In the present work, the quantum theoretical calculations of the molecular structure of the 1-(1, 3-Benzothiazol-2-yl)-3-(thiophene-5-carbonyl) thiourea has been predicted and are evaluated using Density Functional Theory (DFT) in gas phase. The geometry of the title compound was optimized by B3LYP/6-311+G and B3LYP/6-311+G* methods and the experimental geometrical parameters of the title compound such as bond lengths (Å), bond angles (°) and torsion angels (°) were compared with calculated results. The theoretical 1H and 13C NMR chemical shift (GIAO method) values of the title compound are calculated and compared with the experimental results. The computed data are in good agreement with the experimental data. Frontier molecular orbitals (FMOs) such as HOMO orbital, LUMO orbital and HOMO-LUMO energy gap, molecular electrostatic potential (MEP), electronic properties such as ionization potential, electron affinity, global hardness, electronegativity, electronic chemical potential, electrophilicity, chemical softness and NBO analysis of the title compound were investigated and discussed by theoretical calculations. پرونده مقاله

In the present work, the quantum theoretical calculations of the molecular structure of the (N-(2-benzoylphenyl) oxalamate has been investigated and are evaluated using Density Functional Theory (DFT). The geometry of the title compound was optimized by B3LYP method with 6-311+G(d) basis set. The theoretical 1H and 13C NMR chemical shift (GIAO method) values of the title compound are calculated and compared with the experimental results. The computed data of the chemical shift are in good agreement with the experimental data. Frontier molecular orbitals (FMOs) such as HOMO orbital, LUMO orbital and energy gap between HOMO and LUMO, molecular electrostatic potential (MEP), electronic properties such as ionization potential (I), electron affinity (A), global hardness, global hardness (η), electronegativity (χ), electronic chemical potential (μ), electrophilicity (ω) and chemical softness (S) of the title compounds were investigated discussed by theoretical calculations. The FMO analysis suggests that charge transfer is taking place within the molecule. Also the electronic structure of the title compound was studied by using Natural Bond Orbital (NBO) analysis in order to understand hyper conjugative interactions and charge delocalization. پرونده مقاله

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. پرونده مقاله

To investigate non-bonded interaction of Phenanthrene and BN nanostructure, geometric structure of Phenanthrene and B12N12 nano-ring with B3LYP method and 6-31g* basis set are optimized by using ab initio gaussian quantum chemical package. The main purpose of this study was to evaluate changes of electronic properties of aromatic compound in presences Nano ring field. Therefore reactivity and stability of Phenanthrene alone and in the presence of B12N12 nanoring checked by density functional theory. To studying the non-bonded interaction energies between Phenanthrene and B12N12 nano-ring at the first time we determined the best orientation and distance of optimized structure and then NBO and NMR calculations have been done that explains reduce the reactivity, increase stability of Phenanthrene. So that shows HOMO orbitals matches the Phenanthrene and LUMO orbitals matches the Nano ring. Then charge transfer of Phenanthrene and Phenanthrene -B12N12 studies that represents the flow of electrons from the Nano ring to the Phenanthrene. پرونده مقاله

The N-(2-benzoyl-phenyl) oxalyl derivatives are important models for studying of three-centered intramolecular hydrogen bonding in organic molecules. The quantum theoretical calculations for two crystal structures of N-(2-benzoyl-phenyl) oxalyl (compounds I and II) were performed by Density Functional Theory (B3LYP method and 6-311+G* basis set). From the optimized structures, geometric parameters were obtained and experimental measurements were compared with the calculated data. The NMR parameters such as chemical shift isotropic (CSI) and chemical shift anisotropic (CSA), natural charge (NBO), thermodynamic parameters such as relative energy (ΔE), standard enthalpies (ΔH), entropies (ΔS), Gibbs free energy (ΔG) and constant volume molar heat capacity (Cv), frontier molecular orbitals (FMOs), total density of states (DOS), molecular electrostatic potential (MEP) of the two structures were investigated by theoretical calculations. Molecular properties such as Ionisation Potential (I), Electron affinity (A), chemical hardness (η), electronic chemical potential (μ) andelectrophilicity (ω) obtained and three-centered intramolecular hydrogen bonding were investigated by NBO analysis. پرونده مقاله