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Öğe Determination of free radical on polycrystal of 4,4 '-bis(chloroacetyl)diphenylether: An ESR study(ELSEVIER SCIENCE BV, 2013) Ceylan, Yusuf; Usta, Ayhan; Usta, Keziban; Durmaz, Fatih; Coskun, Ahmet4,4'-Bis(chloroacetyl)diphenylether was synthesized and its polycrystal form was produced. This polycrystal sample was irradiated by gamma rays (Co-60) for 72 h. The ESR method was used to observe formation of free radical on the sample. ESR signal was not recorded from the non-irradiated sample, but the irradiated polycrystal sample exhibited complex ESR spectra. The measurements were carried out in the temperature range of 120-450 K. It was observed that the shape of the spectrum was dependent on the temperature. Two identical radicals were determined on the irradiated sample. Respectively, the spin density, hyperfine, and g values were found to be rho(Ha) = 0.53, rho(Hb) = 0.23, a(Cl) = 1.263 mT, a(Ha) = 1.486 mT, a(Hb) = 0.637 mT, and g(1) = 2.0115 for the Radical rho(Hx) = 0.22, rho(Hy) = 0.14, a(Cl) = 0.905 mT, a(Hx) = 0.615 mT, a(Hy) = 0.391 mT, and g(2) = 2.0383 for the Radical II. (C) 2013 Elsevier B.V. All rights reserved.Öğe Facilitated Proton Transfer by a Novel 2-Aminothiazole Derivative Across the Water/1,2-Dichloroethane Interface(SPRINGER/PLENUM PUBLISHERS, 2011) Bingol, Haluk; Coskun, AhmetThe behavior of proton transfer facilitated by a novel thiazole derivative, N-methyl-4-(4-phenoxyphenyl)thiazol-2-amine (MPPT), across the water/1,2-dichloroethane (1,2-DCE) interface was investigated electrochemically. The ionic partition diagram for MPPT was obtained from interpretation of the cyclic voltammograms. The apparent partition coefficient of MPPT was evaluated by the shaking-flask method under experimental conditions, while that for the protonated form of MPPT was calculated from its transfer potential obtained from the ionic partition diagram. It was suggested that the mechanism for transfer of MPPT across the water/1,2-DCE) interface depends on the pH of the aqueous phase. The parameters of the facilitated proton transfer across the water/1,2-DCE interface were evaluated as a quantitative measure of its lipophilicity.Öğe The Novel Triazine Cored Tripodal and Trinuclear Schiff Base-Oxime Metal Complexes: Their Magnetic Properties and Thermal Decompositions(WILEY, 2011) Uysal, Saban; Coskun, Ahmet2,4,6-tris(4-hydroxybenzimino)-1,3,5-triazine [ 1,2] (III) have been synthesized by the reaction of 1 equiv melamine and three equiv 4-hydroxybenzaldehyde, and characterized by means of elemental analysis, H-1-NMR (nuclear magnetic resonance spectroscopy), Fourier transform infrared (FTIR) spectrscopy, liquid chromatography-mass spectroscopy (LC-MS). L (IV) has been synthesized by the reaction of one equiv (III) and three equiv 4-(thiophenoxy) phenyloxylohydroxymoyl chloride (II), and characterized by means of the same methods. Then, four novel trinuclear Fe(III) and Cr(III) complexes involving tetradentate Schiff bases N,N'-bis(salicylidene)ethylenediamine-(salenH(2)) or bis(salicylidene)-o-phenylenediamine-(salophen H-2) with L (IV) have been synthesized and characterized by means of elemental analysis, FTIR spectrscopy, LC-MS, thermal analyses. The metal ratios of the prepared complexes have been determined using AAS. The aim of the present study is synthesis of novel tridirectional-trinuclear systems and to present their effects on magnetic behavior of [salenFe(III)], [salophenFe(III)], [salenCr(III)], and [salophenCr(III)] capped complexes. The complexes have also been characterized as low-spin distorted octahedral Fe(III) and Cr(III) bridged by keton-oxime group.Öğe Oxidation of some alkoxy-cycloheptatriene derivatives: unusual formation of furan and furanoids from cycloheptatrienes(PERGAMON-ELSEVIER SCIENCE LTD, 2007) Coskun, Ahmet; Guney, Murat; Dastan, Arif; Balci, MetinThe oxidation of some alkoxy tropone and tropone ketal derivatives with singlet oxygen and m-chloroperbenzoic acid was investigated. In most cases furan and furanoid derivatives were isolated. The structures of the formed products were determined by means of spectral data and the formation mechanism of these unusual products is discussed. (c) 2007 Elsevier Ltd. All rights reserved.