Energetic N,N,N',N'-tetraaminopiperazinium salts

Density functional study of guanidine-azole salts as energetic materials

A series of guanidine cations and azole anions were designed for use as energetic salts. Their geometrical structures were optimized by the density functional theory (DFT) method. The counter ions were matched by the similar magnitude of the electron affinity (EA) of the cation and the ionization potential (IP) of the anion. The densities, heats of formation, detonation parameters, and impact sensitivity were predicted. The incorporation of guanidine cations and diazole anions are favorable to form thermal stable salts except cation A1. The diaminoguanidine cation has greater impact on the density and detonation properties of the salts than the triaminoguanidine cation. 2-Amino-3-nitroamino-4,5-nitro-dinitropyrazole is the best anion for advancing the detonation performance among all the anions. Incorporating the C=O bond into the guanidine cations enhances the density and detonation performance of the guanidine-azole salts. The salts containing III1–III4 anion have better detonation properties than HMX, indicating that these salts are potential energetic compounds. Compared with RDX or HMX, some salts with diaminoguanidine cation display lower impact sensitivity.

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.

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.

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.