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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.
  • [ X ]
    Öğe
    Syntheses, structural characterization and biological activities of spiro-ansa-spiro-cyclotriphosphazenes
    (Royal Soc Chemistry, 2015) Basterzi, Nisan Sevin; Kocak, Selen Bilge; Okumus, Aytug; Kilic, Zeynel; Hokelek, Tuncer; Celik, Omer; Turk, Mustafa
    The replacement reactions of the Cl-atoms in partly substituted spiro-ansa-spiro-cyclotriphosphazenes (7 and 8) with excess pyrrolidine, 4-(2-aminoethyl) morpholine, and 1,4-dioxa-8-azaspiro[4,5] decane in dry THF led to the formation of heterocyclic amine substituted cyclotriphosphazenes (9a-c and 10a-c). All cyclotriphosphazene derivatives were characterized by elemental analysis, FTIR, MS, 1D H-1, C-13 and P-31 NMR and 2D HSQC, and HMBC techniques, and the crystal structure of partly substituted cyclotriphosphazene 8 was verified by X-ray diffraction analysis. Cyclotriphosphazene derivatives (5-8, 9a-c, and 10a-c) were subjected to antimicrobial activity against seven clinic bacteria and one yeast strain, and the interactions of the phosphazenes with plasmid pBR322 DNA were investigated. Phosphazene derivatives [(5, 7, 8, 9b and 9c) and (10a and 10b)] caused a slight increase and substantial decrease in the mobility of form I DNA, respectively, while 9a caused retardation on gel. Cytotoxic, apoptotic and necrotic effects against L929 fibroblast and A549 lung cancer cells were also evaluated. While the highest toxic effect was obtained for 9a in L929 fibroblast cells and for 9c in A549 lung cancer cells at 100 mg mL(-1) concentration, the highest apoptotic effect was determined for 10a in L929 fibroblast cells and for 9a in A549 lung cancer cells at the same concentration. It was found that 9a and 10b exhibited the most necrotic effects against L929 fibroblast and A549 lung cancer cells, respectively. The toxic and necrotic effects of the phosphazenes against A549 lung cancer cells were greater than those against L929 fibroblast cells, whereas, the apoptotic effect of the compounds was greater in L929 fibroblast cells than in A549 lung cancer cells.