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Atilim University,

Chemical Engineering and Applied Chemistry, ATOMSEL

Incek, Golbasi, 06836
Ankara-Turkey
Phone: +903125868304-8817
Fax: +903125868091
E-mail: cihaner@atilim.edu.tr

45. Soluble Alkyl Substituted Poly(3,4-Propylenedioxyselenophene)s: A New Platform For Optoelectronic Materials

Samed Atak, Merve Içli-Özkut, Ahmet M. Önal and Atilla Cihaner
Journal of Polymer Science Part A: Polymer Chemistry,49, 4398–4405 (2011)

Optical and electrochemical properties of regiosymmetric45.jpg and soluble alkylenedioxyselenophene-based electrochromic polymers, namely poly(3,3-dibutyl-3,4-dihydro-2H-seleno pheno [3,4-b][1,4]dioxephine) (PProDOS-C4), poly(3,3-dihexyl- 3,4-dihydro-2H-selenopheno[3,4-b][1,4]dioxephine) (PProDOS-C6), and poly(3,3-didecyl-3,4-dihydro-2H-selenopheno[3,4-b][1,4]dioxephine) (PProDOS-C10), are highlighted. It is noted that these unique polymers have low bandgaps (1.57–1.65 eV), and they are exceptionally stable under ambient atmospheric conditions. Polymer films retained 82–97% of their electroactivity after 5000 cycles. The percent transmittance of PProDOS-Cn (n ¼ 4, 6, 10) films found to be between 55 and 59%. Furthermore, these novel soluble PPro- DOS-Cn polymers showed electrochromic behavior: a color change form pure blue to highly transparent state in a low switching time (1.0 s) during oxidation with high coloration efficiencies (328–864 cm2C-1) when compared to their thiophene analogues.

 
44. A Blue to Highly Transmissive Soluble Electrochromic Polymer Based on poly(3,4-propylenedioxyselenophene) With A High Stability and Coloration Efficiency

Merve Içli-Özkut, Samed Atak, Ahmet M. Önal and Atilla Cihaner
Journal of Materials Chemistry, 21, 5268-5272 (2011)

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The optical and electrochemical properties of a regioregular and soluble alkylenedioxyselenophenebased electrochromic polymer, namely poly(3,3-didecyl-3,4-dihydro-2H-selenopheno[3,4-b][1,4] dioxepine (PProDOS-C10), which is synthesized by electrochemical polymerization, are highlighted. It is noted that this unique polymer has a low band gap (1.58 eV) and is exceptionally stable under ambient atmospheric conditions. Polymer films retain 97% of their electroactivity after 40 000 cycles. The percentage transmittance of a PProDOS-C10 film was found to be 56.4% at 638 nm and 55.8% at 700 nm. Furthermore, this novel soluble PProDOS-C10 polymer shows an electrochromic behavior: a color change from pure blue to a highly transparent state in a low switching time (1.0 s) during oxidation, with high coloration efficiencies (328 cm2C-1 at 638 nm and 319 cm2C-1 at 700 nm) when compared to its thiophene analogue.

 
43. Donor-Acceptor Polymer Electrochromes with Tunable Colors and Performance

Merve Içli, Melek Pamuk, Fatih Algi, Ahmet M. Önal and Atilla Cihaner
Chemistry of Materials, in press (2010)

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To demonstrate the effect of donor (D) and acceptor (A) units on the structure-property relationships of electrochromic polymers, design, synthesis, characterization and polymerization of a series of D-A type systems, 1-5, based on thiophene, 3,4-ethylenedioxythiophene, and 3,3-didecyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine as D units and 2,1,3-benzoselenadiazole, 2,1,3-benzothiadiazole and 2-decyl-2H-benzo[d][1,2,3]triazole as A units are highlighted. It is found that these units play key roles on the redox behavior, band gap, neutral state color and the electrochromic performance (stability, optical contrast, coloration efficiency, and switching time) of the system. It is noted that electropolymerization of these D-A systems provides processable low band gap electrochromes, P1-P5, exhibiting high redox stability, coloration efficiency, transmittance and/or contrast ratio and low response time. Furthermore, P1-P5 reflect various hues of blue and green pallets of the RGB color-space in the neutral state. In particular, it is noteworthy that P5 is an excellent blue-to-colorless polymeric electrochrome, which, to our best knowledge, exhibits the highest optical contrast and coloration efficiency among the D-A type systems. The panoramic breadth of the neutral state colors and intriguing features of these polymeric materials further confirm that D-A approach allows engineering tunable electrochromes which hold promise for commercialization of polymeric RGB electrochromics.

