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Öğe Evaluation of new chalcone derivatives as polyphenol oxidase inhibitors(Pergamon-Elsevier Science Ltd, 2011) Sönmez, Fatih; Sevmezler, Sedat; Atahan, Alparslan; Ceylan, Mustafa; Demir, Dudu; Gencer, Nahit; Küçükislamoğlu, MustafaA newly series of 4-(phenylurenyl) chalcone (4a-j) and 4'-(phenylurenyl/thiourenyl)chalcone (9a-l) derivatives were synthesized and their inhibitory effects on the diphenolase activity of banana tyrosinase were evaluated. Tyrosinase has been purified from banana on an affinity gel comprised of Sepharose 4B-L-tyrosine-p-aminobenzoic acid. The result showed that 4a-j inhibited the PPO enzyme activity. Conversely, 9a-h and 9i-l showed activator effect on tyrosinase enzyme activity. (C) 2011 Elsevier Ltd. All rights reserved.Öğe Evaluation of corrosion inhibition of brass-118 in artificial seawater by benzotriazole using Dynamic EIS(Pergamon-Elsevier Science Ltd, 2009) Gerengi, Hüsnü; Darowicki, Kazimierz; Bereket, Gözen; Slepski, PawelThe paper presents the results of corrosion behaviour of brass-118 in artificial seawater and the inhibitor effect of benzotriazole (BTA) by using a novel method called dynamic electrochemical impedance spectroscopy (DEIS). This method allows the tracing of the dynamics of the corrosion and the inhibition process based on the evaluation of electrical parameters of the equivalent circuit. Instantaneous impedance spectra recorded up to 10 h show that an exposure of few hours is not enough for the determination of inhibition efficiency. The results indicate the usefulness of DEIS technique in the field of inhibitor research. (C) 2009 Elsevier Ltd. All rights reserved.Öğe Hyperbranched homo and thermoresponsive graft copolymers by using ATRP-macromonomer initiators(Wiley, 2012) Allı, Sema; Allı, Abdulkadir; Hazer, BakiMacromonomer initiators behave as macro cross-linkers, macro initiators, and macromonomers to obtain branched and cross-linked block/graft copolymers. A series of new macromonomer initiators for atom transfer radical polymerization (MIM-ATRP) based on polyethylene glycol (M-n = 495D, 2203D, and 4203D) (PEG) were synthesized by the reaction of the hydroxyl end of mono-methacryloyl polyethylene glycol with 2-bromo propanoyl chloride, leading to methacryloyl polyethylene glycol 2-bromo propanoyl ester. Poly (ethylene glycol) functionalized with methacrylate at one end was reacted with 2-bromopropionyl chloride to form a macromonomeric initiator for ATRP. ATRP was found to be a more controllable polymerization method than conventional free radical polymerization in view of fewer cross-linked polymers and highly branched polymers produced from macromonomer initiators as well. In another scenario, ATRP of N-isopropylacrylamide (NIPAM) was initiated by MIM-ATRP to obtain PEG-b-PNIPAM branched block/graft copolymers. Thermal analysis, FTIR, H-1 NMR, TEM, and SEM techniques were used in the characterization of the products. They had a thermo-responsive character and exhibited volume phase transition at similar to 36 degrees C. A plasticizer effect of PEG in graft copolymers was also observed, indicating a lower glass transition temperature than that of pure PNIPAM. Homo and copolymerization kinetics were also evaluated. