A theoretical study on the structure and properties of DPO (2,5-dipicryl-1,3,4-oxadiazole)

DPO (2,5-dipicryl-1,3,4-oxadiazole) is optimized to obtain its molecular geometry and electronic structure at the DFT-B3LYP/6-31G* level. It is found that DPO molecule exist good conjugation property, symmetry (C2) and thermal stability. The assigned infrared spectrum is obtained and is used to compute the thermodynamic properties based on the frequencies scaled by 0.96 and the principle of statistic thermodynamics. The gradients of Cp,m0 and Sm0 to the temperature decrease, but that of Hm0 increases as the temperature increases. Detonation velocity (D) and pressure (P) are evaluated using the modified Kamlet-Jacobs equations based on the calculated density (ρ) and heat of formation. Thermal stability and the pyrolysis mechanism of DPO are investigated by calculating the bond dissociation energies (BDE) at the unrestricted B3LYP/6-31G* level. It is found that the trigger bonds of DPO are possibly C-O, C-NO2 and N-N bonds.