Molecular structure, NBO analysis, electronic absorption and vibrational spectral analysis of 2-Hydroxy-4-Methoxybenzophenone: Reassignment of fundamental modes

• The stable geometry of the compound was identified by conformational analysis.
• Scaled quantum mechanical force field methodology was performed for unambiguous assignment of vibrational bands.
• The natural bond orbital analysis, HOMO and LUMO energies confirm that charge transfer occurs within the molecule.
• Molecular Electrostatic potential predicts the most attractive site for electrophilic attack.

Vibrational frequencies of 2-Hydroxy-4-Methoxybenzophenone (HMB) have been reassigned with the aid of normal coordinate analysis (NCA) following the scaled quantum mechanical force field (SQMFF) methodology. The conformational analyses were performed and the energies of the different possible conformers were determined. The geometry of different conformers of the compounds were optimized with B3LYP method using 6-311++G(d,p) basis set to characterize all stationary points as minima. The optimized structural parameters of the most stable conformer were used in the vibrational frequency calculations. The force constants obtained from the B3LYP/6-311++G(d,p) method have been utilized in the normal coordinate analysis. The temperature dependence of the thermodynamic properties, heat capacity at constant pressure (Cp), entropy (S) and enthalpy change (ΔH) for the compound was also determined by B3LYP/6-311++G(d,p) method. The total electron density and Molecular electrostatic potential surfaces of the molecules were constructed by Natural Bond Orbital analysis using B3LYP/6-311++G(d,p) method to display electrostatic potential (electron + nuclei) distribution, molecular shape, size, and dipole moments of the molecule. The electronic properties, HOMO and LUMO energies were measured.

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