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Articles 1 - 30 of 85
Full-Text Articles in Physical Sciences and Mathematics
Synthesis Of Novel Thiazolylpyrazoline Derivatives And Evaluation Of Their Antimicrobial Activities And Cytotoxicities, Aouatef Tabbi, Zafer Asim Kaplancikli, Dahmane Tebbani, Leyla Yurttaş, Zerri̇n Cantürk, Özlem Atli, Merve Baysal, Gülhan Turan Zitouni
Synthesis Of Novel Thiazolylpyrazoline Derivatives And Evaluation Of Their Antimicrobial Activities And Cytotoxicities, Aouatef Tabbi, Zafer Asim Kaplancikli, Dahmane Tebbani, Leyla Yurttaş, Zerri̇n Cantürk, Özlem Atli, Merve Baysal, Gülhan Turan Zitouni
Turkish Journal of Chemistry
Several novel thiazolylpyrazoline derivatives were synthesized by reacting substituted 3,5-diaryl-1-thiocarba\-moyl-2-pyrazolines with phenacylbromides. The structures of the synthesized compounds were confirmed by IR, $^{1}$H NMR, $^{13}$C NMR, and MS spectral data. Their antimicrobial activities against Staphylococcus aureus(ATCC-25923), Enterococcus faecalis} (ATCC-29212), Enterococcus faecalis (ATCC-51922), Listeria monocytogenes (ATCC-1911), Klebsiella pneumoniae (ATCC-700603), Pseudomonas aeruginosa (ATCC-27853), Escherichia coli (ATCC-35218), Escherichia coli (ATCC-25922), Candida albicans (ATCC-90028), Candida glabrata (ATCC-90030), Candida krusei (ATCC-6258), and Candida parapsilosis (ATCC-22019) were investigated. The compounds were also studied for their cytotoxic effects using a MTT assay. Compound 7c showed the highest antimicrobial activity, possessing the same potential as chloramphenicol against K. …
Ag(I) Complexes Of Benzimidazol-2-Ylidene Ligands: A Study Of Catalytic Efficiency Towards Three-Component Coupling Reactions, Rafet Kilinçarslan, Nai̇m Sadiç, Beki̇r Çeti̇nkaya
Ag(I) Complexes Of Benzimidazol-2-Ylidene Ligands: A Study Of Catalytic Efficiency Towards Three-Component Coupling Reactions, Rafet Kilinçarslan, Nai̇m Sadiç, Beki̇r Çeti̇nkaya
Turkish Journal of Chemistry
The $N$-heterocyclic carbene (NHC)--Ag(I) complexes 3a-c were synthesized from benzimidazolium chlorides (2a-c = NHC.HCl), incorporating benzyl derivatives and a 2-methoxyethyl group (a: $^{3}$N = 2,4,6-trimethylbenzyl; b: $^{3}$N = 2,3,5,6-tetramethylbenzyl; c: $^{3}$N = pentamethylbenzyl). The compounds were characterized by spectroscopic and elemental analyses. The synthesized NHC-Ag(I) complexes (3a-c) were tested as catalysts for the catalytic three-component coupling reaction of aldehyde, alkyne, and amine to propargylamines in various solvents. All complexes were active catalysts for catalytic three-component coupling reactions with good yields under neat and mild conditions (after 4 h, yields of up to 94%).
