Synthesis and Characterization of Bis(triaminoguanidinium) 5,5′-Dinitrimino-3,3′-azo-1H-1,2,4-triazolate - A Novel Insensitive Energetic Material

The synthesis of 5,5′-diamino-3,3′-azo-1H-1,2,4-triazole (3) by reaction of 5-acetylamino-3-amino-1H-1,2,4-triazole (2) with potassium permanganate is described. The application of the very straightforward and efficient acetyl protection of 3,5-diamino-1H-1,2,4-triazole allows selective reactions of the remaining free amino group to form the azo-functionality. Compound 3 is used as starting material for the synthesis of 5,5′-dinitrimino-3,3′-azo-1H-1,2,4-triazole (4), which subsequently reacted with organic bases (ammonia, hydrazine, guanidine, aminoguanidine, triaminoguanidine) to form the corresponding nitrogen-rich triazolate salts (5–9). All substances were fully characterized by IR and Raman as well as multinuclear NMR spectroscopy, mass spectrometry, and differential scanning calorimetry. Selected compounds were additionally characterized by low temperature single-crystal X-ray diffraction measurements. The heats of formation of 4–9 were calculated by the CBS-4M method to be 647.7 (4), 401.2 (5), 700.4 (6), 398.4 (7), 676.5 (8), and 1089.2 (9) kJ·mol–1. With these values as well as the experimentally determined densities several detonation parameters were calculated using both computer codes EXPLO5.03 and EXPLO5.04. In addition, the sensitivities of 5–9 were determined by the BAM drophammer and friction tester as well as a small scale electrical discharge device.