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012Öğe Highly Efficient and Reusable Pd/AlO(OH) Catalyzed Synthesis of Acridinedione Derivatives(Bentham Science Publ Ltd, 2019) Kılbaş, Benan; Ergen, Sinem; Çakıcı, DavutBackground: Synthesis of acridinedione derivatives via one-pot multi-component approaches using highly active and reusable Pd/AlO(OH) heterogenous catalyst was studied. This process provided a convenient method to obtain various acridinediones with potential biological activities. The reactions were performed in mild conditions such as low temperature and short reaction time with desirable yields. Methods: Commercially available Pd/AlO(OH) nanoparticles characterized by XRD and SEM methods were afforded for the synthesis of acridinedione derivatives with high yields. Crude products were analyzed by GC and H-1 NMR. The reactions were completed within 1h at 40 degrees C by the assistance of ultrasound system. Results: Optimization of reaction conditions is of critical case for successful synthesis. Solvent, temperature, time and amount of catalyst were studied. At the end of the experiments, the synthesis of 1 mmol of acridinedione was optimized by using 25 mg of Pd/AlO(OH) NPs, 3 ml of DMF for 60 min at 40 degrees C in the ultrasound system. An experimental work to check the reusability of the catalyst was also studied. Pd/Al(O) OH catalyst in the first run was higher than that of the reused catalyst in the fifth run. ICP-OES analyses showed palladium leaching into the reaction medium was only 1.1% which is negligible. Nanocatalyst employed a high activity and good reusability. Conclusion: A convenient and versatile method was developed for the synthesis of acridinediones in a mild condition with absolute conversion and high yield using ultrasound system in the presence of nanocatalyst.Öğe High temperature bromination Part XXIII: Bromination of octahydro-1H-indene and octahydro-1H-4,7-methanoindene(Arkat Usa Inc, 2013) Özer, Melek Şermin; Kılbaş, Benan; Balcı, MetinThermal and photobromination of octahydro-1H-indene and octahydro-1H-4,7-methanoindene were investigated. Three isomeric tetrabromides (1,3,4,7-tetrabromo-2,3,4,5,6,7-hexahydro-1-H-indene) were formed along with a smaller amount of tribromoindane and a pentabromide by thermal bromination of octahydro-1H-indene. The thermodynamically most stable isomers were formed. Morover, thermal and photochemical bromination of octahydro-1H-4,7-methanoindene furnished bromides resulting regiospecifically from the allylic bromination of the five-membered ring. Furthermore, the double bond formed as the intermediate functional group was also brominated due to its pyramidalization. The mechanism proposed for the formation of product distribution was discussed.Öğe Fluorescent detection of dipicolinic acid as a biomarker of bacterial spores using lanthanide-chelated gold nanoparticles(Elsevier Science Bv, 2017) Dönmez, Mert; Yılmaz, M. Deniz; Kılbaş, BenanGold nanoparticles (GNPs) functionalized with ethylenediamine-lanthanide complexes (Eu-GNPs and Tb-GNPs) were usedfor the selective fluorescent detection of dipicolinic acid (DPA), a unique biomarker of bacterial spores, in water. Particles were characterized by transmission electron microscopy and zeta potential measurements. The coordination of DPA to the lanthanides resulted in the enhancement of the fluorescence. A selective response to DPA was observed over the nonselective binding of aromatic ligands. The ligand displacement strategy were also employed for the ratiometric fluorescent detection of DPA. 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedion (TFNB) was chosen as an antenna to synthesize ternary complexes. The addition of DPA on EuGNP:TENB ternary complex quenched the initial emission of the complex at 615 nm and increased the TFNB emission at 450 nm when excited at 350 nm. The results demonstrated that the ratiometric fluorescent detection of DPA was achieved by ligand displacement strategy. (C) 2016 Elsevier B.V. All rights reserved.