Zr(Iv), Ti(Iv), And V(Iii) Complexes Of Some Benzimidazole, Benzothiazole, And Benzoxazole Ligands: Characterization And Catalyst Efficiency In Ethylene Polymerization, Hamdi Ali Elagab, Helmut G. Alt
Zr(Iv), Ti(Iv), And V(Iii) Complexes Of Some Benzimidazole, Benzothiazole, And Benzoxazole Ligands: Characterization And Catalyst Efficiency In Ethylene Polymerization, Hamdi Ali Elagab, Helmut G. Alt
Turkish Journal of Chemistry
Fifteen complexes of 2, 2-bis- (benzimidazole, benzothiazole, and benzoxazole) compounds with Zr(IV), Ti(IV), and V(III) metal centers were synthesized, characterized, activated with methyalumoxane (MAO), and then tested for catalytic ethylene polymerization. The activities of the various catalysts were found to be functions of the hetero atoms in the ligand frameworks. The activity of the catalyst system \textbf{6}/MAO was found to be 1372 kg PE/mol cat. h. The polyethylene produced with the catalyst system 6/MAO showed high molecular weights (1.84 $\times $ 10$^{6}$ g/mol) and broad molecular weight distributions (PD = 11). This could result from different interactions of the MAO …
Newly Synthesized Furanoside-Based Nhc Ligands For The Arylation Of Aldehydes, Serpi̇l Deni̇zalti, Fatma Çeti̇n Telli̇, Seli̇n Yildiran, Azi̇ze Yeşi̇m Salman, Beki̇r Çeti̇nkaya
Newly Synthesized Furanoside-Based Nhc Ligands For The Arylation Of Aldehydes, Serpi̇l Deni̇zalti, Fatma Çeti̇n Telli̇, Seli̇n Yildiran, Azi̇ze Yeşi̇m Salman, Beki̇r Çeti̇nkaya
Turkish Journal of Chemistry
New furanoside-based NHC precursor salts (2) were synthesized using amino alcohols from the chloralose derivatives of glucose (a), galactose (b), and mannose (c). The novel compounds were fully characterized by $^{1}$H NMR, $^{13}$C NMR, and elemental analyses. The catalytic activities of these salts were tested in the arylation of aldehydes as catalysts that were generated in situ from [RhCl(COD)]$_{2}$. In addition, 2a was converted to the rhodium complex 3a in order to compare the results obtained in situ. The newly synthesized compounds were very efficient in terms of yield; nevertheless they did not exhibit a chiral induction.
Adsorption Of Cellulase On Poly(2-Hydroxyethyl Methacrylate) Cryogels Containing Phenylalanine, Murat Yavuz, Oğuz Çakir, Zübeyde Baysal
Adsorption Of Cellulase On Poly(2-Hydroxyethyl Methacrylate) Cryogels Containing Phenylalanine, Murat Yavuz, Oğuz Çakir, Zübeyde Baysal
Turkish Journal of Chemistry
The aim of this study was to prepare a supermacroporous cryogel that can be used for the adsorption of cellulase. The macroporous cryogel of poly(2-hydroxyethyl methacrylate-N-methacryloyl-l-phenylalanine) [p(HEMA-MAPA)] was prepared by copolymerization of 2-hydroxyethyl methacrylate (HEMA) with a functional monomer of N-methacryloyl-l-phenylalanine (MAPA). The cryogel was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and swelling tests. The effects of several parameters such as medium pH, temperature, ionic strength, and flow rate on cellulase adsorption were also investigated. Maximum cellulase adsorption was observed at 25 $^{\circ}$C and pH 4.0. Furthermore, adsorbed cellulase was desorbed from the cryogel by using 1.0 …
Comparison Of Influence Of Nanomaterials On A Glassy Carbon Paste Electrode-Based Bioanode In Biofuel Cells, Sema Aslan, Murat Tutum, Yudum Tepeli̇, Ülkü Anik
Comparison Of Influence Of Nanomaterials On A Glassy Carbon Paste Electrode-Based Bioanode In Biofuel Cells, Sema Aslan, Murat Tutum, Yudum Tepeli̇, Ülkü Anik
Turkish Journal of Chemistry
This paper presents a comparative study of nanomaterial modified glassy carbon paste electrodes (GCPEs) used as bioanodes in enzymatic biofuel cells. The developed bioanode electrodes were obtained by modification of composite GCPEs with glucose oxidase (GOx) and different nanomaterials like manganese(IV) oxide nanoparticle (MnO$_{2}$ np) and aluminum titanate (Al$_{2}$O$_{3}$-TiO$_{2})$ bimetallic nanostructure. These nanostructures were utilized in a GCPE-based enzymatic bioanode construction for the first time. P-benzoquinone mediator was used for the electron transfer between enzyme redox center and bioanode electrode where glucose analyte was used as substrate. A laccase-modified plain GCPE was used as biocathode electrode. Then these electrodes were …
