Preparation, crystal structures, thermal decomposition and explosive properties of two novel energetic compounds M(IMI)_4(N _3)_2 (M = Cu~(II) and Ni~(II), IMI = imidazole): The new high-nitrogen materials (N 46%)

摘要

Two novel multiligand coordination complexes of imidazole-copper(II) azide and imidazole-nickel(II) azide, Cu(IMI)4(N3)2 and Ni(IMI)_4(N_3)_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(N_3)_2 and Ni(IMI)_4(N_3)_2 crystallize in the orthorhombic Pna2_1 and monoclinic P2_1 space groups, respectively. The metal cations are six-coordinate, and are bound to two azido ligands by μ_1-azido bridges and to four imidazole molecules through nitrogen atoms. Under nitrogen, with a heating rate of 5 Kmin~(-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(N_3) _2 were also determined by standard methods, and the results showed that Cu(IMI)_4(N_3)_2 had high impact and friction sensitivities and low flame sensitivity. Ni(IMI)_4(N _3)_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(N_3)_2 (M = CuII and Ni II) compounds have potential application as energetic materials. Cu(IMI)_4(N_3)_2 (IMI = imidazole) crystallizes in the orthorhombic space group Pna2_1. The metal cations are six-coordinate, and are linked to two azido ligands by μ_1-azido bridges and to four imidazole molecules through nitrogen atoms. In addition, this compound has high impact and friction sensitivity and therefore has potential application as an energetic material.