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Öğe A Calix[4]arene-tren modified electrode for determination of Lead ions in aqueous solution(ACG PUBLICATIONS, 2019) Kocer, Mustafa Baris; Erdogan, Zehra Ozden; Oguz, Mehmet; Kucukkolbasi, Semahat; Yilmaz, MustafaIn this study, a simple and sensitive electrochemical sensor based on Calix[4]arene-tren (Calix-tren) modified glassy carbon (GC) electrode was developed for the determination of Pb (II) ions. Electrochemical behavior of Calix-tren modified electrodes were investigated by using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results indicate that Calix-tren modified GC electrode provides good electron transmission pathway than bare GC electrode. The amount of Pb (II) was determined by differential pulse anodic stripping voltammetric analysis as a sensitive detection technique. The experimental parameters such as pH, deposition time and deposition potential were optimized. The optimum pH value was selected as 7.0. The effect of deposition potential and deposition time on the peak current was tested and the optimum values were chosen as -1.2 V and 120 s, respectively. Under the optimal conditions, the working range of the developed sensor was determined as 0.48-2.31 mu M, limit of detection (LOD) was 0.11 mu M and the RSD obtained in the reproducibility study was 2.78 %. It was also found that the developed method could be used in the determination of Pb (II) ions in real samples with satisfactory results.Öğe Dual Fluorescence Response of Newly Synthesized Naphthalene Appended Calix[4]arene Derivative towards Cu2+ and I-(SPRINGER/PLENUM PUBLISHERS, 2017) Bhatti, Asif Ali; Oguz, Mehmet; Memon, Shahabuddin; Yilmaz, MustafaIn the present work new naphthalene appended calix[4]arene (NAC4) i.e. 5,11,17,23-tetra-tert-butyl-25,27-di((2-amido(1-naphthlene)ethyl)-26,28-dihydroxy calix[4]arene (6) was designed and successfully synthesized. NAC4 was characterized by (HNMR)-H-1 and FTIR. To explore the complexation behavior and fluorescence response of NAC4, UV-visible and fluorescence studies were carried out with series of metal ions and anions that include solvatochromic effect, ion-ligand response and interference on absorption and fluorescence spectra. Results show that the NAC4 is highly Cu2+ and I(-)selective. The ligand ion interaction follow photoinduced electron transfer (PET) mechanism. The stiochiomatric ratio of ion-ligand was calculated as 1:1 by using Job's plot method and binding constant K-a values were calculated by using Benesi-Hildebrand equation as 1x10(3) and 8x10(2) M-1 with detection limit of 1.05x10(-5) and 4.0x10(-5) M for Cu2+ and I- respectively.Öğe Magnetizing Calixarene: Azo Dye Removal from Aqueous Media by Fe3O4 Nanoparticles Fabricated with Carboxylic-Substituted Calix[4]arene(AMER CHEMICAL SOC, 2017) Bhatti, Asif Ali; Oguz, Mehmet; Yilmaz, MustafaCalix[4]arene was reacted with isonipecotic acid to synthesize the Mannich base derivative, and Fe3O4 magnetic nanoparticles were bonded to the lower rim of the calix[4]arene derivative through ether linkage to obtain carboxylic calix[4]arene magnetic nanoparticles (CCMN). After characterization with transmission electron microscopy and Fourier transform infrared spectroscopy, adsorption studies were carried out for the removal of azo dyes (Evans Blue and Chicago Sky Blue 6 B). Adsorption parameters such as effects of pH, dosage, concentration, temperature, and time were optimized. Results showed that adsorption equilibrium was achieved within 15 min, and maximum % adsorption was calculated as 95% for both dyes at pH 2.5. An equilibrium isotherm study suggests that the adsorption mechanism follows a chemical ion exchange process with an adsorption capacity value of 13.9 and 17.5 mmol g(-1) for Evans Blue and Chicago Sky Blue 6 B, respectively. The adsorption kinetic follows pseudo second-order kinetics as anticipated from R-2 values, whereas thermodynamic parameters suggest an endothermic reaction that can also be evident from Delta G degrees values, which decreased with an increase in temperature suggesting a spontaneous reaction. In addition, the dye removal efficiency of CCMN was hardly effected after 10 consecutive cycles. The study suggests that the magnetically retrievable calix[4]arene is a promising adsorbent for removal of azo dyes from aqueous solution.