Yazar "Yilmaz, Ismail" seçeneğine göre listele

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    Spectroscopic and electrochemical studies of transition metal complexes with N,N?-bis(2-aminothiophenol)-1,7-bis(2-formylphenyl)-1,4,7-trioxaheptane and structure effects on extractability of ligand towards some divalent cations
    (Springer Wien, 2007) Temel, Hamdi; Alp, Hueseyin; Ilhan, Salih; Ziyadanogullari, Berrin; Yilmaz, Ismail
    La(III), Cu(II), Ni(II), and Zn(II) metal complexes with a novel quadridentate Schiff base derived from 1,7-bis(2-formylphenyl)-1,4,7-trioxaheptane and 2-aminothiophenol were synthesized and characterized by microanalytical data, elemental analysis, magnetic measurements, H-1 NMR, C-13 NMR, UV-Vis, IR, mass spectra, cyclic voltammetric and conductance measurements. The extractability of divalent cations was evaluated as a function of relationship between distribution ratio of the metal and pH or ligand concentration. The highest extraction percentage of Cu2+ and Ni2+ showed pH 7.0 and 6.4. It was concluded that the ligand can effectively be used in solvent extraction of copper(II) and nickel(II) from the aqueous phase to the organic phase.
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    Synthesis and characterization of new macrocyclic Schiff base derived from 2,6-diaminopyridine and 1,7-bis(2-formylphenyl)-1,4,7-trioxaheptane and its Cu(II), Ni(II), Pb(II), Co(III) and La(III) complexes
    (Pergamon-Elsevier Science Ltd, 2007) Ilhan, Salih; Temel, Hamdi; Yilmaz, Ismail; Sekerci, Memet
    A new macrocyclic ligand, 1,3,5-triaza-2,4:7,8:16,17-tribenzo-9,12,15-trioxacyclooktadeca-1,5-dien (L) was synthesized by reaction of 2,6-diaminopyridine and 1,7-bis(2-formylphenyl)-1,4,7-trioxaheptane. Then, its Cu(II), Ni(II), Pb(II), Co(III) and La(III) complexes were synthesized by template effect by reaction of 2,6-diaminopyridine and 1,7-bis(2-formylphenyl)-1,4,7-trioxaheptane and Cu(NO3)(2) (.) 3H(2)O, Ni(NO3)(2).6H(2)O, Pb(NO3)(2), Co(NO3)(2) (.) 6H(2)O, La(NO3)(3) (.) 6H(2)O, respectively. The ligand and its metal complexes have been characterized by elemental analysis, IR, H-1 and C-13 NMR, UV-Vis spectra, magnetic susceptibility, thermal gravimetric analysis, conductivity measurements, mass spectra and cyclic voltarnmetry. All complexes are diamagnetic and Cu(II) complex is binuclear. The Co(II) was oxidized to Co(III). The comparative electrochemical studies show that the nickel complex exhibited a quasi-reversible one-electron reduction process while copper and cobalt complexes gave irreversible reduction processes in DMSO solution. (C) 2007 Elsevier Ltd. All rights reserved.