Experimental And Theoretical Investigation Of The Reaction Between Co$_{2}$ And Carbon Dioxide Binding Organic Liquids, Hi̇lal Tankal, Özge Yüksel Orhan, Erdoğan Alper, Telhat Özdoğan, Hakan Kayi
Experimental And Theoretical Investigation Of The Reaction Between Co$_{2}$ And Carbon Dioxide Binding Organic Liquids, Hi̇lal Tankal, Özge Yüksel Orhan, Erdoğan Alper, Telhat Özdoğan, Hakan Kayi
Turkish Journal of Chemistry
The reaction kinetics of CO$_{2}$ absorption into new carbon dioxide binding organic liquids (CO$_{2}$BOLs) was comprehensively studied to evaluate their potential for CO$_{2}$ removal. A stopped-flow apparatus with conductivity detection was used to determine the CO$_{2}$ absorption kinetics of novel CO$_{2}$BOLs composed of DBN (1,5-diazabicyclo[4.3.0]non-5-ene)/1-propanol and TBD (1,5,7-triazabicyclo[4.4.0]dec-5-ene)/1-butanol. A modified termolecular reaction mechanism for the reaction of CO$_{2}$ with CO$_{2}$BOLs was used to calculate the observed pseudo-first-order rate constant k$_{0}$ (s$^{-1})$ and second-order reaction rate constant k$_{2}$ (m$^{3}$/kmol.s). Experiments were performed by varying organic base (DBN or TBD) weight percentage in alcohol medium for a temperature range of 288-308 K. …
Mn-Doped Zns Quantum Dots As A Room-Temperature Phosphorescent Probe For Analysis Of Glutamic Acid In Foodstuffs, Hayri̇ye Eda Şatana Kara, Burak Demi̇rhan, Buket Er Demi̇rhan
Mn-Doped Zns Quantum Dots As A Room-Temperature Phosphorescent Probe For Analysis Of Glutamic Acid In Foodstuffs, Hayri̇ye Eda Şatana Kara, Burak Demi̇rhan, Buket Er Demi̇rhan
Turkish Journal of Chemistry
L-cysteine-capped Mn-doped ZnS quantum dots (QDs) were used for the determination of glutamic acid in foodstuffs. This method is based on measurement of the quenching of the phosphorescence intensity of the QDs after interacting with glutamic acid. A linear response was observed from 50 to 500 ng mL$^{-1}$ glutamic acid with a limit of detection of 6.79 ng mL$^{-1}$. Room temperature phosphorescence (RTP) intensity of the QDs was quenched rapidly upon the addition of the quencher and the reaction reached equilibrium within 2 min. The quenching mechanism of phosphorescence of Mn-doped ZnS QDs by glutamic acid is dynamic and the …
Degradation Of Bisphenol-A Using A Sonophoto Fenton-Like Hybrid Process Over A Lafeo$_{3}$ Perovskite Catalyst And A Comparison Of Its Activity With That Of A Tio$_{2}$ Photocatalyst, Meral Dükkanci
Turkish Journal of Chemistry
Oxidation of bisphenol-A (BPA) was investigated using a sonophoto Fenton-like hybrid process under visible light irradiation in the presence of iron-containing perovskite LaFeO$_{3}$ catalysts. For this purpose, firstly the perovskite catalyst (LaFeO$_{3})$ was prepared by the sol-gel method and calcined at different temperatures (500, 700, and 800 $^{\circ}$C). The prepared catalysts were characterized using XRD, SEM, FTIR, nitrogen adsorption, UV-vis DRS, and ICP/OES measurements. Among the prepared catalysts the catalyst that was calcined at 500 $^{\circ}$C showed better catalytic activity with respect to degradation and chemical oxygen demand (COD) reduction (of 21.8% and 11.2%, respectively, after 3 h of reaction …
Synthesis Of New Hexahydro-1h-Isoindole-1,3(2h)-Dione Derivatives From 2-Ethyl/Phenyl-3a,4,7,7a-Tetrahydro-1h-Isoindole-1,3-(2h)-Dione, Ayşe Tan, Bi̇rgül Koç, Nurhan Ki̇shali, Ertan Şahi̇n, Yunus Kara
Synthesis Of New Hexahydro-1h-Isoindole-1,3(2h)-Dione Derivatives From 2-Ethyl/Phenyl-3a,4,7,7a-Tetrahydro-1h-Isoindole-1,3-(2h)-Dione, Ayşe Tan, Bi̇rgül Koç, Nurhan Ki̇shali, Ertan Şahi̇n, Yunus Kara
Turkish Journal of Chemistry
A new and appropriate synthesis for hexahydro-1H-isoindole-1,3(2H)-dione derivatives has been developed starting from 3-sulfolene. The epoxidation of 2-ethyl/phenyl-3a,4,7,7a-tetrahydro-1H-isoindole-1,3-(2H)-dione and then the opening of the epoxide with nucleophiles gave hexahydro-1H-isoindole-1,3(2H)-dione derivatives. Amino and triazole derivatives of hexahydro-1H-isoindole-1,3(2H)-dione were synthesized from the formed product by the opening reaction of the epoxide with sodium azide. Hydroxyl analogues were obtained from cis-hydroxylation of 2-ethyl/phenyl-3a,4,7,7a-tetrahydro-1H-isoindole-1,3-(2H)-dione. The hydroxyl groups were converted to acetate.