Öğe Flexible arene ruthenium metalla-prisms(Elsevier Science Sa, 2015) Orhan, Ersin; Garci, Amine; Therrien, BrunoCationic arene ruthenium metalla-prisms of the general formula [Ru-6(p-cymene)(6)(tpmtt)(2)(OO boolean AND OO)(3)](6+) (tpmtt = 1,3,5-tris(pyridin-4-ylmethyl)-1,3,5-triazinane-2,4,6-trione) have been obtained from the corresponding dinuclear arene ruthenium complexes [Ru-2(p-cymene)(2)(OO boolean AND OO)Cl-2] (OO boolean AND OO = oxalato (ox), 2,5-dioxido-1,4-benzoquinonato (dobq), 2,5-dichloro-1,4-benzoquinonato (dClbq), 2,5-dioxido-3-undecyl-1,4-benzoquinonato (dubq), 5,8-dioxido-1,4-naphtoquinonato (donq)) by reaction with the tridentate tpmtt ligand and silver trifluoromethanesulfonate. These cationic arene ruthenium metalla-prisms have been isolated and characterized as their triflate salts. Upon formation of the metalla-prisms, the two tpmtt panels are in close proximity and do not allow encapsulation of guest molecules. (C) 2015 Elsevier B.V. All rights reserved.Öğe ELECTROCHEMICAL OXIDATION OF ATORVASTATIN AND ITS ADSORPTIVE STRIPPING DETERMINATION IN PHARMACEUTICAL DOSAGE FORMS AND BIOLOGICAL FLUIDS(Inst Organic Chem And Biochem, 2011) Eskikoy, Dilek; Durmuş, Zehra; Kılıç, EsmaElectrochemical behavior of atorvastatin (AT) and optimum conditions to its quantitative determination were investigated using voltammetric methods. Some electrochemical parameters such as diffusion coefficient, surface coverage of adsorbed molecules, electron transfer coefficient, standard rate constant and number of electrons were calculated using the results of cyclic voltammetry. A tentative mechanism for the oxidation for AT has been suggested. The oxidation signal of AT molecule was used to develop fully validated, new, rapid, selective and simple square-wave anodic adsorptive stripping voltammetric (AdsSWV) and differential pulse anodic stripping voltammetric (AdsDPV) methods to direct determination of AT in pharmaceutical dosage forms and biological samples. For the AdsDPV and AdsSWV techniques, linear working ranges were found to be 1.0 x 10(-7)-5.0 x 10(-6) and 3.0 x 10(-7)-5.0 x 10-6 mol l(-1), respectively. The detection limits obtained from AdsDPV and AdsSWV were calculated to be 6.55 x 10(-8) and 1.53 x 10(-7) mol l(-1), respectively. The methods were successfully applied to assay the drug in tablets, human blood serum and human urine.Öğe Effects of Some Adsorbents on the Pre-purification of Taxol (Anticancer Drug) from Hazelnut Nutshells(Asian Network Scientific Information-Ansinet, 2018) Oğuzkan, Sibel Bayıl; Karadeniz, Şeref; Karagül, Bora; Uzun, Ayşe; Aksoy, Elif Sine; Güler, Özen Özensoy; Uğraş, Halil İbrahimBackground and Objective: The most important pharmaceutically active substance in plant-derived chemotherapy drugs is paclitaxel. Taxane compounds such as paclitaxel, cephalomannine, baccatin III and 10-Deacetylbaccatin III are found in hazelnut shells of Turkey's Black Sea region. This study aimed to determine the most effective adsorbent on the purity and efficiency of these taxane compounds from nutshells. Materials and Methods: The adsorbent effect on the purification of taxane compounds from hazelnut shells was studied using different adsorbent materials. For this purpose, extracts were obtained from samples of hazelnut shells collected, dried and ground into solvents. The resulting extract was concentrated into a stock solution. Samples taken from the stock solution were separately treated with seven different adsorbent materials and then filtered and analyzed with HPLC (High Performance Liquid Chromatography). Results: The HPLC analysis of taxane compounds determined on taxane, both the purification and whether or not the substance was lost, by measuring the efficiency at the same time. Graphene-oxide was found to be the adsorbent with the highest positive effect on the purification of paclitaxel in hazelnut nutshells in all cases. Graphene-oxide also had the least loss in terms of paclitaxel yield efficiency in hazelnut nutshells. Conclusion: The effects of adsorbent treatment increased both the purity and efficiency of taxane compounds and was, thus, a useful pre-purification method for shells obtained from Turkish hazelnuts. This shell waste material may prove to be a good alternative source of taxol as an anticancer drug.