Yazar "Koca, Atif" seçeneğine göre listele

Listeleniyor 1 - 4 / 4
  • [ X ]
    Öğe
    Effects of peripheral and nonperipheral substitution to the spectroscopic, electrochemical and spectroelectrochemical properties of metallophthalocyanines
    (Elsevier Ltd, 2013) Arican, Duygu; Arici, Mürsel; Ugur, Ahmet Lütfi; Erdoğmuş, Ali; Koca, Atif
    The syntheses, spectroscopic and electrochemical properties of metallo-phthalocyanine complexes, tetra- and octa-substituted with 3,4-(dimethoxyphenylthio) moieties at non-peripheral and peripheral positions were studied. These complexes were characterized by FT-IR, mass spectroscopy, electronic spectroscopy and electrochemical methods. 3,4-(Dimethoxyphenylthio) moieties increase the solubility of the complexes in various polar and nonpolar organic solvents and prevent the aggregation (in the same solvents) within a wide concentration range. Electronic absorption spectroscopy revealed that the presence of electron donating sulphur on synthesized complexes shift the Q-band of the complexes to the higher wavelengths. Redox active metal centers, Co II, FeII and MnIIIOAc into the phthalocyanine core extend the redox worthy of the complexes due to the reversible metal-based reduction and oxidation couples of the metal centers. In situ electrocolorimetric measurements of the complexes allow quantification of color coordinates of each electrogenerated anionic and cationic redox species. Electrochemical and in situ spectroelectrochemical analysis indicate that cobalt and manganese phthalocyanines catalyze the molecular oxygen in aprotic media. © 2013 Elsevier Ltd. All rights reserved.
  • [ X ]
    Öğe
    Electrochemical and spectroelectrochemical characterization of newly synthesized manganese, cobalt, iron and copper phthalocyanines
    (2013) Arici, Mürsel; Arican, Duygu; U?ur, Ahmet Lütfi; Erdoğmuş, Ali; Koca, Atif
    Manganese, cobalt, iron, and copper phthalocyanines, tetra-substituted with 3,4-(dimethoxyphenylthio) moieties at peripheral positions, were synthesized and characterized by FT-IR, mass spectroscopy, and electronic spectroscopy. Electrochemical and spectroelectrochemical measurements exhibit that while copper phthalocyanine gives only ring-based electron transfer reactions, incorporating redox active metal centers, CoII, FeIIIAc, and MnIIIAc, into the phthalocyanine core extends the redox richness of the phthalocyanine ring with the metal-based reduction and oxidation couples of the metal centers in addition to the common phthalocyanine ring-based electron transfer processes. In situ electrocolorimetric measurements of the complexes allow quantification of color coordinates of the each electrogenerated anionic and cationic redox species. Presence of O2 in the electrolyte system influences the redox couples of the complexes due to the interaction between O2 and metallophthalocyanines having redox active metal center. © 2012 Elsevier Ltd.
  • [ X ]
    Öğe
    Electrochemical and spectroelectrochemical properties of methylendioxy-phenoxy-substituted novel lutetium (III) mono- and bis-phthalocyanines
    (2014) Bozo?lu, Ceyda; Arici, Mürsel; U?ur, Ahmet Lütfi; Erdoğmuş, Ali; Koca, Atif
    Peripheral (LuPc(p)) and non-peripheral (LuPc(np)) derivatives of lutetium (III) mono-phthalocyanines and peripheral analogue of lutetium (III) bis-phthalocyanine (LuPc2) substituted with 3,4-(methylendioxy)- phenoxy have been synthesized and characterized by elemental analysis, FT-IR, UV-vis spectroscopy, and mass spectroscopy. Electrochemical and spectroelectrochemical analyses of the complexes were performed in solution. While LuPc(p) and LuPc(np) gave common Pc ring-based electron transfer processes, ring-to-ring interaction of LuPc2 completely altered the redox behaviors of the complex. The first reduction reaction of LuPc2 was recorded even at positive potentials, while the LuPc(p) and LuPc(np) gave this reduction reaction at around -1.00 V. Due to the ?-? interaction of phthalocyanine rings around the lutetium core of LuPc2, a very narrow ?E1/2 (0.50 V) was recorded. LuPc2 illustrated distinct color differences between the electrogenerated anionic and cationic forms of the complex, while LuPcs did not give obvious color changes. © 2014 Elsevier B.V.
  • Küçük Resim
    Öğe
    Polyindole coated NiCo 2 S 4 composites as high-performance supercapacitor electrode materials
    (Elsevier, 2024) Otluca, Hayriye Ece; Budak, Özlem; Bilici, Ali; Koca, Atif
    NiCo 2 S 4 (NCS) and Polyindole (PIn) are two effective electrode materials used in energy storage systems. In this study, NCS@PIn hybrid structures were synthesized for the first time and the effects of PIn amount on the supercapacitor performance of NCS were evaluated. For this purpose, first, the PIn hollow microspheres were obtained by oxidative polymerization reaction. Then, the NCS was produced by a one-step hydrothermal synthesis approach and NCS@PIn composites in three different composition ratios were prepared by a simple ultrasonic mixing process. The NCS exhibited a specific areal capacitance value of 834.6 F g -1 at a current density of 1 A g -1 . The electrochemical performance of NCS was improved via a hybridization process. After composing NCS with 5 % PIn (NCS@PIn-5), the specific capacitance value reached up to 1442.8 F g -1 which was higher than those of PIn, NCS, and the other NCS@PIn hybrid electrodes. In addition, the NCS@PIn-5 coated electrode exhibited a charged retention of 94.7 % after 5000 cycles.