Vibrational spectra and normal coordinate analysis of 2-hydroxy-3-(2-methoxyphenoxy) propyl carbamate

• In this work, the experimental and theoretical spectra of 2H3MPPLC are studied.
• Vibrational assignments are performed on the basis of the potential energy distribution (PED).
• Hyperpolarizabilities and HOMO–LUMO energies were performed by HF/DFT approach.
• Thermodynamic properties at different temperatures have been calculated in gas phase.

In this work, the vibrational spectral analysis was carried out by using FT-Raman and FTIR spectroscopy in the range 50–4000 cm−1 and 450–4000 cm−1 respectively, for 2-hydroxy-3-(2-methoxyphenoxy) propyl carbamate (2H3MPPLC) molecule. The molecular structure, fundamental vibrational frequencies and intensities of the vibrational bands were interpreted with the aid of structure optimizations and normal coordinate force field calculations based on density functional theory (DFT) and ab initio HF methods with 6-31G(d,p) basis set. The complete vibrational assignments of wave numbers were made on the basis of potential energy distribution (PED). The results of the calculations were applied to simulated spectra of the title compound, which show excellent agreement with observed spectra. The scaled B3LYP/6-31G(d,p) results show the best agreement with the experimental values over the other method. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The results confirm the occurrence of intramolecular charge-transfer (ICT) within the molecule. The dipole moment (μ), polarizability (α) and hyperpolarizability (β) of the investigated molecule has been computed using B3LYP/6-31G(d,p) method. Mulliken population analysis on atomic charges was also calculated. Besides, frontier molecular orbitals, molecular electrostatic potential (MEP) and thermodynamic properties were performed.

Molecular structure of 2H3MPPLC molecule was studied using HF and DFT/B3LYP methods with 6-31G(d,p) basis set. All results were compared with experimental (FT-IR and FT-Raman) spectra. The scaled theoretical frequencies show very good agreement with experimental values. HOMO and LUMO energies are calculated that these energies show charge transfer occurs within the molecule. The statistical thermodynamic properties and their correlations with temperature have been obtained from the theoretical vibrations.Figure optionsDownload as PowerPoint slide