Computational studies on the structure and vibrational spectra of 2-hydroxy-5-methyl-3-nitropyridine

The molecular-structure and vibrational spectra of 2-hydroxy-5-methyl-3-nitropyridine have been investigated by Hartree-Fock and Density Functional Theory (DFT) using standard B3LYP functional and 6-311G(d) and 6-311G(3d,2p) basis sets. The results of the calculations are applied to simulate infrared spectra of the title compound which showed good agreement with the experimentally determined data. It has been found that both methods yield consistent data for the geometric parameters but DFT with a basis set of 6-311G(3d,2p) yielded vibrational frequencies much closer to the experimental data. Computed values at DFT(B3LYP)/6-311G(3d,2p) have been analyzed and their characterization was made with the help of Gaussview visualization program utilizing the data obtained from the Gaussian 03 calculation. A few of the discrepancies observed between the experimental and computed data of vibrational frequencies and their assignments have also been discussed.