Molecular structure, vibrational spectra and theoretical NBO analysis of N′-[6-(3,5-dimethyl-1H-pyrazol-1-yl)-1,2,4,5-tetrazin-3-yl] propanehydrazide by density functional theory

Based on the full optimized molecular geometric structures at the DFT-B3LYP/6-31+G(d,p) level, there exist intramolecular hydrogen bond interactions for N'-[6-(3,5-dimethyl-1H-pyrazol-1-yl)-1,2,4,5-tetrazin-3-yl]propanehydrazide. The assigned infrared spectrum is obtained. Theoretical vibrational spectra of the title compound have been interpreted by means of potential energies distributions (PEDs) using MOLVIB program. The results show that there are seven main characteristic regions in the calculated ER spectra. NBO analysis substantiates the weak C-H center dot center dot center dot O and N-H center dot center dot center dot O hydrogen bond, which is consistent with the analysis of molecular structure. Energies of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) have been predicted.