1,2,3-Triazole with linear and branched catenated nitrogen chains – The role of regiochemistry in energetic materials

Two energetic molecules possessing a linear and branched N8 structure were synthesized based on the oxidative coupling of N-aminotriazoles. Despite the same chemical formula and azo functionality, the decomposition temperatures (T_d) of these two regioisomers reflect a gap of more than 80 °C. Based on the data of single crystal X-ray diffraction, comparative investigation associated with the bond length and stacking pattern rationalize the different properties of density and molecular stability. Theoretical analyses, e.g., charge distribution and Hirshfeld surface, were carried out subsequently to gain more insight into the regiochemistry of catenated nitrogen-atom chains. The difference of charge distribution between two molecules caused by regional heterogeneity is the main reason for their different stabilities.