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    Synthesis, characterization and electro-spectroelectrochemical studies of four macrocyclic Schiff-base Co(II) complexes having N2O2 set of donor atoms
    (Springer, 2009) Yilmaz, Ismail; Ilhan, Salih; Temel, Hamdi; Kilic, Ahmet
    Four macrocyclic Schiff-base cobalt complexes, [CoL1][NO3](2) center dot A 3H(2)O, [CoL2][NO3](2) center dot A 4H(2)O, [CoL3][NO3](2) center dot A 4H(2)O and [CoL4][NO3](2) center dot A 2H(2)O, were synthesized by reaction of salicylaldehyde derivatives with 1,4-bis(3-aminopropoxy)butane or (+/-)-trans-1,2-diaminocyclohexane and Co(NO3)(2) center dot A 6H(2)O by template effect in methanol. The metals to ligand ratio of the complexes were found to be 1:1. The Co(II) complexes are proposed to be tetrahedral geometry. The macrocyclic Co(II) complexes are 1:2 electrolytes as shown by their molar conductivities (I >(M)) in DMF (dimethyl formamide) at 10(-3) M. The structure of Co(II) complexes is proposed from elemental analysis, Ft-IR, UV-visible spectra, magnetic susceptibility, molar conductivity measurements and mass spectra. Electrochemical and thin-layer spectroelectrochemical studies of the complexes were comparatively studied in the same experimental conditions. The electrochemical results revealed that all complexes displayed irreversible one reduction processes and their cathodic peak potential values (E (pc)) were observed in around of -1.14 to 0.95 V. It was also seen that [CoL1][NO3](2) center dot A 3H(2)O and [CoL2][NO3](2) center dot A 4H(2)O exhibited one cathodic wave without corresponding anodic wave but, [CoL3][NO3](2) center dot A 4H(2)O and [CoL4][NO3](2) center dot A 2H(2)O showed one cathodic wave with corresponding anodic wave, probably due to the presence of different ligand nature even if the complexes have the same N2O2 donor set. In view of spectroelectrochemical studies [CoL3][NO3](2) center dot A 4H(2)O showed distinctive spectral changes in which the intensity of the band (lambda A = at 316 nm, assigned to n -> pi* transitions) decreased and a new broad band in a low intensity about 391 nm appeared as a result of the reduction process based on the cobalt center in the complex.
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    Synthesis, characterization and redox properties of macrocyclic Schiff base by reaction of 2,6-diaminopyridine and 1,3-bis(2-carboxyaldehyde phenoxy) propane and its CuII, NiII, PbII, CoIII and LaIII complexes
    (Springer, 2007) Ilhan, Salih; Temel, Hamdi; Yilmaz, Ismail; Kilic, Ahmet
    A new macrocyclic ligand, 1,3,5-triaza-2,4:7,8:, 14,15-tribenzo-9,13-dioxacyclohexadeca-1,5-diene ( L) was synthesized by reaction of 2,6-diaminopyridine and 1,3-bis(2-carboxyaldehyde phenoxy) propane. Then, its Cu-II, Ni-II, Pb-II, Co-III and La-III complexes were synthesized by a template effect by reaction of 2,6-diaminopyridine and 1,3-bis (2-carboxyaldehyde phenoxy) propane and Cu(NO3)(2) center dot 3H(2)O, Ni(NO3)(2) center dot 6H(2)O, Co(NO3)(2) center dot 6H(2)O, La(NO3)(3) center dot 6H(2)O, respectively. The ligand and its metal complexes have been characterized by elemental analysis, IR, H-1- and C-13-NMR-, UV-vis spectra, magnetic susceptibility, conductivity measurements, mass spectra and cyclic voltammetry. All complexes are diamagnetic and the Cu-II complex is binuclear. The diamagnetic behaviour of the binuclear complex may be explained by a very strong anti-ferromagnetic interaction in the Cu-Cu pair. The Co-II was oxidised to Co-III.
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    Synthesis, characterization, electrochemical behaviors and applications in the Suzuki-Miyaura cross-coupling reactions of N2S2O2 thio Schiff base ligand and its Cu(II), Co(III), Ni(II), Pd(II) complexes and their usage in the fabrication of organic-inorganic hybrid devices
    (Elsevier Science Sa, 2012) Temel, Hamdi; Pasa, Salih; Ocak, Yusuf Selim; Yilmaz, Ismail; Demir, Serpil; Ozdemir, Ismail
    The thio Schiff base ligand N,N'-bis(o-hydroxy-1-naphtaldehydene)-1,2-bis(o-amino phenilthio)ethane (L) was synthesized by the condensation of o-hydroxy-1-naphthaldehyde and 1,2-bis(2-amino thiophenol)ethane. The reactions of the ligand with different transition metal(II) salts under reflux system condition afforded a series of metal complexes such as Cu(II), Co(III), Ni(II) and Pd(II). Ligand and its complexes were characterized by a combination of elemental analysis, UV-vis spectroscopy, FT-IR, H-1 NMR, MS and TGA/DTA. The electrochemical properties of L and [Cu(L)] were investigated using cyclic voltammetry (CV) in the solutions of dimethyl sulfoxide (DMSO). The catalytic property of thio Schiff base ligand with Suzuki cross-coupling reactions were also determined with different substituted aryl halides in the presence of aryl boronic acid and Pd(AcO)(2) as catalyst. In addition, the fabrication of organic-inorganic hybrid devices using L and its Co(III), Ni(II) and Pd(II) complexes and their electrical properties have been reported. (C) 2011 Elsevier B.V. All rights reserved.
