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Öğe Adsorptive removal of Cu(II) and Ni(II) ions from aqueous media by chemical immobilization of three different aldehydes(ELSEVIER, 2011) Dumrul, Hakan; Kursunlu, Ahmed Nuni; Kocyigit, Ozcan; Guler, Ersin; Ertul, SerefThe three aldehydes were chemically immobilized onto silica gel modified with 3-aminopropyltrimethoxy silane, just as the classic condensation reaction of Schiff bases. The obtained silica gel structures used as adsorbent were characterized by infrared spectroscopy, elemental analysis and thermogravimetric analysis. The adsorption capabilities of these adsorbents towards Cu(II) and Ni(II) from aqueous solutions were studied and values of adsorption were detected by an atomic absorption spectrometer. The maximum adsorption capacities and isotherm parameters were found from the Langmuir and Freundlich equations. The characteristics of Ni(II) and Cu(II) metal bindings were interpreted by using Scatchard plot graphics, and it was showed that in different concentrations multi-type and/or nonspecific interactions among metal ions and modified silica gel structures were the prevailing effects causing the Ni(II) and Cu(II) adsorptions. Conclusively, probable benefit of each specific binding type in adsorptions of Ni(II) and Cu(II) from aqueous media has been discussed in detail. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.Öğe Effect of macrocyclic lactam receptors on extraction of heavy metals and chromate anions(SPRINGER, 2011) Ertul, Seref; Azak, HacerThe article presents the syntheses and extraction properties of new lactam ionophores. These lactam derivatives were easily synthesized via aminolysis of 2,2'-methylenebis(4-chlorophenol) dimethylester with corresponding diamine compounds in methanol-dichloromethane solvent systems at one step, respectively. The extraction studies of lactam ionophores were performed toward dichromate anion and alkaline and transition metals such as Li+, Na+, K+, Co2+, Hg2+ and Pb2+. All the structures of the ionophores were confirmed by spectroscopic techniques and elemental analysis.Öğe Fabrication of Langmuir-Blodgett thin films of calix[4]arenes and their gas sensing properties: Investigation of upper rim para substituent effect(ELSEVIER SCIENCE SA, 2014) Ozmen, Mustafa; Ozbek, Zikriye; Buyukcelebi, Sumeyra; Bayrakci, Mevlut; Ertul, Seref; Ersoz, Mustafa; Capan, RifatThis study reports the characterization and organic vapor sensing properties of Langmuir-Blodgett (LB) thin films of calix[4] arene derivatives that contain different numbers of tert butyl groups on their upper rims. Surface pressure-area isotherms show that very stable monolayers are formed at the air-water interface. The LB films are deposited onto different substrates, which allowed us to characterize the films by contact angle measurements, quartz crystal microbalance (QCM), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The results indicate that good quality, uniform LB films can be prepared with transfer ratios of over 0.95. Meanwhile, our QCM results show that the deposition of LB film layers depends heavily on the number of p-tert-butyl groups and calix[4]arene with four p-tert-butyl groups yields the highest slope with a mass value of 1145 ng per layer. Furthermore, our AFM and SEM studies reveal a dense surface morphology for all prepared LB films. The kinetic response of calix[4]arenes containing p-tert-butyl groups and without p-tert-butyl groups as an LB film to chloroform, benzene, toluene, and ethanol vapors were investigated as a function of time. After attaching tert-butyl groups onto the calix[4]arene structure, the response of LB film to chloroform vapor increased. LB films of compounds 1-4 yield a response to all vapors and more often select chloroform with a larger, faster, and more reproducible response. We thus conclude that these calix[4]arenes could be applied to research concerning vapor sensing devices operating at room temperature. (C) 2013 Elsevier B.V. All rights reserved.