38 results
Search Results
Now showing 1 - 10 of 38
Article Citation - WoS: 21Citation - Scopus: 21Synthesis and Properties of a Novel Redox Driven Chemiluminescent Material Built on a Terthienyl System(Pergamon-elsevier Science Ltd, 2009) Atilgan, Nurdan; Algi, Fatih; Onal, Ahmet M.; Cihaner, AtillaA novel redox driven chemiluminescent material built on a terthienyl system, namely 5,7-di-ethylenedioxythiophen-2-yl-2,3-dihydro-thieno[3,4-d]pyridazine-1,4-dione (ETE-Lum), which is soluble in both organic media and basic aqueous solution was synthesized and characterized. Furthermore, its polymer, PETE-Lum, which is one of the most rare examples of chemiluminescent polymeric materials bearing a pyridazine unit, was obtained successfully by electrochemical means. Both of the materials give chemiluminescence either by treatment with oxidants (H2O2 and/or KMnO4) or by the application of a potential pulse. (C) 2009 Elsevier Ltd. All rights reserved.Article Citation - WoS: 52Citation - Scopus: 57Members of Cmy Color Space: Cyan and Magenta Colored Polymers Based on Oxadiazole Acceptor Unit(Amer Chemical Soc, 2012) Ozkut, Merve Icli; Algi, Melek Pamuk; Oztas, Zahide; Algi, Fatih; Onal, Ahmet M.; Cihaner, AtillaIn this study, three novel oxadiazole-based polymers were synthesized and their electrochemical and optical properties were investigated. The polymers were found to have both p- and n-type doping properties accompanied by electrochromic response. Two polymer films exhibit cyan and magenta colors, which constitute two legs of CMY color spaces, in their neutral states and they are soluble in common-organic solvents. According to the color mixing theory, all colors in the visible spectrum including black color can be obtained by using these polymers with a yellow colored electrochromic polymer. Among these polymers, the polymer bearing propyledioxythiophene donor units has some superior properties like high stability (it retains 94% of its electroactivity after 2000 cycles), solubility, and high coloration efficiency (230 cm(2)/C), whereas as expected ethylenedioxythiophene containing one has the lowest band gap as 1.08 eV.Article Citation - WoS: 2Citation - Scopus: 3Impedance Spectroscopy of N-Substituted Oligo-Oxyethylene Polypyrrole Films(John Wiley & Sons inc, 2008) Cihaner, Atilla; Onal, Ahmet M.The electrochemical properties of neutral (dedoped) and oxidized (doped) poly(1,11-bis(1,1-pyrrole)-3,6,9-trioxaundecane) (poly-I) film electrodes were investigated using cyclic voltammetry and electrochemical impedance spectroscopy (EIS) techniques. Poly-I was deposited on glassy carbon electrode (GCE) from acetonitrile solution containing 5.0 x 10(-3) M 1,11-bis(1,1-pyrrole)-3,6,9-trioxaundecane (I) and 0.1 M LiClO4 supporting electrolyte. Doped poly-I exhibits a single semicircle in its complex-capacitance plots, indicating a single dominant ion transport process, together with high capacitance values. These features make this polymer film a candidate for an energy storage material. Also, poly-I can be a candidate as a sensory material for the detection of Ag+ based on impedance parameters. (C) 2008 Wiley Periodicals, Inc.Article Citation - WoS: 10Citation - Scopus: 10Synthesis and Electropolymerization of Donor-Acceptor Type Monomers Based on Azobenzene-Substituted Thieno[3,4-C]pyrrole Acceptors(Pergamon-elsevier Science Ltd, 2021) Cakal, Deniz; Cihaner, Atilla; Onal, Ahmet M.By using donor-acceptor-donor approach, a new series of photo responsive and electroactive trimeric monomers, namely (E)-5-(4-(phenyldiazenyl)phenyl)-1,3-di(thiophen-2-yl)-4H-thieno[3,4- c]pyrrole-4,6(5H)-dione (T-2-AB ), (E)-1,3-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-5-(4-(phenyldiazenyl)phenyl)- 4H-thieno[3,4-c]pyrrole-4,6(5H)-dione (E-2-AB ) and (E)-1,3-bis(3,3-didecyl-3,4-dihydro-2H-thieno[3,4- b][1,4]dioxepin-6-yl)-5-(4-(phenyldiazenyl)phenyl)-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione (P-2-AB ), was synthesized and characterized. The oxidation potential of the monomers was controlled by the strength of donor units and the following trend was observed for them: Eox (T-2-AB ) > E-ox (P-2-AB ) > E-ox (E-2-AB ). Also, a similar behavior was observed for their band gap values: 2.53 eV for T-2-AB , 2.18 eV for E-2-AB and 2.28 eV for P-2-AB . The monomers were polymerized successfully via electrochemical methods in order to give electrochromic ambipolar conjugated polymers bearing narrow optical band gaps: 1.71 eV, 1.54 eV and 1.68 eV for PT2-AB, PE2-AB , and PP2-AB, respectively. Also, the polymer films are stable and robust. Moreover, the three monomers and soluble PP(2-)AB polymer exhibited trans to cis photo-isomerization upon irradiation with UV light. In addition, the photoluminescence intensity of the monomers in toluene was found to decrease with increasing acid concentration, which makes them potential candidates to be amenable as pH sensors. (C) 2021 Elsevier Ltd. All rights reserved.Article Citation - WoS: 8Citation - Scopus: 8Electropolymerization and Ion Sensitivity of Chemiluminescent Thienyl Systems(Pergamon-elsevier Science Ltd, 2009) Asil, Demet; Cihaner, Atilla; Onal, Ahmet M.Redox driven chemiluminescent (CL) compounds based on thienyl and pyridazine systems, namely 2,3-dihydrothieno(3,4-d)pyridazine-1,4-dione (T-Lum) and 5,7-di-thiophen-2-yl-2,3-dihydrothieno[3,4-d]pyridazine-1,4-dione (TTT-Lum), were synthesized. Soluble compounds both in organic media and basic aqueous solution were found to give CL and electroluminescent (EL) reactions by the treatment of oxidants (H2O2 and KMnO4) and by an external potential pulse on the working electrode, respectively. Furthermore, the CL reaction can be speeded up by Fe3+ ion or blood samples. On the other hand, one of the compounds. TTT-Lum, can be polymerized successfully via electrochemically both in 0.1 M LiClO4/acetonitrile containing 5% of borontrifluoro diethylether (BF3-Et2O) and neat BF3-Et2O solution. The corresponding polymer film (PTTT-Lum) bearing CL units has a very stable and a well-defined reversible redox couple. Also, the electrochromic polymer film has a band gap of 1.74 eV and exhibits EL behavior. (C) 2009 Elsevier Ltd. All rights reserved.Article Synthesis and Characterization of a Luminol Based Chemiluminescent Trimeric System(Springer/plenum Publishers, 2023) Kesimal, Busra; Balci, Burcu; Cakal, Deniz; Onal, 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 x 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.Article Citation - WoS: 11Citation - Scopus: 11Electrochemical and Optical Properties of Substituted Phthalimide Based Monomers and Electrochemical Polymerization of 3,4-Ethylenedioxythiophene Oligomeric Silsesquioxane (poss) Analogue(Elsevier Sci Ltd, 2019) Cakal, Deniz; Ertan, Salih; Cihaner, Atilla; Onal, Ahmet M.A new series of donor-acceptor-donor type trimeric monomers bearing substituted phthalimide units as acceptor units and thiophene and 3,4-ethylenedioxythiophene (EDOT) as donor units was synthesized and characterized. The strength of acceptor units and intramolecular charge transfer between donor and acceptor units were investigated by using electrochemical and optical methods. The main advantage of phthalimide unit over other acceptor units is the ease of its functionalizability. Thus, utilizing this property, a phthalimide derivative (E2P-POSS) bearing polyhedral oligomeric silsesquioxane (POSS) cage was introduced successfully with EDOT and polymerized electrochemically. The corresponding electroactive polymer, PE2P-POSS, has a band gap of 1.72 eV and is an electrochromic polymer: gray when neutralized and eggplant purple when oxidized.Article Citation - WoS: 14Citation - Scopus: 12Electrochemical Synthesis of New Conjugated Polymers Based on Carbazole and Furan Units(Elsevier Science Sa, 2015) Oguzturk, H. Esra; Tirkes, Seha; Onal, Ahmet M.In this study, synthesis of