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Dive into the research topics where Hakkı Türker Akçay is active.

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Featured researches published by Hakkı Türker Akçay.


Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy | 2013

Synthesis, characterization and electrical properties of peripherally tetra-aldazine substituted novel metal free phthalocyanine and its zinc(II) and nickel(II) complexes

Rıza Bayrak; Fatih Dumludağ; Hakkı Türker Akçay

The novel phthalonitrile containing azine segment and its corresponding tetra aldazine substituted metal free- and metallo-phthalocyanines (Zn(II) and Ni(II)) were synthesized and characterized by IR, (1)H NMR, Mass, UV-Vis spectroscopy and elemental analysis and addition to these techniques for substituted phthalonitrile (13)C NMR have been used. In addition, dc and ac electrical properties of the films of these novel phthalocyanines were investigated as a function of temperature (295-523 K) and frequency (40-10(5)Hz). Activation energy values of the films of the phthalocyanines were calculated from straight portions of the Arrhenius plot (lnσ(dc)-1/T curves) as 0.70 eV, 0.93 eV and 0.91 eV for the films of metal free, nickel- and zinc-phthalocyanines, respectively. From impedance spectroscopy measurements, it is observed that bulk resistance decreases with increasing temperature indicating semiconductor property.


Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy | 2014

Synthesis, aggregation and spectroscopic studies of novel water soluble metal free, zinc, copper and magnesium phthalocyanines and investigation of their anti-bacterial properties

Rıza Bayrak; Hakkı Türker Akçay; Fatih Şaban Beriş; Ertan Şahin; Hacer Bayrak; Ümit Demirbaş

In this study, novel phthalonitrile derivative (3) was synthesized by the reaction between 4-nitrophthalonitrile (2) and a triazole derivative (1) containing pyridine moiety. Crystal structure of compound (3) was characterized by X-ray diffraction. New metal free and metallo-phthalocyanine complexes (Zn, Cu, and Mg) were synthesized using the phthalonitrile derivative (3). Cationic derivatives of these phthalocyanines (5, 7, 9, and 11) were prepared from the non-ionic phthalocyanines (4, 6, 8, and 10). All proposed structures were supported by instrumental methods. The aggregation behaviors of the phthalocyanines (4-11) were investigated in different solvents such as dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), chloroform and water. Water soluble cationic Pcs (5, 7, 9, and 11) aggregated in water and sodium dodecyl sulfate was used to prevent the aggregation. The second derivatives of the UV-Vis spectra of aggregated Pcs were used for analyzing the Q and B bands of aggregated species. Thermal behaviors of the phthalocyanines were also studied. In addition, anti-bacterial properties of the phthalocyanines were investigated. We used four gram negative and two gram positive bacteria to determine antibacterial activity of these compounds. Compound 7 has the best activity against the all bacteria with 125μg/mL of MIC value. Compounds 4, 6, and 10 have the similar effect on the bacteria with 250μg/mL of MIC value.


Desalination and Water Treatment | 2015

Simultaneous separation and preconcentration of Cd(II), Co(II), and Ni(II) ions in environmental samples by carrier element-free coprecipitation method prior to their flame atomic absorption spectrometric determination

Celal Duran; Duygu Ozdes; Hakkı Türker Akçay; Huseyin Serencam; Mehmet Tufekci

ABSTRACTIn the present study, Cd(II), Co(II), and Ni(II) ions were separated and preconcentrated via carrier element-free coprecipitation (CEFC) method by using an organic coprecipitating agent, 1,2-bis-(2-tosyl ethoxy) benzene (BTEB), prior to their flame atomic absorption spectrometric (FAAS) detections. The experimental conditions were optimized in terms of pH of the aqueous solution, BTEB amount, standing time, centrifugation rate and time, and sample volume. Under the optimum experimental conditions, the detection limits for Cd(II), Co(II), and Ni(II) ions were found to be 0.13, 0.67, and 0.46 μg L−1, respectively, and the relative standard deviations for the analyte ions were found to be lower than 4.0%. The accuracy of the method was tested by analyzing certified reference material and spike tests. The method was applied to determine the levels of Cd(II), Co(II), and Ni(II) ions in sea and stream water, macaroni, red lentil, and cracked wheat samples.


Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy | 2013

Experimental and computational studies on 4-[(3,5-dimethyl-1H-pyrazol-1-yl)methoxy]phthalonitrile and synthesis and spectroscopic characterization of its novel phthalocyanine magnesium(II) and tin(II) metal complexes.

