Synthesis, Characterization, and Properties of Heat-Resistant Energetic Materials Based on C-C Bridged Dinitropyrazole Energetic Materials.

Polycyclic energetic materials make up a distinctive class of conjugated structures that consist of two or more rings. In this work, 1,3-bis(3,5-dinitro-1-pyrazol-4-yl)-4,6-dinitrobenzene () was synthesized and investigated in detail as a polycyclic heat-resistant energetic molecule that can be deprotonated by bases to obtain its anionic (-) salts. All compounds were thoroughly characterized by H and C NMR, infrared spectroscopy, high-resolution mass spectrometry, and elemental analysis.

Enhancing Conjugation Effect to Develop Nitrogen-Rich Energetic Materials with Higher Energy and Stability.

This work reports a strategy by enhancing conjugation effect and synthesizes a symmetrical and planar compound, 1,2-bis (4,5-di(1-tetrazol-5-yl)-2-1,2,3-triazol-2-yl)diazene (). The incorporation of azo and 1,2,3-triazole moieties manifests a synergistic effect, amplifying the conjugation effect of the azo bridge and thereby elevating the stability of (: 263 °C, IS: 7 J). Notably, , possessing a structural configuration comprising four tetrazoles harboring a total of 24 nitrogen atoms, exhibits excellent detonation performances (Δ: 6.

Progress of charge carrier dynamics and regulation strategies in 2D CN-based heterojunctions.

Two-dimensional carbon nitrides (CN) have gained significant attention in various fields including hydrogen energy development, environmental remediation, optoelectronic devices, and energy storage owing to their extensive surface area, abundant raw materials, high chemical stability, and distinctive physical and chemical characteristics. One effective approach to address the challenges of limited visible light utilization and elevated carrier recombination rates is to establish heterojunctions for CN-based single materials ( CN, g-CN, CN, CN, CN, and CN). The carrier generation, migration, and recombination of heterojunctions with different band alignments have been analyzed starting from the application of CN with metal oxides, transition metal sulfides (selenides), conductive carbon, and CN heterojunctions.

Thermodynamic Analysis and Pyrolysis Mechanism of 4,4'-Azobis-1,2,4-triazole.

The nonisothermal thermal decomposition kinetics of 4,4'-azobis-1,2,4-triazole (ATRZ) at different heating rates (5, 10, 15, and 20 °C·min) were investigated by thermogravimetry (TG) and differential scanning calorimetry (DSC) studies. The thermal decomposition kinetic parameters such as apparent activation energy () and pre-exponential factor () were calculated by the Kissinger, Ozawa, and Šatava-Šestak methods. The and values calculated by the above three methods are very close, which are 391.

Polyvalent Ionic Energetic Salts Based on 4-Amino-3-hydrazino-5-methyl-1,2,4-triazole.

The synthesis of the new energetic material 4-amino-3-hydrazino-5-methyl-1,2,4-triazole, which shows excellent performance and reliable safety, has drawn attention recently. To fully characterize this material, a comprehensive analysis was performed using various techniques, including differential scanning calorimetry (DSC), infrared spectroscopy (IR), elemental analysis, and H and C NMR spectroscopy. Additionally, three compounds, , and , were further characterized using single X-ray diffraction.

Anxiety and self-efficacy in Chinese international students' L3 French learning with L2 English and L3 French.

The present study explored the relationship between international students' Third Language Anxiety (TLA) and self-efficacy. The research data were collected through questionnaires involving 243 Chinese International students' L3 French Learning with L2 English and L3 French at one university in the U.K.

Lithium-Promoted Formation of (M = NH or NHOH and = Anion of 1-Hydroxytetrazole-5-hydrazide)-Type "Quaternary" Complexes with Nitrogen-Rich Characteristics: Construction of Novel Insensitive Energetic Materials.

Lithium-based nitrogen-rich complexes are important research objects in the field of high-energy materials. However, the weak coordination abilities of lithium ions relative to those of other metal ions with greater atomic numbers have hindered their applications in the field of nitrogen-rich complexes. Herein, we successfully prepared novel lithium-based nitrogen-rich complexes ( and ) by exploiting the structural properties of 1-hydroxytetrazolium-5-hydrazine ().

A series of -trinitromethyl-substituted polynitro-pyrazoles: high-energy-density materials with positive oxygen balances.

An -trinitromethyl strategy was employed for the synthesis of polynitro-pyrazole based high-energy-density compounds with great potential as energetic materials. The new compounds were characterized by H and C NMR, IR spectroscopy, elemental analysis, differential scanning calorimetry, and single-crystal X-ray diffraction. Compound 10 exhibits high energetic properties, has a positive oxygen balance (OB) of +2.

Density functional theory studies on N and N species: Focusing on various structures and excellent energetic properties.