Öğe Eco-friendly hydrogenation of aryl azides to primary amines on graphene oxide-decorated bimetallic Rh-Pt nanoparticles (RhPt@GO NPs)(Elsevier Science Bv, 2019) Kılbaş, Benan; Kara, Belgüzar YaseminGraphene oxide-supported rhodium/platinum (Rh-Pt) nanoparticles (Rh-Pt@GO NPs) are a promising catalyst for the reduction of aryl azides to primary amines. Rh-Pt@GO NPs have been produced by the microwave-assisted sonochemical method. This catalyst showed superior catalytic activity to afford quantitative yields of primary amines under an extremely mild condition in the presence of sodium borohydride. The synthesized novel catalyst was easily recovered by centrifugation and reused without loss of its catalytic activity. The spectroscopic analyses of the RhPt@GO NPs indicated the formation of highly crystalline, monodisperse, and colloidally stable RhPt@GO NPs.Öğe Dicarboxylate-Bridged Ruthenium Complexes as Building Blocks for Molecular Nanostructures(Amer Chemical Soc, 2012) Kılbaş, Benan; Mirtschin, Sebastian; Johannessen, Thomas Riis; Scopelliti, Rosario; Severin, KayRuthenium complexes with bridging dicarboxylate ligands were combined with 1,2-di-4-pyridylethylene (dpe), 2,4,6-tri-4-pyridyltriazine (4-tpt), or 2,4,6-tri-3-pyridyltriazine (3-tpt) to give a tetranuclear rectangle or hexanuclear coordination cages. The cages display a trigonal-prismatic geometry, as evidenced by single-crystal X-ray crystallography. The 4-tpt-based cages are able to encapsulate polyaromatic molecules such as pyrene, triphenylene, or coronene, whereas the 3-tpt-based cages were found to be incompetent hosts for these guests.Öğe Determination of taxanes by validated LC-MS/MS method in hazelnut collected from different regions and altitudes in Turkey(Acg Publications, 2018) Oğuzkan, Sibel Bayıl; Karagül, Bora; Aksoy, Elif Sine; Uzun, Ayşe; Can, Merve; Yılmaz, Hasibe; Gören, Ahmet C.In this study, mass fractions of paclitaxel, cephalomannine, 10-DAB III and baccatin III in hazelnut were measured with new and validated LC-MS/MS method. Green outer nut husk and nutshell of Turkish hazelnut (Corylus colurna L.) were collected from Duzce, Trabzon, Adapazari and Samsun at several altitudes during August and September in 2014. The target analytes were prepared using solid-liquid extraction and analysed by LC-MS/MS. High amount of baccatin III, used for synthesizing semi-synthetic paclitaxel, was found in the nutshells collected at 250-500 m altitude in Cumayeri district of Duzce. In the husk samples from Vakfikebir district of Trabzon, the highest amount of baccatin III was obtained. The mass fractions of baccatin III in nutshell and husks were between 164.38-1020.85 mu gkg-1 and 166.12-923.64 mu gkg-1, respectively.Öğe Cytotoxicity of arene ruthenium metalla-rectangles incorporating bis-pyridyl diimide linkers(Elsevier Science Sa, 2016) Orhan, Ersin; Garci, Amine; Riedel, Tina; Dyson, Paul J.; Therrien, BrunoA series of tetranuclear arene ruthenium complexes of the general formula [Ru-4(p-cymene)(4)(mu(2)-L)(2)(mu(4)-OO boolean AND OO)(2)][CF3SO3](4) (L-1 = N,N'-bis(4-pyridylmethyl)-pyromellitic diimide, L-2 = N,N'-bis(4-pyridylmethyl)-naphthalene diimide) were obtained from the corresponding dinuclear arene ruthenium complexes Ru-2(p-cymene)(2)(mu 4-OO boolean AND OO)Cl-2 (OO boolean AND OO = oxalato (oxa), 2,5-dioxido-1,4-benzoquinonato (dobq), 2,5-dihydroxy-3-phenyl-1,4-benzoquinonato (dhpb), 2,5-dichloro-1,4-benzoquinonato (dClbq), 2,5-dioxido-3-undecyl-1,4-benzoquinonato (dubq), 2,5-dihydroxy-3,6-diphenyl-1,4-benzoquinonato (dhdb), 5,8-dioxido-1,4-naphtoquinonato (donq)) by reaction with the bidentate ligands (L-1 and L-2) and silver trifluoromethanesulfonate. The antiproliferative activity of the tetranuclear arene ruthenium metalla-rectangles was evaluated on cancerous (A2780 and A2780cisR) and non-cancerous (HEK293) cell lines, showing in all cases cancer cell selectivity. In general, the metalla-rectangles obtained with L-2 are more potent than those incorporating L-1, and with the exception of [Ru-4(p-cymene)(4)(mu(2)-L-1)(2)(m(4)-dClbq)(2)][CF3SO3](4), they are all more active than cisplatin on the cisplatin resistant A2780cisR cell line. (C) 2016 Elsevier B.V. All rights reserved.Öğe Cytotoxic double arene ruthenium metalla-cycles that overcome cisplatin resistance(Elsevier Science Sa, 2016) Orhan, Ersin; Garci, Amine; Riedel, Tina; Soudani, Mylene; Dyson, Paul J.; Therrien, BrunoTetranuclear arene ruthenium complexes of the general formula [{Ru-2(p-cymene)(2)(mu(4)-L)}(2)(mu(4)-tpom)](4+) (tpom = tetrakis(4-pyridyloxymethylene)methane) were obtained from the corresponding dinuclear arene ruthenium complexes [Ru-2(p-cymene)(2)(m(4)-L)Cl-2] (L = diethyl-1,2-diazenedicarboxylato (dadc), oxalato (oxa), bis(2-hydroxyethyl)oxamidato (bho), bis{2-(2-hydroxyethoxy)ethyl}ethanediamidato (bhe), 2,5-dioxido-1,4-benzoquinonato (dobq), 2,5-dihydroxy-3-phenyl-1,4-benzoquinonato (dhpb), 2,5-dibromo-1,4-benzoquinonato (dBrbq), 2,5-dioxido-3-undecyl-1,4-benzoquinonato (dubq), 2,5-dihydroxy-3,6-diphenyl-1,4-benzoquinonato (dhdb), 2,5-dihydroxy-3,6-(3,5-dimethylphenyl)-1,4-benzoquinonato (dhdm), 5,8-dioxido-1,4-naphtoquinonato (donq)) by reaction with the tetradentate tpom ligand and silver trifluoromethanesulfonate. The antiproliferative activity of the tetranuclear complexes was evaluated on cancerous (A2780 and A2780cisR) and non-cancerous (HEK293) cell lines, showing in most cases cancer cell selectivity and, in some cases, low micromolar cytotoxicities (similar to 1 mu M) against a cancer cell line that has acquired resistance to cisplatin. (C) 2015 Elsevier B.V. All rights reserved.Öğe Tunable Arene Ruthenium Metallaprisms to Transport, Shield, and Release Porphin in Cancer Cells(Amer Chemical Soc, 2015) Garcı, Amine; Mbakidi, Jean-Pierre; Chaleix, Vincent; Sol, Vincent; Orhan, Ersin; Therrien, BrunoThree neutral dinuclear p-cymene ruthenium complexes (1a-1c) of the general formula (p-cymene)(2)Ru-2(mu(4)-L)Cl-2, bridged by substituted hydroxybenzoquinonato spacers (L-a = 2,5-dihydroxy-3-pheny1-1,4-benzoquinonato; L-b = 2,5-dihydroxy-3,6-diphenyl-1,4-benzoquinonato; L-c = 2,5-dihydroxy-3,6-(3,5-dimethylphenyl)-1,4-benzoquinonato) have been synthesized and characterized. The corresponding p-cymene ruthenium metallaprisms, [{(p-cymene)(2)Ru-2(mu(4)-L)}(3)(tpt)(2)][CF3SO3](6) (2a-2c), were obtained by mixing in methanol the neutral dinuclear complexes 1a-1c, AgCF3SO3, and 2,4,6-tri(pyridin-4-yl)-1,3,5-triazine (tpt). In a similar fashion, addition of porphin during the formation of the metallaprisms afforded the host guest systems [porphin subset of{(p-cymene)(2)Ru-2(mu(4)-L)}(3)(tpt)(2)][CF3SO3](6) ([porphin subset of 2][CF3SO3](6)). The biological activity of all complexes was estimated on the colon cancer cell line HT-29, showing low cytotoxicity in the dark (IC50 > 5 mu M). On the other hand, the phototoxicity of the porphin-in-the-cage systems under standard irradiation conditions (20 J/cm(2)) is quite spectacular, being in the lower nanomolar range for [porphin subset of 2c] [CF3SO3](6).