Hydrogen Peroxide Solvates of 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane

Novel strategies for synthesizing energetic materials based on BTO with improved performances

The layer-by-layer assembly of molecules is ubiquitous in nature. Highly ordered structures formed in this manner often exhibit fascinating material properties. A layer hydrogen bonding pairing approach allows the development of tunable energetic materials with targeted properties. A series of unusual energetic compounds based on 1H,1'H-5,5'-bistetrazole-1,1'-diolate (1), such as the salts of 3-amino-1,2,4-triazolium (2), aminoguanidinium (3), and hydrazinium (4), and the cocrystals of 4-amino-1H-pyrazole (5), 2-methylimidazole (6), and imidazole (7), were synthesized using this strategy. The structures of the obtained products 2-7 were fully characterized by elemental analysis, IR spectroscopy, ¹H NMR and ¹³C NMR spectroscopy, and single-crystal X-ray analysis. Their thermal decomposition behavior was studied by differential scanning calorimetry and thermogravimetry. Their mechanical sensitivities and detonation performances were also analyzed in detail. Results show that products 2-7 exhibit higher density, better detonation performances, and more excellent sensitivities than those of the same species of cation salts previously reported.

Decomposition Mechanism of Hexanitrohexaazaisowurtzitane (CL-20) by Coupled Computational and Experimental Study

A novel degradation pathway of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) was identified using computational and experimental methods. Density functional theory (DFT) calculations were employed to obtain its unimolecular degradation pathway, and ultrahigh-performance liquid chromatography-high-resolution mass spectrometry, thermogravimetry-Fourier transform infrared spectrometry, thermogravimetry, and differential scanning calorimetric experimental data were used to validate the computationally deduced degradation pathways. Based on the indications from computational and experimental results, the cleavage of the strained fragment from CL-20 was identified instead of NO₂ or HONO elimination as in conventional high energy materials. This fragmentation results in the formation of two energetic species, dinitrodihydropyrazine and dinitroformimidamide, which makes CL-20 one of the most powerful energetic materials. This novel degradation pathway of CL-20 will be useful in understanding the decomposition of cage molecules, design of new practical energetic molecules, and development/improvement of thermokinetic codes used for energetic property calculations.

Hypergolic zeolitic imidazolate frameworks (ZIFs) as next-generation solid fuels: Unlocking the latent energetic behavior of ZIFs

Hypergolic materials, capable of spontaneous ignition upon contact with an external oxidizer, are of critical importance as fuels and propellants in aerospace applications (e.g., rockets and spacecraft). Currently used hypergolic fuels are highly energetic, toxic, and carcinogenic hydrazine derivatives, inspiring the search for cleaner and safer hypergols. Here, we demonstrate the first strategy to design hypergolic behavior within a metal-organic framework (MOF) platform, by using simple "trigger" functionalities to unlock the latent and generally not recognized energetic properties of zeolitic imidazolate frameworks, a popular class of MOFs. The herein presented six hypergolic MOFs, based on zinc, cobalt, and cadmium, illustrate a uniquely modular platform to develop hypergols free of highly energetic or carcinogenic components, in which varying the metal and linker components enables the modulation of ignition and combustion properties, resulting in excellent hypergolic response evident by ultrashort ignition delays as low as 2 ms.

C8N12O10: a promising energetic compound with excellent detonation performance and desirable sensitivity

A promising energetic molecule bis(4-nitro-1,2,5-oxadiazole-2-oxid-3-yl)-azo-1,2,4-oxadiazole was synthesized and characterized. It has high density, acceptable thermal stability, high heat of formation, outstanding detonation properties and desirable mechanical properties.

In situ nitroso formation induced structural diversity of uranyl coordination polymers

This work presents three possible pathways that could exist in the in situ reaction system. Structural analysis of these compounds revealed that the introduction of nitroso group exerted significant influences on the conformations of ligands, skeletons and 3D structures.

Determining the kinetics of desolvation of a TNT/aniline solvate

The kinetic desolvation process of TNT/aniline solvates was investigated using various experimental techniques.

Unusual isomorphism in crystals of organic solvates with hydrazine and water

Unusual isomorphism and isomorphous substitution in crystals of organic solvates with hydrazine and water are observed for the first time.