All-nitrogen materials, as a unique branch of energetic materials, have gained huge attentions, of which derivatives are the representative synthetically reported materials. However, the energetic performance of compounds has certain limitations and cannot go beyond that of CL-20. In order to reach the higher energy, in this work, we presented two kinds of polynitrogen species, N and N.

Nitrogen-rich ion salts of 1-hydroxytetrazole-5-hydrazide: a new series of energetic compounds that combine good stability and high energy performance.

High-efficiency explosives that combine high stability and excellent energy performance are one of the key directions of energetic materials research. In this study, a novel monocyclic hydroxytetrazole derivative (3) with high stability was prepared, and a series of insensitive energetic ionic salts were derived from it. Benefiting from their outstanding performance in terms of density, 3D hydrogen bonding and π-electron interactions, these salts are excellent in both detonation performance ( = 8709 to 9314 m s and = 29.

Variations in concentration and solubility of iron in atmospheric fine particles during the COVID-19 pandemic: An example from China.

Iron (Fe) in the atmosphere can affect atmospheric chemical processes and human health. When deposited into oceans, it can further influence phytoplankton growth. These roles of Fe fundamentally depend on its concentration and solubility.

Pentazolate coordination polymers self-assembled by generated [Pb(OH)] cubic cations trapping -N.

A series of -N-based lead-containing energetic coordination polymers [Pb(OH)](N) (1), [Pb(N)(HO)(NO)](N)(HO) (2), [Pb(OH)](N)(NO)(HO) (3), and [Pb(OH)](N)(ClO)(HO) (4) were synthesized by self-assembly and characterized by single-crystal X-ray diffraction, powder X-ray diffraction, infrared and Raman spectroscopy, high resolution mass spectrometry, elemental analysis, scanning electron microscopy, and differential scanning calorimetry. In addition, their thermal decomposition kinetics have been studied theoretically and experimentally. The results revealed that the synthesized CPs possess regular structures, very high densities (2.

Novel metal-organic frameworks assembled from the combination of polynitro-pyrazole and 5-nitroamine-1,2,4-oxadiazole: synthesis, structure and thermal properties.

Energetic metal organic frameworks (EMOFs) is a hot topic in the field of energetic materials research. This paper reports two kinds of EMOFs based on methylene-linked polynitropyrazole and nitroamine 1,2,4-oxadiazole. Their structures were fully characterized by crystallography and their detonation performance and stability performance were explored.

Oxygen-Enriched Metal-Organic Frameworks Based on 1-(Trinitromethyl)-1-1,2,4-Triazole-3-Carboxylic Acid and Their Thermal Decomposition and Effects on the Decomposition of Ammonium Perchlorate.

Energetic metal-organic frameworks (EMOFs) with a high oxygen content are currently a hot spot in the field of energetic materials research. In this article, two series of EMOFs with different ligands were obtained by reacting 1-(trinitromethyl)-1H-1,2,4-triazole-3-carboxylic acid (tntrza) with metal iodide and metal nitrate, respectively. Furthermore, their structure, thermal stability, thermal decomposition kinetics, and energy performance are fully characterized.

Atmospheric fine particles in a typical coastal port of Yangtze River Delta.

In recent decades, coastal ports have experienced rapid development and become an important economic and ecological hub in China. Atmospheric particle is a research hotspot in atmospheric environmental sciences in inland regions. However, few studies on the atmospheric particle were conducted in coastal port areas in China, which indeed suffers atmospheric particle pollution.

Iron solubility in fine particles associated with secondary acidic aerosols in east China.

Soluble iron (Fe) in aerosols contributes to free oxygen radical generation with implications for human health, and potentially catalyzes sulfur dioxide oxidation. It is also an important external source of micronutrients for ocean ecosystems. However, factors controlling Fe concentration and its contribution to total iron (Fe) in aerosols remain poorly understand.

Syntheses of Energetic cyclo-Pentazolate Salts.

Three energetic salts of cyclo-N were synthesized via a metathesis reaction of barium pentazolate and sulfates which was driven by the precipitation of BaSO . All the energetic cyclo-N salts were characterized by single-crystal X-ray diffraction, infrared (IR), H and C multinuclear NMR spectroscopies, thermal analysis (TGA and DSC), and elemental analysis. The salts exhibit relatively good detonation performance with low sensitivities and good thermal stabilities.

Tetracyclic pyrazine-fused furazans as insensitive energetic materials: syntheses, structures, and properties.

Energetic compounds with fused tetracyclic backbones were synthesized and fully characterized, and their structures were confirmed by single crystal X-ray diffraction. Changes from nonplanar to planar structures led their densities to increase from 1.800 to 1.

Recent advances in the syntheses and properties of polynitrogen pentazolate anion cyclo-N and its derivatives.

