Stable high-nitrogen energetic trinuclear compounds based on 4-amino-3, 5-dimethyl-1, 2, 4-triazole: Synthesis, structures, thermal and explosive properties

Six multi-ligand coordination compounds of the general formula [M ₃(AMTz)₄(N₃)₆] [M = Cu (1), Co (2), Ni (3), Zn (4), Mn (5), and Cd (6), AMTz = 4-amino-3, 5-dimethyl-1, 2, 4-triazole] were synthesized using 4-amino-3, 5-dimethyl-1, 2, 4-triazole (AMTz) and azido groups. Compounds 1-6 were characterized by elemental analysis and FT-IR spectroscopy. Furthermore, compound 4 was characterized by X-ray single crystal diffraction. The crystal structure of 4 belongs to the monoclinic P2₁/c space group. Surprisingly, the Zn1 cations are five-coordinated with two AMTz molecules as the bidentate ligands through N1 and N5 atoms, two azido ligands with μ-1 coordination modes and one azido ligand with μ-1, 1 coordination mode. In addition, the Zn2 cation is six-coordinated with four AMTz molecules as the bidentate ligands through N2 and N6 atoms, and two azido ligands with μ-1, 1 coordination modes. Thermal decomposition mechanisms were determined based on differential scanning calorimetry (DSC), and kinetic parameters of the first exothermic process were studied using Kissinger's and Ozawa's method, respectively. The critical temperatures of thermal explosion, entropies of activation (ΔS^≠), enthalpies of activation (ΔH^≠), and free energies of activation (ΔG ^≠) were calculated. In the end, the sensitivities properties were also determined with standard methods.