Yazar "Ozpinar, Gul Altinbas" seçeneğine göre listele

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    7-Oxy-3-(3,4,5-trimethoxyphenyl)coumarin substituted phthalonitrile derivatives as fluorescent sensors for detection of Fe3+ ions: Experimental and theoretical study
    (Elsevier Science Sa, 2014) Kaya, Esra Nur; Yuksel, Fatma; Ozpinar, Gul Altinbas; Bulut, Mustafa; Durmus, Mahmut
    The novel 7-hydroxy-3-(3,4,5-trimethoxyphenyl) coumarin (1) has been synthesized via Perkin reaction and its phthalonitrile derivatives (2, 3, 4 and 5) have also been prepared from the reaction of this coumarin (1) with 3-nitrophthalonitrile, 4-nitrophthalonitrile or 4,5-dichlorophthalonitrile compounds for the first time in this study. The newly synthesized compounds have been fully characterized by H-1 NMR, MALDI-TOF, FT-IR, UV-vis and fluorescence spectral data as well as elemental analysis. The exact structure of the coumarin substituted phthalonitrile derivatives (2, 3 and 5) have also been determined using X-ray diffraction. The electronic absorption and fluorescence properties of these new compounds have been studied in different solvents. The chemosensor behaviors of these compounds to metal ions have also been examined by fluorescence spectroscopy and these compounds exhibited as fluorescence chemosensor for the determination of Fe3+ ions in solution. Fe3+ complex structures of mono-coumarin ring substituted derivatives (1-4) have been investigated by using density functional theory computations. (C) 2013 Elsevier B.V. All rights reserved.
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    Effects of position (? or ?) and linker heteroatom (O or S) of substituent on the photophysicochemical behavior of poly(oxyethylene) substituted ZnPcs and assessment of J-aggregation or protonation using TD-DFT computations
    (Royal Soc Chemistry, 2013) Ayhan, Mehmet Menaf; Ozpinar, Gul Altinbas; Durmus, Mahmut; Gurek, Ayse Gul
    A series of zinc phthalocyanines (ZnPcs) tetra-substituted with 1,3-di[2-(2-ethoxyethoxy)ethoxy]-2-propanol (1a) or 1,3-di[2-(2-ethoxyethoxy)ethoxy]-2-propanethiol (1b) at peripheral (beta) (6a-b) and non-peripheral (a) (7a-b) positions have been synthesized and characterized. The spectroscopic, photophysical (fluorescence quantum yields and lifetimes) and photochemical (singlet oxygen generation and photodegradation) properties of these newly synthesized phthalocyanines have been investigated in DMSO. The effects of the position of the substituents on the phthalocyanine skeleton and the nature of the linker heteroatom on their spectroscopic, photophysical and photochemical properties have been determined. The quenching behavior of the zinc phthalocyanines by 1,4-benzoquinone has been studied in DMSO. All of the zinc(II) Pc complexes (6a-b and 7a-b) showed similar electronic absorption spectra in various solvents (chloroform, dichloromethane, DMF, DMSO, THF and toluene). However, complex 7a gave an extra red-shifted band at 742 nm in chloroform and dichloromethane. DFT and TD-DFT computations were performed on the model structures (8a-d, p-8a-d and 9a-d) to find out the cause of the extra red-shifted Q band (J-type aggregation or protonation of the Pc ring). The computational results showed that monoprotonation of a meso nitrogen atom leads to the formation of this extra band. Photophysical and photochemical measurements indicated that these newly synthesized ZnPc derivatives are promising candidates for use as photosensitizers in the application of PDT.
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    Intramolecular excimer formation in hexakis(pyrenyloxy)cyclotriphosphazene: photophysical properties, crystal structure, and theoretical investigation
    (Royal Soc Chemistry, 2014) Yesilot, Serkan; Cosut, Bunyemin; Alidagi, Husnuye Ardic; Hacivelioglu, Ferda; Ozpinar, Gul Altinbas; Kilic, Adem
    A hexakis(pyrenyloxy) cyclotriphosphazene is synthesized by the reaction of N3P3Cl6 with 2-hydroxypyrene, and its excimer emission through intramolecular interactions in solution and in the solid state has been investigated by fluorescence spectroscopy and X-ray crystallography. Thermal and electrochemical properties were investigated. A DFT benchmark study has been performed to evaluate the intramolecular interactions and molecular orbital levels by comparing with the experimental results.
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    Synthesis of (3,6-dihydro-2H-pyran-2-yl)phosphonate derivatives and investigation of catalyst effect on frontier molecular orbitals using DFT method
    (Taylor & Francis Ltd, 2016) Hossain, Md Shakhawoat; Cakir, Sidika Polat; Ozpinar, Gul Altinbas; Nadeem, Said; Demir, Ayhan S.
    Hetero Diels-Alder (HDA) reactions between 2,3-dimethyl-1,3-butadiene and diethyl ester of aroyl phosphonates catalyzed by AlCl3 to afford (3,6-dihydro-2H-pyran-2-yl) phosphonate derivatives were investigated. Aroyl phosphonates with electron-withdrawing groups generally resulted in better isolated chemical yields. A stoichiometric amount of AlCl3 rather than a catalytic amount was necessary to activate the cycloaddition reaction. The amount of AlCl3 catalyst and its effect on LUMO of ethyl ester benzoyl phosphonate were also investigated by performing density functional theory (DFT) (B97D/6-31+G(d,p)) computations in dichloromethane. An increased loading of AlCl3 induced a considerable decrease in the LUMO energy of ethyl ester of benzoyl phosphonate. The computed Gibbs free activation energy is 17.03kcal/mol in DCM at 0 degrees C using the same computational level.
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    The effect of on/off molecular switching on the photophysical and photochemical properties of axially calixarene substituted activatable silicon(IV)phthalocyanine photosensitizers
    (Royal Soc Chemistry, 2016) Gungor, Omer; Ozpinar, Gul Altinbas; Durmus, Mahmut; Ahsen, Vefa
    Silicon(IV) phthalocyanines (4 and 5) bearing two calixarene groups as axial ligands were synthesized. Surprisingly, both phthalocyanines were obtained as two different isomers (4a-b and 5a-b) depending on the distance between calixarene benzene groups and the phthalocyanine ring. DFT and TD-DFT computations were performed to model plausible structures of these isomers and to simulate electronic absorption spectra. These isomers converted into each other depending on the polarity of the used solvent, temperature and light irradiation. The photophysical and photochemical properties of each isomer were investigated in dimethylsulfoxide (DMSO) for the determination of photodynamic therapy (PDT) activities of these compounds. The more blue-shifted isomers (4b and 5b) showed higher fluorescence quantum yields and singlet oxygen generation compared to more red-shifted counterparts (4a and 5a). This behavior is extremely important for developing activatable photosensitizers for cancer treatment by PDT. Although these photosensitizers produce lower singlet oxygen in normal cells, they produce higher singlet oxygen (six times higher for 5b) in cancer cells since these photosensitizers converted to more blue-shifted isomers by using light irradiation.