Browsing by Author "Cihaner, Atilla"
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Article D-A-D type conjugated polymers in dual electrochromic devices tuning from green to blue colors(Synthetic Metals, 2023-07) İçli Özkurt, Merve; Önal, Ahmet M.; Cihaner, AtillaIn this study, the electrochemical and electro-optical properties of four different dual electrochromic devices were unraveled. In all devices, soluble donor-acceptor-donor (D-A-D) type conjugated electrochromic polymers based on didecyl substituted 3,4-propylenedioxythiophene and heterodiazole analogues were used, and they were coated on ITO electrochemically for the construction of the electrochromic devices. Because all D-A-D polymers and PEDOT are colorful in their neutral states and colorless in their oxidized states, it is possible to observe one-to-one colors of pure two polymers in their electrochromic devices rather than a mixture of colors. It was observed that devices changed their colors from the tunes of green to blue under applied external voltage. Switching times, coloration efficiencies and stabilities of the electrochromic devices were calculated as ranging from 1.0 to 6.0 s, 133 to 544 cm2/C and 54% to 91%, respectively, after 5000 cycles. The P(PSeP-C10)-P(PNP-C10) device showed the highest coloration efficiency (544 cm2/C) as well as the best optical and electrochemical stabilities among the electrochromic devices after 5000 cycles (91% and 92%, respectively).thesis.listelement.badge DETECTION OF BLOOD TRACES: SYNTHESIS AND CHARACTERIZATION OF A LUMINOL-TYPE COMPOUND(2022-06-13) KESİMAL, BÜŞRA; Cihaner, AtillaLuminol is a compound used in many fields, including analytical measurements mainly for forensic science. The synthesis of new luminol-type compounds has gained great importance due to the use of luminol in many fields and also having some disadvantages. In this thesis, a trimeric chemiluminescent 5,8-di(thiophen-2-yl)-2,3- dihydrophthalazine-1,4-dione (T2B-Lum) compound with pyridazine ring has been studied. After the synthesis and characterization, the chemiluminescence reactions of the compound was investigated in basic medium (0.1 M sodium hydroxide solution) with different oxidants (hydrogen peroxide, potassium permanganate, potassium dichromate). Afterwards, the optical property and chemiluminescence reaction of T2B-Lum with hydrogen peroxide in alkaline solution in the presence of various metal ionswere studied. T2B-Lum exhibits two absorption bands at 262 and 330 nm in dichloromethane and emits green light at 495 nm when excited. The quantum yield was calculated as 15.11% in dichloromethane when considering the luminol quantum yield is 100%. On the other hand, it was observed that some metal cations, especially copper(II) ions, catalyze the chemiluminescent reaction. It was also observed that the chemiluminescent emission was catalyzed by iron(III) ions. After this observation, the chemiluminescent behaviors of T2B-Lum with hydrogen peroxide in alkaline solution were studied in the presence of hemin and blood samples used as catalysts since these samples contain iron ions. Finally, the ion recognition property of T2B-Lum was investigated. Except for other metal cations (silver(I), cadmium(II), cobalt(II), iron(III), lithium(I), magnesium(II), manganese(II), nickel(II), zinc(II)), it has been observed that T2B-Lum is mostly sensitive to copper(II) ions with a detection limit value of 2.2×10-3 M.Article Effect of phthalimide and thieno[3,4-c]pyrrole-4,6,dione acceptors on π-conjugated donor-acceptor-donor monomers: Experimental and theoretical investigations of photophysical and electrochemical properties(Tetrahedron, 2023-06-29) Çakal, Deniz; Demir Arabacı, Elif; Yıldırım, Erol; Cihaner, Atilla; Önal, Ahmet M.In this study, two novel donor-acceptor-donor monomers were synthesized by coupling a phthalimide (PI) acceptor unit with thiophene (T) and ethylenedioxythiophene (EDOT (E)) donor units. These two novel PI-based monomers, namely 2-(2-ethylhexyl)-4,7-di(thiophen-2-yl)isoindoline-1,3-dione (T-PI) and 4,7-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-2-(2-ethylhexyl)isoindoline-1,3-dione (E-PI), were fully characterized via UV-vis and fluorescence spectroscopy as well as electrochemical methods, and the results were directly compared with those of previously synthesized thieno[3,4-c]pyrrole-4,6-dione (TPD)-based analogues to report the results for four classes of monomers. In this regard, the effects of different donor groups and structural modifications in the acceptor unit as changed from PI to TPD have been investigated to reveal the precise effect of the donor and acceptor on the optical and electrochemical properties of the monomers. All monomers exhibits an intramolecular charge transfer band in the low energy region due to strong donor and acceptor interactions. The oxidation and reduction potentials of the monomers are found to vary depending on the strengths of both donor and acceptor units. PI-based monomers show more positive oxidation and less negative reduction potentials than TPD-based analogues. Similarly, thiophene-based analogues reveal the same trend in their oxidation and reduction potentials as compared to EDOT-based analogues. Lastly, PI-based monomers could not undergo polymerization via electrochemical method, unlike TPD-based monomers, since the dihedral angle