Öğe The synthesis of new 3,4-(bisaryl)-1,8-naphthalimide and 2,3-(bisaryl)-7 H-benzimidazo[2,1-a]benzo[d]isoquinolin-7-one compounds and an investigation of their photochromic properties(Scientific Technical Research Council Turkey-Tubitak, 2018) Orhan, Ersin; Köse, Mahmut; Yazan, TolgaThree new photochromic compounds, 3-(2,5-dimethyl-3-thienyl)-4-(2-phenyl-5-methyl-4-thiazolyl)-l,8-naphthalimide (1-O), 2,3-bis(2-phenyl-5-methyl-4-thiazolyl)-7H-benzimidazo[2,1-a]benzo[de]isoquinolin-7-one (2-O), and 2,5-dimethyl-3-thienyl)-7H-benzimidazo[2,1-a]benzo[de]isoquinolin-7-one (3-O), were synthesized and their photochromic properties were studied. Compound 1-O was synthesized by two consecutive Suzuki coupling reactions using 2,5-dimethylthiophene-3-boronic acid and 5-methyl-2-phenylthiazole-4-boronic acid. Photochromic compounds 2-O and 3-O were prepared by multistep reactions starting with 3-iodo-4-bromo-1,8-naphthalic anhydride and 2,5-dimethylthiophene3-boronic acid or 2-phenyl-5-methylthiazole-4-boronic acid. All photochromic compounds showed a color change from colorless (or light yellow) to blue-green, purple, or orange colors (depending on the nature of the structures) on exposure to UV light at 365 nm in ethyl acetate solutions. The colored solutions can be reversed to the original colorless (or light yellow) solution by exposure to visible light at 530 nm.Öğe Güneydoğu Anadolu Bölgesinde Yetişen Yeşil Acı Biberlerdeki Kapsaisinin DNA Koruyuculuğu Üzerine Etkisi(Kahramanmaras Sutcu Imam Univ, 2018) Oğuzkan, Sibel Bayıl; Can, Merve; Kılıç, Halil İbrahim; Uğraş, Halil İbrahim; Özaslan, MehmetGüneydoğu Anadolu bölgesinde yaygın olarak yetiştirilen Capsicum annuum L. türü yeşil biber özellikle hem üretilmekte hem de yoğun bir şekilde tüketilmektedir. Bu bitkinin doğal içeriği olan kapsaisin biberlerdeki en önemli sekonder metobilitlerden biri olup antikarsinojenik ve antimutajenik potansiyele sahip olduğu bilinmektedir. Bu çalışmada Gaziantep bölgesinde tüketilmekte olan acı yeşil biberlerden saflaştırdığımız kapsainin antiradikalik, antioksidan durumları ve DNA koruyucu aktivitesi üzerine etkileri incelenmiştir. Bu amaçla, toplanıp, gölgede kurutulup öğütülen yeşil acı biber numunelerinden düşük polariteli diklormetan çözücüsünün yanı sıra metanol gibi yüksek polariteli çözücüler ekstraksiyon için kullanılmı olup 72 saat’lik bir yöntem ile saf kapsaisin ekstraktı elde edilmiştir. Saflaştırılan kapsaisinden antioksidan aktivitesi tespiti için Rel Assay Diagnostics kitleri (TAS, TOS) ve antiradikalik aktivite tespiti için de DPPH yöntemi kullanılmıştır. DNA koruyucu aktivite için pBR322 plazmid DNA’sı ve UV-C yöntemi kullanılmıştır. Kapsaisinin diklormetandaki ekstraktı hem antioksidan hem de antiradikalik aktivite yönünden metanole göre daha iyi bulunmuştur. Kapsaisinin oksidan değerlerinin ise standartlara göre oldukça düşük olduğu gözlenmiştir. DNA koruyucu aktivite yönünden sonuçlar incelendiğinde kapsaisinin diklormetan ekstrakı düşük konsantrasyonlarda daha yüksek koruyucu ekti gösterirken metanoldeki ekstraktı yüksek konstrasyonlarda daha iyi koruyucu etki göstermiştir. Sonuç olarak bu çalışma ile yeşil biberlerdeki kapsaisinin antioksidan, antiradikalik ve DNA koruyucu aktivitesinin olduğu ortaya konulmuştur.Öğe The comparative investigation on synthesis, characterizations of silver ion-imprinting and non-imprinting cryogels, their impedance spectroscopies and relaxation mechanisms(Springer, 2019) Şarkaya, Koray; Demir, AhmetIn the present study, a novel ion-imprinting and non-imprinting cryogel samples have been prepared using ion-imprinting technique and the dielectric properties have been investigated using an impedance spectroscopy method. In the preparation of ion-imprinted cryogel, at the first attempt, N-methacryloly-(l)-cysteine methyl ester was used as the metal