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    Amine-derivatized calix[4]arenes for sensitive extraction of cupric ion and formation of amine radical cation
    (ELSEVIER, 2014) Tabakci, Begum; Yilmaz, Aydan
    We report herein some calix[4]arene amine (C[4]A) derivatives, which are the copper(II)-induced fluorescence "turn-off" and "naked eye" chemosensors and the agents for the formation of amine radical intermediates. In this way, concurrently, the sensitive extraction of cupric ions and the formation of amine radical cations with calixarenes have been documented for the first time. These data were confirmed by using some experimental studies such as UV-visible, fluorescence, electron spin resonance, and cyclic voltammetric. (C) 2014 Elsevier B.V. All rights reserved.
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    Calix[4]arene-based Mannich and Schiff bases as versatile receptors for dichromate anion extraction: synthesis and comparative studies
    (PERGAMON-ELSEVIER SCIENCE LTD, 2012) Sap, Asli; Tabakci, Begum; Yilmaz, Aydan
    A series of novel calix[4]arene-based Mannich (5 and 6) and Schiff base (9-11) receptors have been synthesized and characterized by various analytical techniques. Competitive two-phase extraction experiments of these novel calix[4]arene amine- and imine-containing derivatives revealed a strong affinity for dichromate anions (Cr2O72-/HCr2O7-). The protonated alkylinium form of 5, 6 and 9-11 proved to be effective extractants for transferring the dichromate anions from an aqueous into an organic phase. Moreover, the extraction of dichromate anions by 5 and 9 in the presence of competitive anions such as F-, Cl-, Br-, NO3-, NO2-, PO43- and SO42- showed that 5 and 9 could be selective anion receptors for dichromate anions in the presence of those anions. (C) 2012 Published by Elsevier Ltd.
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    Evaluation of the performance of calix[8]arene derivatives as liquid phase extraction material for the removal of azo dyes
    (ELSEVIER SCIENCE BV, 2008) Gungor, Omer; Yilmaz, Aydan; Memon, Shahabuddin; Yimaz, Mustafa
    This pit per presents a study on the removal of azo dyes (Reactive Black 5, Trapaeolin 000, Methyl Orange and Direct Violet 51) with calix[n]arene derivatives from aqueous solution into the organic phase in order to explore the potential use of calixarenes as low-cost efficient extractants for wastewater dye removal. The carboxylic acid derivative of calix[8]arene shows highest affinity towards the azo dyes. The influence of NaCl (present in the solution) on extraction process was also Studied. The extent of the dye removal increased with the addition of NaCl. The proposed extraction mechanism involves several kinds of interactions: electrostatic repulsion between carboxylic acid groups of calix[8]arenes and sulfonate groups of azo dyes, hydrogen bonding and formation of an inclusion complex due to three dimensional cavity type calix[n]arene molecules through host-guest interactions. (C) 2008 Elsevier B.V. All rights reserved.
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    New diamino derivatives of p-tert-butylcalix[4]arene for oxyanion recognition: synthesis and complexation studies
    (TAYLOR & FRANCIS LTD, 2009) Yilmaz, Aydan; Tabakci, Begum; Tabakci, Mustafa
    We have prepared new diamino derivatives of p-tert-butylcalix[4]arene from the reduction of corresponding amide derivatives. The examination of their recognition abilities towards some selected oxyanions shows that the new calix[4]arene amines are mostly more effective receptors than their amide derivatives for dichromate anions and nitrite, and capable of extracting these anions in yields as high as 95%. However, neither the calix[4]arene amines nor their corresponding amides were capable of extracting phosphate or nitrate at pH 1.5.
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    Sorption of heavy metal ions by glass beads-immobilized calix[4]arenes derivative
    (MAIK NAUKA/INTERPERIODICA/SPRINGER, 2013) Gubbuk, Ilkay Hilal; Ozkan, Seyda Cigdem; Yilmaz, Aydan
    Glass beads (GB) immobilized, 5,11,17,23-tetra-tert-butyl-25,27-diethoxycarbonylmethoxy-26,28-dihydroxycalix[4]arene (CA) are prepared and used as a new sorbent in sorption study of removal heavy metal ions. A calixarene derivative bonded to amino-functionalized glass beads sorbent was synthesized via a self assembly technique for sorbent of selected heavy metal ions in aqueous. In order to absorb selected heavy metal ions in aqueous, a calixarene derivative bonded to amino-functionalized glass beads sorbent was synthesized via a self assembly technique. The sorbent which is named GB-APTS-CA was characterized using infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), elemental analysis and thermal analysis (TGA/DTG). The influences of some experimental parameters including pH of the sample solution, weight of sorbent, concentration and temperature have been investigated. The sorption data were evaluated using the Langmuir, Freundlich and Dubinin Radushkevich (D-R) isotherm. The obtained maximum sorption capacity for Cu(II), and Pb(II) is 0.06 mmol g(-1) and 0.02 mmol g(-1), respectively. Thermodynamic parameters such as the standard free energy change (Delta Gau <), enthalpy change (Delta Hau <) and entropy change (Delta Sau <) were calculated to determine the nature of sorption process. Thus, GB-APTS-CA is favorable and useful for the removal of Cu(II) and Pb(II) metal ions.
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    Synthesis and dichromate anion extraction ability of p-tert-butylcalix[4]arene diamide derivatives with different binding sites
    (PERGAMON-ELSEVIER SCIENCE LTD, 2007) Yilmaz, Aydan; Tabakci, Begum; Akceylan, Ezgi; Yimaz, Mustafa
    The article describes the synthesis and evaluation of the dichromate anion (Cr2O72-/HCr2O7-) extraction properties of p-tert- butylcalix[4]arene diamide derivatives (5-7) containing different binding sites. Among these compounds, 6 and 7 have been synthesized via aminolysis in a toluene-methanol solvent system with 3-aminomethylpyridine and 3,6-dioxa-1,8-diamino octane, respectively. On the other hand, compound 5 has been synthesized via an acid chloride method due to its inefficiency under aminolysis. The extraction properties of these diamides toward dichromate anions are studied by liquid-liquid extraction. The results show that p-tert-butylcalix[4]arene diamide derivative 7 exhibited a much higher affinity toward dichromate anions than that of 6 due to its special structure, while 5 was an ineffective ligand for these anions. (c) 2007 Elsevier Ltd. All rights reserved.
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    Synthesis of new calix[4] arene amide derivatives and investigation of their DNA cleavage activity
    (TAYLOR & FRANCIS LTD, 2014) Ozkan, Seyda Cigdem; Yilmaz, Aydan; Ozmen, Ismail
    This study comprises the synthesis of new p-tert-butylcalix[4]arene with different amide functional groups and summarises an investigation of their DNA cleavage activities. The structural investigations of the synthesised compounds were examined by FTIR, H-1 NMR, C-13 NMR, elemental analysis and FAB-MS techniques. The interaction between these compounds and pBR322 plasmid DNA has been investigated via agarose gel electrophoresis and, according to the results, compounds 5, 7, 8 and 13 exhibit efficient DNA cleavage activity. In the electrophoresis images of 5, 7 and 8, Form IV which is small DNA fragment was observed in addition to supercoiled Form I, open circular Form II and linear Form III.