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Öğe Calixarene Nanofiber Design for Human Colon Cancer 3D-Cell Culture(IEEE, 2017) Arpacı, P. Uyar; Özcan, Fatih; Ağaç, Müslüm; Ertul, ŞerefA growing body of evidence has suggested that 3D cell culture systems, in contrast to the 2D systems, represent more accurately the actual microenvironment where cells reside in tissues. Therefore, researchers have concentrated on developing realistic and sophisticated in-vitro 3D cell culture models that actually resemble the complex environment of native tissues. Calixarenes, similar to a ring basket, represent a third generation of supramolecular hosts could be promising candidates in this regard. Due to having a cyclic structure and large surface area, calixarenes, can be functionalized easily with polar and apolar groups, be a good carrier for cations, anions and neutral molecules. Electrospinning of p-tert-butylcalix[4] arene nanofibers with different functional groups were performed and their endothelial (Caco-2) and fibroblastic (L-929) cytocompatibility behaviour on cell adhesion function were examined. Cell attachment kinetics revealed that the (Caco-2) and L-929 attached to the nanofibers functionalized with pyridinumat position 3 at the same rate as to tissue culture plates. In this report, for the first time in literature, it was shown that 3D cultured systems designed with calixarene nanofibers provide excellent in vitro models, allowing the study of cellular responses in a setting that resembles in vivo environments.Öğe Electrospun Nanofibrous Polyacrylonitrile/calixarene Mats: an Excellent Adsorbent for the Removal of Chromate Ions from Aqueous Solutions(SLOVENSKO KEMIJSKO DRUSTVO, 2017) Bayrakcı, Mevlüt; Özcan, Fatih; Yılmaz, Bahar; Ertul, ŞerefHerein, calixarene molecules containing piperidine units at lower rim or upper rim of calix skeleton was turned into a water resistant composite nanofiber adsorbent using polyacrylonitrile (PAN) polymeric support via electrospinning process. The PAN based calixarene nanofibrous adsorbents showed an excellent adsorption capacity toward the toxic chromate anions in aqueous solution. Furthermore, this new nanofiber mats would be promising filter materials for drinking water purification.Öğe Fabrication of Calixarene Based Protein Scaffold by Electrospin Coating for Tissue Engineering(AMER SCIENTIFIC PUBLISHERS, 2018) Çağıl, Esra Maltaş; Özcan, Fatih; Ertul, ŞerefIn this study, calixarene was synthesized by using different functional groups as p-tert-butyl-Calix[4] arene ester and amides. Calixarene nanofibers were produced by electrospin coating. Protein immobilization onto the calixarene nanofibers was carried out with human serum albumin (HSA). The maximum amount of binding on produced three different calixarene nanofibers (DE, 2-AMP and 3-AMP) was compared by using a fluorescence technique for protein analysis. Result showed that maximum binding amount was found to be as 177.85 mg cm(-2) for 3-AMP surface. The protein binding was also characterized by using SEM, TEM, AFM and FT-IR. From obtained results, calixarene-albumin nanofiber was also fabricated by spin coating using 3-AMP which has ability max binding of protein.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) Özmen, Mustafa; Özbek, Zikriye; Büyükçelebi, Sümeyra; Bayrakçı, Mevlüt; Ertul, Şeref; Ersöz, Mustafa; Çapan, RıfatThis 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 Improved Anticancer Efficacy of p-tert-butylcalix[4]arene through Surface Modifications(IEEE, 2017) Arpacı, Pembegül Uyar; Özcan, Fatih; Gök, Emine; Ertul, ŞerefThe search for new potent anticancer drugs that can only target cancer cells, rather than affecting normal tissues is very much commendable. Supramolecular Calixarene (p-tert-butylcalix[4]arene) is a highly promising candidate in this regard and could be modified to enhance preferential cytotoxicity for targeted therapy. Calixarenes are a family of bowl or cone shaped synthetic supramolecular macrocycles, composed of phenol units linked by methylene bridges through and an aldehyde. The proliferation rate of L-929 were observed higher than MCF-7 cells in the Real-Time Cell Analysis (RTCA) Systems. Our research directs that calixarene shows effective preferential cytotoxicity at a concentration range of 25 to 100 mu g/mL with enhanced preferential cytotoxicity shown by the modification of pyridinium group at the position 3 against MCF-7 breast cancer cells. In this present study, the effect of surface altered calixarene by pyridinium groups on preferential cytotoxicity in cancer cell in-vitro by comparing with innate preferential toxicity shown by unaltered. The results reported in this study demonstrated that tumor-preferential in-vitro cytotoxicity of p-tert-butylcalix[4] arene against MCF-7 over L-929 cells present a promising approach for efficient and safe cancer therapy.