3,3′-Dinitroamino-4,4′-azoxyfurazan and Its Derivatives: An Assembly of Diverse N–O Building Blocks for High-Performance Energetic Materials

Three new energetic complexes with N,N-bis(1H-tetrazole-5-yl)-amine as high energy density materials: syntheses, structures, characterization and effects on the thermal decomposition of RDX

Three new complexes can be used as HEDMs. Insensitive 2 is a safer form for storage and transportation than sensitive 3.

Synthesis of 5,5′-azoxybistetrazole via nitration and de-oxygen rearrangement of triazene

An unusual transformation of tetrazole triazene into 5,5′-azoxybistetrazole by a sequential treatment with fuming nitric acid and acetyl anhydride.

A novel multi-nitrogen 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane-based energetic co-crystal with 1-methyl-3,4,5-trinitropyrazole as a donor: experimental and theoretical investigations of intermolecular interactions

A new strategy for the design and preparation of CL-20-based multi-nitrogen energetic co-crystals was revealed by experimental and theoretical approaches.

Green primary energetic materials based on N-(3-nitro-1-(trinitromethyl)-1H-1,2,4-triazol-5-yl)nitramide

A series of green primary energetic materials based on N-(3-nitro-1-(trinitromethyl)-1,2,4-triazol-5-yl)nitramide were synthesized and structurally characterized.

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

An N-trinitroethylamino derivative and amminonium salt based on the 1,4,2,5-dioxadiazene-furazan system are synthesized and characterized. Due to their layer-by-layer structure, these two compounds show good thermal stabilities and low sensitivities.

Synthesis and theoretical studies on nitrogen-rich salts of bis[4-nitraminofurazanyl-3-azoxy]azofurazan (ADNAAF)

Multi-furazan compounds bis[4-nitramino- furazanyl-3-azoxy]azofurazan (ADNAAF) and its derivatives were first synthesized by our research group, and their structures were characterized by IR, ¹H-NMR, ¹³C-NMR spectrums, and element analysis. ADNAAF was synthesized by nitration reaction of bis[4-aminofurazanyl-3-azoxy]azofurazan (ADAAF), and then reacted with ammonium hydroxide, hydrazine hydrate, and guanidine nitrate to obtain three salts marked as salt 1, 2, and 3, respectively. The thermal stabilities of the three salts were supported by the results of DSC analysis, which shows the decomposition temperatures are all above 190 °C. Their densities, enthalpies of formation, and detonation properties were studied by density functional theory (DFT) method. Salt 1 has the best detonation pressure (P), 37.42 GPa, and detonation velocity (D), 8.88 km/s, while salt 2 has the best nitrogen content and heat of detonation (Q), 1.27 kcal mol^-1. The detonation properties of salt 1 is similar to that of 1,3,5-trinitro-1,3,5-triazineane (RDX). It means that the ammonium cation can provide the better D and P than the cation of hydrazine and guanidine. The three cations offer the enthalpies of formations in the order of hydrazinium > guanidinium > ammonium. Graphical Abstract Nitrogen-rich salts of bis[4-nitraminofurazanyl-3-azoxy]azofurazan(ADNAAF).

1-(3,5-Dinitro-1H-pyrazol-4-yl)-3-nitro-1H-1,2,4-triazol-5-amine (HCPT) and its energetic salts: highly thermally stable energetic materials with high-performance

A novel energetic heat-resistant explosive, 1-(3,5-dinitro-1H-pyrazol-4-yl)-3-nitro-1H-1,2,4-triazol-5-amine (HCPT), has been synthesized along with its salts. An intensive characterization of the compounds is given, including ¹H and ¹³C NMR spectroscopy, IR spectroscopy, and elemental analysis. The crystal structures of neutral HCPT (3), its triaminoguanidinium salt (10), 3,4,5-triamino-1,2,4-triazolium salt (12), and copper(ii) complex (16) were determined by single-crystal X-ray diffraction. The physicochemical properties of the compounds, such as density, thermal stability, and sensitivity towards impact and friction were evaluated; all energetic compounds exhibited excellent thermal stabilities with decomposition temperatures ranging from 215 °C to 340 °C, and high positive heats of formation between 622.8 kJ mol^-1 and 1211.7 kJ mol^-1. The detonation pressures and velocities for the energetic compounds were calculated using EXPLO5 (V6.01) based on experimental densities and calculated heats of formation, and the corresponding values were in the ranges of 26.5 GPa to 37.8 GPa and 8236 m s^-1 to 9167 m s^-1. Based on thermal stability values and energetic parameters, compounds 3 and 7 were superior to those of all of the commonly used heat-resistant explosives, which may find potential application as heat-resistant energetic materials.