Öğe Fabrication of protein scaffold by electrospin coating for artificial tissue(ELSEVIER SCIENCE BV, 2016) Ozcan, Fatih; Ertul, Seref; Maltas, EsraProtein nanofiber scaffolds were produced by electrospin coating for biomedical applications. Therefore, protein such as bovine serum albumin, gobulin and hemoglobin were used as scaffold for tissue engineering. The nanofiber diameters were found to be 75 nm of globulin, 117 nm for hemoglobin and 220 nm for BSA. The protein nanofibers were characterized by using Fourier transform infrared spectroscopy, Scanning electron microscopy, Transmission electron microscopy and Atomic force microscopy. (C) 2016 Elsevier B.V. All rights reserved.Öğe Humic-makeup approach for simultaneous functionalization of polyacrylonitrile nanofibers during electrospinning process, and dye adsorption study(TAYLOR & FRANCIS INC, 2016) Gezici, Orhan; Guven, Idris; Ozcan, Fatih; Ertul, Seref; Bayrakci, MevlutA useful methodology is represented to functionalize polyacrylonitrile nanofibers by using humic acid as a makeup agent in electrospinning process. Both morphology and surface chemistry of polyacrylonitrile nanofiber mats were understood to be influenced by incorporation of humic acid into the structure. Physicochemical changes were evidenced by Fourier transform infrared spectroscopy, scanning electron microscope, and surface charge measurements. Unlike some anionic dyes (i.e., methyl orange, methyl red, and Congo red), there was an enhancement in crystal violet (a cationic dye) adsorption after incorporation of humic acid. The Langmuir model fitted well to crystal violet data, and monolayer adsorption capacity was calculated as 81.6 mg/g (r(2) = 0.998).Öğe A new calix[4]azacrown ether based boradiazaindacene (Bodipy): Selective fluorescence changes towards trivalent lanthanide ions(ELSEVIER SCI LTD, 2013) Bayrakci, Mevlut; Kursunlu, Ahmed Nuri; Guler, Ersin; Ertul, SerefWe report on the synthesis and photophysical properties of a new calix[4]azacrown derivative, capped with two amide bridges, in the cone conformation bearing two boradiazaindacene (Bodipy) groups at the narrow rim. Its binding properties towards trivalent lanthanide ions such as La3+, Gd3+, Tb3+, Dy3+, Er3+ and Yb3+ were investigated by using spectroscopic techniques. With respect to fluorescence intensity changes upon trivalent lanthanide ion complexation, calix[4]azacrown ether based Bodipy showed higher selectivity towards Yb3+ ion over other ions. Presence of proximal two amide groups in calix[4] azacrown ether based Bodipy were observed to play an important role in exhibiting its lanthanide ion binding. (C) 2013 Elsevier Ltd. All rights reserved.Öğe Preparation and gas sensing properties of Langmuir-Blodgett thin films of calix[n]arenes: Investigation of cavity effect(ELSEVIER SCIENCE SA, 2014) Ozmen, Mustafa; Ozbek, Zikriye; Bayrakci, Mevlut; Ertul, Seref; Ersoz, Mustafa; Capan, RifatCharacterization and organic vapor sensing properties of Langmuir-Blodgett (LB) thin films of calix[n]arene (n=4, 6, 8) derivatives are reported in this work. Surface pressure-area isotherm graph shows that very stable monolayers are formed at the water surface. The results indicate that good quality, uniform LB films can be prepared with a transfer ratio of over 0.95. Calix[n]arene LB films have been characterized by contact angle measurements, quartz crystal microbalance (QCM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). LB film of calix[8]arene which has the largest cavity yields a gradient with a mass value of 773 ng per layer according to the QCM results. AFM and SEM images showed a dense surface morphology obtained for all samples. QCM system was used for the measurement of sensor response against chloroform, benzene, toluene and ethanol vapors. These LB film samples yield a response to all vapors with a large, fast, and reproducible due to the adsorption of vapors into the LB film structures. Among them, calix[8]arene LB film has higher sensitivity toward the organic vapors because of a large cavity size. This study can be concluded that the cavity size of calix[n]arene molecule could have an important role in the research area of room temperature vapor sensing devices. (C) 2014 Elsevier B.V. All rights reserved.