A Novel Ion-Imprinted Polymeric Sorbent For Separation And Determination Of Chromium(Iii) Species In Wastewater, Barbara Lesniewska, Iwona Jakubowska, Elzbieta Zambrzycka, Beata Godlewska - Zylkiewicz
A Novel Ion-Imprinted Polymeric Sorbent For Separation And Determination Of Chromium(Iii) Species In Wastewater, Barbara Lesniewska, Iwona Jakubowska, Elzbieta Zambrzycka, Beata Godlewska - Zylkiewicz
Turkish Journal of Chemistry
A new chromium(III) ion-imprinted polymer (IIP) was prepared from a Cr(III)-nicotinate complex (template), acrylamide (functional monomer), and ethylene glycol dimethacrylate (cross-linking agent) using 2,2'-azobisisobutyronitrile as the radical initiator. IIP was characterised and used as a selective sorbent for the solid-phase extraction of Cr(III) ions. The conditions for dynamic separation of Cr(III) on IIP were optimised. Cr(III) ions are selectively retained on the sorbent in a pH range from 9 to 10 and can be eluted with 4 mol L$^{-1}$ acetic acid. Cr(III) ions were determined by flame atomic absorption spectrometry (FAAS) with a detection limit of 0.08 $\mu $g mL$^{-1}$. …
Chromate Surface-Imprinted Silica Gel Sorbent For Speciation Of Cr In Surface Waters, Mariya Mitreva, Ivanka Dakova, Tanya Yordanova, Irina Karadjova
Chromate Surface-Imprinted Silica Gel Sorbent For Speciation Of Cr In Surface Waters, Mariya Mitreva, Ivanka Dakova, Tanya Yordanova, Irina Karadjova
Turkish Journal of Chemistry
This study is focused on the synthesis of chromate anion imprinted sorbent supported on silica gel for nonchromatographic Cr speciation in surface waters. The preparation procedure is based on grafting of 3-methyl-1-trimethoxysilylpropylimidazolium, preliminarily coordinated to CrO$_{4}^{2-}$ as a template ion, onto the surface of silica gel. Sorption and desorption characteristics of surface-imprinted sorbent toward Cr(III) and Cr(VI) were examined by batch solid-phase extraction. An excellent separation of Cr(VI), selectively retained on the sorbent, from Cr(III) remained in the solution, was achieved at pH 2-3 for 20 min. A freshly prepared mixture of ascorbic acid and nitric acid was selected as …
Chromium Redox Speciation In Food Samples, Krystyna Pyrzynska
Chromium Redox Speciation In Food Samples, Krystyna Pyrzynska
Turkish Journal of Chemistry
Chromium is an element with important biological characteristics, depending on its different species. Cr(III) is considered as essential; however, the Cr(VI) form is classified as carcinogenic.~For this reason, speciation analysis in food samples is a very important question. The proposed data procedures for chromium redox speciation in the literature can be divided into those with the use of online hyphenated techniques and those where appropriate sample pretreatment is necessary. The strategies for nonchromatographic speciation are mainly based on selective liquid--liquid extraction procedures, coprecipitation, selective separation of chromium species using a solid phase extraction column, or complexation reactions. In this paper, …
Schiff Base Immobilized Silica Gel Framework As An Efficient Sorbent For Preconcentration Of Pb And Zn Ions In Aqueous Media, Murat Koluman, Feyzullah Tokay, Sema Bağdat
Schiff Base Immobilized Silica Gel Framework As An Efficient Sorbent For Preconcentration Of Pb And Zn Ions In Aqueous Media, Murat Koluman, Feyzullah Tokay, Sema Bağdat
Turkish Journal of Chemistry
A novel preconcentration method for Pb and Zn ions using a column packed with Schiff base modified silica gel is described. The method was based on the sorption of analytes on N,N'-bis(4-methoxysalicylidene)-1,3-propanediamine modified silica gel and elution with HNO$_{3}$ prior to flame atomic absorption analysis. The parameters pH, flow rate, sample volume, eluent volume, and concentration were optimized using a central composite design. The detection limits were 10.0 $\mu $g L$^{-1}$ for Pb and 1.1 $\mu $g L$^{-1}$ for Zn. The suggested procedure was validated with Lake Ontario water as a certified reference material and recovery percentages were 101.8% for …
