Theoretical Study on the Azido‐cyclization of 3,6‐Di(azido)‐1,2,4,5‐tetrazine

Abstract

The reactions of azido-cyclization in 3,6-di(azido)-1,2,4,5-tetrazine were studied by B3LYP hybrid density functional method. The geometries of the reactants, transition states and products were optimized, and the conformation of the initial reactant was determined by IR spectra. In addition, the nucleus-independent chemical shift (NICS) indices were used to discuss the aromaticity of the products. Moreover, solvent effects were investigated. Results show that the polar solvent DMSO can hardly influence the activation barriers of all the reaction paths; however, it can stabilize the products. Since the activation barriers of azido-rotation are far less than that of the rate-determining step (the cyclization of second azido), the products are most probably the mixtures of two isomers (DAT2c and DAT2c'). Figure 1 IR spectra of DAT and DAT' (the unit of vertical axis is 10-40 esu 2 •cm 2 ). Figure 2The possible pathways of the cyclization of 3,6-di(azido)-1,2,4,5-tetrazine.Theoretical Study on the Azido-cyclization of 3,6-Di(azido)-1,2,4,5-tetrazineChin.

The trans–cis and the azide–tetrazole ring-chain isomerization of 2-azido-1,3-azoles: Quantum chemical study

“…Nevertheless, the ring-chain isomer equilibrium between isomeric azido and tetrazole species strongly depends on the nature of atom X, on the type and position of substituent groups on the 1,3-azole ring, on the temperature and, on the polarity of the solvent. Knowledge of the relative stabilities of isomers of heterocyclic as well as the conversion from one isomer to another is important from the point of view of structural chemistry [23][24][25][26][27][28][29][30][31].…”

Two High Nitrogen Content Energetic Compounds: 3,6-Diguanidino-1,2,4,5-Tetrazine and Its Diperchlorate

“…Such transformations are accompanied by an enormous energy release due to the wide difference in the average bond energies of NN (160 kJ·mol –1 ) and NN (418 kJ·mol –1 ), compared to that of NN (954 kJ·mol –1 ). Nitrogen heterocyclic triazole, ,− tetrazole, ,,,,− ,− tetrazine, − and their monosubstitute or multisubstitute derivatives have gained a large amount of interest as preeminent energetic materials and are widely used in some areas.…”

Theoretical study on the azido-cyclization of 3,6-diazido-1,2,4,5-tetrazine (DAT) with the dimethylsulfoxide (DMSO) solvent

“…As observed, the electron redistribution easily occurs in the DMSO polar solvent compared to the gas phase. [40] The electrons transfer rapidly from the tetrazine ring to azido group, which makes two closer nitrogen atoms (the terminal atom of azido group and the nearest nitrogen atom of the tetrazine ring) possessing strong Coulombic interaction. The analysis of charge population along with azido-cyclization indicates that most of the electron redistributions occur in the conversion azido→tetrazole.…”