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All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Simple and Efficient Synthesis of Explosive Cocrystals containing 3,5-Dimethylpyrazol-1-yl-substituted-1,2,4,5-tetrazines

The reaction of 3,4–dinitropyrazole, 5–nitrotetrazole, or 4–nitro–1,2,3–triazole with 1,2,4,5–tetrazines substituted with 3,5–dimethylpyrazolyl (dmp) groups results in energetic cocrystals after 1 minute of reflux and cooling to room temperature in yields of 89–92 %. Hydrogen–bonding between the dmp group to the N–H of the energetic heterocycles are the predominant interaction that stabilizes the new cocrystals. Each cocrystal packs in a different lattice structure and the cocrystals with sheet–like and herring–bone crystal packing orientations are less sensitive than the cocrystal with the interlocked structure. Electrostatic potential mapping helps rationalize why dmp–substituted tetrazines readily form cocrystals, whereas more electron–deficient pyrazolyl tetrazines do not. Furthermore, the calculated energetic performance of the new cocrystals approaches that of 2,4,6–trinitrotoluene (TNT) and importantly, these materials will aid in the rational design of new cocrystalline energetic materials.

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