Browsing by Author "Kizilok, S"

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    Targeted Singlet Oxygen Generation Using Different DNA-Interacting Perylene Diimide Type Photosensitizers
    Dinçalp, H; Kizilok, S; Içli, S
    Singlet oxygen quantum yields (I broken vertical bar (Delta)) of different perylene diimides (PDIs) containing phenyl (PDI-Ph), pyrene (PDI-Pyr), and indole (PDI-In) units in bay positions of the ring were determined using 1,3-diphenylisobenzofuran (DPBF) method in toluene/methanol (99:1) system. Pyrene-substituted PDI were the most efficient singlet oxygen generator among the investigated photosensitizers with a quantum yield of I broken vertical bar (Delta) = 0.93 in toluene/methanol. Additionally, their binding affinities to G-quadruplex DNA structure were investigated by steady-state measurements. There were marked red shifts of absorbance bands for PDI-Pyr/DNA strand complexes with respect to the absorption maxima of DNA-free solution of PDI-Pyr in phosphate buffer at pH 6.
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    Synthesis and G-quadruplex binding study of a novel full visible absorbing perylene diimide dye
    Dinçalp, H; Kizilok, S; Birel, OH; Içli, S
    A novel perylene diimide dye containing glucopyranosyl groups in 1- and 7-positions of the perylene ring has been synthesized and characterized to obtain highly efficient and stable photosensitized material in photodynamic therapy. Solvatochromic studies on this dye in solvents of different polarities have indicated that absorption bands of the dye cover the whole visible spectrum in more polar organic solvents. It shows absorption bands localized at 350-500 nm and 600-850 urn in benzonitrile giving a green color. Also, the dye has a wide absorption region which covers the wavelength between 400 and 800 nm in more polar solvents by changing the dye concentration in the solvents. Singlet oxygen generation efficiency and G-quadruplex binding affinity of the dye have been tested. Theoretical calculations through semi-empirical methods have been performed and a detailed spectroscopic assignment of the molecule has been also presented. (C) 2012 Elsevier B.V. All rights reserved.
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    Fluorescent macromolecular perylene diimides containing pyrene or indole units in bay positions
    Dinçalp, H; Kizilok, S; Içli, S
    Novel, symmetric and unsymmetric perylene diimide dyes with pyrene or indole units in the bay positions of the perylene ring were synthesized and characterized using FT-IR, H-1 and C-13 NMR, MS, UV-Vis spectra and cyclic voltammetry. The lambda(max) different solvents were in the range 526-585 nm and emission wavelengths of the dyes exhibited positive solvatochromism with increasing solvent polarity. Long wavelength emissions >750 nm of dyes with pyrene units displayed charge-separated state of perylene-pyrene system. Dyes with pyrene or indole units showed greater photostability in toluene than dyes which did not contain these bulky substituents. Incorporating electron-donating indole substituents lowered the band gap energies and, therefore, the HOMO energy levels were increased. The energy density and shape of the molecular orbitals were calculated theoretically. (C) 2009 Elsevier Ltd. All rights reserved.