Candidates Of High Energy Density Compounds Research Articles

Theoretical exploration of the stabilities and detonation parameters of nitro-substituted 1H-benzotriazole.

The nitro group was introduced into the nitrogen heterocycle of 1H-benzotriazole to design a total of 31 derivatives. To estimate the thermal stability of these derivatives, the heat of formation (HOF) is calculated based on the isodesmic reaction. The bond dissociation energy (BDE) was also predicted based on the homolytic reaction to further evaluate the dynamic stability. To evaluate the possibility of utilizing as high energy density compounds (HEDCs), the detonation parameters including the detonation pressure (P), detonation velocity (D), and explosive heat (Q) are predicted by taking advantage of the Kamlet-Jacobs empirical equation. To measure the sensitivity to impact, both the characteristic height (H50) and free space in crystal (∆V) are considered in this paper. Based on our calculations, D-series and E are found to be the candidates for HEDCs. The Gaussian 09 software package was used in this paper. The B3PW91 hybrid function with the 6-311 + G(d,p) basis set was chosen to perform the structural optimization, frequency analysis, heat of formation, and bond dissociation energy. The detonation parameters were calculated following the Kamlet-Jacobs equation.

Theoretical design of novel high energy metal complexes based on two complementary oxygen-rich mixed ligands of 4-amino-4H-1,2,4-triazole-3,5-diol and 1,1'-dinitramino-5,5'-bistetrazole.

In this study, 16 new energetic metal complexes [M(DNABT)(ATDO), M=Cu, Ni] were designed using the mixed complex construct strategy, which was based on two complementary oxygen-rich high-energy ligands of 1,1'-dinitramino-5,5'-bistetrazole (DNABT) and 4-amino-4H-1,2,4-triazole-3,5-diol (ATDO), then combined with metals Cu and Ni, and further adjusted by the introduction of NO2 and NH2. The molecular and electronic structures, heat of formation (HOF), density, detonation velocity, detonation pressure, and sensitivity were investigated by the density functional theory method. The results showed that in metals, the position and amount of NO2/NH2 have great effects on the structure and property of metal complexes, and these effects coupled with each other. N-NO2 bond is the relatively weak bond, and its max length is related with the sensitivity closely. The designed metal complexes all have high HOF (673~868 kJ mol-1), high density (2.06~2.14 g cm-3), and ideal oxygen balance (- 19.2~- 6.7%), which further make them have higher detonation velocity (8.76~9.84 km s-1) and detonation pressure (37.4~46.6 GPa) than three famous high-energy compounds 1,3,5-trinitro-1,3,5-triazine (RDX); 1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX); or even 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20). At the same time, they are less sensitive than RDX, HMX, and CL-20, making them potential candidates for high-energy density compounds.

DFT studies on nitrogen-rich pyrazino [2, 3-e] [1, 2, 3, 4] tetrazine-based high-energy density compounds.

By using the density functional theory method, we investigated the heats of formation (HOFs), electronic structure, detonation properties, thermal stability and sensitivity for a set of pyrazino [2, 3-e] [1, 2, 3, 4] tetrazine derivatives with different substituents and different numbers of N-oxides. Our findings reveal that the HOFs of the derivatives decrease dramatically with the increasing number of N-oxides. The effects of the substituents on the HOMO-LUMO gaps are coupled with those of the N-oxides. The calculated detonation properties point out that -NF2, -ONO2 and an increasing number of N-oxides are very helpful for improving the detonation performance of the designed derivatives. The bond dissociation energies of the weakest bonds indicate that a majority of our designed compounds have better thermal stability. The -NH2 group is very useful to decrease the free space value. Most of the derivatives have higher h50 values compared with parent molecules. Considering the sensitivity, thermal stability and detonation performance, four compounds could be considered as potential candidates of high-energy density compounds.

Theoretical studies on vicinal-tetrazine compounds: furoxano-1,2,3,4-tetrazine-1,3,5-trioxide (FTTO-α) and furoxano-1,2,3,4-tetrazine-1,3,7-trioxide (FTTO-β).

The derivatives of 1,2,3,4-tetrazine may be promising candidates of high-energy density compounds and are receiving more and more attention. In this study, two 1,2,3,4-tetrazines, furoxano-1,2,3,4-tetrazine-1,3,5-trioxide (FTTO-α) and furoxano-1,2,3,4-tetrazine-1,3,7-trioxide (FTTO-β), were theoretically studied. The geometrical structures in gas phase were studied at the B3LYP/6-311++G(d,p) level of density functional theory (DFT). The gas phase enthalpies of formation were calculated by the homodesmotic reaction method. The enthalpies of sublimation and solid phase enthalpies of formation were predicted with corrections of electrostatic potential method at the B3PW91/6-31G(d,p) level. The detonation properties were estimated with the Kamlet-Jacobs equations based on the predicted densities and enthalpies of formation in solid state. The available free space in the lattice was calculated to evaluate their stability. Calculations of potential energy surface and structure interconversion thermodynamics under different temperatures were carried out to further confirm their stability. FTTOs have better performance than HMX and FTDO but are easy to decompose to 5,6-dinitroso-v-tetrazine 1,3-dioxide. A synthesis route for FTTO-β was proposed to provide a consideration for the further study. We believe FTTOs could be the key compounds to synthesize other v-tetrazines such as TTTO.

Computational characterization of 2, 4, 6, 8, 10, 12, 13-heptaazatetracyclo [5.5.1.03,11.05,9]tridecanes as potential energetic compounds

The characters of high density and high heat of formation of cage molecules have attracted a lot of investigations as potential energetic materials. Several such compounds have been synthesized, e.g., octanitrocubane, hexanitrohexaazaisowurzitane (CL-20), and 4-trinitroethyl-2, 6, 8, 10, 12-pentanitrohexaazaisowurtzitane(TNE-CL-20). In the present study, a new cage compound, namely 2, 4, 6, 8, 10, 12, 13-heptaazatetracyclo [5.5.1.03,11.05,9] tridecane (HATT), was proposed. Density functional theory has been employed to study the geometric and electronic structures for a series of nitro derivatives of HATT at the B3LYP/6-31G(d,p) level. Thermodynamic properties derived on the basis of statistical thermodynamic principles are linearly correlated with the numbers of nitro group as well as the temperature. Detonation performance was evaluated based on the calculated densities and heats of formation. It is found that some title compounds have high densities of ca. 1.9 g cm−3, detonation velocities over 9.0 km s−1, and detonation pressures of about 40.0 GPa and may be novel potential candidates of high energy density compounds (HEDCs). Thermal stability and pyrolysis mechanism of the nitro HATTs were investigated by calculating the bond dissociation energies (BDE). In conjunction with the detonation performance and thermal stability, HATTs with no less than five nitro groups are recommended as the preferred candidates of HEDCs. These results provide basic information for the further studies of cage compounds.