJ mol-1) beyond the most powerful organic explosives in use today. Additionally, the two E-MOFs show completely different sensitivity properties: the Mn-based E-MOF is an insensitive high-energy-density material (IS > 40 J; FS > 360 N; EDS > 20 J), while the Cu-based E-MOF can be classified as a sensitive energetic material (IS = 13 J; FS = 216 N; EDS = 10.25 J), demonstrating their diverse applications in different fields. Our research proposes a unique class of high-energy-density materials.

A green metal-free fused-ring initiating substance.

Over the past century, the search for lead-free, environmentally friendly initiating substances has been a highly challenging task in the field of energetic materials. Here, an organic primary explosive featuring a fused-ring structure, 6-nitro-7-azido-pyrazol[3,4-d][1,2,3]triazine-2-oxide, was designed and synthesized through a facile two-step reaction from commercially available reagents. This organic initiating substance meets nearly all of the stringent criteria of environmentally friendly primary explosives for commercial applications: it is free of toxic metals and perchlorate, has a high density, high priming ability, unusual sensitivities towards non-explosive stimuli, excellent environmental resistance, decent thermal stability, high detonation performance, satisfactory flowability and pressure durability, and is low-cost and easy to scale-up. These combined properties and performance measures surpass the current and widely used organic primary explosive, DDNP. The fused-ring organic primary explosive reported herein may find real-world application as an initiating explosive device in the near future.

Designing Explosive Poly(Ionic Liquid)s as Novel Energetic Polymers.

The development of ionic-liquid-derived functional materials would be vital for stimulation of the interdisciplinary research in the fields of ionic liquid chemistry and material science. Here, a series of novel poly(ionic liquid)s with explosive capability were designed and prepared by introducing the energetic nitrato group and nitro-rich anions, such as nitrate, dinitramide, and nitroform into the polymeric chains. The as-synthesized explosive poly(ionic liquid)s (E-PILs) were fully characterized, and their physicochemical and detonation properties were investigated. All E-PILs show higher detonation performances than state-of-the-art energetic polymers including glycidyl azide polymer (GAP) and poly(glycidyl nitrate) [poly(GLYN)]. Some E-PILs exhibit higher calculated detonation velocities and pressures than 2,4,6-trinitrotoluene (TNT). These E-PILs are promising candidates for applications as new high-performance energetic polymers.

Carbonyl-bridged energetic materials: biomimetic synthesis, organic catalytic synthesis, and energetic performances.

In order to obtain high-performance energetic materials, in this work, carbonyl groups (C[double bond, length as m-dash]O) have been newly introduced as sole bridging groups in the field of energetic materials. To this end, two tailored green methods for the synthesis of carbonyl-bridged energetic compounds have been developed for the first time. One is a biomimetic synthesis, in which the conversion route of heme to biliverdin has been used to obtain metal-containing energetic compounds. The other one is an organocatalysis, in which guanidinium serves as an energetic catalyst to afford other energetic compounds. Experimental studies and theoretical calculations have shown that carbonyl-bridged energetic compounds exhibit excellent energetic properties, which is promising for the carbonyl group as a new important and effective linker in energetic materials.

[Effect of critical process parameters on luminescence properties of Eu2+/Dy3+ co-doped high silica luminescence glass].

In the present work, Eu2+/Dy3+ co-doped high silica glasses with different process parameters were prepared and the effect of critical process parameters including phase separation temperature, solution concentration and sintering temperature on the luminescence properties of Eu2+/Dy3+ co-doped high silica glasses was investigated by means of measuring pore surface parameters of porous glasses, emission spectra, infrared absorption spectra and densities of high silica glasses. Pore structure parameters of porous glass samples and emission spectra of corresponding high silica glass samples with different phase separation temperatures show that the phase separation temperature has indirect effect on luminescence properties of high silica glass by influencing specific surface area value of corresponding porous glass. Specific surface area of porous glass changes when phase separation temperature changes. High silica glass achieves maximum emission intensity when the maximum specific surface area of porous glass is obtained. Luminescence intensity of high silica glass increases when specific surface area of porous glass increases. Emission spectra of high silica glass samples with different solution concentrations show that the emission intensities of Eu2+ and Dy3+ in high silica glass are enhanced with the increase in the Dy3+ concentration in solution; when the Dy3+ concentration is beyond 0.1 mol x L(-1), the emission intensities of Eu2+ and Dy3+ in high silica glass are both decreased due to the occurring of concentration quench of Dy3+ in the glass. Emission spectra and infrared absorption spectra of high silica glass samples with different sintering temperatures show that the emission intensity of high silica glass is increased with the increase in the sintering temperature because the content of residual hydroxyl groups -OH in the glass is decreased; when the sintering temperature is beyond 1000 degrees C, the high silica glass exhibits crystalline and the luminescence intensity decreases.