four new monomers; 3,6-di(2-furyl)-9H-carbazole (M1), 3,6-di(2-furyl)-9-ethyl-carbazole (M2), 2,7-di(2-furyl)-9-H-carbazole (M3), 2,7-di(2-furyl)-9-(tridecan-7-yl)-9H-carbazole (M4), was achieved via Stifle cross-coupling reaction. The monomers were electrochemically polymerized, via repetitive cycling in acetonitrile-tetrabutylammonium hexafluorophosphate electrolytic medium. Optical and electrochemical properties of the monomers and their corresponding polymers were investigated and it was found that optical properties show slight variations depending on the connectivity between the carbazole and furan moieties. However, all the monomers synthesized in this work exhibited an irreversible oxidation peak at around 1.0 V. Electrochemically obtained polymer films, on the other hand, exhibited quasi-reversible redox behavior due to doping/dedoping of the polymers which was accompanied by a reversible electrochromic behavior. Their band gap values (E-g) were elucidated utilizing spectroelectrochemical data and it was found that polymers obtained from 2,7-substituted carbazole derivatives have slightly lower band gap values. Furthermore, scanning electron micrographs were used for morphological examinations. (C) 2015 Elsevier B.V. All rights reserved.Article Citation - WoS: 21Citation - Scopus: 21Synthesis and Electro-Optical Properties of New Conjugated Hybrid Polymers Based on Furan and Fluorene Units(Pergamon-elsevier Science Ltd, 2013) Gunes, Arzu; Cihaner, Atilla; Onal, Ahmet M.A novel series of hybrid monomers containing furan and fluorene units, namely 2-(2-(furan-2-yl)-9H-fluoren-7-yl)furan (FFF), 2,7-di(furan-2-yl)-9H-fluoren-9-one (FOF) and 2-(2-(furan-2-yl)-9,9-dihexyl-9H-fluoren-7-yl)furan (FHF), was synthesized and their electrochemical polymerization was achieved via potential cycling. Optical and electrochemical properties of the polymers, poly(2-(2-(furan-2-yl)9H-fluoren-7-yl)furan (PFFF), poly(2,7-di(furan-2-yl)-9H-fluoren-9-one) (PFOF) and poly(2-(2-(furan2-yl)-9,9-dihexyl-9H-fluoren-7-yl)furan) (PFHF), were investigated and it was found that polymer films exhibited quasi-reversible redox behavior (E-p(ox) =0.92V for PFFF, E-p(ox) = 1.08V for PFOF and E-p(ox) = 0.99V for PFHF) accompanied with a reversible electrochromic behavior, yellow to dark blue for PFFF, orange to green for PFOF and orange to green for PFHF. Their band gap values (E-g) were found to be 2.49, 2.32 and 2.61 eV for PFFF, PFOF and PFHF, respectively. (C) 2012 Elsevier Ltd. All rights reserved.Article Citation - WoS: 30Citation - Scopus: 32Effect of Fluorine Substituted Benzothiadiazole on Electro-Optical Properties of Donor-Acceptor Type Monomers and Their Polymers(Elsevier Sci Ltd, 2020) Cakal, Deniz; Ercan, Yunus Emre; Onal, Ahmet M.; Cihaner, AtillaA series of trimeric monomers bearing thiophene donor units and fluorinated analogues of benzothiadiazole acceptor units was synthesized via donor-acceptor-donor approach and polymerized electrochemically in order to investigate the effect of fluorine atom on electro-optical properties of both monomers and their corresponding polymers. All monomers exhibited solvatochromic and fluorescent properties. The introduction of fluorine atom into the conjugated backbone increased the oxidation potentials. Upon moving from nonfluorinated to fully fluorinated analogues, the oxidation potential shifts anodically from 1.30 V to 1.7 V. As in the case of monomers, the fluorine atom substitution also resulted in a decrease in the HOMO energy level of the corresponding polymers, leading to an increase in the electrochemical band gap energy (1.71-1.97 eV). This result can be attributed to deviations from planarity and also to decrease in the effective conjugation length. The polymeric film also exhibited electrochromic properties under various external potentials. Switching time and coloration efficiency values decreased with increasing number of fluorine atom substitution.
