DFT studies of the structure and vibrational assignments of 4-hydroxy quinazoline and 2-hydroxy benzimidazole

The solid phase FT-IR and FT-Raman spectra of 4-hydroxy quinazoline and 2-hydroxy benzimidazole have been recorded in the regions 4000–400 and 3500–100 cm−1, respectively. Theoretical information on the optimised geometry, harmonic vibrational frequencies, infrared and Raman intensities were obtained by means of density functional theory using standard B3LYP/6-31G* level. This information was used in the assignment of the various fundamentals. Comparison of the simulated spectra with the experimental spectra provides important information about the ability of the computational method to describe the vibrational modes.