Preparation Of Fe$_{3}$O$_{4}$ @ Montmorillonite Composite As An Effective Sorbent For The Removal Of Lead And Cadmium From Wastewater Samples, Hande Tinas, Ece Çalişkan, Ni̇l Özbek, Süleyman Akman
Preparation Of Fe$_{3}$O$_{4}$ @ Montmorillonite Composite As An Effective Sorbent For The Removal Of Lead And Cadmium From Wastewater Samples, Hande Tinas, Ece Çalişkan, Ni̇l Özbek, Süleyman Akman
Turkish Journal of Chemistry
A magnetic Fe$_{3}$O$_{4}$ @ montmorillonite composite was prepared and used for the separation of lead and cadmium from aqueous solutions. For this purpose, magnetite (Fe$_{3}$O$_{4})$ was generated by co-precipitation of FeSO$_{4}$ and FeCl$_{3}$ onto montmorillonite. The effects of various experimental parameters such as pH of the solution, amount of sorbent, initial concentration of analytes, and contact time on the sorption efficiencies of lead and cadmium ions were investigated and optimized by applying a batch technique. The concentrations of analytes were determined by high resolution continuum source flame atomic absorption spectrometry. The maximum adsorption occurred at pH 2.0. The adsorption capacity …
A Simple And Efficient Approach For Preconcentration Of Some Heavy Metals In Cosmetic Products Before Their Determinations By Flame Atomic Absorption Spectrometry, Nai̇l Altunay, Ramazan Gürkan
A Simple And Efficient Approach For Preconcentration Of Some Heavy Metals In Cosmetic Products Before Their Determinations By Flame Atomic Absorption Spectrometry, Nai̇l Altunay, Ramazan Gürkan
Turkish Journal of Chemistry
In the current study, a simple and efficient analytical method for preconcentration and determination of Cd(II), Pb(II), and Sn(II) in some cosmetic samples, using ultrasonic assisted-cloud point extraction and flame atomic absorption spectrometry, was developed. The method is based on the ternary complex formations of Sn(II), Pb(II), and Cd(II), which are available in the form of neutral and/or anionic hydroxo complexes (Sn(OH)$_{3}^{-}$, Pb(OH)$_{3}^{-}$, Cd(OH)$_{2}$, and/or Cd(OH)$_{3}^{-})$, with Victoria Pure Blue BO (VPB$^{+})$ in the presence of cetylpyridinium chloride at pH 8.5, and then extraction of the formed ternary complexes into the micellar phase of polyoxyethylene sorbitan monostearate (Tween 60). Using …
Solidified Floating Organic Drop Microextraction For Speciation Of Se (Iv) And Se (Vi) In Water Samples Prior To Electrothermal Atomic Absorption Spectrometric Detection, Demi̇rhan Çitak, Mustafa Tüzen
Solidified Floating Organic Drop Microextraction For Speciation Of Se (Iv) And Se (Vi) In Water Samples Prior To Electrothermal Atomic Absorption Spectrometric Detection, Demi̇rhan Çitak, Mustafa Tüzen
Turkish Journal of Chemistry
A simple and fast solidified floating organic drop microextraction (SFODME) method is suggested for the speciation of Se (IV) and Se (VI) in water samples prior to electrothermal atomic absorption spectrometric (ETAAS) detection. For that purpose, 1-phenylthiosemicarbazide (PTC) was used as chelating agent and undecanol was used as extraction solvent. The pH of solution, extraction solvent volume, amount of ligand, effect of time for complex formation, and effect of possible foreign ions were also evaluated for quantitative and effective extraction of analyte. Under optimized parameters, detection limit (0.19 $\mu $g L$^{-1})$, limit of quantification (0.60 $\mu $g L$^{-1})$, relative standard …
Analytical Capabilities Of Two-Phase Hollow-Fiber Liquid Phase Microextraction For Trace Multielement Determination In Aqueous Samples By Means Of Portable Total Reflection X-Ray Instrumentation, Eva Margui, Manuela Hidalgo
Analytical Capabilities Of Two-Phase Hollow-Fiber Liquid Phase Microextraction For Trace Multielement Determination In Aqueous Samples By Means Of Portable Total Reflection X-Ray Instrumentation, Eva Margui, Manuela Hidalgo
