Person: KOCA, ATIF
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KOCA
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ATIF
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Publication Metadata only Novel 4-(2-(benzo[d]thiazol-2-yl)phenoxy) substituted phthalocyanine derivatives: Synthesis, electrochemical and in situ spectroelectrochemical characterization(ELSEVIER SCIENCE SA, 2014) KOCA, ATIF; Nas, Asiye; Kantekin, Halit; Koca, AtifIn this study, the new tetra peripherally 4-(2-(benzo[d]thiazol-2-yl)phenoxy)-substituted metal-free (4), zinc(II) (5), lead(II) (6), cobalt(II) (7) and copper(II) (8) phthalocyanine derivatives, which are organosoluble, have been synthesized for the first time and their structures characterized by using electronic absorption, infrared spectroscopy, nuclear magnetic resonance spectroscopy, elemental analysis and mass spectra. Voltammetric characterization of the phthalocyanine derivatives (4-7) was performed with cyclic voltammetry and square wave voltammetry. Cobalt phthalocyanine (7) gave metal based electron transfer reactions in addition to the phthalocyanine ring based reduction and oxidation reactions. Although lead phthalocyanine (6) illustrated reversible reduction process during the voltammetric measurements, it was de-metallized and thus it turned back to the metal free phthalocyanine during the in situ spectroelectrochemical measurements under the applied potentials. Spectroelectrochemical measurements were performed to assign the redox processes and spectroscopic responses of the electrogenerated species. (C) 2014 Elsevier B.V. All rights reserved.Publication Metadata only 1,4-Dithiaheterocycle-fused porphyrazines: Synthesis, characterization, voltammetric and spectroelectrochemical properties(ELSEVIER SCI LTD, 2009) KOCA, ATIF; Tuncer, Serap; Koca, Atif; Guel, Ahmet; Avciata, UlviPorphyrazines (M = H, Mg, Zn and Co) with a 2,3-dicyano-5-phenyl-5,6-dihydro-1,4-dithiin group fused to each pyrrole unit were synthesized and characterized starting with the corresponding unsaturated dicarbonitrile derivative. The voltammetric and spectroelectrochemical characterizations of the metallo-porphyrazines (M=2H(+), Mg2+, Zn2+ and Co2+) substituted with 2,3-dicyano-5-phenyl-5,6-dihydro-1,4-dithiin groups on peripheral positions are described. Cyclic voltammetry and differential pulse voltammetry studies showed that while metal-free, magnesium, and zinc porphyrazines represented well-defined one-electron ligand-based reductions and ligand-based one-electron oxidation couples, cobalt porphyrazine gave both metal-based and ligand-based reduction and oxidation couples. Assignments of the redox couples were confirmed by spectroelectrochemical measurements. (C) 2008 Elsevier Ltd. All rights reserved.Publication Open Access Synthesis, electrochemistry, and electrocatalytic activity of thiazole-substituted phthalocyanine complexes(2022-03-01) KOCA, ATIF; Demir F., Yenilmez H. Y., KOCA A., Bayır Z.We report the synthesis of non-peripheral metallophthalocyanines which carry four 4-(4-methoxyphenyl)-2-thiazole-2-thio units. H-1-NMR, FT-IR, UV-Vis, and MS data were acquired to characterize the synthesized compounds. Voltammetric and in situ spectroelectrochemical measurements shed light on the redox properties of the metallophthalocyanines (MPcs) in order to show the influence of the metal cations and thiazole-bearing substituents. In solution, the redox processes had an influence to the electrochromic responses, which were examined with in situ spectrocolorimetry. Phthalocyanines having cobalt (II), manganese (III), iron (III), and zinc (II) at the center yielded characteristic redox couples which are metal- and/or Pc-based and which are harmonious with the common redox properties of these types of compounds. In situ spectroelectrochemistry provided the information that MPc species underwent distinct color changes during electron transfer reactions. Electropolymerization of all complexes was performed on glassy carbon electrode, and the electropolymerized film of FePc was evaluated as an active electrocatalyst, in the alkaline medium, for oxygen evolution reaction (OER).Publication Metadata only Synthesis, electrochemical, in situ spectroelectrochemical and in situ electrocolorimetric characterization of new metal-free and metallophthalocyanines substituted with 4-{2-[2-(1-naphthyloxy)ethoxy]ethoxy} groups(PERGAMON-ELSEVIER SCIENCE LTD, 2010) KOCA, ATIF; Acar, Irfan; Biyiklioglu, Zekeriya; Koca, Atif; Kantekin, HalitThe synthesis of novel metal-free and metallophthalocyanines [Ni(II), Zn(II), Co(II), Cu(II)] were prepared by cyclotetramerization of a novel 