Öğe Preparation of Langmuir-Blodgett thin films of calix[6]arenes and p-tert butyl group effect on their gas sensing properties(ELSEVIER SCIENCE BV, 2015) Ozmen, Mustafa; Ozbek, Zikriye; Bayrakci, Mevlut; Ertul, Seref; Ersoz, Mustafa; Capan, RifatOrganic vapor sensing properties of Langmuir-Blodgett (LB) thin films of p-tert-butyl calix[6]arene and calix[6]arene, and their certain characterization are reported in this work. LB films of these calixarenes have been characterized by contact angle measurement, quartz crystal microbalance (QCM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). QCM system was used for the measurement of sensor response against chloroform, benzene, toluene and ethanol vapors. Forming of stable monolayers was observed at the water surface using surface pressure-area isotherm graph. The results indicate that good quality, uniform LB films can be prepared with a transfer ratio of over 0.95. Due to the adsorption of vapors into the LB film structures; they yield a response to all vapors as of large, fast, and reproducible. (C) 2015 Elsevier B.V. All rights reserved.Öğe Removal of chromate and phosphate anion from aqueous solutions using calix[4]aren receptors containing proton switchable units(ELSEVIER SCIENCE BV, 2010) Ertul, Seref; Bayrakci, Mevluet; Yilmaz, MustafaIn the present study four new calix[4]arene amide ionophores (4-7) have been prepared by aminolysis of calix[4]arene diester (3) and investigated their extraction ability toward phosphate and dichromate anions at different pH. The H-1 NMR data showed that the synthesized compounds exist in the cone conformation. Liquid-liquid extraction experiments have been performed to evaluate the dichromate and phosphate anions extraction efficiency of both calix[4]arene bearing amide-pyridinium units (4-7) and the calix[4]arene derivative bearing aminomethyl pyridinium units (8, 9). It was observed that, compounds 4-7 exhibited lower affinity toward phosphate ions than the calix[4]arene derivative bearing amine pyridinium units (8, 9). The extraction of phosphate and dichromate anions by these compounds indicates that the partially protonated pyridyl or amino groups play the major role for the formation of hydrogen bonds and electrostatic interactions. (C) 2010 Elsevier B.V. All rights reserved.Öğe Removal of Phosphate Anions from Aqueous Solutions by Using Macrocyclic Receptors-Based Polyether, Lactone and Lactam Derivatives(TAYLOR & FRANCIS INC, 2011) Ertul, Seref; Bayrakci, Mevlut; Yilmaz, MustafaIn this study, the phosphate anions extraction efficiency of a series of receptors-based lactones 1a-d, 2, and 3, polyethers 4 and 5, lactam derivatives 6a-b, 7a-b, and 8a-d towards phosphate anion was evaluated by solvent extraction. It was observed that compounds 7a-b exhibited higher affinity toward phosphate ions than the other receptors. The extraction of phosphate anions by these compounds 7a-b indicates that the partially protonated amino groups play the major role for the formation of hydrogen bonds and electrostatic interactions at low pH. Furthermore, the effect of the polyethylene linkage and cavity of crown moieties on anion extraction was investigated. To evaluate the selectivity of receptors 6a-b and 7a-b, we also examined the retention of phosphate anions in the presence of Cl-, [image omitted], and [image omitted] anions at pH 1.5.Öğe The Syntheses and Characterization of Three Novel Macrocyclic Polyether Ligands and Some of Their Alkaline Metal Complexes(JIHAD DANESHGAHI, 2008) Ertul, Seref; Bayraki, Mevlut; Beduk, A. DincerThe macrocyclic ligands 2,3,5,6-Bis{3'-bromo-5'-tert-butyl benzo-5-phenyl benzo} 12C3 (L-1), 2,3,5,6-bis{3'-bromo-5'-tert butyl-benzo-5'-phenyl-benzo} 15C4 (L-2), 2,3,5,6-bis{3'-bromo-5'-tert butyl-benzo-5'-phenyl-benzo} 18C5 (L-3) have been synthesized and their alkaline metal compounds with NaClO4 center dot H2O and KClO4 have been prepared. Chemical formulas of all compounds have been characterized by using elemental analyses and spectroscopic techniques.