Theoretical study into structure-properties relationship on energetic derivatives coupling by nitroimidazoles and polynitrobenzenes

Three series of energetic nitroimidazoles and polynitrobenzenes derivatives containing different substituents (for instance -NH2, -N3) were designed and have been optimized at the B3LYP-D3/6-311 + G** level. The effects of multiple substituents on the properties of these energetic materials were analyzed. The electronic structure, energy gap, heat of formation, detonation performance, thermal stability, and surface electrostatic potential of the compounds were systematically studied. As the number of -NH2 substituents increases, the energy of ΔEHOMO-LUMO descends, and the electronic absorption spectrum of the derivatives moves to a low frequency. The substitution of -NH2 on the benzene ring is not conducive to increasing HOF value of energetic materials. Among all mentioned compounds, trinitroimidazole substituted polynitrobenzene displays the most attractive detonation pressure (33 GPa), and with a high density of 1.88 g/cm3, which has exceeded TATB (31.1 GPa, 1.94 g/cm3).