Browsing by Author "Flakus H.T."

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    Combined experimental and theoretical studies on the molecular structures, spectroscopy, and inhibitor activity of 3-(2-thienyl)acrylic acid through AIM, NBO,FT-IR, FT-Raman, UV and HOMO-LUMO analyses, and molecular docking
    (Elsevier B.V., 2017) Issaoui N.; Ghalla H.; Bardak F.; Karabacak M.; Aouled Dlala N.; Flakus H.T.; Oujia B.
    In this work, the molecular structures and vibrational spectral analyses of 3-(2-Theinyl)acrylic acid (3-2TAA) monomer and dimer structures have been reported by using density functional theory calculations at B3LYP/6-311++G(d,p) level of theory. The complete assignments of the fundamental vibrational modes were obtained using potential energy distribution. Intermolecular interactions were analyzed by orbital NBO and topological AIM approaches. The electronic properties have been carried out using TD-DFT approach. Great agreements between experimental and theoretical values were achieved throughout the analysis of structural parameters and spectroscopic features. Inhibitor characteristics on human monoamine oxidase B (MAOB) enzyme of two determined stable conformers of 3-2TAA (β and γ) along with four selective inhibitors, namely safinamide, a coumarin analogue, farnesol, and phenyethylhydrazine were investigated via molecular docking. Moreover, molecular electrostatic potential (MEP) and temperature dependency of thermodynamic functions have been reported. © 2016 Elsevier B.V.
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    Experimental FTIR and FT-Raman and theoretical studies on the molecular structures of monomer and dimer of 3-thiopheneacrylic acid
    (Elsevier B.V., 2017) Issaoui N.; Ghalla H.; Brandán S.A.; Bardak F.; Flakus H.T.; Atac A.; Oujia B.
    This work presents an experimental and theoretical investigation on the properties of 3-thiopheneacrylic acid (3TAA) by using the FT-Raman and FT-IR spectra in the solid state. The structural, electronic, topological and vibrational properties of 3TAA were theoretically studied by using the hybrid B3LYP method with the 6-311++G (d,p) basis set. The complete assignments of the bands observed in both spectra were performed taking into account the presence of both monomer and dimer species of the acid. Two bands observed at 1682 and 1625 cm−1 attributed to the C[dbnd]C and C[dbnd]O stretching modes, respectively support the presence of the dimeric species in the solid phase. The percentages of intermolecular interactions are analyzed by Fingerprint plots of Hirshfeld surface. The natural bond orbital (NBO), atoms in molecules (AIM), frontier molecular orbitals (FMOs) and molecular electrostatic potential surface (MEPs) calculations were employed to determine the structural properties while the chemical selectivity or reactivity sites were revealed by using the Fukui functions. The GIAO and time-dependent density functional theory (TD-DFT) methods were used to predict the 1H and 13C NMR and electronic spectra of the acid. The diagrams of the density of state of that acid have been also presented. Finally, reasonable correlations between experimental and theoretical vibrational spectra were found. Effect of positioning and orientation of the acrylic group on the inhibitor characteristics on human MAOB enzyme of stable conformers of 3TAA is investigated in comparison with that of 3-2TAA and four selective inhibitors via molecular docking. © 2017 Elsevier B.V.