Theoretical Investigation on Structure and Performance of Furazano-[3, 4- d ]-pyridazine-based Fused-ring Compounds

Abstract

Three series of novel furazano-[3, 4-d]-pyridazine-based fused-ring compounds were designed, and their structures and performance were studied by density functional theory (DFT) at B3LYP/6-311g(d, p) level. Detonation performance was estimated by Kamlet-Jacobs equations. The results show that the compounds of A and B series exhibit good coplanarity and their dihedral angles vary within ±5°, but the coplanarity of C series was particularly damaged because of electron-withdrawing effect of more functional groups. Otherwise, all designed nitro-containing compounds possess high densities (1.896-2.153 g/cm3), detonation velocities (8.55-9.98 km/s) and detonation pressures (33.70-48.90 GPa) compared with RDX and HMX. As the number of nitro-containing groups increases, the densities, detonation performance and specific impulse (Isp) and impact sensitivities gradually increase (the trend of detonation performance is contrary for N3-substituted compounds), but the heats of formation (HOFs), bond dissociation energies (BDEs), band gaps (ΔE), and electric spark sensitivities (EES) gradually decrease (the trend of HOFs and EES is contrary for N3-substituted compounds). Otherwise, these functional groups decrease molecular stabilities in the order of -ONO2 > -C(NO2)3 > -CF(NO2)2 > -NO2 > -N3. Four kinds of NO2-replaced(A1, B1 and C1) and CF(NO2)2-substituted (A3) fused-ring compounds have the potential to become high-energy density materials (HEDMs).