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    A calix[4]arene derived dibenzonitrile receptor modified at its "lower rim" by a polymerizable group
    (TAYLOR & FRANCIS INC, 2004) Tabakci, M; Memon, S; Sap, B; Roundhill, DM; Yilmaz, M
    The present work describes the synthesis of a new monomeric dibenzonitrile derivative of p-tert-butylcalix[4]arene containing a polymerizable group at its lower rim. This monomer with an acryl amide group has been copolymerized with styrene yielding a linear polymer with pendant calixarene groups. Extraction studies with this monomer and its copolymer show no selectivity for metal cations. Nevertheless, dibenzonitrile groups with calixarene moiety provide a suitable binding site for transferring metal salt (NaHCr2O7) as an ion-pair.
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    A convenient approach towards the synthesis of a "Proton switchable" chromium(VI) extractant calix[4]arene
    (TAYLOR & FRANCIS LTD, 2004) Ediz, O; Tabakci, M; Memon, S; Yilmaz, M; Roundhill, DM
    A convenient synthesis and Cr(VI) extraction properties of a new calix[4]arene-based receptor (5), which has been synthesized from 5,17-diformyl-25,27-dimethoxy-carbonylmethoxycalix[4]arene (4) by treatment with 3-aminomethylpyridine in one step, are described. The receptor 5 contains four pyridinyl groups, two on each rim. Two of them are joined by an amide linkage onto the lower rim, and other two are linked by an imine-type linkage onto the upper rim of the calix[4]arene moiety. Receptor 5 is very soluble in water at low pH (<2.5). Calixarene 5 also represents a good extractant for HCr2O7-. Thus, the partially protonated form of 5 is an effective extractant for transferring HCr2O7- ions from an aqueous into a chloroform layer. Deprotonation of 5 results in a reversal, with HCr2O7- migrating back into the aqueous layer.
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    Design and synthesis of new chiral calix[4]arenes as liquid phase extraction agents for alpha-amino acid methylesters and chiral alpha-amines
    (SPRINGER, 2005) Tabakci, M; Tabakci, B; Yilmaz, M
    The article describes the synthesis and extraction properties of new (S)(-)-1-phenylethylamine substituted p-tert-butylcalix[4]arene/calix[4]arene. These compounds have been synthesized via nucleophilic substitution reactions involving 5,11,17,2 3-tetra-tert-butyl-25,26,27,28-tetra(2-hydroxyethoxy)calix[4]arene (4a), or 5,11,17,23-tetra-H-25,26,27,28-tetra(2-hydroxyethoxy)calix[4]arene (4b) with (S)(-)-1-phenylethylamine in dry THF. The extraction properties of ligands 5a and 5b towards the some selected alpha-amino acid methylesters and chiral alpha-amines are also reported. It has been observed that receptor 5a was an excellent ionophore for alpha-amino acid methylesters/alpha-amines and good extractant than 5b. However, both of the ligands did not display any selectivity towards the configurations of this species.
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    Oligomeric calix[4]arene-thiacrown ether for toxic heavy metals
    (JOHN WILEY & SONS INC, 2004) Tabakci, M; Memon, S; Yilmaz, M; Roundhill, DM
    A new oligomeric calix[4]arene-thiacrown-4 (5) was synthesized via a condensation reaction of 5,11,17,23-tetra-tert-butyl-25,27-bis-(4-aminobenzyloxy)-calix[4]arene-thiacrown-4 (4) with adipoyl dichloride. In this oligomerization reaction only five/six calix[4]arene-thiacrown-4 units were linked in the oligomeric chain. The complexation studies of 5 were made with liquid-liquid- extraction and solid-liquid-sorption procedures. For comparison, the extraction efficiencies of monomers 1, 3, and 4 to selected transition metals are reported. The selectivity of monomers 3 and 4 toward Cu2+, Hg2+, and Pb2+ was lost after oligomerization in the two-phase extraction systems. (C) 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 186-193, 2004.
