Furazan-functionalized tetrazolate-based salts: a new family of insensitive energetic materials.

Insensitive energetic salts: A series of furazan-functionalized tetrazolate-based energetic salts (see figure) were synthesized and characterized. All of the salts exhibit excellent thermal stabilities and high positive heats of formation.Furazan-functionalized tetrazolate-based energetic salts (1-13) were prepared by direct treatment of neutral 4-amino-3-(5-tetrazole)furazan and a Lewis base or by simple metathesis reactions of its barium salt formed in situ with the corresponding sulfate salts in aqueous solution. Key physical properties, such as melting point, thermal stability, density, hypergolicity, and sensitivity to shock, were measured. The relationship between their structures and these properties was determined. Most of salts exhibit better thermal stability than their 5-nitrotetrazolate and 5-nitraminotetrazolate analogues as well as other furazan-based salts. The structures of representative aminoguanidinium (4), carbonic hydrazylhydrazidinium (9), and 1,4-dimethyl-5-aminotetrazolium salts (13) were further confirmed by single-crystal X-ray analysis. Their densities, heats of formation, detonation pressures and velocities, and specific impulses were calculated. All of the salts possess high positive heats of formation. The effect of the furazan ring on these physicochemical properties was examined and discussed.