The pentazolate anion, or cyclo-N5-, which is a five-membered ring composed solely of nitrogen atoms, has a unique structure among polynitrogen compounds. Cyclo-N5- is receiving ever-increasing levels of attention because of its potential ability to store large amounts of energy compared to the azide ion, its environmentally friendly decomposition products, and its carbon- and hydrogen-free composition, which are promising characteristics for advancing the field of high-energy-density materials (HEDMs), that include explosives, oxidisers, and propellants in closed environments. In this review, we provide a detailed introduction to cyclo-N5- and cover the following topics: (1) substituted pentazoles as precursors of cyclo-N5-, with a focus on the syntheses and stabilities of substituted pentazole derivatives; (2) routes to cyclo-N5- through cleavage of C-N bonds in substituted pentazoles, during which competitive reactions between pentazole decomposition and C-N bond cleavage need to be considered to ensure a successful outcome; (3) complexes of cyclo-N5-, summarising recent progress toward producing cyclo-N5--based complexes through the assembly of isolated cyclo-N5- with both metallic and nonmetallic components; and (4) interactions between cyclo-N5- and metal cations and non-metal species, as well as factors that influence the stability of these complexes; in particular, the thermal stabilities of prepared cyclo-N5- salts are discussed.

Alkali Metals-Based Energetic Coordination Polymers as Promising Primary Explosives: Crystal Structures, Energetic Properties, and Environmental Impact.

Coordination polymers (CPs) consisting of alkali metals (Na, K, Rb, and Cs) and a powerful nitrogen- and oxygen-rich energetic ligand (4,4'-bis(dinitromethyl)-3,3'-bisnitramide-methylene-furazanate, DBMF ) were developed. Molecular structures of these CPs, confirmed by single-crystal X-ray diffraction analysis, indicated that the same ligand takes on a U-shaped state for Na and an N-shaped state for K, Rb, and Cs. Explosion tests demonstrated that both Na DBMF and K DBMF efficiently detonated the secondary explosive RDX.

Author Correction: A series of energetic metal pentazolate hydrates.

In this Letter, under Methods section '[Na(HO)(N)]⋅2HO (2)', the description "the intermediate product arylpentazole (5.000 g, 26.18 mmol)" should have read "the intermediate product sodium salt of arylpentazole (5.

Syntheses, Crystal Structures and Properties of a Series of 3D Metal-Inorganic Frameworks Containing Pentazolate Anion.

Pentazolate anion (cyclo-N ), and/or N , NO were used as the ligands to obtain a series of nitrogen-rich energetic three-dimensional (3D) frameworks [Cu(N )(N )] , [Ag(N )] , [Ba(N )(NO )(H O) ] , and [NaBa (N ) (NO )(H O) ] by self-assembly. These frameworks were characterized by single-crystal X-ray diffraction, SEM, IR and Raman spectroscopy, elemental analysis, and thermal analysis. All the frameworks exhibited regular supramolecular structures and excellent stabilities at room temperature which can be attributed to the strong coordination bonds between cyclo-N anions and metal ions.

Stabilization of the Pentazolate Anion in Three Anhydrous and Metal-Free Energetic Salts.

According to previous reports, metal cations or water molecules are necessary for the stabilization of pentazolate anion (cyclo-N ) at ambient temperature and pressure. Seeking a new method to stabilize N is a big challenge. In this work, three anhydrous, metal-free energetic salts based on cyclo-N 3,9-diamino-6,7-dihydro-5 H-bis([1,2,4]triazolo)[4,3-e:3',4'-g][1,2,4,5] tetrazepine-2,10-diium, N-carbamoylguanidinium, and oxalohydrazinium (oxahy ) pentazolate were synthesized and isolated.

Self-assembled energetic 3D metal-organic framework [Na(N)(HO)] based on cyclo-N.

From a 1D sodium-N framework, a new zeolite-like metal-organic framework (MOF) with a fascinating 3D structure was successfully constructed. It exhibited an enhanced thermal stability with a decomposition temperature (onset) of 129 °C and an enhanced coordination ability (five-coordination) of cyclo-N in weak alkaline conditions. The 3D MOF with a bulky size offers new opportunities not only for the formation of porous materials but also to control the balance between the performance and stability of polynitrogen materials.

An interesting 1,4,2,5-dioxadiazine-furazan system: structural modification by incorporating versatile functionalities.

Herein, the 1,4,2,5-dioxadiazine ring is combined with two furazan rings. Interestingly, the structure of the 1,4,2,5-dioxadiazine-furazan system can be modified by incorporating versatile functionalities. The N-trinitroethylamino functionalization derivatives and energetic salts based on 3,6-bis(4-amino-1,2,5-oxadiazol-3-yl)-1,4,2,5-dioxadiazine are investigated.