Theoretical studies on vibrational spectra, thermodynamic properties, and detonation properties for 1,2,4,5-tetrazine derivatives

A density functional theory calculation was performed to study the molecular structures, heats of formation (HOFs), infrared spectra, detonation properties, and thermodynamic properties for five 1,2,4,5-tetrazine derivatives. Based on the full optimized molecular structures at the B3LYP/6-311++G** level, the assigned infrared spectra of the studied compounds were obtained. The isodesmic reaction method was employed to calculate the HOFs of the derivatives. The detonation velocities and pressures were also evaluated by using Kamlet-Jacobs equations with the calculated densities and condensed HOFs. The result shows that 3,6-diazido-1,2,4,5-tetrazine may be a potential candidate of high-energy density materials (HEDMs). Natural bond orbital analysis indicated that the title compounds all have higher bond dissociation energies when compared with 1,3,5,7-tetranitro-1,3,5,7-tetrazocane and 1,3,5-trinitro-1,3,5-triazinane. The results may provide basis information for the molecular design of new HEDMs.