Energetic nitrogen-rich Cu(II) and Cd(II) 5,5'-azobis(tetrazolate) complexes

Graphene Oxide-Intercalated Tetrazole-Based Coordination Polymers: Thermally Stable Hybrid Energetic Crystals with Enhanced Photosensitivity

High-energy-density photosensitive pyrotechnics with good thermal stability have been in increasing demand in recent years. In this paper, graphene oxide (GO)-intercalated energetic coordination polymers (ECPs) are prepared with improved thermostability but great photosensitivity by using high nitrogen compounds azotetrazole (AT) and 5,5'-bistetrazole-1,1'-diolate dehydrate (BTO) as ligands. The decomposition activation energy (E_a) of Cu-AT has been increased from 135.7 to 151.9 kJ·mol^-1 after intercalating 5 wt% GO, and in the meantime, the exothermic peak temperature (T_p) was increased by 12.6 °C. However, the decomposition E_a of Cu-BTO decreased under the effect of the same amount of GO with little effect on T_p. This confirms that GO has stabilization effects on the Cu-AT crystal, whereas the catalytic effects on Cu-BTO would dominate after dehydration with its crystal lattice collapse. Also, when the content of GO was 3%, the resultant GO_0.03-Cu-AT exhibits a higher density (2.88 g·cm^-3) and good thermostability (T_p = 293.7 °C). This ECP shows excellent low-energy laser ignition performance, which can be ignited with an energy of less than 1 mJ at a wavelength of 976 nm. Low-energy laser initiation is considered to be a safer but more reliable method than the traditional electrical-based ones.

Pushing the Limit of Nitro Groups on a Pyrazole Ring with Energy-Stability Balance

Polynitro compounds exhibit high density and good oxygen balance, which are desirable for energetic material applications, but their syntheses are often very challenging. Now, the design and syntheses of a new three-dimensional (3D) energetic metal-organic framework (EMOF) and high-energy-density materials (HEDMs) with good thermal stabilities and detonation properties based on a polynitro pyrazole are reported. Dipotassium 3,5-bis(dinitromethyl)-4-nitro-1H-pyrazole (5) exhibits a 3D EMOF structure with good thermal stability (202 °C), a high density of 2.15 g cm^-3 at 100 K (2.10 g cm^-3 at 298 K) in combination with superior detonation performance (D_v = 7965 m s^-1, P = 29.3 GPa). Dihydrazinium 3,5-bis(dinitromethyl)-4-nitro-1H-pyrazole (7) exhibits a good density of 1.88 g cm^-3 at 100 K (1.83 g cm^-3 at 298 K) and superior thermal stability (218 °C), owing to the presence of 3D hydrogen-bonding networks. Its detonation velocity (8931 m s^-1) and detonation pressure (35.9 GPa) are considerably superior to those of 1,3,5-trinitro-1,3,5-triazine (RDX). The results highlight the syntheses of a 3D EMOF (5) and HEDM (7) with five nitro groups as potential energetic materials.

A DFT study of the structure-property relationships of bistetrazole-based high-nitrogen energetic metal complexes

In this work, six series of new energetic metal complexes were designed. Each complex contained a large, high-energy, high-nitrogen, anionic chelating ligand (either the 5,5'-bistetrazolate anion, the 5,5'-azobistetrazolate anion, or the 5,5'-(hydrazine-1,2-diyl)bis-[1H-tetrazol-1-ide] anion-each of which has a different bridging group), Cu or Ni as the metal atom, and two small complexing agent ligands (NH₃ and/or NH₂NO₂). The molecular and electronic structures, heats of formation, densities, detonation properties, and impact sensitivities of the novel complexes were studied using density functional theory. Furthermore, the effects of varying the large chelating ligand (and thus the bridging group), the small complexing agents, and the metal atom on the structure and properties of the complex were investigated and analyzed in depth. The results show that the particular metal, bridging group, and complexing agents included in the energetic complex influence its structure and properties, but the effects of varying the constituents of the complex are complicated or unclear, and these effects are sometimes intertwined. In addition, the detonation pressures, detonation velocities, and impact sensitivities of the novel complexes ranged from 25.9 to 38.6 GPa, from 7.21 to 8.80 km s^-1, and from 17 to 48 cm, respectively. Five of the complexes (B3, C3, D3, E3, and F3) appear to possess comparable performance to the famous and widely used high explosive 1,3,5-trinitro-1,3,5-triazinane, making these new complexes attractive to energetic materials experimentalists.

In-situ nano-crystal-to-crystal transformation synthesis of energetic materials based on three 5,5'-azotetrazolate Cr(III) salts

The in-situ nano-crystal-to-crystal transformation (SCCT) synthesis provides a powerful approach for tailoring controllable feature shapes and sizes of nano crystals. In this work, three nitrogen-rich energetic nano-crystals based on 5,5'-azotetrazolate(AZT^2-) Cr(III) salts were synthesized by means of SCCT methodology. SEM and TEM analyses show that the energetic nano-crystals feature a composition- and structure-dependent together with size-dependent thermal stability. Moreover, nano-scale decomposition products can be obtained above 500 °C, providing a new method for preparing metallic oxide nano materials.

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.

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.

Studies on sodium polymers based on di(1H-tetrazol-5-yl)methanone oxime

[Na(Hbto)(H₂O)₂·2H₂O]_n (1), [(NH₃OH)₂Na₂(bto)₂(H₂O)₄·H₂O]_n (2) and [(NH₃OH)Na(bto)(H₂O)₂]_n (3), eco-friendly coordination polymers, have been synthesized.

Insensitive energetic 5-nitroaminotetrazolate ionic liquids

Combustible 5-nitroaminotetrazolate-based energetic ionic liquids with high stability as well as environmentally friendly decomposition gases were prepared and fully characterized.

A Si–MnOOH composite with superior lithium storage properties

The Si–MnOOH composite electrode shows excellent rate capability, which can be attributed to the γ-MnOOH component that significantly promotes the catalyzing effect.

3,4-Diamino-1,2,4-triazole based energetic salts: synthesis, characterization, and energetic properties

A series of energetic salts based on 3,4-diamino-1,2,4-triazole with promising detonation performances have been synthesized using a metathesis reaction method or a protonation reaction method.

In situ synthesized 3D heterometallic metal–organic framework (MOF) as a high-energy-density material shows high heat of detonation, good thermostability and insensitivity

A 3D heterometallic metal–organic framework has been synthesized in situ using Mtta formed from acetonitrile and azide, and structurally characterized.

Two nitrogen-rich Ni(ii) coordination compounds based on 5,5′-azotetrazole: synthesis, characterization and effect on thermal decomposition for RDX, HMX and AP

Two novel efficient burning promoters of solid propellants based on Ni salt and azotetrazole have been successfully prepared and characterized.

Explosive Werner-type cobalt(iii) complexes

A series of potentially explosive Werner-type cobalt(iii) complexes comprising the anions azotetrazolate, nitrotetrazolate, picrate and dipicrylamide have been prepared via simple metathetical routes. Representative studies of the energetic properties (impact and friction sensitivity, combustion) revealed that some of the new compounds are primary explosives.

Structures, photoluminescence and photocatalytic properties of two novel metal–organic frameworks based on tetrazole derivatives

Two novel, efficient metal organic framework photocatalysts based on silver salts and tetrazolate derivatives have been successfully prepared and characterized.