 
42. A New Soluble Neutral State Black Electrochromic Copolymer via A Donor–Acceptor Approach

Merve Içli, Melek Pamuk, Fatih Algi, Ahmet M. Önal and Atilla Cihaner
Organic Electronics,11, 1255-1260 (2010)

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Two donor–acceptor systems, 2-decyl-4,7-bis(3,3-didecyl-3,4-dihydro-2H-thieno[3,4- b][1,4]dioxepin-6-yl)-2H-benzo[d][1,2,3]triazole (1) and 4,7-bis(3,3-didecyl-3,4-dihydro- 2H-thieno[3,4-b][1,4]dioxepin-6-yl)-2,1,3-benzoselenadiazole (2) are explored in order to attain a low bandgap black polymer electrochrome, which is highly difficult to attain due to the complexity of designing such materials. Electrochemical polymerization of 1 and 2 in 1:4 monomer feed ratio was performed in a mixture of acetonitrile and dichloromethane solution containing 0.1 M tetrabutylammonium hexafluorophosphate. It was found that electropolymerization provides a processable neutral state black copolymer, (P(1-co-2)), which absorbs virtually the whole visible spectrum (400–800 nm). (P(1-co- 2)) is the first low bandgap (1.45 eV) electropolymerized material, which switches from black color (L = 14.3, a = 0.29, b = 0.35) in the neutral state to transmissive grey (L = 39.2, a = 0.29, b = 0.33) in the oxidized state with 15.3% of the transmittance change at 522 nm. Furthermore, it exhibits excellent operational and/or environmental stability under ambient conditions.

 
41. A Diverse-Stimuli Responsive Chemiluminescent Probe with Luminol Scaffold and Its Electropolymerization

Demet Asil, Atilla Cihaner, Fatih Algi and Ahmet M. Önal
Electroanalysis, in press (2010)

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A diverse-stimuli responsive chemiluminescent system, SNS-Lum, and its electropolymerization to give PSNS-Lum, which is the first example of conjugated polymers with pendant luminol arms inducing chemiluminescence in the presence of super oxide radical anion under neutral conditions, are highlighted.

 
40. Electrochromic Performance and Ion Sensitivity of A Terthienyl Based Fluorescent Polymer

Nurdan Atilgan, Atilla Cihaner and Ahmet M. Önal
Reactive and Functional Polymers, in press (2010)

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A novel terthienyl based fluorescent polymer bearing strong electron-withdrawing substituents directly attached to the 3,4-positions of the central thiophene ring was synthesized by electrochemical polymerization of diethyl 2,5-di(3,4-ethylenedioxythiophen-2-yl)thiophene-3,4-dicarboxylate. The corresponding polymer was characterized by cyclic voltammetry, FT-IR and UV–vis spectroscopy. The polymer has a well-defined redox process (Ep,1/2 = 0.74 V) and demonstrates a reversible electrochromic behavior; lilac in the neutral state and transparent sky blue in the oxidized state. Also, the polymer had low band gap (Eg = 1.82 eV) and high redox stability (retaining 94.0% of its electro-activity after 500th switch). Moreover, the sensitivity of both the monomer and its polymer towards metal cations was investigated by monitoring the change in the fluorescence intensity. Among various common ions both the monomer and its polymer were found to be selective towards Cu+2 and Cu+ ions by quenching the fluorescence efficiency with a Stern–Volmer constant (Ksv) of (1.4–1.6x103 M-1) and (1.5–1.8x102 M-1) for monomer and polymer solutions, respectively.

 
39. A New Low-Voltage-Driven Ambipolar Donor-Acceptor Type Polymer and Its Electrochromic Properties

Melek Pamuk, Seha Tirkes, Atilla Cihaner and Fatih Algi
Polymer, 51, 62-68 (2010)

39.jpgDesign, synthesis, and properties of a novel donor-acceptor-donor type low-voltage-driven green polymeric electrochrome, P1, which is based on 8-(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-11-(2,3-dihydrothieno[3,4-b][1,4]dioxin-7-yl)acenaphtho[1,2-b]quinoxaline (1) are highlighted. It is noted that P1 has an ambipolar (n- and p-doping processes) character in 0.1 M tetrabutylammonium hexafluorophosphate/ dichloromethane solution and switches to a transmissive blue state upon oxidation. Furthermore, this new polymeric electrochromic candidate exhibits high redox stability, high coloration efficiency and/or contrast ratio, high percent transmittance (%T) and low response time (1.0 s) with a band gap of 1.10 eV– 1.25 eV.

