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    Interaction of nucleic acid bases and nucleosides with cobalt ions immobilized in a column system
    (Elsevier Sci Ltd, 2006) Ayar, A; Mercimek, B
    The interactions of ligands, such as adenine, adenosine, uracil and uridine with Co(II) ions immobilized by carboxylated diaminoethyl matrix on sporopollenin were investigated as a function of temperature by the breakthrough technique. The adsorption characteristics of ligands on Co(II)carboxylated diaminoethyl sporopollenin [Co(II)-CDAE-S] were investigated by Scatchard plot analysis under optimized conditions of flow rate and temperature. Equilibrium binding data used in Scatchard plot analysis for adenosine gave rise to a linear plot, indicating the presence of specific interaction and Langmuirean behavior. However, the adsorption of uracil on this ligand-exchange stationary phase was affected by the electrostatic or hydrophobic interaction in the whole concentration range. In the case of adenine and uridine, the adsorption performance was strongly affected by the initial ligand concentration. At high concentration, adenine and uridine were adsorbed specifically to the ligand exchanger matrix exposed on the adsorbent. At lower concentrations, the binding to the second sets of adsorbent was appeared because of nonspecific interaction such as hydrophobic and electrostatic. (c) 2006 Elsevier Ltd. All rights reserved.
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    Ligand adsorption of adenine and adenosine on poly(vinyl chloride) bound cobalt(II)-carboxylated diaminoethyl complex
    (ELSEVIER SCIENCE BV, 2003) Ozdere, G; Kurt, G; Mercimek, B; Ayar, A
    Ligand adsorption of adenine and adenosine has been studied by using cobalt(II)-poly(vinyl chloride) carboxylated diaminoethyl (PVC-CDAE) resin. Column runs were conducted to study the performance of the ligand exchanger. The adsorption of adenine and adenosine from solutions of different initial concentrations onto resin was measured using by breakthrough technique at 25 degreesC. The ligand concentration was chosen to be 0.0125-0.2 mmol l(-1). The characteristics of the adsorption process were investigated by using Scatchard plot analysis (q/C versus q). And the adsorption behaviour of these ligands on cobalt(II)-PVC-CDAE is expressed by the Langmuir and Freundlich isotherms. The adsorption data with respect to all ligands provide an excellent fit to the Freundlich isotherm, giving correlation coefficients in the range of 0.95-0.99 for the Freundlich isotherm. On the contrary, when the Langmuir isotherm model was applied to these data, a good lit was not obtained for the high ligand concentrations. (C) 2003 Elsevier B.V. All rights reserved.
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    Selective extraction of iron(III) from aqueous nitrate solution in the presence of cobalt(II), copper(II) and nickel(II) ions using BiS(Delta(2)-2-imidazolinyl)-5,5 '-dioxime
    (JAPAN SOC ANALYTICAL CHEMISTRY, 2004) Teke, M; Mercimek, B; Ozler, MA; Ayar, A
    The feasibility of using bis(Delta(2)-2-imidazolinyl)-5,5'-dioxime (H2L) for the selective extraction of iron(III) from aqueous solutions was investigated by employing an solvent-extraction technique. The extraction of iron(III) from an aqueous nitrate solution in the presence of metal ions, such as cobalt(II), copper(II) and nickel(II), was carried out using H2L in binary and multicomponent mixtures. Iron(III) extraction has been studied as a function of the pH, equilibrium time and extractant concentration. From the extracted complex species in the organic phase, iron(III) was stripped with 2 M HNO3, and later determined using atomic-absorption spectrometry. The extraction was found to significantly depend on the aqueous solution pH. The extraction of iron(III) with H2L increases with the pH value, reaching a maximum in the zone of pH 2.0, remaining constant between 2 and 3.5 and subsequently decreasing. The quantitative extraction of iron(III) with 5 x 10(-3) M H2L in toluene is observed at pH 2.0. H2L was found to react with iron(III) to form ligand complex having a composition of 1:2 (Fe:H2L).
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    Synthesis and characterization of new Schiff bases and their cobalt(II), nickel(II), copper(II), zinc(II), cadmium(II) and mercury(II) complexes
    (TAYLOR & FRANCIS INC, 2005) Ucan, SY; Ucan, M; Mercimek, B
    Nickel(II), copper( II), cobalt( II), zinc( II), cadmium( II) and mercury( II) complexes chelates containing the Schiff base ligands methyliminoisonitroso-2-acetylnaphthalene (HL1) and benzyliminoisonitroso-2-acetylnaphthalene (HL2) have been prepared. The results suggest that the Schiff bases function as bidentate ligands and indicate a mononuclear structure for the Cu(II) complexes with square-planar geometry. The Ni(II), Zn(II), Hg(II) and Cd(II) complexes are of tetrahedral geometry and the Co(II) complexes with octahedral geometry with water molecules at the axial positions. These compounds have been characterized by elemental analyses, magnetic susceptibility, mass, IR, UV, H-1 and C-13 NMR spectroscopy.
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    Synthesis and characterization of tetradentate N2O2 Schiff base ligands and their transition metal complexes
    (TAYLOR & FRANCIS INC, 2005) Ucan, SY; Mercimek, B
    Two new ligands, 1,2-propylimino-bis(isonitroso-2-acetylnaphthalene) (H2L1) and 1,2-ethyl-imino-bis(isonitroso-2-acetylnaphthalene) (H2L2), have been synthesized by the reaction of isonitroso-2-acetylnaphthalene with 1,2-diaminopropane or 1,2-diamino-ethane. These ligands were reacted with nickel(II), copper( II), cobalt( II), zinc( II), cadmium( II) and mercury( II) ions to form complexes containing tetradentate Schiff bases. Each metal ion is in a four-coordinate environment of two imine nitrogen atoms and two oxime oxygen atoms. The new compounds have been characterized by elemental analyses, magnetic susceptibility, mass, IR, H-1 and C-13 NMR spectroscopy.
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    The synthesis of four new bis(amino-p-chlorophenylglyoximes) and their polymeric complexes
    (MARCEL DEKKER INC, 1997) Pekacar, AI; Mercimek, B; Ozcan, E
    In this study, four new bis(amino-p-chlorophenylglyoximes), 1,2-phenylenebis(amino-p-chlorophenylglyoxime) L(1)H(2), 1,5-naphthylenebis(amino-p-chlorophenylglyoxime) L(2)H(2), 3,4-tolylenebis(amino-p-chlorophenylglyoxime) L(3)H(2), and 2,6-pyridylbis(amino-p-chlorophlenylglyoxime) L(4)H(2), have been synthesized from anti-p-chlorophenylchloroglyoxime and the corresponding aromatic diamines. Their polymeric complexes with Ni(II), Co(II) and Cu(II) have been prepered. The Ni(II) and Cu(II) complexes of these ligands have been found to be square-planar, while the Co(II) complexes are octahedral with water molecules as axial ligands. H-1 NMR, AAS, IR, magnetic susceptibility and elemental analytical data of the complexes and ligands are discussed.