Preparation, Crystal Structures, Thermal Decomposition and Explosive Properties of Two Novel Energetic Compounds M(IMI)4(N3)2 (M = CuII and NiII, IMI = Imidazole): The New High–Nitrogen Materials (N > 46 %)



Two novel multiligand coordination complexes of imidazole–copper(II) azide and imidazole–nickel(II) azide, Cu(IMI)4(N3)2 and Ni(IMI)4(N3)2, were synthesized and characterized by elemental analysis and FTIR spectroscopy. The crystal structures were determined by single-crystal X-ray diffraction. The results show that the crystals of Cu(IMI)4(N3)2 and Ni(IMI)4(N3)2 crystallize in the orthorhombic Pna21 and monoclinic P21/n space groups, respectively. The metal cations are six-coordinate, and are bound to two azido ligands by μ1-azido bridges and to four imidazole molecules through nitrogen atoms. Under nitrogen, with a heating rate of 5 K min–1,these compounds go through two main exothermic stagesbetween 420 K and 750 K during their thermal decompostion, as seen in the differential scanning calorimetry (DSC) and thermogravimetry–differential thermogravimetry (TG-DTG) curves. The nonisothermal kinetic parameters were calculated by the Kissinger and Ozawa methods. The sensitivity properties of M(IMI)4(N3)2 were also determined by standard methods, and the results showed that Cu(IMI)4(N3)2 had high impact and friction sensitivities and low flame sensitivity. Ni(IMI)4(N3)2 had low sensitivity to external stimuli, but it had a very high energy of combustion. The results of all the studies showed that these M(IMI)4(N3)2 (M = CuII and NiII) compounds have potential application as energetic materials.