arising between donor and PI acceptor disturbs molecular planarity significantly, as demonstrated by first principle calculations.Article Side Chain effect on the electrochemical and optical properties of TPD based donor acceptor donor type monomers and polymers(Molecular Systems Design and Engineering, 2023) Çakal, Deniz; Demir Arabacı, Elif; Yıldırım, Erol; Cihaner, Atilla; Önal, Ahmet M.In organic π-conjugated materials, side chains play great roles that are far beyond solubility. In this work, we mainly focused on the synthesis of new donor-acceptor-donor (D-A-D) type conjugated monomers and their corresponding polymers appending TPD acceptor with a new side chain, fluorene, to investigate the side chain effect. In this context, to reveal the precise effect of the side chains on the optical and electrochemical properties of the monomers and polymers synthesized in this work, four series of D-A-D monomers, each containing a TPD core unit with a different side chain, have been discussed in comparison to each other. Notably, it was discovered that TPD acceptor unit can be modified by any functional group other than common alkyl chains to impart new functionalities by keeping their superior optoelectronic properties. New kind of side chains can be used to tune the physical characteristics such as solubility, absorption, emission and molecular packing. In this paper, fluorene-appended monomers as a new class of D-A-D type π-conjugated molecules were studied and it was found that E(Fl) and P(Fl) exhibited resonable quantum yields and their corresponding polymers revealed ambipolar character with slightly lower band gap as compared to the previous analougs containing other side chains. Observed experimental results were elucidated by first principle calculations. In this paper, we discussed that using side chain engineering is an effective strategy to improve next-generation organic π-conjugated materials with the desired properties.thesis.listelement.badge SYNTHESIS AND CHARACTERIZATION OF A LOW BAND GAP POLYMER BASED ON SELENOPHENE AND BENZOBIS(THIADIAZOLE)(2022-02-24) Abdulrazzaq, Mohammed; Cihaner, AtillaA new derivative of benzobis(thiadiazole) based electron donor–acceptor–donor type monomers, namely 4,7-di(selenophen-2-yl)benzo[1,2-c;4,5-c']bis[1,2,5]thiadiazole (SeBTSe), was synthesized and its polymerization was carried out successfully via electrochemical polymerization in an electrolyte solution of 0.1 M tetrabutylammonium hexafluorophosphate dissolved in dichloromethane. The monomer SeBTSe is a deep red chromophore and it has four redox states: one oxidation, one neutral and two reduction states. The electrochemical behaviour of the corresponding polymer called PSeBTSe was studied by cyclic and differential pulse voltammetry. There is a good agreement between electrochemical (0.62-0.66 eV) and optical (0.63 eV) bandgaps of the polymer. Like the monomer, the ambipolar polymer has four redox states and electrochromic properties: gray beige at neutral state, smoky azurite at oxidized state, beige at first reduced state and dark beige at second reduced state.Article Synthesis and Characterization of A Luminol Based Chemiluminescent Trimeric System(Journal of Fluorescence, 2023-07) Kesimal, Büşra; Balcı, Burcu; Çakal, Deniz; Önal, Ahmet M.; Cihaner, AtillaA luminol based chemiluminescent trimeric system, namely 2,3-dihydro-5,8-di(thiophen-2-yl)phthalazine-1,4-dione (T2B-Lum), bearing thiophene rings as donor units and 2,3-dihydrophthalazine-1,4-dione as an acceptor unit was synthesized in two steps via donor-acceptor-donor approach using two different methods. It was found that T2B-Lum emits chemiluminescent light when exposed to H2O2 in a basic medium, and the presence of substituents and the type of aromatic ring bearing chemiluminescent active group have a direct effect on the compound's sensitivity. Among the members of a large family of metal ions, fluorescent and chemiluminescent T2B-Lum exhibited high sensitivity to Cu2+ and Fe3+ ions. Except for other metal cations (silver(I), cadmium(II), cobalt(II), iron(III), lithium(I), magnesium(II), manganese(II), nickel(II), zinc(II)), it has been observed that T2B-Lum is mostly sensitive to copper(II) ions with a detection limit value of 2.2×10-3 M. On the other hand, T2B-Lum was also found to exhibit a high sensitivity to extremely dilute aqueous solutions (e.g., 1:50.000 dilution) of blood samples, making it a promising candidate for use in forensic applications.thesis.listelement.badge SYNTHESIS AND CHARACTERIZATION OF HIGH SULFUR CONTENT POLYMERIC MATERIALS FROM FATTY ACIDS(2022-06-13) BERK, Hasan; Cihaner, AtillaAlthough elemental sulfur obtained from natural sources and petroleum refineries is widely available and inexpensive nontoxic material, it would be a significant advance to find productive uses for it in large scales. On the other hand, vegetable oils are expected to play a key role in polymer production from renewable resources in the future. In this study, a new series of high sulfur content polymers containing various amounts of fatty acids (oleic acid (OA), linoleic acid (LA) and linolenic acid (LnA)) was synthesized via inverse vulcanization method and characterized successfully. In particular, the effect of double bonds and free alkyl chains on polysulfur copolymers has been investigated systematically by using OA with one