Quantum Chemical Modeling of 2-(Cyclohexylamino)-2-oxo-1-(quinolin-4-yl)ethyl 4-Chlorobenzoate: Molecular Structure, Spectroscopic (FT-IR, NMR, UV) Investigations, FMO, MEP and NBO Analysis Based on HF and DFT Calculations

In the present work, the quantum theoretical calculations of the molecular structure of the compound 2-(Cyclohexylamino)-2-oxo-1-(quinolin-4-yl)ethyl 4-Chlorobenzoate have been predicted using Density Functional Theory (DFT) in the gas phase. The geometry of the title structure was optimized by B3LYP/6-31+G* and HF/6-31+G* levels of theory. The theoretical 1H and 13C NMR chemical shift values of the title structure are calculated and compared with the experimental results. The calculated results are in good agreement with the experimental data. The theoretical vibrational frequencies values are obtained and compared with the experimental data. The electronic spectra of the title structure in the gas phase were carried out by TDB3LYP/6-31+G* and TDHF/6-31+G* levels of theory. Frontier molecular orbitals (FMOs), the molecular electrostatic potential (MEP), natural charges distribution (NBO charges), electronic properties such as ionization potential (I), electron affinity (A), global hardness (η), electronegativity (χ), electronic chemical potential (μ) and electrophilicity (ω), chemical softness (S=1/η), and NBO analysis were investigated and discussed by theoretical calculations.