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Article Citation - WoS: 5Citation - Scopus: 5Electrochemical Polymerization of Para-Substituted Haloanilines(Taylor & Francis inc, 2006) Cihaner, A; Önal, AMPolyhaloanilines: poly(4-fluoroaniline) (P4FAN), poly(4-chloroaniline) (P4CAN), and poly(4-bromoaniline) (P4BAN), are synthesized from para-substituted haloaniline monomers; 4-fluoroaniline (4FAN), 4-chloroaniline (4CAN), and 4-bromoaniline (4BAN), respectively, via constant potential electrolysis (CPE) in acetonitrile-water mixture (1:1 v/v) with NaClO4 as supporting electrolyte. Prior to CPE, electrochemical behavior of the monomers were investigated in organic medium utilizing cyclic voltammetry (CV). The course of CPE was monitored using in-situ UV-VIS spectroscopic technique. Characterization of polymer products have been carried out using FT-IR and NMR spectroscopic techniques and thermal behaviors were studied using differential scanning calorimeter (DSC). Polyhaloanilines synthesized by electrochemical oxidation were doped using iodine and the change in the paramagnetic behavior was monitored by ESR, UV-VIS, and FT-IR.Article Citation - WoS: 14Citation - Scopus: 19Electrochemistry of nickel(II) complexes with N,N'-bis(3,5-di-tert-butylsalicylidene)polymethylenediamines(Pergamon-elsevier Science Ltd, 2005) Özalp-Yaman, S; Kasumov, VT; Önal, AMThe electrochemical oxidation of several N,N'-polymethylenebis(3,5-di-tert- butylsalicylaldiminato)nickel(II) complexes, Ni(L-x), has been studied by cyclic voltammetry and in situ UV-Vis spectroscopy in DMF Cyclic voltammograms of Ni(L-x) (x = 1-4) complexes displayed two-step oxidation processes under nitrogen gas atmosphere. The first oxidation peak potentials of all the Ni(II) complexes corresponds to the reversible one-electron oxidation process of the metal center, yielding Ni(III) species. EPR spectrum of the electrolysis solution was recorded after one electron transfer at liquid nitrogen temperature also confirms the formation of [Ni-III (L-3)](+) species (g(x) > g(y) > g(z)) with a (2)A(1)(d(z)(2))(1) ground state. Upon addition of pyridine to one electron oxidised solutions a new penta coordinated species, [Ni-III(L-3)Py](+) (g(perpendicular to) > g(parallel to), a(parallel to)(N-14) = 8 G), was produced. The second oxidation peak of the complexes was assigned as the ligand based oxidation, generating a coordinated phenoxy radical species. (c) 2005 Elsevier Ltd. All rights reserved.Article Citation - WoS: 5Citation - Scopus: 5Electrochemical Polymerization of 4-Allylanisole(Pergamon-elsevier Science Ltd, 2001) Cihaner, A; Testereci, HN; Önal, AMElectrochemical polymerization of 3-allylanisole (4AA). via constant potential electrolysis, has been investigated in acetonitrile using two different supporting electrolytes. Redox behavior of the monomer was also studied in the same solvent-electrolyte couples at room temperature. Electrochemical polymerization of the monomer yielded insoluble polymer films on the electrode surface, which bears a very low conductivity, together with the low molecular weight polymers in the bulk of the solution. The decrease in the monomer concentration, during the electrochemical polymerization. was monitored by taking the cyclic voltammogram of the electrolysis solution. The effect of temperature on the rate of electrochemical polymerization was: also studied. The polymers were characterized by taking the H-1-NMR and FTIR spectra. Molecular weight of the soluble polymer was determined by vapor pressure osmometry. Thermal analysis of the polymer film and soluble polymer were done by DSC. (C) 2001 Elsevier Science Ltd. All rights reserved.Article Citation - WoS: 13Electrochemical and Quantum Chemical Studies on Mitomycin and Adriamycin(Elsevier, 2003) Özalp-Yaman, S; Önal, AM; Türker, LIn-situ spectroelectrochemical redox behaviour of two prominent chemotherapeutic agents, mitomycin and adriamycin were studied at constant potential. AM 1 (UHF) type quantum chemical calculations on the neutral as well as radical anion and cation forms of mitomycin and adriamycin were performed. (C) 2003 Elsevier Science B.V. All rights reserved.Article Citation - WoS: 20Citation - Scopus: 21Electrochemical Behaviour and Electrochemical Polymerization of Fluoro-Substituted Anilines(Wiley, 2002) Cihaner, A; Önal, AMThe electrochemical behaviour of three fluoro-substituted aniline monomers, 2-fluoroaniline (2FAN), 3-fluoroaniline (3FAN) and 4-fluoroaniline (4FAN), was investigated in aqueous acidic and organic media by means of cyclic voltammetry (CV) studies. Constant potential electrolysis (CPE) of the monomers in acetonitrile-water mixture (1: 1 by volume) using NaClO4 as supporting electrolyte yielded soluble polymers. The mechanism of electrochemical polymerization was investigated using in situ electron spin resonance (ESR) and in situ UV-VIS spectroscopic techniques for one of the monomers (4FAN). Both CV and in situ LTV-VIS measurements indicated that the polymers obtained are in the emeraldine base form. In situ ESR studies indicated that electrochemical polymerization involves a radical-cation as an intermediate. Characterization of polymer products have been carried out using FTIR and NMR spectroscopic techniques, and thermal behaviour was studied using differential scanning calorimetry (DSC). It was found that conductivity can be imparted to assynthesized polyfluoroanilines