ABSTRACT
In this work, we realized the detection of diamino-pentazolium cation (DAPZ+) in the reaction solution experimentally and proved it to be meta-diamino-pentazole based on the transition state theory. Quantum chemical methods were used to predict its spectral properties, charge distribution, stability and aromaticity. Considering that DAPZ+ has excellent detonation properties, it was further explored by assembling it with N5-, N3- and C(NO2)3- anions, respectively. The results show a strong interaction between DAPZ+ and the three anions, which will have a positive effect on its stability. Thanks to the high enthalpy of formation and density, the calculated detonation properties of the three systems are exciting, especially [DAPZ+][N5-] (D: 10,016 m·s-1; P: 37.94 GPa), whose actual detonation velocity may very likely exceed CL-20 (D: 9773 m·s-1). There is no doubt that this work will become the precursor for the theoretical exploration of new polynitrogen ionic compounds.
ABSTRACT
Polycyclic energetic materials make up a distinctive class of conjugated structures that consist of two or more rings. In this work, 1,3-bis(3,5-dinitro-1H-pyrazol-4-yl)-4,6-dinitrobenzene (BDPD) was synthesized and investigated in detail as a polycyclic heat-resistant energetic molecule that can be deprotonated by bases to obtain its anionic (3-5) salts. All compounds were thoroughly characterized by 1H and 13C NMR, infrared spectroscopy, high-resolution mass spectrometry, and elemental analysis. The structural features of BDPD and its salts were investigated by single-crystal X-ray diffraction and analyzed by different kinds of computing software, like Multiwfn, Gaussian 09W, and so on. In addition, their thermal decomposition temperatures were evaluated by differential scanning calorimetry to be 319.8-329.0 °C, revealing that they possessed high thermal stabilities. The results of impact sensitivity and friction sensitivity analysis confirm that these energetic compounds were insensitive. The detonation properties of neutral compound BDPD and all its nonmetallic salts were calculated by the EXPLO5 v6.05.04 program. The results revealed that their detonation performances were higher than those of the widely used heat-resistant explosive 2,2',4,4',6,6'-hexanitrostilbene (HNS). Combining the above results, it is reasonable to suggest that these compounds have the potential to be heat-resistant energetic materials.
ABSTRACT
This work reports a strategy by enhancing conjugation effect and synthesizes a symmetrical and planar compound, 1,2-bis (4,5-di(1H-tetrazol-5-yl)-2H-1,2,3-triazol-2-yl)diazene (NL24). The incorporation of azo and 1,2,3-triazole moieties manifests a synergistic effect, amplifying the conjugation effect of the azo bridge and thereby elevating the stability of NL24 (Td: 263 °C, IS: 7 J). Notably, NL24, possessing a structural configuration comprising four tetrazoles harboring a total of 24 nitrogen atoms, exhibits excellent detonation performances (ΔHf: 6.06 kJ g-1, VD: 9002 m s-1). This strategy achieves the balance of energy and stability of polycyclic tetrazoles and provides a direction for high-performance energetic materials.
ABSTRACT
Lithium-based nitrogen-rich complexes are important research objects in the field of high-energy materials. However, the weak coordination abilities of lithium ions relative to those of other metal ions with greater atomic numbers have hindered their applications in the field of nitrogen-rich complexes. Herein, we successfully prepared novel lithium-based nitrogen-rich complexes (N2H5-2AZTO-Li and NH3OH-2AZTO-Li) by exploiting the structural properties of 1-hydroxytetrazolium-5-hydrazine (HAZTO). Both N2H5-2AZTO-Li and NH3OH-2AZTO-Li were found to exhibit physicochemical parameters (including the density, stability, and energetic properties) that were intermediate between those of the simple ionic compounds (3 and 4) and the complexes (5) that formed them, enabling a favorable balance between high energy, high stability, and environmental friendliness (for N2H5-2AZTO-Li: detonation velocity (D) = 9005 m s-1, detonation pressure (P) = 35.5 GPa, decomposition temperature (Tdec) = 238.1 °C, impact sensitivity (IS) = 24 J, friction sensitivity (FS) = 210 N, and detonation product (DP) (CO) < 2%; for NH3OH-2AZTO-Li: D = 9028 m s-1, P = 35.7 GPa, Tdec = 211.2 °C, IS = 20 J, FS = 180 N, and DP (CO) < 2%). This study transcends the conventional structural forms of nitrogen-rich complexes, opening new horizons for the design of novel insensitive energetic materials.
