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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.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: 1Electrochemistry of Acetate-, Carbonate-, Sulfate-, and Dihydrogenphosphate-Bridged Dirhodium(ii) Complexes(verlag Z Naturforsch, 2003) Yaman, SO; Önal, AM; Isci, HComplexes, [Rh-2(B-B)(4)L-2](n) (B-B = CH3CO2-, L = CH3CN, H2O, Cl-, Br-, SCN-; B-B CO32-, SO42-, H2PO4-, L = H2O, Cl-, Br-, SCN-) were prepared and their cyclic voltammograms (CV) and electronic absorption spectra were measured in solution. The CV of the complexes exhibits a reversible one-electron transfer from a metal-based orbital. Constant potential electrolysis at the oxidation peak potential of [Rh-2(O2CCH3)(4)(NCCH3)(2)] in acetonitrile yielded [Rh-2(O2CCH3)(4)(NCCH3)(2)](+), a mixed valent Rh(II)-Rh(III) cation complex. The formation of the mixed valent complex was monitored by measuring electronic absorption spectra of the solution in situ during the oxidative electrolysis. The reductive electrolysis of the mixed valent complex solution, in the same electrolysis cell, yielded the original electronic absorption spectrum of the starting complex. The changes in the oxidation and reduction potentials of the complexes with different axial ligands, L = H2O, Cl-, Br-, SCN-, are correlated to the relative energy changes of HOMO and LUMO of the complexes, which indicates the metal-axial ligand sigma- and pi-bonding interactions. Spectroscopic and CV data indicate that the degree of a-interaction is Cl- > Br- > SCN-, and that of pi-interaction is Br- > SCN- > Cl-.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: 7Citation - Scopus: 9Electrochemical Copolymerization of 2-Substituted Thiophene Derivative Linked by Polyether Bridge With Thiophene(Elsevier Science Sa, 2005) Cihaner, A; Önal, AMNew conducting copolymers have been synthesized via electrochemical oxidation of thiophene (Th) in the presence of monomer bis(2-thienyl)ethyl (1). Cyclic voltammetry (CV) studies showed that the presence of monomer I in the electrolytic solution greatly changes the CV behaviour of the formation of the polythiophene films. It is found that the increasing ratio of I was found to decrease electroactivity of copoly(I-Th). Electrochemical synthesis of copolymer films was achieved via constant potential electrolysis (CPE) in an electrolytic solution containing 0.1 M tetrabutylammonium hexafluorophosphate (TBAPF(6)) dissolved in CH3CN. Spectroelectrochemical (SPEL) properties of the films were investigated using UV-vis spectroscopic technique. (C) 2005 Elsevier B.V. All rights reserved.Article Citation - WoS: 28Citation - Scopus: 31Electrochemical Polymerization of 9-Fluorenone(Elsevier Science Sa, 2004) Cihaner, A; Tirkes, S; Önal, AMElectrochemical polymerization of 9-fluorenone, FO, was studied in CH2Cl2 solution with tetrabutylammonium tetrafluoroborate, TBABF(4), as the electrolyte, via constant potential electrolysis, CPE. Prior to CPE, the redox behavior of FO was investigated in the same solvent/electrolytic medium using cyclic voltammetry, CV. CPE of FO yielded an insoluble polymer deposit on the electrode surface. The product was characterized by FTIR spectroscopy techniques. The redox and spectroelectrochernical, SPEL, behavior of the polymer were studied by CV and in situ UV-Vis spectrophotometric techniques at various potentials, respectively. The conductivity was measured using a two-probe technique and the paramagnetic behavior of the polymer was monitored using in situ ESR spectroscopy. (C) 2004 Elsevier B.V. All rights reserved.Article Citation - WoS: 10Citation - Scopus: 10Electroinitiated Polymerization of 2-Allylphenol(Springer-verlag, 2000) Cihaner, A; Önal, AMRedox behaviour of 2-allylphenol (2APhOH) was studied by using cyclic voltammetry (CV) and electroinitiated polymerization was conducted at the measured peak potentials. Constant potential electrolysis (CPE) of the monomer was carried out in acetonitrile-sodium perchlorate, solvent-electrolyte couple, at room temperature. Polymerization of the monomer yielded insoluble polymer films on the surface of the electrode together with the low molecular weight polymers in the bulk of the solution. The structural analysis of the polymers were carried by H-1-NMR and FTIR spectroscopy. Molecular weight of the soluble polymer was determined by GPC. Thermal properties of the polymer film and soluble polymer were studied by DSC. The course of electroinitiated polymerization was monitored by in-situ UV-VIS spectroscopy.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: 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.