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    Synthesis and binding properties of two polymeric thiacalix[4]arenes
    (ELSEVIER SCIENCE BV, 2006) Tabakci, B; Beduk, AD; Tabakci, M; Yilmaz, M
    Two new polymeric thiacalix[4]arenes were synthesized by the reaction of 5,11,17,23-tetra-tert-butyl-25,27-bis[(4-aminobenzyloxy)-26,28-dihydroxy]thiacalix[4]-arene 3 with terephthaloyl dichloride and 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrahydroxy-thiacalix[4]arene 1 with chloromethylated polystyrene (Merrifield's resin). Complexation studies were made by using liquid-liquid and solid-liquid extraction procedures. It was found that the soluble polymeric thiacalix[4]arene derived from terephthaloyl dichloride is better at removing alkali (Li+, Na+, K+, and Cs+) and heavy metal (Cu2+, Cd2+, Hg2+, Pb2+, Co2+ and Ni2+) cations than the precursor thiacalix[4]arenes. Both the soluble polymer and the cross-linked polymer derived from Merrifield's resin are more efficient at removing transition metals from solution than the precursor thiacalix[4]arene. (c) 2005 Elsevier B.V. All rights reserved.
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    Synthesis and evaluation of extraction ability of calix[4]-crown-6 cone conformer and its oligomeric analogue
    (ELSEVIER SCIENCE BV, 2004) Tabakci, M; Memon, S; Yilmaz, M; Roundhill, DM
    The synthesis of the cone conformers of 5,11,17,23-tetra-tert-butyl-25,27-bis[(4-nitrobenzyloxy)-26,28-dihydroxy]calix[4]-arene (2), 5,11,17,23-tetra-tert-butyl-25,27-bis[(4-nitrobenzyloxy)]calix[4]arene-crown-6 (3) and 5,11,17,23-tetra-tert-butyl-25,27-bis[(4-aminobenzyloxy)]calix[4]arene-crown-6 (4) containing polymerizable side arms, along with their oligomeric analogue 5, is reported. Extraction studies with monomers 3 and 4 and the oligomer 5 show no difference in their extraction behavior and selectivity, whereas, ionophore 2 is a poor extractant for alkali metal cations. These observations suggest that, substitution of side arms on the lower rim of calix moiety can enhance the calix[4]crown-6 cone conformers function to extract alkali metal cations in two phase extraction systems. (C) 2003 Elsevier B.V. All rights reserved.
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    Synthesis of p-tert-butylcalix[4]arene dinitrile bonded aminopropyl silica and investigating its usability as a stationary phase in HPLC
    (TAYLOR & FRANCIS INC, 2006) Gezici, O; Tabakci, M; Kara, H; Yilmaz, M
    The chromatic separation of adenine, adenosine, cytosine, phenol, benzene, and toluene were investigated by using 5,11,17,23-tert-butyl-25,27-bis(cyanomethoxy)-26-(chloroformyl)-28-hydroxy-calix[4]arene bonded aminopropyl silica (CDBAPS) as a stationary phase. The separation ability of the stationary phase was observed to be good for target species. The effect of non-polar calix[n]arene network was observed in chromatographic processes, and it was thought that, thanks to the relatively polar nitrile groups, further selectivity would be obtained in various chromatographic separations.
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    A useful approach toward the synthesis and metal extractions with polymer appended thioalkyl calix[4]arenes
    (ELSEVIER SCI LTD, 2005) Memon, S; Tabakci, M; Roundhill, DM; Yilmaz, M
    This article describes a convenient method for the synthesis of two new polymeric resins via nucleophilic substitution reactions involving 5,11,17,23-tetrakis[(propylthio)methyl]-25,26,27,28-tetrahydroxycalix[4]arene 4, and 5,11,17,23-tetrakis[(methylthio)methyl]-25,26,27,28-tetrahydroxycalix[4]arene 6, as precursors with Merrifield's resin. The extraction studies were made using both liquid-liquid extraction and solid-liquid batchwise sorption procedures. The calix[4]arene based polymeric resins have high extraction ability toward metal cations and Na2Cr2O7 as compared to their monomeric precursors. (C) 2004 Elsevier Ltd. All rights reserved.