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    Polymer Supported Calix[4] Arene Derivatives for the Extraction of Metals and Dichromate Anions
    (Kluwer Academic/Plenum Publ, 2003) Memon, Shahabuddin ; Akceylan, Ezgi; Sap, Begüm; Tabakçı, Mustafa; Roundhill, D. Max; Yılmaz, Mustafa
    Three newly synthesized polymer supported calix[ 4] arene ionophores (7-9) were synthesized, and their ion binding properties toward selected alkali (Li+, Na+, K+, Cs+) and transition metal (Hg2+, Ni2+, Cu2+, Co2+, Cd2+, and Pb2+) cations were investigated. It has been observed that these ionophores are not selective toward a particular metal cation but show better ion binding property as compared to monomeric calixarene derivatives (2 and 6). Ionophore 6 and its supported polymer were also employed in dichromate anion extraction experiments. The polymeric ionophore (9) was found an effective extractant for dichromate anion even at pH 7.
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    Synthesis and evaluation of the Cr(VI) extraction ability of amino/nitrile calix[4]arenes immobilized onto a polymeric backbone
    (ELSEVIER SCIENCE BV, 2006) Memon, Shahabuddin; Tabakci, Mustafa; Roundhill, D. Max; Yimaz, Mustafa
    Three new calix[4]arene based polymeric resins (6, 7 and 8) have been synthesized via nucleophilic substitution reactions involving 5,11,17,23-tetrakis-[(N,N-dimethylamino)methyl]-25,26,27,28-tetrahydroxycalix[4]arene 3, and 5,11,17,23-tetracyanomethyl-25,26,27,28-tetrahydroxycalix[4]arene 4 as precursors with a Merrifield resin. The extraction studies were made by using liquid-liquid extraction, solid-liquid batchwise and packed-column sorption procedures, and effect of different anion to extraction of dichromate anion was examined by using NO3-, Cl-, SO42- and their mixtures. The experimental tal results showed that these calix[4]arene based polymeric resins have high extraction abilities towards Na2Cr2O7 as compared to their monomeric precursors, and also dichromate anion was extracted in high ratios even in presence of different anions. (c) 2006 Elsevier B.V. All rights reserved.
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    Synthesis and Extraction Studies of a Versatile Calix[4]arene-Based "Proton-switchable Extractant" for Toxic Metals and Dichromate Anions
    (Springer, 2003) Tabakcı, Mustafa; Memon, Shahabuddin; Yılmaz, Mustafa; Roundhill, D. Max
    The article describes the syntheses and extraction properties of a new calixarene based extractant 5, which has been synthesized from 5,11,17,23-tetra-tert-butyl-25,27-bis(chlorocarbonyl-methoxy)-26,28-dihydroxycalix[4]arene (4) by treatment with isoniazid (isonicotinic acid hydrazide) in the presence of pyridine. The compound 5 was converted to its methyl iodide salt (6) by refluxing 5 with methyl iodide in acetonitrile. In this synthesis it was thought to explore the role of pyridinium sites in the extraction of HCr2O7-/Cr2O72- anions. The complexing properties of 5 toward selected alkali/transition metal cations and HCr2O7-/Cr2O72- anions are reported. It has been observed that receptor 5 does not extract alkali metal cations but shows an excellent selectivity toward transition metals. The protonated pyridinium form of 5 is an effective form for transferring the HCr2O7-/Cr2O72- anions from an aqueous into a dichloromethane layer.