Comparison of 6-311G(d) and 3-21G(Dft/Hf) Methods of 3-Methyl-4-[3-(3-methoxybenzoxy)-benzylidenamino]-4,5-dihydro-1H-1,2,4-triazol-5-one

3-Methyl-4-[3-(3-methoxybenzyl)benzylidenamino]-4, 5-dihydro-1H-1, 2,4triazol5onewas synthesized by the reaction of 3-methyl-4-amino-4,5-dihydro-1H-1,2,4-triazole-5-one with 3-(3methoxybenzyl)-benzaldehyde which was synthesized by the reaction of 3-hydroxybenzaldehyde with 3-methoxybenzoyl chloride by using triethylamine. This compound was optimized by using B3LYP/6-311G (d) HF/6-311G (d) and B3LYP/3-21G, HF/3-21G basis sets. Electronic properties (total energy, dipole moment), thermodynamic parameters, geometric properties (bond angles and bond lengths), the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), Mulliken atomic charges, the molecular electrostatic potential (MEP) of 3-methyl-4-[3-(3-methoxybenzyl)-benzylidenamino]-4,5-dihydro-1H-1,2,4-triazol-5-one have been performed. H-NMR and C-NMR isotropic shift values of 3-methyl-4-[3-(3-methoxybenzyl)benzylidenamino]-4,5-dihydro-1H-1,2,4-triazol-5-one in the ground state and in DMSO solvent were Original Research Article Medetalibeyoğlu et al.; AJOCS, 4(2): 1-21, 2018; Article no.AJOCS.40462 2 calculated by using the gauge-including atomic orbital (GIAO) method. The structural and spectroscopic data of the molecule in the ground state have been calculated by using density functional method (DFT/B3LYP) and Hartree–fock method (HF) with the 6-311G (d) and 3-21G basis sets. The veda4f program was used for the identification of calculated IR data. The UV-vis values in ethanol were found and compared with experimental results. All experimental data were compared with theoretical data.