Searching for a new family of high energy explosives by introducing N atoms, N-oxides, and NO2 into a cage adamantane

A design strategy that including N atoms, N-oxides, and nitro groups into a cage azaadamantane at the same time was used to design 10 polyazaoxyadamantanes (PAOAs) and eight polynitroazaoxyadamantanes (PNTAOAs). First, four stable azaadamantanes were built by replacing the tertiary C atoms of an adamantane with N atoms. Then, 10 PAOAs were designed by introducing one to four N-oxides into the four azaadamantanes. After that, eight PNTAOAs were formed when the H atoms of four N-oxide-substituted azaadamantanes were replaced with different numbers of nitro groups. Finally, their heats of formation, densities, detonation properties, and impact sensitivity were estimated by using density functional theory. Among the eight PNTAOAs, seven compounds had better detonation performances than CL-20, the outstanding, novel, high-energy, and relatively insensitive cage explosive. Two compounds had higher detonation performance and lower sensitivity than CL-20 and HMX, suggesting that their overall performances are outstanding and they may be considered as the potential candidate of high-energy explosives.

Isomerization Pathways of ONCNO: Unstable or Metastable?

Fulminates containing the CNO(-) ion have been widely utilized as high-energy density materials (HEDMs) for more than 120 years. Yet no purely covalently bound CNO molecule, i.e., nitrile oxide, is known to behave as an HEDM. In this study, we performed a thorough investigation of the potential energy surface of nitrile oxide ONCNO and related isomers, applying various sophisticated methods including G4, CBS-QB3, W1BD, CCSD(T)/CBS, and CASPT2/CBS. The Gibbs free energy calculations showed that the decomposition of ONCNO to the considerably endothermic products CNO + NO is favored compared to that into the highly exothermic products CO2 + N2. Thus, ONCNO fails to be the long expected nitrile oxide HEDM. However, with the rate-determining barrier of 23.3 kcal mol(-1) at the W1BD level, ONCNO should be experimentally accessible.

From FOX-7 to H-FOX to insensitive energetic materials with hypergolic properties

Nitrogen/halogen rich derivatives, , , , and of FOX-7 (1,1-diamino-2,2-dinitroethene), and H-FOX (1-hydrazinyl-2,2-dinitroethenamine) have been synthesized, characterized and found to exhibit good energetic properties. Compound displays hypergolic properties with commonly utilized fuels such as monomethyl hydrazine (MMH), and hydrazine hydrate (HH), as well as with ethylenediamine (EN), and 1,3-diaminopropane (DAP) showing ignition delay times between 2.5 to 10 ms. Additionally, the hypergolic properties of 4 and 8 were further studied by using ammonia borane as a fuel solubilized in a green ionic liquid, 1-allyl-3-methyl imidazolium dicyanamide, (1 : 1 molar ratio). This is a new role for a derivative of H-FOX. The energetic and physical properties of all the molecules were either measured or calculated. All of materials were characterized by NMR, and infrared spectra, elemental analyses, and differential scanning calorimetry. Single crystal X-ray structural measurements for and were helpful in their confirmation.

Preparation, crystal structure, thermal behavior, and theoretical studies of N,N′-dinitro-4, 4′-azo-bis(1,2,4-triazolone) (DNZTO)

N,N′-Dinitro-4,4′-azo-bis(1,2,4-triazolone) (DNZTO) is synthesized by the reaction of 4,4′-azo-bistriazolone (ZTO) with a mixture of nitric acid and acetic anhydride. The product was fully characterized by IR, NMR, matrix-assisted laser desorption/ionization with time-of-flight mass spectrometry, and single-crystal X-ray analysis. The explosive performance including detonation pressures (P), velocities (D) of DNZTO, and heats of formation were predicted using gaussian 09 at B3LYP/6-311+G**.

Nitrogen-rich 4,4′-azo bis(1,2,4-triazolone) salts—the synthesis and promising properties of a new family of high-density insensitive materials

4,4′-Azo-bis(1,2,4-triazolone) (ZTO) based salts from alkaline (Li⁺, K⁺, Na⁺, and Cs⁺), alkaline earth metal salts (Mg²⁺, Ca²⁺, Sr²⁺, and Ba²⁺) and hydrazinium salt were synthesized in a simple, straightforward manner and were characterized by IR and NMR spectroscopy, elemental analysis.

Hydrazine 5,5′-bitetrazole-1,1′-diolate: a promising high density energetic salt with good properties

The salt HA·BTO has proved to be a good insensitive explosive alternative, and has promising application as an RDX replacement.

