Copper Bis(1-methyl-5-nitriminotetrazolate): A Promising New Primary Explosive

Copper bis(1‐methyl‐5‐nitriminotetrazolate) (1) was synthesized and investigated as a new primary explosive. Compound 1 was obtained by dehydration of diaquabis(1‐methylnitriminotetrazolato)copper(II) dihydrate (2) or diaquabis(1‐methylnitriminotetrazolato)copper(II) (3) at 120 °C. Complexes 2 and 3 are easily formed by the reaction of 1‐methyl‐5‐nitrimino‐1,2,3,4‐tetrazole (4) with copper(II) nitrate in aqueous solution in high yields. Single crystals of 1 were obtained by recrystallization from dry methanol, whereas wet methanol favors the yield of diaquabis(1‐methyl‐nitriminotetrazolato)copper(II) dimethanolate (5). Compound 1 was characterized by using single‐crystal X‐ray diffraction, IR spectroscopy, elemental analysis, and differential scanning calorimetry (DSC). The sensitivities were investigated by using the BAM drophammer and friction tests, and the heat of formation was calculated on the basis of electronic energies at the B3LYP/SDD level of theory. Compound 1 shows an impact sensitivity that is five times higher and a friction sensitivity that is ten times lower than that of lead azide, which is appropriate. In addition, the long‐term stability of 1 at higher temperatures was tested by using isothermal safety calorimetry (TSC). Compounds 2 and 3 were characterized by single‐crystal X‐ray diffraction, IR spectroscopy, elemental analysis, DSC, bomb calorimetry, and BAM sensitivity tests. In addition, compound 5 was characterized by single‐crystal X‐ray diffraction and elemental analysis. The dehydration of 2 was determined by using thermal gravimetry (TG) to occur by the loss of crystal water in one discrete step. (© WILEY‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)