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    Synthesis, electrochemistry and in situ spectroelectrochemistry of a new Co(III) thio Schiff-base complex with N,N?-bis(2-aminothiophenol)-1,4-bis(carboxylidene phenoxy)butane
    (Pergamon-Elsevier Science Ltd, 2008) Yilmaz, Ismail; Temel, Hamdi; Alp, Hueseyin
    A new cobalt Schiff-base complex, [Co(L)(OH)(H2O)] (where L = [N,N'-bis(2-aminothiophenol)-1,4-bis(carboxylidene phenoxy)butane), was synthesized and its electrochemical and spectroelectochemical properties were investigated using cyclic voltammetry (CV), differential pulse voltammetry (DPV) and thin-layer spectro-electrochemistry in solutions of dimethyl sulfoxide (DMSO) and dichloromethane (CH2O2). The [Co(L)(OH)(H2O)] complex displays two well-defined reversible reduction processes with the corresponding anodic waves. The half-wave potentials of the first and second reduction processes were displayed at E-1/2 = 0.08 V and E-1/2 = -1.21 V (scan rate: 0.100 Vs(-1)) in DMSO, and E-1/2 = -0.124 V and E-1/2 = -1.32 V (scan rate: 0.100 Vs(-1)) in CH2Cl2. The potentials of the reduction processes in DMSO are shifted toward negative potentials (0.220-0.112 V) compared to those in CH2O2. The electrochemical results are assigned to two one-electron reduction processes; [Co(III)L] + (-)e -> [Co(II)L](-) and [Co(II)L](-) + (-)e -> [Co(I)L](2-). The six-coordination of the complex remains unchanged during the reduction processes and the electron transfer processes were not followed by a chemical reaction upon scan reversal. It was also seen that [Co(L)(OH)(H2O)1 was reduced at a more positive potential than the corresponding salen analogs. The shift and reversibility are apparently related to the high degree of electron delocalization of the [Co(L)(OH)(H2O)] complex, having a N2O2S2 donor set and two additional benzene units. Additionally, in situ spectro-electrochemical measurements support Co(III)/Co(II) and Co(II)/Co(I) reversible reduction processes with the observation of the corresponding spectral changes with the applied potentials E-app = -0.40 and -1.60 V. Application of the spectroelectrochernical results allowed the determination of E-1/2 and n (the number of electrons) from the spectra of the fully oxidized and reduced species in one unified experiment as well. The results obtained by this method are in agreement with those by the CV and DPV methods. (C) 2007 Elsevier Ltd. All rights reserved.
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    Synthesis, spectral characterization and electrochemical properties of new vic-dioxime complexes bearing carboxylate
    (Springer, 2006) Kilic, Ahmet; Tas, Esref; Gumgum, Bahattin; Yilmaz, Ismail
    Three new vic-dioxime ligands, [N-(ethyl-4-amino-1-piperidine carboxylate)-phenylglyoxime ((LH2)-H-1), N-(ethyl-4-amino-1-piperidine carboxylate)-glyoxime (L(2)pH(2)), and N,N'-bis(ethyl-4-amino-1-piperidine carboxylate)-glyoxime ((LH2)-H-3)], and their Co(II) with Cu(II) metal complexes, were synthesized for the first time. Mononuclear complexes of these ligands with a 1:2 metal-ligand ratio were prepared with Co(II) and Cu(II) salts. The BF2+-capped Co(II) and mononuclear complexes of the vic-dioxime were prepared for [Co(L-1 center dot BF2)(2)] and [Co(L-2 center dot BF2)(2)]. The ligands act in a polydentate fashion bonding through nitrogen atoms in the presence of a base, as do most vic-dioximes. The cobalt(II) and copper(II) complexes are non-electrolytes as shown by their molar conductivities (Lambda(M)) in DMF. The structures of the ligands and complexes were determined by elemental analyses, FT-i.r., u.v.-vis., H-1- and C-13-n.m.r. spectra, magnetic susceptibility measurements, and molar conductivity. The comparative electrochemical studies show that the stabilities of the reduced or oxidized species and the electrode potentials of the complexes are affected by the substituents attached on the oxime moieties of the complexes.
