Yazar "Topal, G" seçeneğine göre listele

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    All-solid-state PVC membrane Ag+-selective electrodes based on diaza-18-crown-6 compounds
    (Springer Wien, 2004) Isildak, I; Yolcu, M; Isildak, O; Demirel, N; Topal, G; Hosgoren, H
    Two diaza-crown ether compounds were synthesized and evaluated as Ag+-selective carriers in polyvinylchloride (PVC) membrane electrodes of solid-state type. The all-solid-state PVC membrane electrode based on N,N-Dibenzyl-dibenzo-diaza-18-crown-6 exhibited a super-Nernstian response (75+/-10 mV per decade) over the concentration range of 1x10(-1) to 7x10(-6) M of Ag+ ion and a detection limit of 3x10(-6) M, at a wide range of pH (pH 4-7). The response time of the electrode was fast (less than similar to10s), and it can be used for three months without any significant deviation in potential. The proposed all-solid-state PVC membrane electrodes revealed high selectivity toward Ag+ ion with respect to alkali, alkaline earth, heavy and transition metal ions. A flow-through cell of all-solid-state PVC membrane Ag+-selective electrode based on N,N-Dibenzyl-dibenzo-diaza-18-crown-6 has also been prepared and applied for flow-injection analysis of Ag+ ion in solution.
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    Asymmetric reduction of acetophenone using lithium aluminium hydride modified with some novel amino alcohol Schiff bases
    (Pergamon-Elsevier Science Ltd, 2005) Tümerdem, R; Topal, G; Turgut, Y
    Some new chiral Schiff bases have been prepared in good yields from various carbonyl groups and two 2-amino alcohols. LiAlH4 was treated with different equivalents of the Schiff bases. Enantioselective reduction of acetophenone is achieved in high chemical yield (up to 93%) with moderate enantiomeric excess (up to 22%) by use of the new reducing agents. (C) 2005 Elsevier Ltd. All rights reserved.
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    Öğe
    Effect of structural modifications of diaza-18-crown-6 on the extractability and selectivity of univalent metal picrates
    (Elsevier Science Bv, 2001) Ziyadanogullari, B; Topal, G; Erdogan, S; Hamamci, C; Hosgoren, H
    The solvent extraction of univalent metal cations with N,N'-dibenzyl-1,4,10,13-tetraoxa-7,16 diaza-2,3,11,12-dibenzocycloocta deca-2,11-diene (L-1), N,N'-didodecyl-1,4,10,13-tetraoxa-7,16-diaza-2,3-benzocylooctadeca-2-ene (L-2) and N,N'-dibenzyl-1,4,10,13-tetraoxa-7,16-diaza-2,3,11,12-dibenzocyclo octadeca-2,11-diene (L-3) with picrate anion into dichloromethane has been studied at 25 degreesC by UV-visible spectroscopy. The extractability and selectivity of univalent metal picrates (Li+, Na+, Ag+, PhCH2NH3+, NH4+) was evaluated as a function of [ligand]/[metal cation]. L-2 showed the highest extractability and selectivity for Lit over the larger studied cations, and also exhibited the highest [Li+]/[NH4+] selectivity as L/M = 1. (C) 2001 Elsevier Science B.V. All rights reserved.
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    Öğe
    Preparation of new o-carboxyanilinotellurium(IV) bromides and their dyeing properties
    (Marcel Dekker Inc, 2001) Topal, G; Temel, H; Yavuz, Ö; Coskun, M; Sekerci, M
    This study represents a new synthesis of two organotellurium compounds and their dyeing properties. The structure of these tellurium derivatives are proposed based on elemental analyses, IR, UV-Vis, H-1 and C-13 NMR spectra and thermogravimetric analyses (TGA).
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    Synthesis and complexation of new substituted dibenzodiaza macrocyclic diester compounds
    (Taylor & Francis Inc, 2002) Topal, G; Temel, H; Çakir, Ü; Ugras, HI; Karadeniz, F; Hosgören, H
    The synthesis of some new precoursers that contain substituted benzo units and their use in the preparation of azama-crocyclic diester compounds are reported. These precoursers and ligands were characterized by Elemental analysis, H-1 and C-13 NMR spectroscopy, and IR spectroscopy. The complexation constants Ke and DeltaGdegrees values for the diesters with several transition metal cations (Ag+, Zn2+ and Cu2+) in a dioxan-water system using a conductometric method at 25degreesC are also reported.
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    Synthesis of R-(-)-2-ethyl-N-benzyl (monoaza-15-crown-5) and the crystal structure of its sodium perchlorate complex
    (Springer, 2001) Özbey, S; Hosgören, H; Turgut, Y; Topal, G
    A new complex of a chiral monoaza-crown ether, [R-(-)-2-ethyl-N-benzyl-4,7,10,13-tetraoxa-1-azacyclopentadeceane) NaClO4], has been prepared and studied by x-ray diffraction. The compound crystallizes in space group P2(1) with cell dimensions a = 9.480(1), b = 15.978(2), c = 15.816(2) Angstrom, beta = 105.51(1)degrees, Z = 4. The final R value is 0.055 for 2711 observed reflections and 540 parameters. There are two molecules in the asymmetric unit labelled A and B. The sodium ion is hexacoordinated. The average values for the Na-O-eth (etheric) distances are 2.364(6), 2.317(7) Angstrom and the Na-N distances are 2.679(6), 2.611(7) Angstrom; the Na-O(ClO4) contacts are 2.497(7) and 2.257(10) Angstrom, for A and B, respectively.