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    Removal of chromate and phosphate anion from aqueous solutions using calix[4]aren receptors containing proton switchable units
    (ELSEVIER SCIENCE BV, 2010) Ertul, Seref; Bayrakci, Mevluet; Yilmaz, Mustafa
    In the present study four new calix[4]arene amide ionophores (4-7) have been prepared by aminolysis of calix[4]arene diester (3) and investigated their extraction ability toward phosphate and dichromate anions at different pH. The H-1 NMR data showed that the synthesized compounds exist in the cone conformation. Liquid-liquid extraction experiments have been performed to evaluate the dichromate and phosphate anions extraction efficiency of both calix[4]arene bearing amide-pyridinium units (4-7) and the calix[4]arene derivative bearing aminomethyl pyridinium units (8, 9). It was observed that, compounds 4-7 exhibited lower affinity toward phosphate ions than the calix[4]arene derivative bearing amine pyridinium units (8, 9). The extraction of phosphate and dichromate anions by these compounds indicates that the partially protonated pyridyl or amino groups play the major role for the formation of hydrogen bonds and electrostatic interactions. (C) 2010 Elsevier B.V. All rights reserved.
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    Synthesis of di-substituted calix[4]arene-based receptors for extraction of chromate and arsenate anions
    (PERGAMON-ELSEVIER SCIENCE LTD, 2009) Bayrakci, Mevluet; Ertul, Seref; Yilmaz, Mustafa
    The article describes the synthesis of a family of novel calix[4]arene ionophores, 25,27-bis-(2-aminomethylpyridine-propoxy)-26,28-dihydroxycalix[4]arene (5a), 25,27-bis-(3-aminomethylpyridine-propoxy)-26,28-dihydroxycalix[4]arene (5b) and two chromogenic calix[4]arenes, 5,17-dinitro-25,27-bis-(2-aminomethylpyridine-propoxy)-26,28-dihydroxycalix[4]arene (5c), 5,17-dinitro-25,27-bis-(3-aminomethylpyridine-propoxy)-26,28-dihydroxycalix[4]arene (5d) bearing pyridinium units. In the synthesis, the upper and lower rims of p-tert-butylcalix[4]arene were modified in order to acquire binding sites for the recognition of arsenate and dichromate anions. It has been observed that protonated alkylammonium forms of the ionophores showed high affinity toward dichromate and arsenate anions. (C) 2009 Elsevier Ltd. All rights reserved.
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    Synthesis of macrocyclic polyethers and polyether diesters and preparation of their cationic complexes
    (VERSITA, 2008) Ertul, Seref; Beduk, A. Dincer; Bayrakci, Mevluet; Guler, Ersin
    New macrocyclic polyethers, 2,3,5,6-bis-[5'(5')-chlorobenzo]-1,7,10-trioxacyclododeca-2,5-diene (I), 2,3,5,6-bis-[5'(5')-chlorobenzo]-1,7,10,13-tetra oxacyclo pentadeca-2,5-diene (II), and 2,3,5,6-bis-[5'(5')-chlorobenzo]-1,7,10,13,16-penta oxa cyclo octadeca-2,5-dien (III), and macrocylic lactones 2,3,5,6-bis-[5'(5')-chlorobenzo]-1,7,10,13-tetraoxacyclopentadeca-2,5-diene-8,15-dione (IV) and 2,3,5,6-bis[5'(5')-chlorobenzo]-1,7,10,13,16-pentaoxacyclooctadeca-2,5-diene-8,18-dione (V) were synthesized. Complexes of ligands III and V with metal cations were prepared. Furthermore, their metal-picrate extraction with some metal salts was attempted. Structures of the ligands and complexes were confirmed using spectroscopic techniques. (C) 2008 Institute of Chemistry, Slovak Academy of Sciences
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    Synthesis of Novel Macrocyclic Lactam Based Receptors for Alkali or Transition Metal Cations and Cr2O72- Anions
    (SLOVENSKO KEMIJSKO DRUSTVO, 2009) Ertul, Seref; Tombak, Haci Ahmet; Bayrakci, Mevluet; Merter, Orhan
    The article describes the syntheses and extraction properties of new lactam ionophores. These lactam derivatives were easily synthesized via aminolysis of 2,2'-methylenebis(4-chlorophenol) dimethylester or its corresponding acyl chloride with corresponding diamine compounds in THF or methanol-dichloromethane solvent systems in one step, respectively. The extraction studies of lactam ionophores were performed toward dichromate anion and alkaline and transition metal cations such as Li+, Na+, K+, Co2+, Hg2+ and Pb2+. All the structures of the ionophores were confirmed by spectroscopic techniques and elemental analysis.