Hakkı Türker Akçay; Rıza Bayrak; Ertan Şahin; Kaan Karaoğlu; Ümit Demirbaş

The molecular structure of the substituted phthalonitrile was analyzed crystallographically and compared with optimized geometric structure. The structural properties of the compound such as energy, vibrational frequency, ground state transitions, (1)H and (13)C NMR chemical shifts, NBO analysis and hyperpolarizability were computed by DFT (Density Functional Theory) method and compared with experimental results. The novel Mg(II) and Sn(II) phthalocyanines synthesized from the substituted phthalonitrile and their aggregation behaviors were investigated in different solvents and at different concentrations in DMSO.


Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy | 2014

Computational studies on the anastrozole and letrozole, effective chemotherapy drugs against breast cancer

Hakkı Türker Akçay; Rıza Bayrak

In this paper, computational studies were carried out on anastrozole and letrozole, chemotherapy drugs used against breast cancer. Optimization and frequency calculations were performed at B3LYP/6-31G (d) basis set and vibrational frequencies were assignment. Single point calculations were performed at DFT method with a hybrid functional B3LYP/6-311G (d, p) basis set. Theoretical NMR data were obtained at DFT method with a hybrid functional B3LYP/6-311G++ (2d, p) with GIAO (Gauge-Independent Atomic Orbital). IEF-PCM method was used as solvation model. NBO calculations were performed by the same basis set and calculation method with single point calculation. Global and localized reactivity parameters; fukui indices (f) chemical hardness (η), softness (S), chemical potential (μ), electronegativity (χ) and electrophilicity index (ω) were calculated. All computational parameters were compared with the experimental results obtained from the literature.


Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy | 2016

The electrochemical and spectroelectrochemical properties of metal free and metallophthalocyanines containing triazole/piperazine units

Ümit Demirbaş; Duygu Akyüz; Arif Mermer; Hakkı Türker Akçay; Neslihan Demirbas; Atıf Koca; Halit Kantekin

The synthesis and characterization of novel peripherally tetra [1,2,4]-triazole substituted metal-free phthalocyanine and its metal complexes (Zn(II), Ni(II), Pb(II), Cu(II) and Fe(II)) and the investigation of electrochemical and spectroelectrochemical properties of metal-free, Zn(II), Pb(II), Fe(II) phthalocyanines were performed for the first time in this study. Electrochemical characterizations of the complexes were performed with voltammetric and in situ spectroelectrochemical measurements. Voltammetric responses of the complexes supported the proposed structures, since complexes bearing redox inactive Pc ring metal centers just gave Pc based electron transfer reactions, while iron phthalocyanine went to metal based electron transfer reaction in addition to the Pc based ones. Electron withdrawing nature of [1,2,4]-triazole substituents shifted the redox processes toward the positive potentials. All complexes were electropolymerized during the oxidation reactions in dichloromethane (DCM) solvent. Types of the metal center of the complexes altered the electropolymerization reactions of the complexes. Spectra and colors of the electrogenerated redox species of the complexes were also determined with in situ spectroelectrochemical and in situ electrocolorimetric measurements.


Journal of Organometallic Chemistry | 2011

Synthesis, photophysical and photochemical properties of highly soluble phthalocyanines substituted with four 3,5-dimethylpyrazole-1-methoxy groups

Rıza Bayrak; Hakkı Türker Akçay; Mahmut Durmuş


Dyes and Pigments | 2013

Synthesis, electrochemical and spectroelectrochemical properties of peripherally tetra-imidazole substituted metal free and metallophthalocyanines

Hakkı Türker Akçay; Rıza Bayrak; Ümit Demirbaş; Atıf Koca; Halit Kantekin


Dyes and Pigments | 2012

Azine-bridged binuclear metallophthalocyanines functioning photophysical and photochemical-responsive

Rıza Bayrak; Hakkı Türker Akçay; Mehmet Pişkin; Mahmut Durmuş


Journal of Organometallic Chemistry | 2012

Synthesis, characterization and spectroscopic studies of novel peripherally tetra-imidazole substituted phthalocyanine and its metal complexes, the computational and experimental studies of the novel phthalonitrile derivative

Hakkı Türker Akçay; Rıza Bayrak; Selami Karslıoğlu; Ertan Şahin

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Ümit Demirbaş

Karadeniz Technical University

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Halit Kantekin

Karadeniz Technical University

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Mahmut Durmuş

Gebze Institute of Technology

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Emre Menteşe

Recep Tayyip Erdoğan University

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Mehmet Pişkin

Çanakkale Onsekiz Mart University

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Burak Barut

Karadeniz Technical University

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