Öğe Spectrophotometric and electrochemical behavior of a novel azocalix[4]arene derivative as a highly selective chromogenic chemosensor for Cr+3(PERGAMON-ELSEVIER SCIENCE LTD, 2011) Bingol, Haluk; Kocabas, Erdal; Zor, Erhan; Coskun, AhmetIn this study, a novel azocalix[4]arene derivative, 5,11,17-tris[(1-naphtyl)azo]-25,26,27,28-tetrahydroxycalix[4]arene (NAC4) bearing napthyl groups on the upper rim was synthesized. Its complexation behavior for alkali, alkaline-earth and various heavy metal ions (Li+, Na+, K+, Rb+, Cs+, Mg2+, Ca2+, Sr2+, Ba2+, Pb2+, Hg2+, Ni2+, Cd2+, Cu2+, Zn2+, Co2+, Fe2+, Cr3+, Ag+) was investigated by spectroscopic and voltammetric methods. This chemosensor exhibits decreased absorbance in the presence of Hg2+ and a unique absorbance quenching effect only for Cr3+. In addition, a new absorption band centered at 565 nm with the formation of the 1:1 host-guest complex (Cr3+-NAC4) was observed in the case of Cr3+, leading to an obvious color change from light orange to dark lilac. In voltammetric experiments, Cr3+ ions decreased voltammetric peaks of NAC4, whereas no significant changes occurred in the presence of the other metal ions. The Benesi-Hildebrand method was used to determine a logarithmic value of 3.76 for the association constant of the complex between Cr3+ and NAC4. (C) 2010 Elsevier Ltd. All rights reserved.Öğe Synthesis and characterization of 4-(alkylaminoisonitrosoacetyl) diphenyl ether and some of their metal complexes(SCIENTIFIC TECHNICAL RESEARCH COUNCIL TURKEY-TUBITAK, 2008) Coskun, Ahmet; Yilmaz, Funda4-(Chloroacetyl) diphenyl ether ( I) was synthesized from chloroacetyl chloride and diphenyl ether in the presence of AlCl3 as catalyst in a Friedel-Crafts reaction. Subsequently, its keto oxime (II) derivative was prepared. Then 3 new substituted 4-(alkylaminoisonitrosoacetyl) diphenyl ether ligands derived from 4-(phenoxy) phenyloxylohydroxymoyl chloride and corresponding amines were synthesized. The following aromatic and aliphatic amines were used for the ligands ethanolamine, 2-amino-4- methylphenol, and 2(aminomethyl) pyridine. Mononuclear or binuclear Co(II), Ni(II), Cu(II), and Cd(II) complexes of the ligands were synthesized. The structures of these ligands were identified by FT-IR, H-1-NMR, and C-13-NMR spectral data and elemental analysis, and the structures of the complexes were identified by FT-IR, ICP-AES, elemental analysis, and magnetic susceptibility measurements.Öğe Synthesis and characterization of a new dioxime and its heterotrinuclear BF(2)(+) capped complexes(TAYLOR & FRANCIS INC, 2008) Uysal, Saban; Coskun, Ahmet; Koc, Ziya Erdem; Ucan, H. Ismetomega-Isonitrosoacetophenone (1), phenylglyoxime (2), chlorophenylglyoxime (1), dopaminophenylglyoxime (3) and [(salen/saloph)Fe](2)O (4) have been synthesized as described in the literature procedure. [Fe(III)(salen/saloph)dopaminophenylglyoxime)] (starting complexes) have been synthesized from dopaminophenylglyoxime and tetradentate schiff bases which contain dinuclear Fe(III) oxygen-bridges N,N'-bis(salicylidene)ethylenediamine (salenH(2)) and bis(salicylidene)-o-phenylenediamine (salophH(2)). The new heterotrinuclear complexes have been obtained from starting complexes and Co(II), Ni(II), Cu(II) salts. Then, heterotrinuclear vic-dioxime complexes containing BF(2)(+) capped have been synthesized. The complexes have been characterized as low-spin distorted octahedral Fe(III) bridged by o-hydroxyphenolic groups. The o-hydroxyphenolic groups play a role as bridges for weak antiferromagnetic intramolecular exchange. The structure of dioxime and its complexes were identified by using elemental analysis, ICP-AES, (1)H-NMR and IR spectral data.