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'-azobis-polynitrodiazoles determine the heat of formation, stability, sensitivity, density, and detonation performance of these compounds.