Öğe Phase Solubility Studies of Poorly Soluble Drug Molecules by Using O-Phosphorylated Calixarenes as Drug-Solubilizing Agents(AMER CHEMICAL SOC, 2012) Bayrakçı, Mevlüt; Ertul, Şeref; Yılmaz, MustafaThis study is the first report on the solubilizing effect of O-phosphorylated calix[n]arenes that form complexes with neutral molecules such as nifedipine, niclosamide, and furosemide by host-guest complexation. These complexation studies were carried out by using the phase solubility technique. From the obtained results, it was observed that the solubility of guest molecules such as nifedipine, niclosamide, and furosemide was significantly increased in the presence of host molecules tetrakis-O-(diethoxyphosphoryl)-p-tert-butylcalix[4]arene (1), tetrakis-O-(diethoxyphosphoryl)-calix[4]arene (2), bis-O-(diethoxyphosphoryl)-p-tert-butylcalix[4]arene (3), bis-O-(diethoxyphosphoryl)-calix[4]arene (4), and octakis-O-(diethoxyphosphoryl)-p-tert-butylcalix[8]arene (5). The increase in solubility of drugs by the calixarene host 1 to 5 was most probably due to inclusion complexation between drug molecules and cavities of the calixarene skeleton similar to drug-cyclodextrin complexes.Öğe Preparation and gas sensing properties of Langmuir-Blodgett thin films of calix[n]arenes: Investigation of cavity effect(ELSEVIER SCIENCE SA, 2014) Özmen, Mustafa; Özbek, Zikriye; Bayrakçı, Mevlüt; Ertul, Şeref; Ersöz, Mustafa; Çapan, RıfatCharacterization 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) Özmen, Mustafa; Özbek, Zikriye; Bayrakçı, Mevlüt; Ertul, Şeref; Ersöz, Mustafa; Çapan, RıfatOrganic 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, Şeref; Bayrakçı, Mevlüt; Yılmaz, 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, Şeref; Bayrakçı, Mevlüt; Yılmaz, 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 Solubilizing Effect of the P-Phosphonate Calix[n]arenes Towards Poorly Soluble Drug Molecules Such as Nifedipine, Niclosamide and Furosemide(SPRINGER, 2012) Bayrakçı, Mevlüt; Ertul, Şeref; Yılmaz, MustafaThis article reports the solubilization of the practically water insoluble drug molecules such as nifedipine, niclosamide and furosemide by guest:host inclusion complexation with p-phosphonates calix[n]arenes as drug soluble agent. This complexation studies were carried out by using the phase solubility technique. From the obtained results, it was observed that the solubility of drug molecules was significantly increased in the presence of calix[n]arene host molecules. The increase in solubility of drugs by the calix[n]arene was most probably due to inclusion complexation between drug molecules and cavities of the calixarene skeleton similar to drug:cyclodextrin complexes.Öğe Synthesis and characterization of novel nanofiber based calixarene and its binding efficiency towards chromium and uranium ions(SPRINGER, 2016) Özcan, Fatih; Bayrakcı, Mevlüt; Ertul, ŞerefThe objective of this study is to obtain nanofibrous precursor based calixarene with high ion adsorption capacity by electrospinning of blended solution of polyacrylonitrile (PAN) and upper rim functionalized calix[4]arene bearing N-methylglucamine (Calix-NMG). The obtained electrospun fibers were characterized using fourier transform infrared (FT-IR-ATR), scanning electron microscope (SEM) equipped with energy-dispersive X-ray spectrometry (EDX) and thermogravimetric analyses (TGA and DSC). Analysis indicated that preparation of nanofibers based Calix-NMG was successfully achieved. The ion binding studies exhibited that the nanofiber based Calix-NMG could be efficiently used for the binding of chromate anions and uranium cations. Nanofiber based calix[4]arene with N-methylglucamine chelating groups may be a good candidate as a filter material for treatment of a large quantity of wastewater owing to their very large surface area as well as both the inclusion and donor-acceptor complexation capability of all surfaces associated with the calixarene skeleton.Öğe Synthesis and Complex-Formation of Substituted Aminoglyoximes of Unsymmetrical Vic-Dioximes(TAYLOR & FRANCIS INC, 1994) Sevindir, Cahit H.; Mirzaoğlu, Ramazan; Özcan, Emine; Ertul, Şeref; Güler, ErsinThree new substituted aminoglyoximes, p-chloroanilinoglyoxime (p-CAGH2), o-chloroanilinoglyoxime (o-CAGH2), M-chloroanilinoglyoxime (M-CAGH2) have been synthesized from anti-chloroglyoxime (CPGH2) and the corresponding substituted amines. The Ni(II) and Cu(II) complexes of these ligands are square-planer while the Co(II) complexes are octahedral with water molecules as axial ligands. H-1-NMR, mass, IR spectra and elemental analyses data of the new compounds are given.