The nitration pattern of energetic 3,6-diamino-1,2,4,5-tetrazine derivatives containing azole functional groups

One of the successful strategies for the design of promising new energetic materials is the incorporation of both fuel and oxidizer moieties into the same molecule. Therefore, during recent years, synthesis of various nitro-azole derivatives, as compounds with a more balanced oxygen content, has become very popular. In the framework of this effort, we studied nitration of N(3),N(6)-bis(1H-tetrazol-5-yl)-1,2,4,5-tetrazine-3,6-diamine (BTATz; ) and its alkylated derivative N(3),N(6)-bis(2-methyl-2H-tetrazol-5-yl)-1,2,4,5-tetrazine-3,6-diamine , using a (15)N-labeled nitration agent and monitoring and analyzing products of these reactions by (15)N NMR. It was seen that the nitration of both compounds takes place only on the exocyclic ("bridging") secondary amine groups. Possible tetranitro derivative isomers N,N'-(1,2,4,5-tetrazine-3,6-diyl)bis(N-(1-nitro-1H-tetrazol-5-yl)-nitramide) and N,N'-(1,2,4,5-tetrazine-3,6-diyl)bis(N-(2-nitro-2H-tetrazol-5-yl)nitramide) , both of which have OB = 0% and calculated VODs of 9790 and 9903 m s(-1), respectively, could not be observed in the reaction mixtures, during the in situ(15)N NMR monitoring of nitration of , using (15)N-labeled nitrating agents. Following a similar strategy, a new analog of BTATz - N(3),N(6)-Bis(1H-1,2,4-triazol-5-yl)-1,2,4,5-tetrazine-3,6-diamine was obtained and its nitration was studied. The reaction of with a HNO3-Ac2O nitration mixture resulted in the formation of a new N(3),N(6)-bis(3-nitro-1H-1,2,4-triazol-5-yl)-1,2,4,5-tetrazine-3,6-diamine derivative in a moderate yield. Structures and properties of (in the form of its perchlorate salt, ) and were measured by FTIR, multinuclear NMR, MS, DSC and X-ray crystallography. It is important to note that compound exhibits exothermic decomposition at 302 °C (DSC) and >353 N (sensitivity to friction), making it a highly-promising thermally-insensitive energetic material for further development.