Energetic Derivatives of 2‐Nitrimino‐5,6‐dinitro‐benzimidazole

Abstract

Abstract2‐Nitrimino‐5,6‐dinitrobenzimidazole (1) was synthesized by nitration of 2‐aminobenzimidazole at ambient temperature in good yield. In order to explore new insensitive explosives four energetic nitrogen‐rich 1 : 1 salts such as the guanidinium (1a), aminoguanidinium (1b), triaminoguanidinium (1c) and hydroxylammonium (1d) were synthesized either by facile acid/base or in situ metathesis reaction. In addition 2‐nitrobenzimidazole (2) was synthesized by the reaction of 2‐aminobenzimidazole using potassium hyperoxide in THF. Different nitration methods were tested to obtain a theoretically 2,4,5,6,7‐pentanitrobenzimidazole but only the already known 4,5,6,7‐tetranitrobenzimidazol‐2‐one (3) could be isolated. All synthesized compounds were characterized especially by low temperature X‐ray diffraction, CHN elemental analysis and 1H and 13C NMR spectroscopy. The heat of formation of all new synthesized compounds was calculated using CBS‐4M electronic enthalpies in combination with the atomization method to calculate their detonation parameters with the EXPLO 5 V5.05 computer code.

The Crystal Structure of Guanidinium Sulphate Hemiperoxosolvate

“…The final residuals were: R 1 = 0.0263 for 2478 reflections with I > 2s(I); wR 2 = 0.0679 for all data and 194 parameters. GoF = 1.026, max/min D1 = 0.221/ À0.240 e 3 À3 , Flack parameter = 0.06 (5). The partial isomorphous substitution of H 2 O 2 by admixed water molecules was not observed since residual peaks with intensity > 0.12 e · À3 were seen in the hydrogen peroxide molecule region [11,12].…”

“…Herein we suggest the usage of small guanidinium cation that is able to form up to six charge-assisted hydrogen bonds. The advantage of this route is based on the fact that guanidinium cations are widely used for the synthesis of nitrogen-rich insensitive explosives [5][6][7].…”

Electrostatic Potentials, Intralattice Attractive Forces and Crystal Densities of Nitrogen-Rich C,H,N,O Salts

“…The next most positive ion in Table 1 is the ammonium ion, NH 4 + , which has four hydrogen maxima of 181 kcal/mol, but they are separated by distinctly less positive regions ( Figure 5). We have surveyed 87 nitrogen-rich C,H,N,O salts that have been synthesized during the past five years [16,30,[34][35][36][37][38][39][40][41][42][43][44][45][46]. (Only anhydrous salts were considered.)…”

Benzimidazole Derivatives as Energetic Materials: A Theoretical Study

“…Benzimidazole is poorly investigated with respect to their polynitro derivatives, although the study of Klapötke et al exhibited 2-aminobenzimidazole as a valuable and inexpensive starting material for the synthesis of energetic materials [ 7 ]. Szala et al described the new energetic compound 5,5′,6,6′-tetranitro-2,2′-bibenzimidazole as a secondary explosive with high thermal stability [ 8 ].…”