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    Molecular structure and density functional modelling studies of 2-[(E)-2-(4-hydroxyphenyl)ethyliminomethyl]phenol
    (Elsevier Science Bv, 2015) Zeyrek, Celal Tugrul; Kocak, Selen Bilge; Unver, Huseyin; Pektas, Serhan; Basterzi, Nisan Sevin; Celik, Omer
    In the present work, the tautomerism in 2-[(E)-2-(4-hydroxyphenyl)ethyliminomethyl]Phenol was investigated by experimental (MS, FT-IR, NMR and X-ray diffraction) and computational method [density functional theory (DFT)]. The optimized geometrical structures, atomic charges, molecular electrostatic potential (MEP), natural bond orbital (NBO) and nonlinear optical (NLO) effects of the compound have been investigated by using DFT calculations. The potential energy surface (PES) scans about three important torsion angles are performed by using B3LYP/6-311+-FG (d,p) level of theoretical approximation for the compound. The experimental (FT-IR) and calculated vibrational frequencies (using DFT) of the title compound have been compared. The H-1 and C-13 NMR chemical shift assignments have been performed using DFT. To investigate the tautomeric stability, some properties such as total energy, HOMO and LUMO energies of the compound were obtained at B3LYP and B1B95/6-311++G(d,p) level in the gas phase. The calculated results showed that the phenol-imine form of the compound was more favorite than keto-amine form. Moreover, a good correlation between experimental and theoretical data for phenol-imine form of the compound was found. (C) 2015 Elsevier B.V. All rights reserved.
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    Öğe
    spiro-Cyclotriphosphazenes containing 4-hydroxyphenylethyl pendant arm: Syntheses, structural characterization and DNA interaction study
    (Elsevier Science Sa, 2018) Pektas, Serhan; Kocak, Selen Bilge; Bosterzi, Nisan Sevin; Kilic, Zeynel; Zeyrek, Celal Tugrul; Coban, Burak; Yildiz, Ufuk
    The reaction of hexachlorocyclotriphosphazene, N3P3Cl6, with tyramine podand (2) afforded partly substituted spiro-cyclotriphosphazene (3). Amine-substituted spiro-cyclotriphosphazenes 4a-g were prepared by substitution of the Cl-atoms in 3 with pyrrolidine, piperidine, morpholine, 1,4-dioxa-8-azaspiro[4,5]decane, 1-(2-aminoethyl)pyrrolidine, 1-(2-aminoethyl) piperidine, and 4-(2-aminoethyl)-morpholine, respectively. All of the cyclotriphosphazene derivatives were characterized by elemental analysis, FTIR, MS, 1D H-1, C-13 and P-31 NMR and 2D HSQC techniques, and the crystal structures of 3 and 4b were verified by X-ray diffraction analysis. The relationships delta P-OPN shifts with exocyclic OPN (alpha') and endocyclic NPN (alpha) bond angles, and electron density transfer parameters Delta(P-N) for spiro-cyclotriphosphazenes were presented. The DNA cleavage activity of cyclotriphosphazene derivatives (3, and 4a-g) was studied on double-stranded pBR322 DNA using gel electrophoresis experiments. It was found that 4e and 4f caused the highest level of DNA damage. The interactions of 3 and 4e with calf thymus DNA were also investigated using absorption spectrometry. The molecular docking was performed to identify the interaction of the compounds (3 and 4b) with the DNA (PDB ID:3V9D for A-DNA and PDB ID:1BNA for B-DNA). (C) 2018 Elsevier B.V. All rights reserved.