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Öğe 4-tert-butylcalix[4]arene having nitrile pendant groups as Hg2+ selective receptors(ELSEVIER SCIENCE BV, 2013) Tabakci, Begum; Alici, Onder; Karatas, IbrahimWe synthesized a series of 4-tert-butylcalix[4]arene nitriles (5-7) by the reaction of 4-tert-butylcalix[4]arene (1) with 4'-(6-bromohexyloxy)biphenyl-4-carbonitrile (2), 4'-(10-bromode-cyloxy)biphenyl-4-carbonitrile (3), and 4'-(12-bromododecyloxy)biphenyl-4-carbonitrile (4) and characterized their structures, respectively. The extraction abilities of newly synthesized 5-7 toward some selected heavy metal cations, such as Co2+, Cu2+, Ni2+, Zn2+, Cd2+, and Hg2+, were first evaluated and compared by the solvent extraction method. The extraction results revealed that 5-7 were efficient and selective cation receptors for Hg2+ over-selected cations. On the other hand, the complexation behavior of Hg2+ with 5-7 was also investigated by using NMR, UV-vis, and IR spectroscopic methods. (C) 2012 Elsevier B.V. All rights reserved.Öğe Amine-derivatized calix[4]arenes for sensitive extraction of cupric ion and formation of amine radical cation(ELSEVIER, 2014) Tabakci, Begum; Yilmaz, AydanWe 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.Öğe 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, AydanA 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.Öğe Fast and reversible "turn on" fluorescent sensors based on bisphenol-a for zn2+ in aqueous solution(SPRINGER/PLENUM PUBLISHERS, 2019) Tabakci, Begum; Ahmed, Hayder Mahdi Ahmed; Erdemir, SerkanTwo novel bisphenol-A derivatives (R1 and R2) linked pyrene and napthylthiazole moieties were synthesized via condensation reaction, and positively applied for the selective recognition of Zn2+ ion in EtOH/H2O. Their optical properties were observed by using UV-vis and fluorescence measurements. R1 and R2 exhibited high selectivity and sensitivity towards Zn2+ over other metal ions. This fluorescence selectivity may be owing to inhibited excited-state intramolecular proton transfer (ESIPT) and photoinduced electron transfer (PET). The fluorescence titration analysis indicated detection limits of R1 and R2 for Zn2+ at 17.5 nM and 0.94 mu M, respectively. Moreover, R1 and R2 were successfully applied to the detection of Zn2+ with different concentrations in water samples.Öğe A highly selective fluorescent sensor based on calix[4]arene appended benzothiazole units for Cu2+, S2- and HSO4- ions in aqueous solution(ELSEVIER SCIENCE SA, 2016) Erdemir, Serkan; Tabakci, Begum; Tabakci, MustafaA novel calix[4]arene receptor containing benzothiazole units in 1,3-alternate conformation (L) was synthesized and characterized by H-1, C-13, APT, COSY NMR, FTIR, elemental analysis, and UV-vis spectral data. The cation and anion binding properties of L were investigated in the presence of various cations and anions. L showed "on-off' type fluorescence response towards Cu2+ with high selectivity in aqueous solution (CH3CN/H2O, 4/1, v/v). Once binding with Cu2+, L-Cu2+ complex displayed high selectivity for sulfide. Among the various anions, only sulfide anion induced the revival of fluorescence of L, resulting in "off-on" type sensing of sulfide anion. Furthermore, L served exclusive response towards HSO4- ion via hydrolysis process with 10-fold fluorescence enhancement at 542 nm. (C) 2016 Elsevier B.V. All rights reserved.