Synthesis and characterization of novel transition metal coordination compounds of 5-(3,5-dinitro-1H-pyrazol-4-yl)-1H-tetrazole

Abstract. Based on the energetic ligand 5-(3,5-dinitro-1H-pyrazol-4-yl)-1H-tetrazole (H₂DNPT) and the transition metals copper and nickel, two novel coordination compounds have been synthesised. The compounds were characterised by a combination of IR spectroscopy, microanalysis, as well as X-ray crystallographic and thermochemical methods. Crystals of the M(DNPT) compounds reveal coordination polymeric structures, involving Cu(II) or Ni(II) coordination centres, respectively, interlinked by DNPT(2-) ligands activating various coordination modes, as well as coordinated water. The crystallographic results indicate high crystal densities. The materials are thermally robust (T^on_dec > 300 °C). According to the Kamlet and Jacobs' method for predicting energetic performance, intriguingly high detonation velocities and pressures were found in the range of secondary explosives and comparable to RDX (CuDNPT: Q = 5741 J g^-1, p_CJ = 461 kbar, D_CJ = 9.28 km s^-1). Considering that metal-based energetics usually display the behaviour of primary explosives, these results warrant further investigation into their initiation and sensitivity characteristics, in particular regarding their potential as lead-free initiators.