Structure, vibrational, electronic, NBO and NMR analyses of 3-methyl-2,6-diphenylpiperidin-4-one (MDPO) by experimental and theoretical approach

The optimized molecular struture,vibrational wavenumbers, atomic charges, molecular electrostatic potential, NBO, electronic properties, NLO, 1H NMR and 13C NMR chemical shifts of molecule 3-methyl-2,6-diphenylpiperidin-4-one (MDPO) have been studied in the best way in this investigation. Theoretical calculations were performed by density functional theory (DFT)/B3LYP method using 6-31+G(d,p) basis set. The results show that the vibrational wavenumbers and chemical shifts calculated were obtained to be in a good agreement with the experimental data. The chair conformation of the piperidine ring was deduced by structural parameters and NMR analysis. The stability and charge delocalization of the molecule were studied by natural bond orbital (NBO) analysis. In addition, a molecular electrostatic potential map (MEP) of the title compound has been analysed for predicting the reactive sites. The reactivity of the compound of interest was described by HOMO–LUMO energies and global descriptors. The electronic properties were also discussed and the transition corresponds to π → π*. The title compound exhibited good nonlinear optical activity and nine times greater than that of urea.