Mono and Bridged Azolium Picrates as Energetic Salts

The energetic mono and bridged imidazolium, triazolium and tetrazolium picrates 7–10, 14, and 16, the dipicrates 23, 25, and 26 and the dinitrates 24, and 27 were synthesized by the quaternization of azolium derivatives (1, 2, 13, 15, 19 and 20) with picric acid and nitric acid or by metathesis of the corresponding quaternary salts (3, 6, 21 and 22) with silver picrate or silver nitrate. The structures of 14 and 16 were determined by single-crystal X-ray diffraction analysis confirming quaterization on the triazolium and tetrazolium rings. Their physical and thermodynamic properties were determined. In some cases, the salts are thermally stable to ca. 300 °C and they exhibit densities averaging ca. 1.6 g/cm3. Nearly all have positive heats of formation with the highest calculated value, ΔfHom = 611.6 kJ/mol, found for 3-azido-1,4-dimethyl-1,2,4-triazolium picrate (10). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)