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    A New Strategy for Photo-Electrochemical Reduction of Carbon Dioxide Using a Carbazole-BODIPY Based Metal-Free Catalyst
    (Wiley-V C H Verlag Gmbh, 2024) Ozdemir, Mucahit; Ulucay, Sude; Altinisik, Sinem; Koksoy, Baybars; Yalcin, Bahattin; Koyuncu, Sermet
    In this study, a cross-linked boron dipyrromethene (BODIPY) photocatalyst containing a carbazole donor group designed for photoelectrocatalytic carbon dioxide (CO2) reduction is synthesized and characterized. The BODIPY-based system, coated onto a platinum surface, is evaluated for its electrochemical and photocatalytic performance under light illumination. Cyclic voltammetry (CV) and chronoamperometry measurements reveals enhanced photocurrent responses, confirming the catalyst's ability to effectively drive CO2 reduction. Gas chromatography/mass spectrometry (GC-MS) analysis identifies the formation of ethanol (C2H5OH) as a major reaction product, showing that its yield increased with extended reaction times. Additionally, the photocatalyst demonstrates remarkable performance with significantly increasing turnover numbers (TON) and turnover frequencies (TOF) over time, indicating stable and sustained catalytic activity. With a Faradaic efficiency of 34.79% at a potential of -1.15 V, this BODIPY system exhibits both high activity and long-term stability. The combination of efficient electron transfer and visible light absorption by the carbazole-BODIPY donor-acceptor structure positions this system as a highly promising candidate for sustainable CO2 conversion applications.
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    New metallophthalocyanines including benzylphenoxy groups and investigation of their organic-field effect transistor (OFET) features
    (Elsevier Sci Ltd, 2022) Ozdemir, Mucahit; Altinisik, Sinem; Koksoy, Baybars; Canimkurbey, Betul; Koyuncu, Sermet; Durmus, Mahmut; Bulut, Mustafa
    In this study, metal and metal-free novel phthalocyanines containing peripheral and non-peripheral tetra 2-ben-zylphenoxy groups were synthesized. The compounds were characterized by UV-Vis, FT-IR, H-1 NMR, and MALDI-TOF mass spectrometry as well as elemental analysis. These new phthalocyanines exhibited excellent solubility in most organic solvents, and their redox behavior was investigated in different solvents such as dimethyl sulfoxide (DMSO) and dichloromethane (DCM). The redox behavior of the peripheral and non-peripheral phthalocyanine compounds 1a -c and 2a -c was determined by cyclic voltammetry and in situ spec-troelectrochemistry. According to organic field-effect transistors (OFETs) measurements, the peripheral and non-peripheral phthalocyanine-cobalt complexes which have higher mobility than others were utilized top-gate bottom-contact OFETs fabrication. The output characteristics of the device show that its mobility is approximately 5 x 10(-2) cm(2)/Vs with p-type accumulation.
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    Photophysical and photochemical properties and comparison of tolyl and tosyl coumarin-bearing phthalocyanines
    (Elsevier, 2023) Kazancicok, Zehra; Guler, Hatice Esar; Ozdemir, Mucahit; Piskin, Mehmet; Bulut, Mustafa; Yalcin, Bahattin; Salan, Umit
    In this study, peripheral and non-peripherally substituted Zn(II) phthalocyanine complexes were synthe-sized from 7-hydroxy-3-(p-tolyl)coumarin and 7-hydroxy-3-(p-tosyl)coumarin compounds. The synthe-sized new compounds were characterized using elemental analysis, FT-IR, UV-Vis, Fluorescence 1 HNMR spectroscopy and MALDI-TOF mass spectrometry. All the synthesized phthalocyanine complexes showed good solubility in organic solvents such as acetone, dichloromethane, chloroform, pyridine, and ethyl acetate. Fluorescent quenching behavior was investigated using 1,4-benzoquinone and potassium io-dide as a quencher. The photophysical (fluorescent quantum yields and lifetimes) and photochemical (single oxygen and photodegradation quantum yields) properties of these new phthalocyanines were examined in dimethyl sulfoxide. Phthalocyanine complexes containing 7-hydroxy-3-(p-tolyl)coumarin had higher singlet oxygen quantum yields than phthalocyanine complexes containing 7-hydroxy-3-(p- tosyl)coumarin. Phthalocyanines to which coumarins are peripherally bound were more advantageous than their non-peripherally bound derivatives. As a result of their photophysical and photochemical prop-erties, coumarin-phthalocyanine complexes containing tolyl-/tosyl-groups can be used as photosensitiz-ing candidates in photodynamic therapy and can be developed with targeted modifications.(c) 2022 Elsevier B.V. All rights reserved.
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    Tetra-Carbazole based electroactive donor-acceptor dyes: Effect of the phenyl bridging unit on the electrochromic performance
    (Elsevier Sci Ltd, 2022) Doyranli, Ceylan; Altinisik, Sinem; Ozdemir, Mucahit; Koyuncu, Sermet
    In this study, a new Donor-Acceptor-Donor (D-A-D) electroactive molecules (HCQM1 and HCQM2) containing 9H-carbazole and 9-phenyl-9H-carbazole as donor along with quinoxaline (HQ) as acceptor were synthesized and then coated on Indium Tin Oxide/Glass (ITO/Glass) surface by the electrochemical oxidation process. The HOMO-LUMO band gap values obtained by electrochemical oxidation and reduction onsets were calculated as 2.64 and 2.68 eV, respectively. On the other hand, UV-Vis absorption measurements showed that the charge transfer band of HCQM1 was detected at 500 nm with 50 nm red shift upon compared with the HCQM2. According to AFM results, it is seen that the roughness of the poly(HCQM2) film is higher than the poly(HCQM1) film. Finally, the polymer film of HCQM2 showed multi-electrochromic color change (yellow, green, and dark blue) upon the oxidation process. When the electrochromic performance of the HCQM1 and HCQM2 polymer films was compared, it was discovered that the HCQM2 with phenylene spacer unit has better stability and a higher percentage transmittance change (& UDelta;T%) between neutral and oxidized states.
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    Visible Light-Induced Synthesis of Conjugated Poly(phenylene butadiynylene) by a Combination of Halide Abstraction and Coupling Reactions
    (Amer Chemical Soc, 2023) Nakipoglu, Busra; Aydogan, Cansu; Ozdemir, Mucahit; Yagci, Yusuf; Koyuncu, Sermet; Kiskan, Baris
    This study describes a simple and efficient method forsynthesizingconjugated poly(phenylene butadiynylene) (PPB)polymers using photo-inducedradical homocoupling. The approach involves irradiating 1,4-bis(bromoethynyl)benzenewith visible light in the presence of dimanganese decacarbonyl (Mn-2(CO)(10)), which acts as a radical generator by abstractinghalides and promoting subsequent radical coupling reactions. The resultingconjugated PPB exhibited a remarkable red shift, andthe optical band gap decreased from -2.76 to -2.27 eV.A similar effect was observed in the electrochemically measured oxidationpotential; the highest occupied molecular orbital position regressedfrom -6.06 to -5.69 eV. Transmission electron microscopyand atomic force microscopy measurements revealed the self-organizationof the polymers to planar 2D nanorods, and the 2D structures of thepolymers were further supported by density functional theory calculations.Moreover, the surface area of the polymer was found to be 53.61 and30.69 m(2)/g according to Brunauer-Emmett-Tellerand Barrett-Joyner-Halenda methods, respectively.