Öğe The synthesis of 4-phenoxyphenylglyoxime and 4,4 '-oxybis(phenylglyoxime) and their complexes with Cu(II), Ni(II) and Co(II)(SCIENTIFIC TECHNICAL RESEARCH COUNCIL TURKEY-TUBITAK, 2006) Coskun, Ahmet4-Acetyldiphenyl ether and 4,4'-diacetyldiphenyl ether were synthesized from diphenyl ether and acetyl chloride in the presence of AlCl3 used as catalyst. Subsequently, their keto oxime and glyoxime derivatives were prepared. The metal complexes of the glyoximes such as Cu(II), Ni(II) and Co(II) were also prepared. The structures of these ligands and their complexes were identified by FT-IR, H-1 NMR and C-13 NMR spectral data, elemental analysis and magnetic measurements.Öğe Synthesis of a Novel Thiadiazine Derivative and Electrochemical Properties for Pb2+ Transfer across Water/1,2-Dichloroethane Interface(PEKING UNIV PRESS, 2011) Baslak, Canan; Bingol, Haluk; Coskun, Ahmet; Atalay, TevfikThe transfer of Pb2+ facilitated by interfacial complexation with 5-(4-phenoxyphenyl)-6H-1,3,4-thiadiazin-2-amine (PPTA) at the polarized water/1,2-dicholoroethane (1,2-DCE) interface was investigated by cyclic voltammetry. We synthesized the thiadiazine derivative, PPTA, firstly. The transfer was performed at different metal concentrations and scan rates, and the obtained voltammetric transfer peaks toward Pb2+ ion over other divalent cations (Zn2+, Co2+, Ni2+, Cd2+, Hg2+, and Cu2+) were reversible. The dependence of the half-wave potentials of the Pb2+ ion on the concentration of PPTA in the organic phase indicates that the ion transfer is facilitated by the formation of 1:2 (metal: ligand) complex in the organic phase with the association constant (Ig beta(2)) of (17.1 +/- 0.2).Öğe Synthesis of N-(4 '-benzo[15-crown-5])thiophenoxyphenylaminoglyoxime and its complexes with some transition metals(SPRINGER, 2008) Coskun, Ahmet; Karapinar, Emin4-(Chloroacetyl)diphenyl thioether (1) was synthesized from chloroacetyl chloride and diphenyl thioether in the presence of AlCl3 as catalyst in a Friedel-Crafts reaction. Subsequently, its keto oxime (2) and glyoxime (3) derivatives were prepared. N-(4'-Benzo[15-crown-5]thiophenoxyphenylaminoglyoxime (H2L) and its sodium chloride complex (H2L center dot NaCl) were prepared from 4-(thiophenoxy)chlorophenylglyoxime (3), 4'-aminobenzo[15-crown-5] and sodium bicarbonate or sodium bicarbonate and sodium chloride. Ni(II), Co(II) and Cu(II) complexes of H2L and H2L center dot NaCl have a metal-ligand ratio of 1:2 and the ligand coordinates through the two N atoms, as do most of the vic-dioximes. The BF2-capped Ni(II) mononuclear complex of the vic-dioxime was prepared. The macrocyclic ligands and their transition metal complexes were characterized on the basis of FT-IR, H-1 NMR, C-13 NMR spectroscopy and elemental analyses data.Öğe Synthesis, characterization and extraction properties of four unsymmetrical vic-dioximes and their complexes with nickel(II), cobalt(II) and copper(II)(TAYLOR & FRANCIS INC, 2007) Karapinar, Emin; Karapinar, Nazan; Ozcan, Emine; Coskun, AhmetFour new unsymmetrical vic-dioximes: [(LH2)-H-1] N-(4-acetanilidyl) amino-amphi-glyoxime, [(LH2)-H-2] N-(4-acetanilidyl) amino-anti-glyoxime, [(LH2)-H-3] N-(2-thiazolyl) amino-amphi-glyoxime and [(LH2)-H-4] N-(2-thiazolyl) amino-anti-glyoxime were prepared by the reaction of amphi-chloroglyoxime and anti-chloroglyoxime with 4-aminoacetanilide and 2-aminothiazol in absolute ethanol. The preparation Ni(II), Co(II), and Cu(II) complexes of the amphi-and anti-isomers of these ligands are described. The ligands and their complexes were characterized by elemental analyses, IR, mass, H-1 and C-13 NMR spectra and magnetic susceptibility measurements. Ligands complexing properties were studied by the liquid-liquid extraction of selected alkali (Li+, Na+, K+, Cs+) and transition metals (Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+, Pb2+). It has been observed that all ligands show a high affinity to Cu2+ and Hg2+ ions, where as almost no affinity to alkali metals. The extraction equilibrium constants (Kex) for complexes of ligands with Cu2+ and Hg2+ metal picrates between dichloromethane and water have been determined at 25 degrees C.
