Quantum Chemical Insights into the Electronic, Vibrational and Thermodynamic Properties of Chloro-Substituted Anisole
Keywords:
Anisole , Density functional theory , Electronic structure , Vibrational analysis , Thermodynamic parametersAbstract
Anisole, also known as methoxybenzene, is an organic compound with the formula \(CH_{3}OC_{6}H_{5}\). It is a colorless liquid with a sweet, aromatic odor similar to anise seeds and is used as an intermediate in the synthesis of pharmaceuticals, agro-chemicals, and fragrances. This study is about the quantum chemical insight into the Electronic, vibrational, and thermodynamic properties. The study first analyzed the optimized molecular structures and identified different physical properties. The Non-Co-valent Interactions (NCI)-Reduced Density Gradient (RDG) reveal weak hydrogen bonding and strong repulsive interactions. Molecular electrostatic potential mapping shows higher reactivity in chlorine-substituted anisole, with key reactive sites at oxygen, chlorine, and carbon atoms. Anisole has an excitation energy of 5.770 eV and a lower electronegativity of 3.2850 eV, indicating kinetic stability. Para-chloroanisole (PCA) exhibits the lowest energy gap at 5.481 eV and chemical hardness of 2.7405 eV, suggesting high reactivity. The quantum energy levels are observed in the density of States (DOS) spectrum. Due to their electronegative nature, chlorine atoms show positive charges while oxygen atoms, owing to their electron-withdrawing properties, show negative Mulliken charges, respectively, and serve as key reactive sites. In addition to that, Infrared (IR), Raman, and UV-visible spectra reveal different vibration modes and spectral intensities. Thermodynamic functions such as constant pressure (Cp), enthalpy (H), and entropy (S) for all studied molecules increase with temperature.
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