A comparative study on vibrational, conformational and electronic structure of 2-(hydroxymethyl)pyridine and 3-(hydroxymethyl)pyridine

Comprehensive theoretical and experimental FTIR and FT-Raman spectroscopic studies of 2-(hydroxymethyl)pyridine (2HMP) and 3-(hydroxymethyl)pyridine (3HMP) have been carried out by using DFT/B3LYP method with 6-311++G**, 6-31G** and cc-pVTZ basis sets. The most stable geometry of the compounds has been determined from the PES scan. The temperature dependence of thermodynamic properties has been analysed. Molecular electrostatic surface potential, total electron density distribution and frontier molecular orbitals are constructed at B3LYP/6-311++G** level to understand the electronic properties. The charge density distribution and site of chemical reactivity of the molecules has been obtained by mapping electron density isosurface with electrostatic potential surfaces. The electronic properties, HOMO and LUMO energies were measured by time-dependent TD-DFT approach. The effect of hydroxymethyl group on the pyridine ring vibrations has been discussed.