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  • Küçük Resim
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    Comparative study on oxidative and enzyme catalyzed oxidative polymerization of aminophenol compound containing dihalogen
    (Springer, 2021) Kaya, İsmet; Karacan Yeldir, Elif
    Properties of polymers were obtained by enzyme catalyzed oxidative polymerization varies according to oxidative polymerization products and thus polymeric materials with diferent properties are obtained. In this study, polymerization of 4-amino2,6-dichlorophenol (ADCP), an aminophenol compound containing dihalogen, was carried out by two diferent methods and the two methods were compared with each other. One of the methods was oxidative polymerization in the presence of hydrogen peroxide with heating, and the other was enzyme-catalyzed oxidative polymerization that took place at room temperature in the presence of Horse Radish Peroxidase (HRP) enzyme and hydrogen peroxide. The structural characterization of the products obtained as a result of oxidative polymerization (PADCP-O) and as a result of enzyme catalyzed oxidative polymerization (PADCP-E) was performed by 1 H-NMR, 13C-NMR, FT-IR, UV–Vis spectroscopy methods. The molecular masses of PADCP-O and PADCP-E were analyzed by GPC and the average molecular mass of PADCP-E was found to be higher than that of PADCP-O. Thermal properties were examined by TGA and it was determined that the thermal stability of the obtained polymers was higher than that of the monomer. Electrochemical and optical properties were determined by CV and UV–Vis spectroscopy methods, respectively. Electrochemical and optical band gap values were calculated as 1.61 and 1.33 eV, and 1.88 and 1.83 eV for PADCP-O and PADCP-E, respectively. In addition, it was observed that PADCP-O emitted green in UV light, while PADCP-E emitted red in DMSO. Surface properties and morphology of polymers were analyzed by SEM and it was observed that PADCP-O obtained by oxidative polymerization had a spongy structure, but the enzymatic polymerization product PADCP-E had a uniformly dispersed nanoparticle structure.
  • Küçük Resim
    Öğe
    Doku mühendisliği uygulamaları için doğal antibakteriyel içeren biyopolimer iskele sistemlerin hazırlanması
    (Çanakkale Onsekiz Mart Üniversitesi, Lisansüstü Eğitim Enstitüsü, 2018) Karacan Yeldir, Elif; Oral, Ayhan
    Bu tez çalışması kapsamında doku mühendisliği uygulamalarında kullanılmak üzere, doğal antibakteriyel maddeler içeren biyopolimer iskele sistemleri hazırlanmıştır. Doğal polimerlerden olan Kitosan'ın asidik ortamdaki çözünürlüğünden faydalanılarak Kitosan küreler hazırlanmış ve bu küreler içerisine ayrı ayrı doğal antibakteriyel maddeler olan Fenil etil alkol ve Sinnamaldehit ilave edilmiştir. Devamında ise elektropüskürtme yöntemi kullanılarak Kitosan nanoküreler hazırlanmış ve hem çözelti hem de yöntem parametreleri değiştirilerek nanokürelerin morfolojileri incelenmiştir. Ayrıca elektropüskürtme yöntemi ile Kitosan nanoküreler doğal bir antibakteriyel madde varlığında da hazırlanarak bu maddenin morfoloji üzerine etkileri de araştırılmıştır.Elektroeğirme yöntemi ile kitosan nanolif ve doğal antibakteriyel madde içeren kitosan lifler elde edilmiştir. Doğal antibakteriyel maddelerden biri olan Linalool'ün termal radikalik ve fotopolimerizasyon yöntemleri ile polimerizasyonu gerçekleştirimiş ve 1H-NMR spektrumları incelenmiştir. Kaprolakton monomeri kullanılarak α-Lipoik asit ve Sitranellol varlığında ve başlatıcı olarak Kalay Oktanoat ile Poli(ε-kaprolakton) makromerleri elde edilmiş ve karakterizasyonu yapılmıştır.
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    Öğe
    Fluorescent Oligomeric Nanoparticle from Diaminopyridine Compound Via Enzyme-Catalyzed Oxidation
    (Springer/Plenum Publishers, 2023) Karacan Yeldir, Elif
    An oligomeric nanoparticle was obtained through an enzyme-catalyzed oxidation reaction using Horse Radish Peroxidase (HRP) with the 2,3-diaminopyridine (DAP) compound as the starting material. The structural characterizations of the synthesized oligomeric nanoparticles [[oligo(DAP)](Enz)] were performed with H-1-NMR and FT-IR. The surface features were determined by scanning electron microscopy. The optical properties were determined by UV-Vis and fluorescence spectra. It was found that the obtained oligomeric nanoparticles had a different fluorescent character with 15.90% quantum yield from the monomer and emitted green color at 485 nm when excited with light at a wavelength of 420 nm. The electrochemical band gap of the oligomeric nanoparticles, whose electrochemical character was investigated by cyclic voltammetry, was calculated as 2.09 eV. The thermal stability of the oligomeric material was determined from the mass loss against increasing temperature. The monomer exhibited greater thermal stability in comparison to the polymer, both in terms of the temperature at which the maximum mass loss occurred and the residual amount after heating concluded.
