A novel stable high-nitrogen energetic compound: Copper(II) 1,2-diaminopropane azide

The multi-ligand coordination compound copper(II) 1,2-diaminopropane (pn) azide, [Cu(pn)(N₃)₂]_n (1), was synthesized using pn and azido groups. It was characterized by X-ray single crystal diffraction, elemental analysis, and FT-IR spectroscopy. The crystal structure of 1 belongs to the monoclinic system, space group C2/c. The copper(II) cation is six-coordinated by one pn molecule and four azido ligands with μ-1 and μ-1,1,3 coordination modes. Thermogravimetric investigations with a heating rate of 10 K·min^-1 under nitrogen showed one main exothermic stage with a peak temperature of 215.7 °C in the DSC curve. The non-isothermal kinetics parameters were calculated by Kissinger and Ozawa methods, respectively. The heat of combustion was measured by oxygen bomb calorimetry, and the enthalpy of formation, the critical temperature of thermal explosion, the entropy of activation (ΔS^≠), the enthalpy of activation (ΔH^≠), and the free energy of activation (ΔG^≠) were calculated. The measurements showed that 1 has very high impact, friction, and flame sensitivities.