 
38. Electrochemical and Optical Properties of Azo Dye Based Conducting Copolymer

Atilla Cihaner and Fatih Algi
Turkish Journal of Chemistry, 33, 759-767 (2009)

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The electrochemical and optical properties of a novel conducting copolymer called poly(2,5-dimethyl-[4-(2,5-di-thiophen-2-yl-pyrrol-1-yl)-phenyl]azobenzene-co-(3,4-ethylenedioxythiophene)) (poly(1-co-EDOT)) are reported. Electrochemically synthesized poly(1-co-EDOT) based on the azo dye has a well-defined and reversible redox couple (0.37 V vs. Ag/AgCl) with good cycle stability. The copolymer film exhibits high conductivity (13 S/cm) as well as electrochromic behavior (magenta when neutralized and transmissive sky blue when oxidized). Furthermore, electro-optically active copolymer film has a low band gap of 1.79 eV with a pi-pi* transition at 555 nm.

 
37. Electropolymerization and Ion Sensitivity of Chemiluminescent Thienyl Systems

Demet Asil, Atilla Cihaner and Ahmet M. Önal
Electrochimica Acta, 54, 6740-6746 (2009)

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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 Fe+3 ion or blood samples. On the other hand, one of the compounds, TTT-Lum, can be polymerized successfully via electrochemically both in 0.1MLiClO4/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.

 
36. The Synthesis, Characterization and Energy Transfer Efficiency of a Dithienylpyrrole and BODIPY Based Donor-Acceptor System

Taner Atalar, Atilla Cihaner and Fatih Algi
Turkish Journal of Chemistry, 33, 313-319 (2009)

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A dithienylpyrrole-BODIPY based donor-acceptor system with 1,4-phenylene spacer as a model system for energy transfer was designed and synthesized. Absorption and emission spectra have revealed an efficient resonance energy transfer from dithienylpyrrole as donor to BODIPY as acceptor.

 
35. Synthesis and Properties of a Novel Redox Driven Chemiluminescent Material Built on Terthienyl System

Nurdan Atilgan, Fatih Algi, Ahmet M. Önal and Atilla Cihaner
Tetrahedron, 65, 5776–5781 (2009)

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A 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.

 
34. Template-free Microsphere and Hollow Sphere Formation of Polymethylanilines

Merve Içli, Ahmet M. Önal and Atilla Cihaner
Polymer International, 58, 674-679 (2009)

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Microsphere and-or hollow sphere formation of methyl-substituted polyaniline derivatives was investigated via chemical polymerization where different sets of conditions were examined. It was found that a variety of parameters (e.g. types and concentrations of monomer and oxidant, polymerization time, solventwith andwithout acid) have a crucial influence on themorphology of the resulting polyaniline derivatives.

 
33. An Ambipolar Neutral State Green Polymeric Electrochromic

Fatih Algi and Atilla Cihaner
Organic Electronics, 10, 704-710 (2009)

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The synthesis and properties of highly stable neutral state green polymeric electrochromic, P1, which is based on 5,8-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-2,3-di(1H-pyrrol- 2-yl)quinoxaline were highlighted. P1 exhibits three well-defined absorption bands with a narrow band gap (1.17 eV). The n- and p-doping (ambipolar) processes suggest that P1 is one of the most promising neutral state green polymers and it can be used in supercapacitors as either cathode or anode electrode material. Apart from the stability and the robustness of the polymer film, P1 shows multi-electrochromic behavior; gray-purple in the reduced form and highly transmissive blue color in the oxidized state.

 
32. An Ambipolar Low Band Gap Material Based on BODIPY and EDOT

Fatih Algi and Atilla Cihaner
Organic Electronics, 10, 453-458 (2009)

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A novel donor–acceptor type conducting polymer based on BODIPY dye as acceptor and EDOT units as donor parts is synthesized electrochemically. The unique combination of BODIPY and EDOT units provides an ambipolar (n- and p-doping processes) low band gap material (4). This is the first example of p–n junction in an organic p-conjugated material where BODIPY unit is incorporated directly in the main chain. Furthermore, the polymer film exhibits electrochromic behavior upon p-doping: a color change from light violet (neutral) to indigo (oxidized).

 
31. Synthesis and Properties of 4,4-Difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-Based Conducting Copolymers

Atilla Cihaner and Fatih Algi
Reactive and Functional Polymers, 69, 62-67 (2009)

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The synthesis, characterization and engineering of a novel polymer based on a unique combination of 1,3,5,7-tetramethyl-8-(4-nitro-phenyl)-2,6-bis(2-thienyl)-4,4-difluoroboradiazaindacene and 3,4-ethylenedioxythiophene are highlighted. It was found that the polymer represents an environmentally robust electroactive material bearing high stability, well-defined quasi-reversible redox couple, and fast response time between redox states as well as high coloration efficiency.