Öğe Synthesis and Extraction Study of Calix[4]Arene Dinitrile Derivatives Incorporated in a Polymeric Backbone with Bisphenol-A(KLUWER ACADEMIC/PLENUM PUBL, 2001) Memon, Shahabuddin; Oğuz, Oğuz; Yılmaz, Aydan; Tabakçı, Mustafa; Yılmaz, Mustafa; Ertul, ŞerefTwo new copolymers containing pendant calix[4]arene units with nitrile functionalities at their lower rim have been synthesized via nucleophilic substitution reactions involving 5,11,17,23-tetra-tert-butyl-25,27-bis(cyanomethoxy)-26,28-dihydroxy-calix[4]arene (3) or 25,27-bis(cyanometh oxy)-26,28-dihydroxy-calix[4]arene (4) with 1,5-dibromopentane and bisphenol-A. The phase transfer studies were performed by using liquid-liquid extraction procedures. It has been deduced from the observations that both copolymers show a good phase transfer affinity toward selected alkali, alkaline earth, and transition metal cations, unlike their precursor (3).Öğe Synthesis of di-substituted calix[4]arene-based receptors for extraction of chromate and arsenate anions(PERGAMON-ELSEVIER SCIENCE LTD, 2009) Bayrakçı, Mevlüt; Ertul, Şeref; Yılmaz, 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 new water-soluble phosphonate calixazacrowns and their use as drug solubilizing agents(SPRINGER, 2012) Bayrakçı, Mevlüt; Ertul, Şeref; Yılmaz, 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 Lactam Ionophores Containing Crown Ether Moieties and Investigation of Their Extraction Abilities Towards Heavy Metal Cations(SPRINGER, 2010) Ertul, ŞerefThe article describes the syntheses and extraction properties of new lactam ionophores. These lactam derivatives were easily synthesized via aminolysis of dimethyl 2,2'-(6,6'-methylenebis(2-tert-butyl-4-methyl-6,1-phenylene)bis(oxy))diacetate or dimethyl 2,2'-(2,2'-methylenebis(4-chloro-2,1-phenylene))bis(oxy)diacetate with corresponding diamine compounds at one step. 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 Synthesis of novel silica gel immobilized-calix[4]arene amide ionophores and their anion binding abilities toward phosphate and chromate anions(WILEY-BLACKWELL, 2012) Yiğiter, Şengül; Bayrakçı, Mevlüt; Ertul, Şeref; Yılmaz, MustafaThis article describes the synthesis and characterization of four new calix[4]arene ionophores 57 and 9 and corresponding two new silica gel-immobilized calix[4]arene ionophores containing pyridine 10 and 11 via modification of calix[4]arene monoamide derivatives 5 and 6 with aminopropyl silica gel, respectively. The extraction studies have been performed using liquidliquid extraction for receptors 57 and 9 and solidliquid batchwise sorption procedures for receptors 10 and 11. Obtained extraction results showed that the immobilized-calix[4] arene ionophores 10 and 11 have high extraction ability toward chromate and phosphate anions as compared to their corresponding monomeric precursors 5 and 6. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012Öğe The Synthesis of Three New Macrocyclic Ligands and Preparation of Some of Their Cationic Complexes(MARCEL DEKKER INC, 1993) Sezgin, Mehmet; Bedük Dinçer, A.; Ertul, Şeref; Koçak, AhmetIn this study the synthesis of macrocyclic ligands 15,21-dinitro-2,5,8,11-tetraoxatricyclo(17,4,0,0(12,17)) tricosa-1 (23),12,14,16,19,21-hexaene-3,10-dione (I); 18,24-dinitro-2,5,8,11,14-pentaoxatricyclo(20,4,0,0(15,20)) hexacosa-1(26),15, 17,19,22,24-hexaene-3,13-dione (II) and 15,21-di-t-butyl-2,5,8,11-tetraoxatricyclo(17,4,0,0(12,17)) tricosa-1(23),12,14,16, 19,21-hexaene-3,10-dione (III) are described. Attemption of the preparation of their complexes in crystalline form with NaClO4.H2O, KClO4, and Ba(ClO4)2 . 3H2O are discussed.Öğe Synthesis of two new p-tert-butylcalix[4]arene beta-ketoimin derivatives for extraction of dichromate anion(SPRINGER, 2009) Bayrakçı, Mevlüt; Ertul, Şeref; Şahin, Özlem; Yılmaz, MustafaIn this study the selective derivatization of p-tert-butylcalix[4]arene was carried out and two new p-tert-butylcalix[4]arene beta-ketoimin, 5,11,17,23-tetra-tert-butyl-25,27-bis-3-methyl-[(beta-ketoimine)-ethoxy]-26,28-dihydroxycalix[4]arene (4), and 5,11,17,23-tetra-tert-butyl-25,27-bis-3-chloro-[(beta-ketoimine)-ethoxy]-26,28-dihydroxycalix[4]arene (5) have been synthesized. In the synthesis, the lower rim of p-tert-butylcalix[4]arene was modified in order to acquire binding site for the recognition of dichromate anion. It was observed that these ionophores 4 and 5 showed high affinity towards dichromate anion. The protonated Schiff-base forms of the receptors were effective for transferring the HCr2O7 (-) anion from aqueous phase to a dichloromethane phase.
