Theoretical study on fused 1,2,3,4-tetrazine-1,3-dinitroxide derivatives under external electric field

Considering the excellent properties of 1,2,3,4-tetrazine-1,3-dinitroxides, several types of energetic derivatives have been synthesized from them. Among them, [1,2,5] oxadiazolo [3,4-e] [1,2,3,4]-tetrazine-4,6-Di-N-dioxide (FTDO), 5,7-dinitrobenzo-1,2,3,4-tetrazine-1,3-nitrogen dioxide (DTND), and [1,2,3,4] tetrazino [5,6-e] [1,2,3,4] tetrazine-1,3,8-tetraoxide (TTTO) are considered excellent energetic materials. However, there is limited research on their behavior under electric fields. The effect of electric fields was studied using density functional theory to calculate trigger bond changes, strain energy, chemical reactivity, and surface electrostatic potential. The results indicate that the planar structure of FTDO is more unique than that of DTND and TTTO, and its trigger bond is located at special position. Increased electric field strength can lengthen the trigger bond, increase sensitivity, and reduce strain energy of FTDO. Under a positive electric field, DTND and TTTO have longer trigger bond lengths, increased sensitivity, and increased strain energy, while exhibiting the opposite behavior under a negative electric field. Electric fields can affect the chemical reactivity of the all three derivatives. FTDO is less active under positive electric fields, DTND is more active under both electric fields, and TTTO becomes more active under negative electric fields. Finally, the electric field can expand their absorption spectrum range, affecting electron transfer between fragments.

All calculations in this article were completed on Gaussian 16 software. The calculation levels are B3LYP/6-311G**, B3LYP/Def2-TZVPP, and PBE1PBE/6-311G**. Multiwfn and VMD were used for wave function analysis. Electric fields have a strength range of - 0.02 to 0.02 a.u., with a growth gradient of 0.01 a.u.