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Öğe Black-to-Transmissive Electrochromic Switching PEDOT-co-poly(N-ethylcarbazole) via a Sustainable and Facile In Situ Photo(co)polymerization Method(Amer Chemical Soc, 2024) Tabak, Tugberk; Altinisik, Sinem; Ulucay, Sude; Koyuncu, Sermet; Kaya, KeremIt is a great challenge to obtain black-to-transmissive switches using one type of polymer. Therefore, the color blending/mixing theory has been previously applied by many research groups to produce black-to-transmissive materials (BTMs) through the (electro)chemical copolymerization of several monomers. However, these (electro)chemical copolymerization methods exhibited numerous drawbacks in terms of sustainability. In this work, for the first time, the synthesis of an electrically conductive (bromide-doped) poly(3,4-ethylenedioxythiophene)-poly(N-ethylcarbazole) (PEDOT-co-PECz) copolymer was demonstrated using an in situ and sustainable photopolymerization technique. Spectrally and microscopically characterized copolymers were then deposited onto ITO/glass using spray coating. The copolymer film demonstrated to switch from a black state (L*: 38.16; a: -0.33; b: -2.89) to a transmissive state (L* = 83, a* = -3, b* = -6) with a contrast of 31.6% Delta T at 650 nm in fast response times (2.28-4.38 s). The results highlight the importance of this advanced method for the sustainable and fast fabrication of smart windows.Öğe Catalytic Role of Nanoconfinement inside MIL-125 (Ti) on the Ring-Opening Polymerization of Simple Benzoxazines(American Chemical Society, 2024) Omrani, Abdollah; Deliballi, Zeynep; Kaya, Kerem; Kıskan, Barış; Akgün, MertThe influence of nanoscale confinement on the thermally induced ring-opening polymerization (ROP) of three different monofunctional benzoxazines (Bzs) was highlighted for the first time. The Bzs were solution-loaded or blended in/with a titanium-based metal-organic framework (MOF), i.e., MIL-125-based. The successful infiltration of the Bzs within the MOF was confirmed through comprehensive analyses using FTIR, BET, and DSC techniques. Remarkably, the nanoconfinement exhibited exceptional promotion of the Bzs ROP, resulting in a significant decrease in the onset temperature of the corresponding exotherms of as much as 127 °C for the nonsubstituted monomer. GPC traces revealed that high-molecular-weight polybenzoxazines (PBzs) were formed when fluorine-substituted Bz polymerized in the MOF-confined nanospaces. The catalytic role of nanoconfinement was further supported by analyzing the effective activation energy through the isoconversional method of Starink. ROP of the Bz-MIL-125 blend, where the effect of nanoconfinement was absent, demonstrated the catalytic role of MIL-125 with a less pronounced impact compared to the nanoconfined system.Öğe N-((5-chloropyridin-2-yl)carbamothioyl)furan-2-carboxamide and its Co(II), Ni(II) and Cu(II) complexes: Synthesis, characterization, DFT computations, thermal decomposition, antioxidant and antitumor activity(Elsevier, 2017) Yesilkaynak, Tuncay; Ozpinar, Celal; Emen, Fatih Mehmet; Ates, Burhan; Kaya, KeremN-((5-chloropyridin-2-yl)carbamothioyl)furan-2-carboxamide (HL: C11H8CIN3O2S) and its Co(II), Ni(II) and Cu(II) complexes have been synthesized and characterized by elemental analysis, FT-IR,H-1 NMR and HR-MS methods. The HL was characterized by single crystal X-ray diffraction technique. It crystallizes in the monoclinic system. The HL has the space group P 1 2(1)/c 1, Z = 4, and its unit cell parameters are a = 4.5437(5) angstrom, b = 22.4550(3) angstrom, c = 11.8947(14) angstrom. The ligand coordinates the metal ions as bidentate and thus essentially yields neutral complexes of the [ML2] type. ML2 complex structures were optimized using B97D/TZVP level. Molecular orbitals of both HL ligand were calculated at the same level. Thermal decomposition of the complexes has been investigated by thermogravimetry. The complexes were screened for their anticancer and antioxidant activities. Antioxidant activity of the complexes was determined by using the DPPH and ABTS assays. The anticancer activity of the complexes was studied by using MTT assay in MCF-7 breast cancer cells. (C) 2016 Elsevier B.V. All rights reserved.Öğe Photoinduced synthesis of poly(N-ethylcarbazole) from phenacylium salt without conventional catalyst and/or monomer(Royal Soc Chemistry, 2019) Kaya, Kerem; Koyuncu, Sermet; Yagci, YusufWe report a new method for the photoinduced synthesis of poly(N-ethylcarbazole) (PEC). Inspired by the photochemical decomposition and electron transfer reactions of N-phenacylethyl carbazolium hexafluorophosphate (ECPhAc) salt, we used ECPhAc as the single molecule possessing both initiator and monomer structures to form PEC with relatively higher yield and higher molecular weight compared to that obtained from the bare monomer. This step-growth approach, eliminating the use of additional oxidizing agent, involves successive photoexcitation, cleavage, electron transfer, proton release, and coupling steps. The structural characteristics, electrochemical properties, and surface morphologies of the obtained PEC before and after the dedoping process were investigated by UV-vis, FT-IR, fluorescence, NMR, MALDI-TOF, SEC, AFM, cyclic voltammetry (CV), and differential pulse voltammetry (DPV). Doped PEC exhibited white light emission covering all visible regions offering a potential application in white light OLEDs.Öğe Polypyrenes by Photoinduced Step-Growth Polymerization(Amer Chemical Soc, 2020) Celiker, Tugba; Kaya, Kerem; Koyuncu, Sermet; Yagci, YusufPhotoinduced processes have been widely utilized in macromolecular synthesis through radical, cationic, anionic, and controlled/living polymerizations and ligation processes. 'While widely utilized, their application in step-growth polymerization has been scarcely investigated. In the present work, we report a new facile photochemical approach for the synthesis of polypyrene (PPy) by step-growth polymerization. Inspired by our previous studies on photoinduced electron-transfer reactions occurring between electron-rich monomers such as thiophene and carbazole derivatives and iodonium salt, we show that pyrene (Py) readily polymerizes under 350 nm irradiation at room temperature in the presence of iodonium salt by consecutive excitation, electron transfer within the exciplex, proton release, and coupling reactions. A detailed investigation on the structural, morphological, electrochemical, and molecular weight characteristics of the polymers revealed that the ratio of iodonium salt/Py plays a crucial role in the chain length and properties. The approach developed here is broadly adaptable to functional pyrenes and other conjugated monomers.
