Synthesis, Structures And Physicochemical Properties Of Tetrazolium Energetic Complexes

This paper embarks from the coordination chemistry and aims to syntheses of energetic complexes which with high energy, high density, insensitivity and good detonation performance. Coordination polymers were formed by the self-assembly of Cu(II) and tetrazole systems, such as 1H-tetrazole (HTZ), 1H-tetrazole-1-acetic acid (HTZA) and N,N-bis(1(2)H-tetrazol-5-yl)-amine (H2BTA), which were employed as the energy souces, and carboxylic acid, such as oxalic acid (OX), p-nitrobenzoic acid (PNBA), 3,5-dinitrobenzoic acid (DNBA), which were introduced to act as co-ligangs.10 energetic complexes were prepared by using solution method and hydrothermal/solvothermal method. The structures and the physicochemical properties were studied. The main research content is summarized as follows:Firstly, the obtained 10 complexes were fully characterized by elemental analysis, IR spectroscopy and X-ray single crystal diffraction. Structural analysis revealed that the tetrazolate ligands and carboxylate ligands all showing varieties of coordination modes and strong coordination ability. They can not only coordinate to the Cu ions in mono or bi dentate-fashion, but also serve as the electrons donor-acceptor or ? conjugative effects in forming hydrogen bonds and ?-? stacking interaction. The cooperation function of two kinds of ligands should result in 3D supermolecular dense structures for complexes 1,2,4-7 and 9. These intermolecular interactions were beneficial to enhance stableness and density of complexes.Secondly, the thermal decomposition processes of the complexes were studied based on TG and DSC analyses. The results indicate that all complexes possess favorable thermal stability. Compound 1 exhibits an outstanding decomposition temperature up to 316?. The non-isothermal kinetics parameters (The apparent activation energy E and the pre-exponential factor A) of the ten complexes were calculated by using Kissinger's and Ozawa-Doyle's method. Furthermore, the thermal decomposition rate constant of complexes can be obtained by Arrhenius equation. According to the thermokinetic research,3,4,6 and 10 were decomposed under high temperature.Finally, in order to calculate the heats of detonation (?Hdet), DFT-B3LYP method with the LanL2DZ basis set was used to optimize the structure of the complexes, then molecular total energies of 1,2,4-7 and 9 were obtained by theoretical methods, respectively. Furthermore, the detonation velocity (D) and pressure (P) of the complexes were estimated by the Kamlet-Jacbos equation. The results of sensitivity tests reveal that all the complexes are insensitive to external stimuli. It is worth noting that complex 6 (N%=40.31%,?=2.012 g·cm+3,?%=-23.02%,?Hdet=2.325 kacl·g-1, D=9530 m·s-1, P=43.78 GPa, IS=38 J) possesses a better physicochemical property than the known energetic complexes. All the complexes can promote the thermal decompositon of AP, which is the main component of solid propllant. The results would provide that all of the complexes can be used as energetic combustion catalysts.