Öğe Highly sensitive fluorometric detection of Zn2+ ion by calix [4] arene derivative appended 4-biphenylcarbonitrile(ELSEVIER SCI LTD, 2018) Erdemir, Serkan; Tabakci, BegumA novel calix[4]arene derivative bearing 4-biphenylcarbonitrile unit (CCP) was developed for the selective fluorescent sensing of Zn2+ with a discriminating enhancement of 14-folds over the other metal ions. CCP exhibited highly selective and sensitive fluorescence "off-on" recognition to Zn2+ with a 1:1 binding stoichiometry in aqueous solution (EtOH/H2O, 8/2, v/v). The binding constant was calculated as 3.50 x 10(5) M-1 with detection limit of 0.31 mu M, which presented a pronounced sensitivity toward Zn2+ ion. To check its applicability, an easy prepared test paper strip of CCP was made for rapid and selective detection of Zn2+. Also, the determination of Zn2+ in water samples was evaluated. Otherwise, the results demonstrated that the binding between CPP and Zn2+ is chemically reversible in presence of only cysteine among the various amino acids and anions, resulting in "on-off" type sensing of cysteine.Öğe 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, MustafaWe 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.Öğe Rapid and real-time detection of arginine enantiomers by QCM sensor having a Calix[4]arene receptor bearing asymmetric centers(ELSEVIER, 2019) Temel, Farabi; Erdemir, Serkan; Ozcelik, Egemen; Tabakci, Begum; Tabakci, MustafaThis paper describes the sensing studies of a chiral calix[4]arene receptor (5) having (R)-2-phenylglycinol moiety for arginine enantiomers (D-/L-arginine) by using Quartz Crystal Microbalance (QCM) technique. The initial experiments have revealed that the chiral calix[4]arene 5 coated QCM (CCC-QCM) sensor showed good sensing for arginine enantiomers, such that it has exhibited higher sensing towards D-arginine than that of L-arginine. It has been determined that the sensitivity, limit of detection values of CCC-QCM sensor for the D-/L-arginine solutions as 0.024/0.023 Hz/mu M and 0.38/1.29 mu M, respectively. On the other hand, the racemic mixture studies were optimized using the response surface methodology with central composite design. Consequently, it has been demonstrated that the QCM sensor modification with a calix[4]arene receptor bearing asymmetric centers provided rapid, real-time, sensitive and effective sensing of arginine enantiomers.Öğe Selective and Sensitive Fluorescein-Benzothiazole Based Fluorescent Sensor for Zn2+ Ion in Aqueous Media(SPRINGER/PLENUM PUBLISHERS, 2017) Erdemir, Serkan; Tabakci, BegumAn efficient fluorescent sensor based on fluorescein-benzothiazole (FB) for Zn2+ ion was synthesized and characterized systematically. FB exhibited selective and sensitive recognition toward Zn2+ in MeCN-H2O (v/v = 2/1) over other cations due to the spirolactam ring-opening power of Zn2+. The complexation property of FB with Zn2+ ion was examined by H-1 NMR, C-13 NMR and FTIR experiments. The stoichiometric ratio of the FB-Zn2+ complex was determined from a Job plot to be 1:1. The binding constant (K-a) of Zn2+ binding to FB was found to be 4.22 x 10(4) M- 1, with a detection limit of 5.64 mu M. In addition, the practical utility of FB was explored in the form of test strips.Öğe Synthesis and application of an efficient calix[4]arene-based anion receptor bearing imidazole groups for Cr(VI) anionic species(PERGAMON-ELSEVIER SCIENCE LTD, 2012) Tabakci, Mustafa; Tabakci, Begum; Beduk, A. DincerWe synthesized the new calix[4]arene amines bearing two and four imidazole or tert-butylamine moieties (9a,b/10a,b) by the reaction of di-or tetra-tosylated calix[4]arene derivatives (7 and 8, respectively) with 1-(3-aminopropyl)imidazole and/or tert-butylamine, respectively. After the characterization of 9a,b/10a,b their extraction abilities toward Cr(VI) anionic species (CAS) was evaluated and compared by the liquid liquid extraction method. The extraction results revealed that calix[4]arene amine having four imidazole groups (10a) was an efficient anion receptor for CAS. Moreover, the extraction of CAS by 10a in the presence of other anions such as Cl-, NO3-, and PO43- showed that 10a could be a selective anion receptor for CAS in the presence of those anions. (C) 2012 Elsevier Ltd. All rights reserved.Öğe 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, MustafaThe 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.
