Catalytic effects of substituents in amino and guanidino derivatives of azolo-annelated and 3,6-disubstituted 1,2,4,5-tetrazines

Abstract

This work describes the synthesis of molecular and molecular-ionic derivatives of azolo[1,2,4,5]tetrazines and 1,2,4,5-tetrazines containing amino and guanidino fragments. Experimental and computational studies on the contribution of various substituents (guanidine, nitroamine, 2,4,6-trinitroaniline, nitrate ions) into thermal stabilities of compounds, their activation energies and the mechanism of response to external thermal effects were carried out. The thermal stabilities of the compounds were evaluated by using the differential scanning calorimetry. In addition, their energetic characteristics were calculated. The kinetic parameters for the key step of thermal decomposition were calculated. High thermal stability values for compounds with amino groups and low stabilities for nitrates and N-nitro derivatives have been shown. The activation energy values in the series of compounds under consideration proved to be varied from 358 to 112 kJ mol⁻¹, the reaction order from 3 to 6. The catalytic effects of the decomposition of the basic structural fragment for the introduced substituents were found to be from 23 to 232kJ mol⁻¹.