Synthesis, crystal structure, thermal decomposition, and sensitive properties of two novel energetic cadmium(II) complexes based on 4-amino-1,2,4-triazole

Two new energetic complexes [Cd(4-ATZ)₂(Ac)₂(H ₂O)](Ac = acetate) and [Cd(4-ATZ)₂(H₂O) ₄](PA)₂ (PA = picrate) were synthesized by using 4-amino-1,2,4-triazole (4-ATZ) as ligand and characterized by FT-IR spectroscopy and elemental analysis. Single-crystal X-ray diffraction analysis revealed that the two compounds crystallize in monoclinic C2/c and triclinic P$\bar{1}$ space groups, respectively. The central cadmium(II) ion is seven-coordinate in [Cd(4-ATZ)₂(Ac)₂(H₂O)] and six-coordinate in [Cd(4-ATZ)₂(H₂O)₄](PA) ₂. The coordination sites of the 4-ATZ ligand in both compounds are the N1 atoms of the triazole rings, which is in agreement with the computational results. Thermal decomposition mechanisms were determined based on DSC and TG-DTG analysis, and kinetic parameters of decomposition were studied by using Kissinger's and Ozawa-Doyle's methods. In the next step, measurements of heat of combustion and sensitivities to mechanical and thermal stimulus were performed. The energies of combustion of the two compounds were determined to be 10.75 MJ·kg^-1 and 11.35 MJ·kg^-1, respectively. Sensitivity tests showed that [Cd(4-ATZ)₂(Ac)₂(H ₂O)] was insensitive to external stimulus and [Cd(4-ATZ) ₂(H₂O)₄](PA)₂ had high impact sensitivity and low friction and flame sensitivities.