Adjacent N→O and C–NH2 groups — a highly efficient amphoteric structure for energetic materials resulting from tautomerization proved by crystal engineering

Adjacent N→O and C–NH₂ groups (O←NC–NH₂) were found to be a highly efficient and fairly balanced amphoteric energetic structure for energetic materials by crystal engineering.

Combining the furoxanylhydrazone framework with various energetic functionalities to prepare new insensitive energetic materials with 3D-cube layer stacking

We provide a new series of energetic salts and neutral compounds containing furoxanylhydrazone with 3D-cube layer stacking.

Novel insensitive energetic-cocrystal-based BTO with good comprehensive properties

Combining a layer construction strategy with cocrystallization techniques, we designed and prepared a structurally unusual 1H,1′H-5,5′-bistetrazole-1,1′-diolate (BTO) based energetic cocrystal, which we also confirmed by single-crystal X-ray diffraction and powder-crystal X-ray diffraction. The obtained cocrystal crystallizes in a triclinic system, P-1 space group, with a density of 1.72 g cm⁻³. The properties including the thermal stability, sensitivity and detonation performance of the cocrystal were analyzed in detail. In addition, the thermal decomposition behavior of the cocrystal was studied by differential calorimetry and thermogravimetry tandem infrared spectroscopy. The results indicated that the cocrystal exhibits strong resistance to thermal decomposition up to 535.6 K. The cocrystal also demonstrates a sensitivity of >50 J. Moreover, its formation enthalpy was estimated to be 2312.0 kJ mol⁻¹, whereas its detonation velocity and detonation pressure were predicted to be 8.213 km s⁻¹ and 29.1 GPa, respectively, by applying K–J equations. Therefore, as expected, the obtained cocrystal shows a good comprehensive performance, which proves that a high degree of layer-by-layer stacking is essential for the structural density, thermal stability and sensitivity.

Combining a layer construction strategy with cocrystallization techniques, we designed and prepared an unusual energetic cocrystal, which confirmed by single-crystal X-ray diffraction.

Asymmetric nitrogen-rich energetic materials resulting from the combination of tetrazolyl, dinitromethyl and (1,2,4-oxadiazol-5-yl)nitroamino groups with furoxan

Three classes of nitrogen-rich energetic compounds were obtained from 3,4-dicyano-furoxan.

The synthesis, crystal structure and thermal properties of an energetic compound: the hydrated azanium salt of 3,6-bis[(1H-1,2,3,4-tetrazol-5-yl)amino]-1,2,4,5-tetrazine

The energetic ionic salt bis(1-aminoguanidin-2-ium) 5,5'-[1,2,4,5-tetrazine-3,6-diylbis(azanediyl)]bis(1H-1,2,3,4-tetrazol-1-ide) dihydrate, 2CH₇N₄⁺·C₄H₂N₁₄^2-·2H₂O, (I), with a high nitrogen content, has been synthesized and examined by elemental analysis, Fourier transform IR spectrometry, ¹H NMR spectroscopy and single-crystal X-ray crystallography. Compound (I) crystallizes in the monoclinic space group P2₁/c with two water molecules. However, the water molecules are disordered about an inversion centre and were modelled as half-occupancy molecules in the structure. The crystal structure reveals a three-dimensional network of molecules linked through N-H...N, N-H...O, O-H...N and O-H...O hydrogen bonds. Thermal decomposition was investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The exothermic peak temperature is 509.72 K, which indicates that hydrated salt (I) exhibits good thermal stability. Non-isothermal reaction kinetic parameters were calculated via both the Kissinger and the Ozawa methods to yield activation energies of E_k = 239.07 kJ mol^-1, lgA_k = 22.79 s^-1 and E_O = 235.38 kJ mol^-1 for (I). Additionally, the thermal safety was evaluated by calculating critical temperatures and thermodynamic values, viz. T_SADT, T_TIT, T_b, ΔS^≠, ΔH^≠ and ΔG^≠. The results reveal that (I) exhibits good thermal safety compared to other ion salts of 3,6-bis[(1H-1,2,3,4-tetrazol-5-yl)amino]-1,2,4,5-tetrazine (BTATz).

Novel dinitromethyl-featured polynitro energetic salts

An unique and facile method was developed to synthesize a new class of energetic salts based on 2-amino-1,1,5,5-tetranitro-4-oxo-3-aza-pentene (ATNP) anion in one-pot reaction. These salts exhibited promising detonation performances (detonation pressure: 28.6 to 34.3 GPa; detonation velocity: 8037 to 8674 m s⁻¹) which were comparable to those of RDX.

An Ag(i) energetic metal–organic framework assembled with the energetic combination of furazan and tetrazole: synthesis, structure and energetic performance

A novel 3D Ag(i) energetic MOF assembled with a furazan derivative (4,4′-oxybis[3,3′-(1H-5-tetrazol)]furazan) shows low sensitivity, good thermostability and ultrahigh detonation pressure and detonation velocity.

1,2,4,5-Dioxadiazine-functionalized [N–NO2]− furazan energetic salts

1,2,4,5-Dioxadiazine is identified as a key bridge to improve the density and detonation performance of energetic materials.

Nitrogen-rich energetic salts of 1H,1′H-5,5′-bistetrazole-1,1′-diolate: synthesis, characterization, and thermal behaviors

A series of nitrogen-rich heterocyclic 1H,1′H-5,5′-bistetrazole-1,1′-diolate salts with excellent thermal stabilities, impact sensitivities and promising detonation performances was synthesized.

Energetic alliance of tetrazole-1-oxides and 1,2,5-oxadiazoles

The connection of highly endothermic heterocycles with high nitrogen as well as oxygen content is a recent trend in the development of new energetic materials in order to increase densities and stabilities.

New thermally stable energetic materials: synthesis and characterization of guanylhydrazone substituted furoxan energetic derivatives

The synthesis and characterization of guanylhydrazone substituted furoxan energetic derivatives with good thermal stabilities and detonation performance are now reported.

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.

Synthesis and characterization of a new family of energetic salts based on guanidinium cation containing furoxanyl functionality

A new family of energetic salts based on a guanidinium cation containing furoxanyl functionality was synthesized and well characterized.

A comparative theoretical study of heterocycle-functionalized tetrazolate- and tetrazolate-1-oxide-based dianionic salts

Density functional theory and volume-based thermodynamics calculations have been performed to study the crystal densities, heats of formation, energetic properties, thermodynamics of formation, and impact sensitivity for a series of heterocycle-functionalized tetrazolate- and tetrazolate1-oxide-based dianionic salts. The results show that the hydroxylammonium cation is better than the tetrazolium cation for increasing the densities and detonation performance of the tetrazolate dianionic salts. The salts containing series B (tetrazolate-1-oxide) have larger densities and detonation performance than corresponding ones containing series A (tetrazolate) with the same cation. Incorporating a zwitterionic N-oxide into the nitrogen system is helpful for increasing its density and detonation performance for each salt series, but it is not favorable for improving its heat of formation. The salt including the tetrazine-dioxide conjugated with two tetrazolide exhibits the best energetic performance. The salts containing the tetrazolium cation could be possibly synthesized by the proposed reactions. Some of the salts with the cation hydroxylammonium show lower impact sensitivity than RDX or HMX.