via iodine doping. (C) 2002 Society of Chemical Industry.Article Citation - WoS: 6Citation - Scopus: 5Synthesis of a regular polymer containing pseudo-polyether cages(Elsevier Science Sa, 2005) Cihaner, A; Önal, AMA new compound consisting of 2-thienyl units linked by polyether bridge has been synthesized and its electrochemical polymerization was performed via constant potential electrolysis (CPE) in an electrolytic solution containing 0.1 M tetrabutylammonium hexafluorophosphate (TBAPF(6)) dissolved in CH3CN. Chemical polymerization was carried out using FeCl3 as oxidizing agent. It is found that both methods gave the same polymer product without any cleavage of the polyether bridge between thiophene (Th) rings. Although as synthesized polymers exhibited no conductivity, they gain conductivity via chemical doping using 12 vapor exposure. The polymers were characterized using FTIR spectroscopic technique and 12 doping was monitored using in-situ electron spin resonance (ESR) spectroscopy. Thermal behavior of electrochemically prepared polymer was investigated using differential scanning calorimetry, DSC and thermogravimetric analysis, TGA. (c) 2005 Elsevier B.V. All rights reserved.Article Citation - WoS: 1Citation - Scopus: 1Spectroelectrochemical Investigation of the Anodic Oxidation of Dibenzo-18(Elsevier Science Sa, 2004) Cihaner, A; Önal, AMPoly(dibenzo-18-crown-6) (poly-DB18C6) was synthesized by electrochemical oxidation of dibenzo-18-crown-6 (DB18C6) using a mixture of acetonitrile and dichloromethane as the solvent and tetrabutylammonium tetrafluoroborate (TBABF(4)) or tetrabutylammonium hexafluorophosphate (TBAPF(6)) as supporting electrolyte. The anodic polymerization of DB18C6 was investigated using in situ ESR and in situ UV-Vis spectroscopic techniques. Spectroelectrochemical (SPEL), properties and thermal analysis of the resulting polymers have been investigated using UV-Vis spectroscopy, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). (C) 2004 Elsevier B.V. All rights reserved.Article Citation - WoS: 4Citation - Scopus: 4Electrical, Optical and Photoconductive Properties of Poly(dibenzo-18(Wiley-v C H verlag Gmbh, 2004) Qasrawi, AF; Cihaner, A; Önal, AMTo investigate the energy levels, absorption bands, band gap, dominant transport mechanisms, recombination mechanisms and the free carrier life time behavior of poly-dibenzo-18-crown-6, poly-DB18C6, films, the dark electrical conductivity in the temperature range of 200-550 K, the absorbance and photocurrent spectra, the photocurrent -illumination intensity and time dependence at 300 K were studied. The dark electrical conductivity measurements revealed the existence of three energy levels located at 0.93, 0.32 and 0.76 eV below the tails of the conduction band. The main transport mechanism in the dark was found to be due to the thermal excitation of charge carriers and the variable range hopping above and below 260 K, respectively. The photocurrent and absorbance spectra reflect a band gap of 3.9 eV. The photocurrent -illumination intensity dependence reflects the sublinear, linear and supralinear characters indicating the decrease, remaining constant and increase in the free electron life time that in turn show the bimolecular, strong and very strong recombination characters at the surface under the application of low, moderate and high illumination intensity, respectively. A response time of 25.6 s was calculated from the decay Of I-ph-time dependence. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.Article Citation - WoS: 34Synthesis and Characterization of Fluorine-Substituted Polyanilines(Pergamon-elsevier Science Ltd, 2001) Cihaner, A; Önal, AMPoly(2-fluoroaniline), P2FAN, poly(3-fluoroaniline). P3FAN. and poly(4-fluoroaniline), P4FAN, have been synthesized from fluorine substituted aniline monomers in aqueous acidic medium using potassium dichromate as oxidizing agent. Characterization of polymer products has been carried out using FTIR, and NMR spectroscopic techniques. Thermal analysis of polyfluoroaniline powders was also investigated using differential scanning calorimetry and thermogravimetric analysis. To compare the structural properties of the polymers, polyfluoroanilines were also synthesized using ammonium peroxydisulfate as oxidizing agent. Polyfluoroanilines synthesized by chemical oxidation were doped by using iodine and the change in the paramagnetic behavior was monitored by electron spin resonance spectroscopy. (C) 2001 Elsevier Science Ltd. All rights reserved.Article Citation - WoS: 2Spectroelectrochemical Investigation of Pentacarbonyl(pyrazine)metal(0) (metal = Cr, Mo, W) Complexes of Group 6 Elements(Walter de Gruyter Gmbh, 2002) Yaman, SO; Esentürk, E; Kayran, C; Önal, AMThe electrochemical behaviour of pentacarbony l(pyrazine) metal (0) complexes of the group 6 elements was studied by cyclic voltammetry in dichloromethane-(n-Bu)(4)NBF4 solvent-electrolyte couple at -20 degreesC vs. Ag/Ag+ or SCE reference electrode. Constant potential electrolyses of the complexes were carried out at their first oxidation peak potentials and monitored in situ by UV-Vis spectrometry. Electrolysis of W(CO)(5)pz produces [W(CO)(5)pz](+) and a similar electrochemical mechanism is expected both for Cr(CO)(5)pz and Mo(CO)(5)pz complexes. In situ low temperature constant current ESR electrolysis also confirmed the production of [W(CO)(5)pz](+) after the electron transfer.
