Ayfer Kalkan Burat
Istanbul Technical University
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Publication
Featured researches published by Ayfer Kalkan Burat.
Journal of Porphyrins and Phthalocyanines | 2010
Ayfer Kalkan Burat; Atıf Koca; Jan P. Lewtak; Daniel T. Gryko
The synthesis, spectroscopic and electrochemical properties of new phthalocyanines bearing four morpholine and four chloro units is reported. Two-step synthesis involved efficient nucleophilic substitution of 4,5-dichlorophthalonitrile as the key step. The free-base phthalocyanine and its several complexes have been characterized using UV-vis, IR, 1HNMR, 13CNMR and mass spectroscopic data. Voltammetric and spectroelectrochemical studies show that while cobalt phthalocyanine gives both metal- and ring-based, diffusion-controlled, multi-electron and reversible/quasi-reversible redox processes, other complexes give ring-based, multi-electron and reversible/quasi-reversible redox processes.
Monatshefte Fur Chemie | 2012
Ayfer Kalkan Burat; Zeliha Pınar Öz; Zehra Altuntaş Bayır
The reaction of 4-[4-(trifluoromethyl)phenoxy]phenol with 4-nitrophthalonitrile in the presence of K2CO3 leads to formation of 4-[4-[4-(trifluoromethyl)phenoxy]phenoxy]phthalonitrile. Tetrakis[4-[4-(trifluoromethyl)phenoxy]phenoxy]-substituted metal-free phthalocyanine was achieved by tetramerization of the phthalonitrile in 2-(dimethylamino)ethanol, whereas metallophthalocyanines were prepared in the presence of zinc, cobalt, or copper salts. These compounds show high solubility in weakly and medium polar solvents, in strongly polar solvents (dimethylformamide, dimethylsulfoxide), and in aromatic hydrocarbons (toluene, benzene). The new phthalocyanines were characterized by elemental analyses, 1H nuclear magnetic resonance (NMR), 13C NMR, 19F NMR, ultraviolet-visible (UV-Vis), Fourier-transform infrared (FT-IR), and mass spectroscopic methods.Graphical Abstract
Journal of Biological Inorganic Chemistry | 2017
Halit Koçan; Kerem Kaya; İbrahim Özçeşmeci; B. Şebnem Sesalan; Meltem Göksel; Mahmut Durmuş; Ayfer Kalkan Burat
In this study, morpholinoethoxy-substituted metal-free (3), zinc(II) (4) and indium(III) (5) phthalocyanines were synthesized. These phthalocyanines were converted to their water-soluble quaternized derivatives (3Q–5Q) using excess methyl iodide as a quaternization agent. All these phthalocyanines (Pcs) were characterized by elemental analysis and different spectroscopic methods such as FT-IR, 1H NMR, UV–Vis and mass spectrometry. The photophysical and photochemical properties such as fluorescence and generation of singlet oxygen were investigated for determination of these phthalocyanines as photosensitizers in photodynamic therapy (PDT) applications. The binding properties of quaternized phthalocyanines (3Q–5Q) to calf thymus DNA (CT-DNA) were investigated by UV–Vis and fluorescence spectrophotometric methods. The quenching effect of all quaternized phthalocyanines on the fluorescence intensity of SYBR Green–DNA complex was determined. The mixtures of 3Q, 4Q or 5Q and DNA solutions were used to determine the change in Tm of double helix DNA with thermal denaturation profile. In addition, thermodynamic parameters considering their aggregation in buffer solution, which shows the spontaneity of the reactions between DNA and quaternized Pcs were investigated. On the other hand, in vitro phototoxicity and cytotoxicity behavior of the quaternized water-soluble phthalocyanine photosensitizers (3Q–5Q) were tested against the cervical cancer cell line named HeLa for evaluation of their suitability for treatment of cancer by PDT method.Graphical abstractPeripherally tetra-substituted neutral and quaternized metal-free and metallophthalocyanines (MPcs) (Zn, In) bearing morpholinoethoxy groups were prepared. The binding of quaternized compounds (3Q–5Q) to CT-DNA were examined using UV–Vis, fluorescence spectra, thermal denaturation profiles and KSV values. Besides, thermodynamic studies indicated that binding of 3Q–5Q to DNA was spontaneous. On the other hand, in vitro phototoxicity and cytotoxicity behavior of the quaternized water-soluble phthalocyanine photosensitizers (3Q–5Q) were tested against the cervical cancer cell line named HeLa for evaluation of their suitability for treatment of cancer by PDT method.
Electroanalysis | 2012
Ayfer Kalkan Burat; Zehra Altuntaş Bayır; Atıf Koca
Dyes and Pigments | 2013
Didem Evren; Ayfer Kalkan Burat; İbrahim Özçeşmeci; B. Şebnem Sesalan
Electrochimica Acta | 2013
İbrahim Özçeşmeci; Ayfer Kalkan Burat; Yeliz İpek; Atıf Koca; Zehra Altuntaş Bayır
Synthetic Metals | 2011
Ayfer Kalkan Burat; Atıf Koca; Jan P. Lewtak; Daniel T. Gryko
Monatshefte Fur Chemie | 2013
Halit Koçan; Ayfer Kalkan Burat
Journal of Organometallic Chemistry | 2014
İbrahim Özçeşmeci; Ayfer Kalkan Burat; Zehra Altuntaş Bayır
Synthetic Metals | 2013
Didem Evren; İbrahim Özçeşmeci; B. Şebnem Sesalan; Ayfer Kalkan Burat