4-{2-[2-(1-naphthyloxy)ethoxy]ethoxy}phthalonitrile and the corresponding metal salts (NiCl2, Zn(CH3COO)(2), CoCl2 and CuCl2). The structures of the target compounds were confirmed using elemental analysis, IR, H-1 NMR, C-13 NMR, UV-Vis and MS spectral data. Voltammetric and in situ spectroelectrochemical measurements show that while cobalt phthalocyanine complex gives both metal-based and ring-based redox processes, metal-free, and zinc phthalocyanines show only ring-based reduction and oxidation processes. All complexes decomposed and coated on the electrode as non-conductive film at positive potential window of the electrolyte. An in situ electrocolorimetric method has been applied to investigate color of the electro-generated anionic and cationic forms of the complexes. (C) 2010 Elsevier Ltd. All rights reserved.Publication Metadata only Electrochemistry of Novel Phthalocyanines Bearing 1,2,4 Triazole Groups(WILEY-V C H VERLAG GMBH, 2020) KOCA, ATIF; Akyuz, Duygu; Demirbas, Umit; Akcay, Hakki Turker; Mentese, Emre; Koca, Atif; Kantekin, HalitThe phthalonitrile (3) and triazole substituted metallo phthalocyanines (MPc) (4-7) were prepared. The novel compounds were characterized with spectroscopic data. Electrochemical analyses of metallophthalocyanines (4-7) bearing triazole substituents were performed to investigate redox activity of phthalocyanines (Pcs) ring. While incorporation of Ni(2+)and Cu(2+)cations in the Pc core only influenced peak positions of Pc ring processes, Co(2+)and Cl(1-)Fe(3+)cations of CoPc and FePc gave extra redox couples to the Pc based ones. Releasing the axial Cl(1-)anion on Fe(3+)cation of FePc during the reduction reactions complicated the redox responses. Redox reactions of Co(2+)and Fe(3+)metal centers also considerable influenced spectral and color responses of these complexes.Publication Metadata only Electrochemical and spectroelectrochemical characterizations of new tetra-substituted metallophthalocyanines bearing 4-(trifluoromethoxy)phenoxy groups on non-peripheral positions(SPRINGER WIEN, 2020) KOCA, ATIF; Farajzadeh, Nazli; Akyuz, Duygu; Koca, Atif; Kocak, Makbule BurkutIn this study, a series of non-peripherally tetra-substituted phthalocyanines [M = Zn(II), Co(II), and In(III)] was successfully prepared by cyclotetramerization of the phthalonitrile derivative bearing 4-(trifluoromethoxy)phenoxy group at 3-position. All newly synthesized compounds were characterized using spectroscopic methods, such as FT-IR, NMR, and UV-Vis spectroscopy. The effect of concentration on aggregation properties of the resulting phthalocyanines was investigated in different concentrations ranging from 4 x 10(-6)to 14 x 10(-6) M in THF. In addition, the spectral properties of the metallophthalocyanines were studied in various organic solvents. Besides, redox responses of metallophthalocyanines and their electro-optical responses were determined. Although {1(4),8(11),15(18),22(25)-tetrakis[4-(trifluoromethoxy)phenoxy]phthalocyaninato}cobalt(II) showed well-resolved reversible redox peaks depicting the anticipated electron transfer reactions, electrochemical investigation of its zinc(II) and indium(III) chloride analogs resulted in complex redox waves, and their chemical reversibility decreased with the aggregation of the complexes. The influence of the redox processes on the optical responses of metallophthalocyanines was studied with in situ spectroelectrochemistry measurements and the peak assignments and optical responses of the electrogenerated species were determined. [GRAPHICS] .Publication Metadata only Functional fluoro substituted tetrakis-metallophthalocyanines: Synthesis, spectroscopy, electrochemistry and spectroelectrochemistry(ELSEVIER SCIENCE SA, 2008) KOCA, ATIF; Gunsel, Armagan; Kandaz, Mehmet; Koca, Atif; Salih, BekirIn this study, electron-withdrawing fluoro-functional ligand and its tetrakis 2,9,16,23-4-(2,3,5,6-tetrafluoro)-phenoxy-phthalocyaninatometal (II) complexes, (ZnPcOBzF(16), CuPcOBzF(16) and CoPcOBzF(16)) (Bz: benzene) which are organo-soluble have been prepared. Their structures were confirmed by elemental analysis, FT-IR, H-1 NMR, UV/vis and MS (Maldi-TOF) spectral data. Electron-withdrawing fluorine atoms on 2,3,5,6-position of benzene at the peripheral sites increases the solubility of the tetrakis-metallophthalocyanines. The cyclic voltammetry and differential pulsed voltammetry of the complexes show that while CuPcOBzF(16) and ZnPcOBzF(16) give ligand-based reduction and oxidation processes, CoPcOBzF(16) gives both ligand and metal-based redox processes, in harmony with the common MPc complexes. Spectroelectrochemical measurements confirm the assignments of the complexes. (c) 