Synthesis, structure and properties of neutral energetic materials based on N-functionalization of 3,6-dinitropyrazolo[4,3-c]pyrazole

Various neutral energetic derivatives based onN-functionalization of DNPP were synthesized, which can be used as new high energy-density materials.

Theoretical design of highly energetic poly-nitro cage compounds

The designed energetic compound, TNOAP, has a superior detonation performance to CL-20 and RDX, as well as satisfactory sensitivity.

Cooperative effects of different temperatures and pressures on the initial and subsequent decomposition reactions of the nitrogen-rich energetic crystal 3,3′-dinitroamino-4,4′-azoxyfurazan

The initiation mechanisms of 3,3′-dinitroamino-4,4′-azoxyfurazan at different temperatures and pressures are bimolecular intermolecular hydrogen transfer and unimolecular N–NO₂ bond breaking.

Synthesis, crystal structure and properties of a new 1D polymeric nitrogen-rich energetic complex {TAG[Li(BTO)(H2O)]}n based on 1H,1′H-5,5′-bitetrazole-1,1′-diolate

The novel polymer {TAG[Li(BTO)(H₂O)]}_n, based on 1H,1′H-5,5′-bitetrazole-1,1′-diolate, opened up a new field on BTO-based energetic materials and anionic metal–organic frameworks.

3D Nitrogen-rich metal–organic frameworks: opportunities for safer energetics

3D Nitrogen-rich MOFs as newly emerged energetic materials have experienced rapid development in the last few years. This Frontier Article highlights the most up-to-date progress in this field.

Energetic salts based on 3-hydrazino-4-amino-1,2,4-triazole (HATr): synthesis and properties

The synthesized energetic salts of 3-hydrazino-4-amino-1,2,4-triazole were fully characterized with respect to their prospective use in energetic applications.

Two energetic complexes incorporating 3,5-dinitrobenzoic acid and azole ligands: microwave-assisted synthesis, favorable detonation properties, insensitivity and effects on the thermal decomposition of RDX

The two energetic complexes reported may act as attractive candidates for green propellants.

A novel insensitive cocrystal explosive BTO/ATZ: preparation and performance

A new insensitive co-crystal explosive, BTO/ATZ, has a promising future for use as an insensitive explosive.

Electrophilic iodination: a gateway to high iodine compounds and energetic materials

Preparation of polyiodopyrazoles and subsequent highly oxygenated nitro compounds.

Comparative DFT-D studies on structural and absorption properties of crystalline 3,3′-dinitroamino-4,4′-azoxyfurazan, 3,3′-dinitro-4,4′-azoxyfurazan, and 3,4-bis(3-nitrofurazan-4-yl)furoxan under high pressures

The structural, electronic, and absorption properties of crystalline 3,3′-dinitroamino-4,4′-azoxyfurazan (DNOAAF), 3,3′-dinitro-4,4′-azoxyfurazan (DNOAF), and 3,4-bis(3-nitrofurazan-4-yl)furoxan (BNTF) under hydrostatic compression of 0–190 GPa have been comparatively studied using density functional theory with dispersion corrections. Their crystal structures were relaxed using three types of vdW corrections such as the PBE-G06, PBE-TS, and PW91-OBS functionals at ambient conditions. The results indicate that PBE-G06 is the best functional for studying them. The compression ratios show that DNOAAF is stiffer than the other two at high pressures. An analysis of the band gaps and density of states indicates that they become more and more sensitive under compression. In the range of 0–120 GPa, BNTF is the most unstable. However, in the range of 120–190 GPa, DNOAF becomes the more unstable. The three crystals have higher optical activity at high pressures, and moreover, applied pressures change their optical adsorption activity order.

Enforced Layer-by-Layer Stacking of Energetic Salts towards High-Performance Insensitive Energetic Materials

Development of modern high-performance insensitive energetic materials is significant because of the increasing demands for both military and civilian applications. Here we propose a rapid and facile strategy called the "layer hydrogen bonding pairing approach" to organize energetic molecules via layer-by-layer stacking, which grants access to tunable energetic materials with targeted properties. Using this strategy, an unusual energetic salt, hydroxylammonium 4-amino-furazan-3-yl-tetrazol-1-olate, with good detonation performances and excellent sensitivities, was designed, synthesized, and fully characterized. In addition, the expected unique layer-by-layer structure with a high crystal packing coefficient was confirmed by single-crystal X-ray crystallography. Calculations indicate that the layer-stacking structure of this material can absorb the mechanical stimuli-induced kinetic energy by converting it to layer sliding, which results in low sensitivity.