Vibrational spectroscopy, intramolecular CH⋯O interaction and conformational analysis of 2,5-dimethyl-benzyl benzoate

• FT-IR, Raman and electronic properties of a benzyl benzoate analogous.
• Several properties: Log P, surface area, dipole moment, refractivity, electrostatic potential.
• Population methods: Chelp, ChelpG, NPA, QTAIM, Mulliken, Lowdin, MK, GAPT, Hirshfeld.
• QTAIM analysis of the CH-O intramolecular bond.
• Relative stability among the regioisomers.

The aim of this study was to report the spectroscopic and electronic properties of 2,5-dimethyl-benzyl benzoate. FT-IR and Raman vibrational spectral analyses were performed, while a computational approach was used to elucidate the vibrational frequency couplings. The electronic properties were predicted using the Density Functional Theory, while the G3MP2 method was employed in the thermochemical calculation. A conformational analysis, frontier orbitals, partial atomic charge distribution and the molecular electrostatic potential were also estimated. Concerning to the dihedral angles in the ester group, a conformational analysis showed a barrier energy of 10 kcal mol−1, while other small barriers (below 0.6 kcal mol−1) were predicted within the potential surface energy investigation. Insights into the relative stability among the different positions of methyl groups in the phenyl ring demonstrated that the energy gaps were lower than 1 kcal mol−1 among the regioisomers. In addition, the Quantum Theory of Atoms in Molecules (QTAIM) was used to understand the intramolecular CH⋯O interaction in the title compound, while various methodologies were applied in the atomic charge distribution to evaluate the susceptibility to the population method.

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