2008 Elsevier B.V. All rights reserved.Publication Metadata only Synthesis and electrochemical characterization of tetra-(5-chloro-2-(2,4-dichlorophenoxy)phenol) substituted Ni(II), Fe(II) and Cu(II) metallophthalocyanines(ELSEVIER SCIENCE SA, 2016) KOCA, ATIF; Demirbas, Umit; Kobak, Rabia Zeynep Uslu; Barut, Burak; Bayrak, Riza; Koca, Atif; Kantekin, HalitThe synthesis and characterization of novel nitrile compound (3) and peripherally tetra 5-chloro-2-(2,4-dichlorophenoxy)phenol substituted nickel(II) (4), iron(II) (5) and copper(II) (6) phthalocyanines were accomplished for the first time in this study. Electrochemical characterizations of the complexes were carried out with voltammetric and in situ spectroelectrochemical measurements. CuPc and NiPc showed common Pc based electron transfer reactions. Small potential differences were observed between the redox responses of these complexes due to the different effective nuclear charges of the metal centers. [Cl1--(FePc2-)-Pc-III] complex gave metal and Pc based electron transfer reactions. While [Cl-1-Fe(III)pc(2-)] reduced to [Cl1--(FePc2-)-Pc-II](1-), [Cl1--(FePc2-)-Pc-I](2-), and [Cl1--(FePc3-)-Pc-I](3-) during reduction reactions, a metal based ([Cl1--(FePc2-)-Pc-III]/[Cl1--(FePc2-)-Pc-IV](1+)) and then a Pc based ([Cl1--(FePc2-)-Pc-IV](1+)/[Cl1--(FePc1-)-Pc-IV](2+)) oxidation reaction was observed the cathodic potential scans. Determination of the spectra, color of the electrogenerated MPc species and peak assignments of the complexes were determinated with in situ spectroelectrochemical measurements. (C) 2016 Elsevier B.V. All rights reserved.Publication Metadata only Electrochromism of electropolymerized cobaltphthalocyanine-quinoline hybrid(ELSEVIER, 2015) KOCA, ATIF; Arican, Duygu; Aktas, Ayse; Kantekin, Halit; Koca, AtifIn this study, electrochromic properties of cobaltphthalocyanine (CoPc) immobilized on ITO electrode with electropolymerization were investigated (ITO/CoPc). CoPc substituted with electropolymerizable quinoline moieties was oxidatively electropolymerized on the working electrode during anodic potential scans with the help of polymerizable quinolone groups. In situ spectroelectrochemical measurements of CoPc in solution and in solid state showed that a metal based redox process of CoPc affected the optical spectrum more than the Pc based redox process as the existed bands shifted and new bands appeared, which showed the electrochromic feature of the complex. In order to investigate potential utility of the complex as electrochromic material, electrochromic properties of ITO/CoPc thin film were investigated in detail with various electrochemical, in-situ spectroelectrochemical and in-situ electrocolorimetric analysis methods. ITO/CoPc thin film showed reversible color change between cyan and purple colors. Short response times, high optic contrast and optical and coulombic stabilities of CoPc film indicate possible application of CoPc as anodic and cathodic coloring material in the display technologies. (C) 2014 Elsevier B.V. All rights reserved.Publication Metadata only 1,2,4-triazole-5(4H)-one based novel peripherally tetrasubstituted metal-free and metallophthalocyanines: Synthesis, characterization, and electrochemical and spectroelectrochemical properties(TAYLOR & FRANCIS INC, 2017) KOCA, ATIF; Aktas, Ayse; Uenlueer, Dilek; Kobak, Rabia Zeynep Uslu; Acar, Irfan; Dugdu, Esra; Koca, Atif; Kantekin, HalitIn this study, the synthesis of metal-free and metallophthalocyanines containing four 4-[2-(4-methoxyphenyl) ethyl]-5-methyl-2,4-dihydro-3H-1,2,4-triazol-3-one substituents at the peripheral positions were reported. The structures of compounds were characterized using IR, H-1 NMR, C-13 NMR, mass spectroscopies, and UV-Vis. Electrochemistry of the complexes were studied with voltammetric and in situ spectroelectrochemical measurements in different electrolytic systems. MPcs having redox inactive metal centers (H+, Zn+2, Cu+2, and Ni+2) just illustrated similar Pc-based electron transfer reactions. Due to the different effective nuclear charge of the ions in the core of Pc ring, small potential shifts and reversibility differences were observed between the redox processes of these complexes. MPcs having redox-active metal centers (Co+2 and TiO+2) gave metal-based electron transfers in addition to Pc-based processes. Electrolyte type of the measurement system significantly influenced oxidation behaviors of CoPc due to the coordination of polar coordinating solvent molecules to the oxidized Co-III center of CoPc. Spectra and color of the electrogenerated MPc species were determined with in situ spectroelectrochemical measurements.