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    Öğe
    Ni(II), Zn(II), and Fe(III) complexes derived from novel unsymmetrical salen-type ligands: preparation, characterization and some properties
    (Taylor & Francis Ltd, 2022) Dilmen Portakal, Eylem; Kaya, Yeliz; Demirayak, Emire; Karacan Yeldir, Elif; Ercag, Ayse; Kaya, İsmet
    By using a half-salen ligand (HL) and substituted salicylaldehydes, new unsymmetrical salen-type ligands (H2L1, H2L2, and H2L3) and their Ni(II), Zn(II) and Fe(III) complexes were synthesized. The compounds were characterized based on elemental analysis, IR, H-1 NMR, X-ray diffraction (for HL), spectroscopy, mass spectrometry, magnetic moment, molar conductance measurements, and thermal analysis (TGA). The unsymmetrical salen ligands, during complexation, are attached to the metal by two imine nitrogen atoms and two phenolic oxygen atoms in all complexes; in the Fe(III) complexes, the fifth coordination is completed by chloride. Square planar geometry or distorted square planar geometry for [NiL1-3], [ZnL1-3], and square pyramidal geometry for [FeL1-3Cl] are proposed. Conductance measurements suggest non-electrolytic nature of the metal complexes. Thermogravimetric analysis showed that the complexes exhibit higher stability than the ligands. The electrochemical properties of the compounds were studied by cyclic voltammetry. HOMO-LUMO energy levels and electrochemical band gaps (E '(g)) were calculated. The solid state electrical conductivity of the iodine-doped compounds was measured and their semiconductor properties were determined. In addition, fluorescence properties of ligands and Zn(II) complexes were investigated.
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    Öğe
    P(2-VP) supported Ru(II) material as catalyst for H2 production from the methanolysis of NaBH4
    (Taylor & Francis Inc, 2020) Tercan, Melek; Karacan Yeldir, Elif; Dayan, Osman; Oral, Ayhan
    Existing energy resources are not sufficient to meet the energy needs of the increasing world population so the need for clean and renewable energy systems is increasing day after day. Hydrogen is a good alternative energy source because of its clean by-products and high energy capacity. Studies on hydrogen storage systems that provide instant hydrogen production in the literature are of great interest. In this study, poly-2-vinylpyridine (p(2-VP)) polymer was prepared by photopolymerization method and reacted with 2,6-bis(2-benzimidazolyl)pyridine ligand containing Ru(II) complex to give p(2-VP) supported Ru(II) material. The synthesized Ru(II) complex was characterized by FT-IR, UV-Vis and H-1-NMR spectroscopic techniques. Also the p(2-VP) polymer was characterized by FT-IR spectroscopy. The obtained p(2-VP) supported Ru(II) material was used as catalyst in hydrogen generation from NaBH4 metanolysis reaction and the reaction kinetic was investigated.
  • Küçük Resim
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    Synthesis of pyrene and pyrrole-appended fluorescent turn-off sensor toward Cr(VI) detection: Chemical oxidative and electrochemical polymerization of carboxamide
    (Elsevier B.V., 2024) Kaya, İsmet; Karacan Yeldir, Elif; Kolcu, Feyza; Erdener, Diğdem
    A carboxylic amide compound containing pyrrole and pyrene groups, referred to as PP, was synthesized and characterized for its structural, optical, and electrochemical properties. Upon excitation with 320 nm light, PP displayed blue emission at 387 nm, which was found to be quenched due to chelate formation in the presence of Cr(VI). Conducted competition experiments involving chloride salts of Ag+, Al3+, Cd2+, Co2+, Cr3+, Fe3+, Hg2+, K+, Mn2+, Ni2+, Pb2+, Sn2+, and Zn2+ demonstrated the notable selectivity of compound PP towards Cr(VI) ions. This selectivity was evidenced by a pronounced turn-off fluorescent effect, attributed to a chelation-enhanced quenching (CHEQ) mechanism by the formation of 1:2 chelation between Cr(VI) and the ligand PP. Moreover, addition of EDTA to PP– Cr(VI) chelation recovered the fluorescence offering receptor PP as a reversible sensor. The PP probe demonstrated remarkable selectivity in detection Cr(VI) ions among various metallic ions, displaying a limit of detection (LOD) value of 0.106 µM. Chemical oxidative and electropolymerization methods were employed to synthesize two distinct polymers, namely Poly(PP)-O and Poly(PP)-E, respectively. The electropolymerization of PP was carried out in 0.1 M TBAF6P serving as a supporting electrolyte solution, while oxidative polymerization was conducted in the presence of FeCl3. Mass average molecular weight of the oxidative polymerization product was 5200 Da, as determined by GPC analysis. Thermal characterization was performed via TG-DTA-DTG curves. The electropolymerization product of PP coated on the ITO surface was further characterized by SEM.