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

• Regioisomeric energetic molecules with linear and branched N8 structures formed. • N-azo functionalization of nitrogen-rich azoles is a method to build energetics. • The thermal stability of N8B (264 °C) is far superior to that of N8L (177 °C). • Regional heterogeneity influential on stability of energetic molecules. • Recombination of structure in different forms as strategy for energetic molecules. 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.