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    The synthesis, spectroscopic and voltametric studies of new metal complexes containing three different vic-dioximes
    (Taylor & Francis Ltd, 2007) Kilic, Ahmet; Tas, Esref; Gumgum, Bahattin; Yilmaz, Ismail
    The synthesis, spectroscopic, and redox properties of some metal complexes with three novel vic-dioxime ligands, N-(1-(2-aminoethyl) piperazine)-phenylglyoxime (L1H2), N-(1-(2-aminoethyl) piperazine)-glyoxime (L2H2), and N, N'-bis(1-(2-aminoethyl) piperazine)-glyoxime (L3H2)], prepared from different glyoxime and 1-(2-aminoethyl) piperazine are reported. The structure of these vic-dioximes have been determined as the anti-form according to H-1 NMR, C-13 NMR, and FT-IR data. The metal to ligand ratios of Co(II), Ni(II), and Cu(II) complexes were found to be 1:2. The Cu(II) complexes of these ligands are proposed to be square planar and Ni(II) complexes of these ligands are proposed to be square planar or octahedral, while the Co(II) complexes are proposed to be octahedral with water molecules as axial ligands. Ni(II), Co(II), and Cu(II) metal complexes are non-electrolytes as shown by their molar conductivities (Lambda(M)) in DMF (dimethyl formamide) at 10(-3) M. The structure of ligands and their complexes is proposed from elemental analysis, FT-IR, UV-VIS, H-1 NMR, C-13 NMR, magnetic susceptibility measurements, and molar conductivity measurements. The cyclic voltammetric measurements of the mononuclear complexes provide an understanding of the electrochemical behaviour of the reduced or oxidized species in DMSO solution.
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    Synthesis, structural characterization and electrochemical studies of new macrocyclic Schiff base containing pyridine head and its metal complexes
    (Elsevier Science Sa, 2007) Ilhan, Salih; Temel, Hamdi; Yilmaz, Ismail; Sekerci, Memet
    A new macrocyclic ligand, 1,3,5-triaza-2,4:7,8:13,14-tribenzo-9,12-dioksa-cyclopentadeca-1,5-diene was synthesized by reaction of 2,6-diaminopyridine and 1,2-bis(2-carboxyaldehyde phenoxy)ethane. Then, its Cu(II), Ni(II), Pb(II), Co(III) and La(III) complexes were synthesized by the template effect by the reaction of 2,6-diaminopyridine and 1,2-bis(2-carboxyaldehyde phenoxy)ethane and Cu(NO3)(2)center dot 3H(2)O, Ni(NO3)(2)center dot 6H(2)O, Pb(NO3)(2), Co(NO3)(2)center dot 6H(2)O, La(NO3)(3)center dot 6H(2)O, respectively. The ligand and its metal complexes have been characterized by elemental analysis, IR, H-1 and C-13 NMR, UV-Vis spectra, magnetic susceptibility, thermal gravimetric analysis, conductivity measurements, mass spectra, and cyclic voltammetry. All complexes are diamagnetic and Cu(II) complex is binuclear. The Co(11) was oxidized to Co(111). The comparative electrochemical studies show that the nickel complex exhibited a quasi-reversible one-electron reduction process, while copper and cobalt complexes gave irreversible reduction processes in DMSO solution. (c) 2007 Elsevier B.V. All rights reserved.