Theoretical study of tri-s-triazine and some of its derivatives

Density functional theory has been used to study the geometries, electronic structures, harmonic vibrational frequencies, and high energy density material properties of tri-s-triazine and ten derivatives (2-R-5,8-dihydrogen-tri-s-triazine with R = NH₂, OH, N₃, NO₂, F, Cl, Br, -C≡N, -CH=CH₂ and -C≡CH) at the B3LYP/aug-cc-pVDZ level of theory. The results show that the tri-s-triazine ring maintains a planar and rigid structure in all the compounds and that there exists considerable conjugation over the parent ring, which is advantageous for the stability of these compounds. Substituent effects on the geometry, electronic structure, conjugation and HOMO/LUMO of the parent ring are discussed in detail. Vibrational frequency studies indicate that the parent ring has a characteristic frequency and that all the studied substituents shift it to lower wave numbers. Moreover, our study shows that some of the discussed compounds may be potential candidates for high energy density materials (HEDMs).