Pharmaceutical solvate formation for the incorporation of the antimicrobial agent hydrogen peroxide

Antimicrobial functionality is introduced into a pharmaceutical formulation of miconazole while improving solubility. The work leverages hydrate formation propensity in order to produce hydrogen peroxide solvates. The ubiquity of hydrate formation suggests that hydrogen peroxide can be broadly deployed in pharmaceuticals, rendering a liquid excipient suitable for solid pharmaceutical formulations.

Nitramino-functionalized tetracyclic oxadiazoles as energetic materials with high performance and high stability: crystal structures and energetic properties

The combination of 1,2,4-oxadiazole and nitramino-1,2,5-oxadiazole is a promising strategy for designing energetic materials with high performance and high stability.

Hydrogen Peroxide Insular Dodecameric and Pentameric Clusters in Peroxosolvate Structures

Peroxosolvates of 2-aminonicotinic acid (I) and lidocaine N-oxide (II) including the largest insular hydrogen peroxide clusters were isolated and their crystal structures were determined by single-crystal X-ray diffraction. An unprecedented dodecameric hydrogen peroxide insular cluster was found in I. An unusual cross-like pentameric cluster was observed in the structure of II. The topology of the (H₂ O₂ )₁₂ assembly was never observed for small-molecule clusters. In I and II new double and triple cross-orientational disorders of H₂ O₂ were found. Cluster II is the first example of a peroxosolvate crystal structure containing H₂ O₂ molecules with a homoleptic hydrogen peroxide environment. In II, a hydrogen bond between an H₂ O₂ molecule and a peptide group -CONH⋅⋅⋅O₂ H₂ was observed for the first time.

Axial substitution of a precursor resulted in two high-energy copper(ii) complexes with superior detonation performances

The design and synthesis of explosives with high performance, good thermal stability, and low sensitivity is an important subject for the development of energetic materials. Energetic complexes have recently emerged as a promising energetic material form. As one of the representatives, [Cu(Htztr)₂(H₂O)₂]_n (H₂tztr = 3-(1H-tetrazol-5-yl)-1H-triazole) was previously reported with good energetic performance, outstanding thermostability (T_dec = 345 °C) and low sensitivity to impact and friction stimuli. However, due to the existence of water molecules, its effective energy density is remarkably decreased, resulting in a diminished detonation performance. In order to further improve the detonation performance, using [Cu(Htztr)₂(H₂O)₂]_n as a precursor, {[Cu(Htztr)(H₂O)]NO₃}_n (1) and [Cu(H₂tztr)₂(HCOO)₂]_n (2) were synthesized by the axial substitution reaction with NO₃^- and HCOO^-. The structures of 1 and 2 were characterized by single crystal X-ray diffraction. Both of them exhibit high thermal stabilities and insensitivities to impact and friction. Moreover, the same DFT calculation methodology shows that the heat of detonation of 2 (3.5663 kcal g^-1) is significantly higher than that of the precursor [Cu(Htztr)₂(H₂O)₂]_n (2.1281 kcal g^-1). Meanwhile, the empirical Kamlet-Jacobs equations were used to theoretically predict the detonation properties of the title complexes, and the results show that 1 and 2 have excellent detonation velocity (D) and detonation pressure (P).

Balancing Excellent Performance and High Thermal Stability in a Dinitropyrazole Fused 1,2,3,4-Tetrazine

The key to successfully designing high-performance and insensitive energetic compounds for practical applications is through adjusting the molecular organization including both fuel and oxidizer. Now a superior hydrogen-free 5/6/5 fused ring energetic material, 1,2,9,10-tetranitrodipyrazolo[1,5-d:5',1'-f][1,2,3,4]tetrazine (6) obtained from 4,4',5,5'-tetranitro-2H,2'H-3,3'-bipyrazole (4) by N-amination and N-azo coupling reactions is described. The structures of 5 and 6 were confirmed by single crystal X-ray diffraction measurements. Compound 6 has a remarkable room temperature experimental density of 1.955 g cm^-3 and shows excellent detonation performance. In addition, it has a high decomposition temperature of 233 °C. These fascinating properties, which are comparable to those of CL-20, make it very attractive in high performance applications.

A promising high-energy-density material

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.

A melt castable energetic cocrystal

Cocrystallization leads to melt-state stabilization of the thermally unstable energetic 4-amino-3,5-dinitropyrazole, allowing for production of a melt castable cocrystalline explosive.