New energetic materials: Synthesis and characterization of copper 5-nitriminotetrazolates

The energetic compounds 5-nitriminotetrazole (H2AtNO2, 1), 1-methyl-5-nitriminotetrazole (1MeHAtNO(2), 2) and 2-methyl-5-nitraminotetrazole (2MeHAtNO(2), 3), were reacted with Cu(NO3)(2) center dot 3H(2)O and CuCl2 center dot 2H(2)O, respectively, in water as well as in aqueous ammonia solution. The syntheses yielded the complexes [Cu(HAtNO2)(2)(H2O)(4)] (4), [Cu(AtNO2)(NH3)(3)](2) (5), (NH4)(2)[Cu(AtNO2)(2)(H2O)(2)] (6), [Cu(1MeAtNO(2))(2)(NH3)(2)] (7), [Cu((2)-MeAtNO2)(2)(2-MeHAtNO2)(2)] (8), [Cu(2MeAtNO(2))(2)](infinity) (9), [Cu(2-MeAtNO2) (2)(NH3)(2)] (10), and [Cu(2MeAtNO(2))(2)(NH3)(4)] center dot H2O (11). All complexes were characterized using low temperature single crystal X-ray diffraction, IR spectroscopy, elemental analysis, and differential scanning calorimetry. The magnetic properties of six of the complexes were investigated. Due to the energetic characters, the sensitivities towards impact and friction were investigated using the BAM drophammer and friction tester. The values range from "very sensitive", comparable to primary explosives, to "insensitive" depending on the amount of water or ammonia coordinated. Since Cu(II) salts can be used for colorants in pyrotechnics, the combustions and flame colors were discovered to be intensively green. (C) 2008 Elsevier B. V. All rights reserved.