Öğe Synthesis and characterization of nickel(II) and copper(II) complexes of the Schiff bases derived from 4-/6-methyl-Delta(3)-tetrahydrobenzaldehyde and glycine(ASIAN JOURNAL OF CHEMISTRY, 2008) Gueler, Ersin; Ertul, Seref; Okudan, Ahmet; Kocyigit, OezcanNickel(II) and copper(II) complexes with the Schiff bases derived from 4-methyl-Delta(3)-tetrahydrobenzaldehyde or 6-methyl-Delta(3)-tetrahydrobenzaldehyde and glycine were synthesized. These compounds have been characterized by elemental analysis, conductivity measurements and infrared spectroscopy. The Schiff base ligands and their complexes have been further characterized by H-1 NMR. The results suggest that the Schiff base acts as a bidentate ligand which bonds to the metal ions through the imino nitrogen and carboxylate oxygen. The potassium salts of the Schiff bases are 1: 1 electrolytes, but all the complexes are non-electrolytes.Öğe Synthesis and Preparation of Novel Magnetite Nanoparticles Containing Calix[4]arenes With Different Chelating Group Towards Uranium Anions(TAYLOR & FRANCIS INC, 2015) Ozcan, Fatih; Bayrakci, Mevlut; Ertul, SerefIn this study, four new magnetite nanoparticle containing different chelating groups as ester, amide and azacrown moieties at the lower rim of calix[4]arenes were prepared by the reaction of formylated calix[4]arenes and amino propyl modified magnetite nanoparticles (APTMS-MN). All of the newly synthesized and prepared compounds were characterized by using different analytical techniques such as nuclear magnetic resonance spectroscopy (NMR), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and thermogravimetric analyses (TGA). Furthermore, uranium binding abilities of newly prepared magnetite nanoparticles were evaluated by using solid-liquid phase extraction process and obtained results showed that magnetite nanoparticles containing picolinamide units exhibited superior and more efficient extraction percentage for uranium ions at lower pH values.Öğe Synthesis and Spectroscopic Studies of Novel Rhodanine Azo Dyes: An Excellent Selective Chemosensor for Naked-eye Detecting of Cu2+ Ion(SLOVENSKO KEMIJSKO DRUSTVO, 2012) Ceylan, Abdullah; Bas, Salih Zeki; Bayrakci, Mevlut; Ertul, Seref; Uysal, AhmetThis study is first report on the synthesis of novel rhodanine based azo dyes and their fluorogenic and chromogenic sensing behaviors with metal ions (Li+, Na+, K+, Rb+, Pb2+, Ni2+, Zn2+, Cu2+) by using UV-vis and fluorescence spectroscopy techniques. The results of spectroscopic experiments for rhodanine based azo dye 1a exhibited excellent selectivity for Cu2+ over the other metal ions. Furthermore, anti-bacterial studies of rhodanine azo dyes were performed towards some selected bacteria via microbroth dilution method. Obtained results showed that rhodanine ionophore 1a showed strong antibacterial activity against S. aureus.Öğe Synthesis and trivalent lanthanide ion complexation studies of new macrocyclic receptors based lactam ionophores(SPRINGER, 2014) Gullu, Fadime; Bayrakci, Mevlut; Kursunlu, Ahmed Nuri; Yigiter, Sengul; Ertul, SerefThis study is the first report on the design, synthesis and photophysical properties of three new macrocyclic receptors based receptors containing two amide bridges. Their binding properties towards trivalent lanthanide ions such as La3+, Gd3+, Tb3+, Dy3+, Er3+ and Yb3+ were investigated by using spectroscopic techniques. With respect to emission intensity changes upon trivalent lanthanide ion complexation, macrocyclic receptors based lactam ionophores showed higher selectivity towards Yb3+ and/or Er3+ ion over other ions. Presence of proximal two amide groups in macrocyclic lactam receptors having different cavity size were observed to play an important role in exhibiting its lanthanide ion binding.Öğe Synthesis of calixamide nanofibers by electrospinning and toxic anion binding to the fiber structures(PERGAMON-ELSEVIER SCIENCE LTD, 2015) Bayrakci, Mevlut; Ozcan, Fatih; Ertul, SerefThis study reports the synthesis of three novel polyacrylonitrile (PAN) nanofibers based calixamide containing pyridine groups by electrospinning. The structures of the newly prepared nanofibers were clarified using spectroscopic techniques. Analysis indicated that preparation of nanofibers based calixamide was successfully achieved. The presence of calixarene molecules in the nanofiber backbones was confirmed by Fourier transform infrared (FTIR-ATR), scanning electron microscope (SEM), and thermogravimetric analyses (TGA and DSC). The toxic anion binding studies exhibited that the nanofiber-based calixamide could be efficiently used for the binding of chromate anions as a model toxic oxoanion. Nanofiber based calixamide may be a good candidate as a filter material for water purification and waste treatment owing to their very large surface area as well as the inclusion complexation capability of all surfaces associated with the calixarene skeleton. (C) 2015 Elsevier Ltd. All rights reserved.