double bond, LA with two double bonds and LnA with three double bonds. Corresponding copolymers are soluble in common organic solvents, processable and electroactive. On the other hand, due to the presence of fatty acids in the polymer structure, the copolymers have reactive functional units (carboxylic group-COOH) and their chemical modifications with diol leads to the formation of ester linkages. This post polymerization results in the production of new polymers with high molecular weights. Finally, the usage of the copolymers was tested in the removal heavy metal ions (Palladium (II) and Mercury (II)). Results showed that the polymers can be potential material for use in heavy metal ion removal.thesis.listelement.badge SYNTHESIS OF CHEMILUMINESCENT COMPOUNDS AND THEIR USAGE IN METAL ION RECOGNITION AND BLOOD DETECTION(2022-06-13) BALCI, BURCU; Cihaner, AtillaLuminescent compounds have gained great importance recently due to their wide application areas. In addition, chemiluminescent compounds have been used for many studies in analytical chemistry due to their high luminescence sensitivity. In this thesis, a new series of chemiluminescent compounds, namely 5,8-di(furan-2-yl)-2,3- dihydrophthalazine-1,4-dione (F2B-Lum), 5,8-di(selenophene-2-yl)-2,3- dihydrophthalazine-1,4-dione (S2B-Lum) and 5,7-di(selenophen-2-yl)-2,3- dihydrothieno[3,4-d] pyridazine-1,4-dione (S2T-Lum), was synthesized via electron donor-acceptor-donor approach. Their structures were confirmed by using NMR, FTIR and HRMS techniques. Then, the chemiluminescence reactions of compounds with hydrogen peroxide in an alkaline solution (0.1 M NaOH(aq)) in the presence of different metal ions, hemin and blood samples were investigated and the results were compared with luminol. As expected, the compounds were sensitive to copper(II), iron(III) ions and blood. It can be easily concluded that the corresponding compounds as new derivatives of luminol are potential candidates for the detection of blood findings in forensic science. In addition, the sensitivity of the compounds to copper(II) ion makes them usable for copper ion recognition in analytical applications. Furthermore, cyclic voltammetry technique was used to investigate the redox behaviors of the compounds and they exhibited irreversible oxidation peaks. Also, reactive oxygen species can be detected by using these compounds via square wave potential method by applying an external potential of -1.05 V. Finally, among the compounds, S2T-Lum was successfully polymerized electrochemically. The corresponding polymer PS2T-Lum can be a precious member of luminol type polymers since it is electroactive and bears chemiluminescent active appendages in its polymeric structure.Article Synthesis, Characterization and Application of High Sulfur Content Polymeric Materials from Fatty Acids(Reactive and Functional Polymers, 2023-06) Berk, Hasan; Kaya, Murat; Topçuoğlu, Mert; Türkten, Nazlı; Karataş, Yunus; Cihaner, AtillaA new series of high sulfur content polymers containing various amounts of fatty acids (oleic acid (OA), linoleic acid (LA) and linolenic acid (LnA)) was synthesized via inverse vulcanization method and characterized successfully. In particular, the effect of double bonds and free alkyl chains on polysulfur copolymers has been investigated systematically by using OA with one double bond, LA with two double bonds and LnA with three double bonds. The copolymers with functional carboxylic acid groups are soluble in common organic solvents, processable and electroactive. Also, the usage of the copolymers was tested in the removal of methylene blue and as a cathode material in Li-S battery. Results showed that the polymers can be a potential material for use in dye removal.thesis.listelement.badge SYNTHESIZE AND PHOTOCATALYTIC APPLICATIONS OF TITANIUM DIOXIDE AND MAGNETIC NANOPARTICLES CONTAINING HIGH SULFUR CONTENT POLYMERIC COMPOSITES(2022-03-01) Topcuoğlu, Mert; Kaya, Murat; Cihaner, AtillaSulfur is one of the most abundant elements in nature. It is not toxic but is a flammable solid even though it is stored outdoors. Approximately 70 million tons of sulfur is obtained as a by-product from oil refineries every year but the use of this huge amount of sulfur is very limited. Therefore, it is very important to convert elemental sulfur into valuable products like polymers and ensure the use of large quantities in industry. In this study, the synthesis of new high sulfur polymeric materials using vegetable fatty acid and their usage as a support material in the preparation of photocatalyst for methylene blue removal is aimed. For this purpose, copolymerization of elemental sulfur and fatty acid, linolenic acid (LnA), was carried out by reverse vulcanization method. The photocatalytic activities of the prepared polysulfur copolymers were tested in the degradation of methylene blue under a solar simulator for comparison study. Then, polysulfur copolymer was prepared again by adding magnetic nanoparticles and titanium dioxide nanoparticles. The photocatalytic activity of the resulting composite material, poly(S-r-FA)-TiO2-MNP, was examined in the same reaction. Also, stability of the composite material was carried out. The characterization of the prepared materials was carried out using SEM, TEM, EDX, FTIR, and NMR. The decrease in dye concentration was followed by UV-Vis spectrometry.