Quantum chemical predictions of IR spectra and thermodynamic properties of tetrazole derivates

We have predicted the optimized geometries, infrared spectrum, and thermodynamic properties for six tetrazole derivates at density functional theory and second-order Møller–Plesset perturbation theory (MP2) level with the 6-31G** basis set. Their heats of formation were calculated accurately using the designed isodesmic and isogyric reactions. The computed total energies, heat of formation, and enthalpy of combustion consistently indicate the stability: 5-(2,4,6-trinitrophenyl)-2H-tetrazole > 5-(2,4,6-trinitrophenyl)-1H-tetrazole > 5-(2,4,6-trinitrophenyl)-5H-tetrazole The similar result for the isomers of 5-(2,4,6-trinitrobenzyl)-tetrazole: 5-(2,4,6-trinitrophenyl)-2H-tetrazole > 5-(2,4,6-trinitrophenyl)-1H-tetrazole > 5-(2,4,6-trinitrophenyl)-5H-tetrazole.