Theoretical investigation on the structure and performance of N, N′-azobis-polynitrodiazoles

Six novel high energy density compounds of N, N′-azobis- polynitrodiazoles were designed. Their optimized geometric and electronic structures, band gaps, and heats of formation were explored at B3LYP/aug-cc-pVDZ level of density functional theory (DFT). Detonation properties were predicted by Kamlet-Jacobs equations. Results show that the designed compounds have high densities (1.80 to 1.84 g·cm^-3) and excellent detonation performance (D 8.51 to 9.02 km·s^-1, P 32.16 to 36.58 GPa). In addition, the bond dissociation energies of C-NO₂ bonds were found to range from 223.59 to 240.46 kJ·mol^-1. All of them appear to be potential explosives compared with the well known ones, 1,3,5-trinitro-1,3,5- triazine (RDX, 8.75 km·s^-1, 34.70 GPa) and octahydro- 1,3,5,7-tetranitro-1,3,5,7-tetraazocane (HMX, 8.96 km·s^-1, 35.96 GPa), especially R3 (8.98 km·s^-1, 36.19 GPa) and R6 (9.02 km·s^-1, 36.58 GPa). Finally, the position and number of nitro groups in the N, N′-azobispolynitrodiazoles determine the heat of formation, stability, sensitivity, density, and detonation performance of these compounds.