 
30. Electrochemical and Optical Properties of New Soluble Dithienylpyrroles Based on Azo Dyes

Atilla Cihaner and Fatih Algi
Electrochimica Acta, 54, 1702-1709 (2009)

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Two dithienylpyrroles based on azo dyes, namely 2,5-dimethyl-[4-(2,5-di-thiophen-2-yl-pyrrol- 1-yl)-phenyl]azobenzene (SNS-AB2) and 2,5-dimethyloxy-[4-(2,5-di-thiophen-2-yl-pyrrol-1-yl)- phenyl]azobenzene (SNS-AB3), were synthesized and their corresponding polymers (PSNS-AB2 and PSNS-AB3) were successfully obtained via electropolymerization. The monomers have lower oxidation potentials (0.75 V and 0.80 V vs. Ag/AgCl for SNS-AB2 and SNS-AB3, respectively) when compared to their analogous. Both monomers exhibited photoisomerism properties under irradiation at 360 nm. During the irradiation process, for example, the color of SNS-AB3 changes from yellow to greenish yellow. The electroactive polymer films have well defined and reversible redox couples with a good cycle stability in both aqueous and organic solutions. The polymer films also exhibited electrochromic behaviors; color changes from yellowish green to dark green for the PSNS-AB2 (435 nm and Eg = 2.31 eV) and from mustard color to green for PSNS-AB3 (430 nm and Eg = 2.34 eV). Furthermore, the soluble polymers demonstrated different hues of yellow and green colors.

 
29. A Glow in the Dark: Synthesis and Electropolymerization of a Novel Chemiluminescent Terthienyl System

Demet Asil, Atilla Cihaner and Ahmet M. Önal
Chemical Communications, 3, 307-309 (2009)

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The synthesis and characterization of a unique (electro)-chemiluminescent monomer based on a terthienyl system, and its corresponding polymer which is the first example of an electro-active chemiluminescent polymer bearing a pyridazine appendage, are described.

 
28. A Novel Electrochromic and Fluorescent Polythienylpyrrole Bearing 1,1-Bipyrrole

Atilla Cihaner, Olcay Mert and Ayhan S. Demir
Electrochimica Acta, 54, 1333-1338 (2009)

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A novel conducting polymer was successfully synthesized via electropolymerization of 1-(1H-pyrrol-1-yl)-2,5-di(thiophen-2-yl)-1H-pyrrole. The electrochemical and electro-optical properties of the corresponding polymer, which was the first example of polymer containing 1,1-bipyrrole units, were elaborated using electroanalytical and spectroscopic techniques. Cyclic voltammograms and electrooptical studies showed that the polymer has a stable and well-defined reversible redox process as well as electrochromic behavior. The processable polymer film also possessed a yellowish orange light emitter property.

 
27. A Novel Neutral State Green Polymeric Electrochromic with Superior n- and p-doping Processes: Closer to Red-Blue-Green (RGB) Display Realization

Atilla Cihaner and Fatih Algi
Advanced Functional Materials, 22, 3583-3589 (2008)

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Two donor-acceptor systems, 4,7-di-2-thienyl-2,1,3-benzoselenadiazole (TSeT) and 4,7-di-2,3-dihydrothieno[3,4-b][1,4]dioxin-5- yl-2,1,3-benzoselenadiazole (ESeE) are synthesized and electropolymerized to give polymers PTSeT and PESeE, respectively. One of the polymers, PTSeT, is blue-green in the neutral state and soluble, exhibiting a deep-red emission color. The other, PESeE, is the first 2,1,3-benzoselenadiazole-based neutral state green polymer with a narrow bandgap (1.04 eV). Furthermore, PESeE has superior and durable n- and p-doping processes. Beyond the stability and the robustness, both of the polymer films exhibit multi-electrochromic behavior.

 
26. Processable Electrochromic and Fluorescent Polymers Based on N-Substituted Thienylpyrrole

Atilla Cihaner and Fatih Algi
Electrochimica Acta, 54, 665-670 (2008)

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A new series of processable conducting polymers based on thienylpyrrole was synthesized by electrochemical polymerization of 1-(1-naphthyl)-2,5-di(thiophen-2-yl)-1H-pyrrole, 1-(2-naphthyl)-2,5- di(thiophen-2-yl)-1H-pyrrole, 1-(9H-fluoren-2-yl)-2,5-di(thiophen-2-yl)-1H-pyrrole and 1-(benzo-15- crown-5)-2,5-di(thiophen-2-yl)-1H-pyrrole. The corresponding polymers have very well-defined and reversible redox processes in both organic and aqueous solutions. Furthermore, they exhibit multielectrochromic behavior: yellow in the neutral state, green and blue in the intermediate state and violet in the oxidized state. The polymer products are soluble in organic solvents and all of them are fluorescent.

 
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