Öğe A New Piperidine Derivatized-Schiff Base Based "Turn-on" Cu(2+)Chemo-Sensor(SPRINGER/PLENUM PUBLISHERS, 2017) Uyanik, Ibrahim; Oguz, Mehmet; Bhatti, Asif Ali; Uyanik, Arzu; Yilmaz, MustafaIn this study, we report the synthesis of new Schiff base E-1-(((1-benzylpiperidin-4-yl)imino)methyl)naphthalenee-2-ol (L) and evaluation of its fluorescence response toward Cu2+ ion. Preliminary, solvent effect, metal selectivity and metal ligand ratio were analyzed through UV-Visible study. Fluorescence response toward Cu2+ was carried to assess the fluorescent property of synthesized Schiff base. The probe exhibited a higher fluorescence enhancement in the presence of Cu2+ over other metal ions (Ni2+, Zn2+, Hg2+, Co2+, Cd2+, Al3+, Fe2+, and Pb2+). The binding stoichiometry between L and Cu2+ has been investigated using Job's plot and Benesi-Hildebrand equation and it was found that ligand L can form 1:1 L-Cu2+ complex with binding constant (K (a)) of 4 x 10(4) LM-1.Öğe New water soluble Hg2+ selective fluorescent calix[4]arenes: Synthesis and application in living cells imaging(PERGAMON-ELSEVIER SCIENCE LTD, 2017) Oguz, Mehmet; Bhatti, Asif Ali; Karakurt, Serdar; Aktas, Mehmet; Yilmaz, MustafaThe present study demonstrates the synthesis of water-soluble fluorescent calix[4]arenes (6 and 7) and its application in living cell imaging for Hg2+ detection at a low level. The synthesized fluorescent ligands 6 and 7 were characterized by H-1 NMR technique. The fluorescent study showed both water soluble ligands were Hg2+ selective and follow photo-induced electron transfer (PET) process. From the fluorimeter titration experiment detection limit was calculated as 1.14 x 10(-5) and 3.42 x 10(-5) for ligand 6 and 7, respectively. From the Benesi-Hildebrand plot binding constant values were evaluated as 666.7 and 733.3 M-1 for 6 and 7, respectively. The interactions between ligands 6 and 7 and Hg2+ were also demonstrated in living cells, SW-620, using Fluorescent Cell Imager. While ligands 6 and 7 alone show fluorescent properties, they loss their action with the presence of Hg2+ in SW-620 cells. (C) 2016 Elsevier B.V. All rights reserved.Öğe One-pot synthesis of Fe3O4@Chitosan-pSDCalix hybrid nanomaterial for the detection and removal of Hg2+ ion from aqueous media(ELSEVIER SCIENCE BV, 2018) Bhatti, Asif Ali; Oguz, Mehmet; Yilmaz, MustafaNew one pot mesoporous hybrid material containing iron nanoparticles fabricated with chitosan and p-sulfonato dansyl calix[4] arene composite (Fe3O4@Chitosan-pSDCalix) has been susccessfully synthesized. These mesoporous fluorescence iron nanoparticles were applied for the detection and removal of environmentally toxic Hg2+ ion from aqueous media. Different techniques were applied to confirm the preparation of Fe3O4@Chitosan-pSDCalix such as HRTEM, TGA/DTA, FTIR and XRD. Synthesized nanoparticles have average size of 17 nm with pore size of 0.19 nm as revealed from HRTEM images. Fluorescence study follow the photoinduced electron transfer process after addition of Hg2+ in the solution with decrease in intensity. Confocal microscope images were also acquired to confirm the presence of Hg2+ on nanoparticles. Adsorption study suggests that the removal of Hg2+ from aqueous media follows Langmuir adsorption isotherm. These studies suggest the synthesized Fe3O4@Chitosan-pSDCalix is an efficient hybrid material for the detection and removal of Hg2+ ion from aqueous media, and that it can also be used in biomolecules for the detection of toxic metal ions. (C) 2017 Elsevier B.V. All rights reserved.Öğe Synthesis and evaluation of fluorescence properties of Cu2+ selective azocalix[4]arenes and their application in living cell imaging(ELSEVIER SCIENCE SA, 2016) Elcin, Serkan; Deligoz, Hasalettin; Bhatti, Asif Ali; Oguz, Mehmet; Karakurt, Serdar; Yilmaz, MustafaThe present article deals with the detailed complexation study along with exploration of possible utilization of 25,26,27,28-tetra-hydroxy-11,23-di-(tert-butyl)-5,17-di-(2-antracenyl)azocalix[4]arene(7) and 25,26,27,28-tetra-hydroxy-11,23-di-(tert-butyl)-5,17-di-(1-pyreneyl)azocalix[4]arene (8) as bio-imaging fluorescent probe to detect Cu2+ in human colon cell line, SW-620, observed by fluorescence microscopy. Complexation properties of ligands 7 and 8 toward selected transition metal ions have been investigated by UV-vis and fluorescence spectroscopies. It has been noticed that ligands 7 and 8 are not only proved to be an efficient Cu2+ selective chromoionophore but also possess effective fluorescence properties by complexing with Cu2+ ions. The FTIR spectroscopic method has also been applied for further confirmation of the complexation phenomenon of ligands 7 and 8 with metal ion and were found to be adequate. Moreover, fluorescence microscopy studies showed that ligand 7 may be used as fluorescent probe to detect Cu2+ in living cells. (C) 2016 Elsevier B.V. All rights reserved.