complexing monomer. Ag+-imprinted poly(hydroxyethyl methacrylate-N-methacryloly-(l)-cysteine methyl ester) cryogel was produced by bulk polymerization. Poly(2-hydroxyethyl methacrylate) was selected as the basic matrix by considering properties, high chemical and mechanical stability. After removal of template (silver ions), the ion-imprinted cryogel was used for the removal of photo-film-containing materials. The dielectric properties of cryogel samples have also been investigated by impedance spectroscopy within the frequency range of 1 Hz-10 MHz. The real part of the permittivity increases at low frequencies as electrode effects become dominant. It shows a constant value at high frequencies due to dipole polarization. On the other hand, the imaginary part does not show a relaxation peak as the relaxation time of samples is very short. The frequency dependence of electrical modulus has also been investigated. The real part of electrical modulus (M ' (f)) is an indicative of negligible electrode polarization phenomenon in the test material. The behavior of the imaginary part of frequency dependent electrical modulus (M '' (f)) exhibit that the dielectric relaxation process is usually not frequency-activated state. Dielectric relaxation process occurs spontaneously due to the hopping mechanism of charge carriers.Öğe Synthesis, photochromic and fluorescence properties of new bithiazole-containing diarylethenes as cation sensors(Elsevier Science Bv, 2018) Gündoğdu, Leyla; Köse, Mahmut; Takeuchi, Sakiko; Yokoyama, Yasushi; Orhan, ErsinTwo new bithiazole-containing diarylethenes, 1[5-methyl-2-(5-methyl-2-thiazolyl)-4-thiazolyl]-2,5-dimethy1-3-thienyl-3,3,4,4,5,5-hexafluorocyclopentene and 1[5-methyl-2-(5-methyl-2-thiazolyl)-4-thiazolyl]1-2-methyl-3-benzothienyl-3,3,4,4,5,5-hexafluorocyclopentene were synthesized and their photochromic and fluorescent properties have been investigated. They exhibited thermally irreversible photochromism and fluorescent switching in toluene. The effects of complexation of these two compounds with various metal cations such as Na+, Ag+, Hg+, Co2+, Ni2+, Cu2+, Ba2+, Zn2+, Cr3+, Pb2+, Cd2+, Sn2+, Al3+, Fe3+ on photochromic and fluorescent properties were also studied. Metal cations caused small effects on the absorption bands of their ring closed forms. However, fluorescence intensities of both compounds were strongly suppressed by Ni2+, Cu2+ and Fe3+.Öğe Synthesis, characterization, crystal structure, magnetic studies of a novel polymeric zig-zag chain copper (II) complex(Elsevier Science Sa, 2014) Yardan, Alper; Yahşi, Yasemin; Kara, Hülya; Karahan, Ahmet; Durmuş, Sefa; Kurtaran, RaifA single crystal of copper (II) complex (1) has been synthesized and its crystal structure has been determined by single crystal X-ray diffraction analysis and characterized by elemental analyses, IR spectroscopy, thermal analysis, H-1 NMR and C-13 NMR spectroscopy. The complex crystallizes in orthorombic space group Pnma, with unit cell dimensions a = 9.8944, b = 25.2972, c = 7.4457 angstrom, ss = 90 degrees. Structural analysis of (1) shows that the Schiff base ligand coordinates toward one metal atom in a pentadentate mode and each Cu atom is six-coordinated. The aliphatic oxygen atom of Schiff base ligand links the [CuL] moieties and creates polymeric zig-zag chain structure. In addition, magnetic susceptibilities for complex (1) have been measured over the temperature range 2-300 K and the magnetic parameters have been determined with fitting procedure. Magnetic measurements on (1) reveal the presence of antiferromagnetic exchange interactions between Cu(II) ions in the dimeric unit via bridging oxygen atoms of pentadentate Schiff base ligand. (c) 2014 Elsevier B.V. All rights reserved.
