FT IR, FT-Raman spectra and chemical computations of herbicide 2-phenoxy propionic acid – A DFT approach

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2014-03, Vol.122, p.661-669
• Main Authors: Joselin Beaula, T., James, C.
• Format: Article
• Language: English
• Subjects: 2-Phenoxy propionic acid; DFT; FT IR; FT Raman; NBO
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2013.10.126

•Strong intermolecular OH⋯O H-bonding interactions enhance the stability of the molecule.•Hyperconjugative interactions in the phenyl ring causes more delocalization in the ring.•Red shift of OH stretching band in IR shows clear evidence of the occurrence of OH⋯O interaction.•Carboxyl-end of the molecule behaves as an active site as it is electron rich relative to the phenyl end. FT IR and FT Raman spectra of herbicidal molecule 2-phenoxy propionic acid have been recorded and analyzed with the aid of normal coordinate analysis and DFT methods. Stability of the molecule arising from hyperconjugative interactions has been probed using NBO analysis. Predicted electronic absorption spectrum from TD-DFT calculation has been compared with the UV–vis spectrum. HOMO–LUMO, Mulliken population analysis and atomic charges, thermodynamic calculation and aromaticity were also calculated. From the PES scan the most stable geometry has been determined. ESP has been mapped over the electron density to obtain information about the size, shape, charge density distribution and chemical reactivity of the molecule.