Density functional theory investigations on the conformational stability, molecular structure and vibrational spectra of 6-methyl-2-chromenone

The objectives were to reproduce the molecular geometry, investigate the energetic behaviour (UV-VIS), reactive sites, delocalization of electron density, energy gap, and non-linear optical properties and to comment the experimental and calculated IR and FT-Raman spectral data of the title compound for the further studies. The value of the energy gap between the HOMO and LUMO reveals that charge transfer may be taking place from the ring to methyl group. The molecular electrostatic potential map shows that the negative potential sites are on the electronegative atoms as well as the positive potential sites are around the hydrogen atoms. These sites give information about the possible areas for inter- and intramolecular hydrogen bonding. Natural bond orbital analysis indicates the strong intramolecular interactions. Natural bond orbital analysis of the molecule confirms that the intramolecular charge transfer caused by π-electron cloud movement from donor to acceptor must be responsible for the non-linear optical properties of the title compound. The results of this study will help researchers to design and synthesis new materials. More commonly, however, the NMR spectrum is used in conjunction with other forms of spectroscopy and chemical analysis to determinate the structures of complicated organic molecules.