Combined Spectroscopic and DFT Studies of Pyridoxine

The Fourier transform Infrared (FTIR) and FT-Raman (FTR) spectra of 4, 5-bis (hydroxymethyl) -2-methylpyridin-3-ol have been recorded in the regions 4000-450 cm-1and 4000-500cm-1respectively. Utilizing the observed FTIR and FT-Raman data, a complete vibrational assignment and analysis of the fundamental modes of pyridoxine have been carried out. The optimum molecular geometry, infrared intensities have been calculated by density functional theory (DFT/B3LYP) method with 6-311G (d, p), 6-311++G (d, p) and RHF/6-31G (d, p) basis sets. The complete vibrational assignments were performed on the basis of the potential energy distribution (PED) of the Vibrational modes calculated using Vibrational Energy Distribution Analysis (VEDA 4) program. The calculated HOMO-LUMO energy gap revealed that charge transfer occurs within the molecule. The thermodynamic properties like Entropy, Enthalpy, Specific Heat Capacity and Zero vibrational energy have been calculated. Besides, molecular Electrostatic potential (MEP) was investigated using theoretical calculations. Stability of the molecule arising from hyper conjugative interactions, charge delocalization have been analyzed using NBO (Natural Bond Orbital) analysis