FT-IR, FT-Raman, Molecular Geometry, Vibrational Assignments, Ab-Initio and Density Functional Theory Calculations for 4-hydroxy-2,6-dimethyl pyrimidine

Fourier transform Raman and infrared spectra of 4-hydroxy-2, 6-dimethyl pyrimidine (HDMP) were recorded and interpreted by comparison with respective theoretical spectra calculated using HF and B3LYP methods. The HDMP equilibrium geometry with Cs symmetry, harmonic vibrational frequencies, infrared and Raman intensities were determined using HF/6-311G and B3LYP/6-311G level of theories. The band assignment was based on potential energy distribution (PED) of normal modes. A sufficient general agreement between the theoretical and experimental spectra has been achieved. In the computed equilibrium geometries by all the levels, the bond lengths and bond angles show changes in the neighborhood of methyl and hydroxyl substituent. The molecular stability and bond strength were investigated by applying the Natural Bond Orbital analysis (NBO). The calculated HOMO-LUMO energies shows that charge transfer occur in the molecule. The dipole moment, polarizability and the hyperpolarizability values of the investigated molecule have been computed using HF and B3LYP methods.