Density Functional Theory (DFT) Study on the Structures and Energy Properties of High Energy Density Materials Based on Polynitroazofurazan Derivatives

In this study, inspired by the structures of the heat resistant explosives 5,5'-bis(2,4,6-trinitrophenyl)-2,2'-bi(1,3,4-oxadiazole) and 2,6-bis(picrylamino)-3,5-dinitro-pyridine, five high energy and low sensitivity energetic materials have been designed by combining the energetic fragments with the high energy azofurazan skeleton, and structure - property relationships have been investigated by means of density function theory. All compounds have excellent explosive properties (Dv: 7946 - 8341 m/s; P: 27.6 - 30.9 GPa) and high positive heats of formation (816.85 - 940.28 kJ/mol). Among them, compounds 3 and 4 have the best explosive properties (3: Dv: 8318 m/s P:30.7 GPa; 4: Dv: 8341 m/s P: 30.9 GPa), which are comparable to 1,3,5-trinitrohexahydro-1,3,5-triazine. The h50 values indicate that all compounds have good impact sensitivity, comparable to 1,3,5,7-tetranitro-1,3,5,7-tetrazocane and 1,3,5-trinitrohexahydro-1,3,5-triazine and superior to hexanitrohexaazaisowurtzitane. In addition, bond dissociation energies, frontier molecular orbitals, and weak interaction, etc. are calculated to further investigate the relationship between structures and properties. The calculated results show that these compounds are expected to be the next generation of high energy density materials with an excellent balance of energetic properties and stability.