Novel Melt‐Castable Energetic Pyrazole: A Pyrazolyl‐Furazan Framework Bearing Five Nitro Groups

Abstract

Continuing advances in energetic pyrazole construction foster further its rational use. This work establishes an approach for the first synthesis of nitropyrazole that bear both furazan and trinitromethyl moieties. The approach to the installation of the C(NO2)3 group exploits the destructive nitration of N‐acetonyl group. The target 3‐(3,4‐dinitro‐1‐(trinitromethyl)‐1H‐pyrazol‐5‐yl)‐4‐methylfurazan (6) has promising explosive properties.

1,12-Diiodo-Ortho-Carborane: A Classic Textbook Example of the Dihalogen Bond

“…The I1-C1 bond length (2.121(2) Å) is slightly longer than average X-ray value for I-C (aromatic) bonds (2.095 Å [62]) and is significantly shorter than the B12-I12 bond (2.179(2) Å). In order to find out the reason of observed differences as well as peculiarities of the crystal packing of 1,12-I 2 -1,2-C 2 B 10 H 10 , we used energetic analysis of intermolecular contacts, that is frequently invoked for crystal packing study [64][65][66]. We calculated halogen bonded dimer for both compound 1,12-I 2 -1,2-C 2 B 10 H 10 and similar dimer in which iodine atoms are replaced with bromines.…”

“…Thermal ellipsoids are given at 50% probability level. The main packing motif of the crystal structure of 1,12-I 2 -1,2-C 2 B 10 H 10 is represented by infinite chains along the b direction formed by the C-I• • • I-B dihalogen bonds of II type [37,63] (the I(12)• • • I(1') distance is 3.5687(9) Å, the B(12)-I(12)• • • I(1') and I(12)• • • I(1')-C(1') angles are 92.98(12) and 172.61(11) • , respectively) (Figure 2), which is very different from 1,12-Br 2 -1,2-C 2 B 10 H 10 studied earlier.In order to find out the reason of observed differences as well as peculiarities of the crystal packing of 1,12-I 2 -1,2-C 2 B 10 H 10 , we used energetic analysis of intermolecular contacts, that is frequently invoked for crystal packing study[64][65][66]. We calculated halogen bonded dimer for both compound 1,12-I 2 -1,2-C 2 B 10 H 10 and similar dimer in which iodine atoms are replaced with bromines.…”

Recent Advances in Synthesis and Properties of Nitrated-Pyrazoles Based Energetic Compounds

“…Dinitropyrazoles bearing other heterocycles are also interesting and notable. To obtain the melt-castable explosives with good compatibility, improved oxygen balance and moderate detonation properties, compound 58 incorporating both N-trinitromethyl and C-methyl substituents in addition to nitro groups was synthesized by Sheremetev's group [99] (Figure 20). This low melting temperature compound has been proved to own higher detonation pressure and velocity values than those of others melt-castable energetic heterocycles bearing methyl group, which provided feasible route to castable energetic materials.…”

Improving the Energetic Properties of Dinitropyrazoles by Utilization of Current Concepts

“…Depending on their application, different requirements are needed such as good thermal stabilities for use in the mining and fracking industry or the application in aeronautics . Nitrated pyrazoles are an interesting class in the research of new energetic materials due to their good thermal stability or the usage as melt‐cast explosives . Further they easily can be synthesized by nitration and rearrangement reactions .…”

“…Various possibilities are known such as salt formation, methylation, N ‐functionalization, azo bridging, amination, N ‐oxidation, ethylene or methylene[1b] bridging (Figure ).…”