Öğe Synthesis of di-substituted calix[4]arene-based receptors for extraction of chromate and arsenate anions(PERGAMON-ELSEVIER SCIENCE LTD, 2009) Bayrakci, Mevluet; Ertul, Seref; Yilmaz, MustafaThe article describes the synthesis of a family of novel calix[4]arene ionophores, 25,27-bis-(2-aminomethylpyridine-propoxy)-26,28-dihydroxycalix[4]arene (5a), 25,27-bis-(3-aminomethylpyridine-propoxy)-26,28-dihydroxycalix[4]arene (5b) and two chromogenic calix[4]arenes, 5,17-dinitro-25,27-bis-(2-aminomethylpyridine-propoxy)-26,28-dihydroxycalix[4]arene (5c), 5,17-dinitro-25,27-bis-(3-aminomethylpyridine-propoxy)-26,28-dihydroxycalix[4]arene (5d) bearing pyridinium units. In the synthesis, the upper and lower rims of p-tert-butylcalix[4]arene were modified in order to acquire binding sites for the recognition of arsenate and dichromate anions. It has been observed that protonated alkylammonium forms of the ionophores showed high affinity toward dichromate and arsenate anions. (C) 2009 Elsevier Ltd. All rights reserved.Öğe Synthesis of macrocyclic polyethers and polyether diesters and preparation of their cationic complexes(VERSITA, 2008) Ertul, Seref; Beduk, A. Dincer; Bayrakci, Mevluet; Guler, ErsinNew macrocyclic polyethers, 2,3,5,6-bis-[5'(5')-chlorobenzo]-1,7,10-trioxacyclododeca-2,5-diene (I), 2,3,5,6-bis-[5'(5')-chlorobenzo]-1,7,10,13-tetra oxacyclo pentadeca-2,5-diene (II), and 2,3,5,6-bis-[5'(5')-chlorobenzo]-1,7,10,13,16-penta oxa cyclo octadeca-2,5-dien (III), and macrocylic lactones 2,3,5,6-bis-[5'(5')-chlorobenzo]-1,7,10,13-tetraoxacyclopentadeca-2,5-diene-8,15-dione (IV) and 2,3,5,6-bis[5'(5')-chlorobenzo]-1,7,10,13,16-pentaoxacyclooctadeca-2,5-diene-8,18-dione (V) were synthesized. Complexes of ligands III and V with metal cations were prepared. Furthermore, their metal-picrate extraction with some metal salts was attempted. Structures of the ligands and complexes were confirmed using spectroscopic techniques. (C) 2008 Institute of Chemistry, Slovak Academy of SciencesÖğe Synthesis of new water-soluble phosphonate calixazacrowns and their use as drug solubilizing agents(SPRINGER, 2012) Bayrakci, Mevlut; Ertul, Seref; Yilmaz, MustafaThis study presents the selective chloromethylation of calix[4](aza)crown ethers 2a-c, using chloromethyl n-octyl ether and SnCl4 in chloroform at room temperature in good yield for the first time. Chloromethylated products 2a-c are used as key intermediates to synthesize new water-soluble p-phosphonato calix[4](aza)crown ethers 5a-c. Liquid-liquid phase extraction and phase solubility studies with poor water soluble drug molecules such as nifedipine, niclosamide and furosemide are performed to evaluate their binding properties. Among the studied drugs, furosemide was the most effectively dissolved drug by p-phosphonato calix[4](aza)crown ethers 5a-c in water.Öğe Synthesis of Novel Macrocyclic Lactam Based Receptors for Alkali or Transition Metal Cations and Cr2O72- Anions(SLOVENSKO KEMIJSKO DRUSTVO, 2009) Ertul, Seref; Tombak, Haci Ahmet; Bayrakci, Mevluet; Merter, OrhanThe article describes the syntheses and extraction properties of new lactam ionophores. These lactam derivatives were easily synthesized via aminolysis of 2,2'-methylenebis(4-chlorophenol) dimethylester or its corresponding acyl chloride with corresponding diamine compounds in THF or methanol-dichloromethane solvent systems in one step, respectively. The extraction studies of lactam ionophores were performed toward dichromate anion and alkaline and transition metal cations such as Li+, Na+, K+, Co2+, Hg2+ and Pb2+. All the structures of the ionophores were confirmed by spectroscopic techniques and elemental analysis.
