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1,2,4‐Triazolium and Tetrazolium Picrate Salts: “On the Way” from Nitroaromatic to Azole‐Based Energetic Materials
Author(s) -
Klapötke Thomas M.,
Miró Sabaté Carles
Publication year - 2008
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200800771
Subject(s) - picrate , chemistry , formazan , standard enthalpy of formation , crystal structure , medicinal chemistry , computational chemistry , ion , crystallography , organic chemistry , biochemistry
A family of energetic salts based on the picrate anion and several azolium cations were synthesized either by new methods or by known literature procedures. The cations of choice were the following: 5‐amino‐1 H ‐tetrazolium ( 1 ), 5‐amino‐1‐methyl‐1 H ‐tetrazolium ( 2 ), 5‐amino‐2‐methyl‐1 H ‐tetrazolium ( 3 ), 5‐amino‐1,4‐dimethyl‐1 H ‐tetrazolium ( 4 ), 5‐amino‐1,3‐dimethyl‐1 H ‐tetrazolium ( 5 ), 1,5‐diamino‐1 H ‐tetrazolium ( 6 ), 1,5‐diamino‐4‐methyl‐1 H ‐tetrazolium ( 7 ), 3,4,5‐triamino‐1,2,4‐triazolium or guanazinium ( 8 ) and 3,4,5‐triamino‐1‐methyl‐1,2,4‐triazolium or methylguanazinium ( 9 ). A summary of the 15 N NMR shifts for all compounds is given, and the proton‐/methyl‐induced shifts (PISs/MISs) are discussed with relation to the crystal structures. Because hydrogen bonding plays an important role in determining the density and thus the performance of energetic materials, the crystal structures are discussed in detail. In addition, tests to assess the impact ( i ) and friction ( f ) sensitivities of the compounds and thermal stability measurements (DSC) were also carried out, revealing insensitive compounds ( i > 40 J, f > 360 N) with high thermal stabilities ( T d >175 °C). The constant volume energies of combustion were determined experimentally by oxygen bomb calorimetry and their validity was checked by quantum chemical calculation (MP2) of electronic energies. The detonation pressures and velocities of 1 (7795 m s –1 , 25.6 GPa), 2 (7343 m s –1 , 21.2 GPa), 3 (7213 m s –1 , 20.4 GPa), 4 (6876 m s –1 , 17.8 GPa), 5 (6846 m s –1 , 17.6 GPa), 6 (7864 m s –1 , 25.4 GPa), 7 (7492 m s –1 , 22.1 GPa), 8 (7495 m s –1 , 22.5 GPa) and 9 (7162 m s –1 , 19.8 GPa) were predicted by use of the EXPLO5 code. Lastly, the ICT code was used to predict the decomposition gases of all salts. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)