Turkish Journal of Chemistry
Liquid phase microextraction (LPME) procedures have been widely used in combination with atomic and emission spectroscopic techniques for the isolation and preconcentration of trace elements. However, its application in combination with total reflection X-ray spectrometry (TXRF) is still scarce. In this paper, we evaluate the possibilities and drawbacks of a two-phase hollow fiber LPME procedure in combination with TXRF for the simultaneous determination of trace amounts of Cr, Ni, Cu, Zn, Pb, and Cd in aqueous samples. After extraction of the analytes by using the optimum conditions (sample volume: 25 mL, complexing agent: APDC, organic solvent: hexylbenzene, extraction time: 2 …
Development Of A Method For The Determination Of Cadmium Levels In Seawater By Flame Atomic Absorption Spectrometry Using An Online Cloud-Point Extraction System, Rafael Vasconcelos Oliveira, Uelber Silva Vieira, Mardson Vasconcelos Maciel, Thais Souza Neri, Graziele Santos Sales, Rebeca Moraes Menezes, Valfredo Azevedo Lemos
Development Of A Method For The Determination Of Cadmium Levels In Seawater By Flame Atomic Absorption Spectrometry Using An Online Cloud-Point Extraction System, Rafael Vasconcelos Oliveira, Uelber Silva Vieira, Mardson Vasconcelos Maciel, Thais Souza Neri, Graziele Santos Sales, Rebeca Moraes Menezes, Valfredo Azevedo Lemos
Turkish Journal of Chemistry
A new system was developed for the preconcentration and determination of cadmium levels in water following online cloud-point extraction and analysis by flame atomic absorption spectrometry. The method uses cloud-point extraction of the complex formed between Cd(II) ions and the reagent 2-(5-bromo-2'-thiazolylazo)-$p$-cresol (Br-TAC) using Triton X-114 as a surfactant. The main steps of the procedure, extraction, filtration, and detection were conducted online. Parameters that influence the experimental conditions of online preconcentration systems were examined, including pH, concentration of reagent and surfactant, and flow of sample and eluent. The limit of detection of the method is 0.2 $\mu $g L$^{-1}$. The …
Biosorption Potential Of Surface-Modified Waste Sugar Beet Pulp For The Removal Of Reactive Yellow 2 (Ry2) Anionic Dye, Si̇bel Tunali Akar, Sema Çeli̇k, Di̇lek Tunç, Yasemi̇n Yeti̇moğlu Balk, Tamer Akar
Biosorption Potential Of Surface-Modified Waste Sugar Beet Pulp For The Removal Of Reactive Yellow 2 (Ry2) Anionic Dye, Si̇bel Tunali Akar, Sema Çeli̇k, Di̇lek Tunç, Yasemi̇n Yeti̇moğlu Balk, Tamer Akar
Turkish Journal of Chemistry
Tetra-$n$-butylammonium bromide modified sugar beet pulp (TBAB-SBP) with good biosorption and regeneration potential was prepared for removal of dye from contaminated solutions. The decolorization performance of TBAB-SBP was investigated using Reactive Yellow 2 (RY2) as a model dye. The characterization of the modified biosorbent was investigated by IR, SEM, zeta potential, and BET surface area analysis to discuss the decolorization mechanism. The effects of initial pH, biosorbent amount, contact time, dye concentration, and flow rate on the treatment process were examined. The experimental kinetic data were well predicted by the pseudo-second-order kinetic model and Langmuir isotherm with a maximum monolayer …
Synthetic Protocols On 6$H$-Benzo[$C$]Chromen-6-Ones: A Review, Ofentse Mazimba
Synthetic Protocols On 6$H$-Benzo[$C$]Chromen-6-Ones: A Review, Ofentse Mazimba
Turkish Journal of Chemistry
6$H$-Benzo[$c$]chromen-6-ones serve as core structures of secondary metabolites and are of considerable pharmacological importance. Natural sources produce limited quantities, hence the need for synthetic procedures for 6$H$-benzo[$c$]chromen-6-ones, which are herein reviewed. The literature describes protocols such as the Suzuki coupling reactions for the synthesis of biaryl, which then undergoes lactonization, reactions of 3-formylcoumarin (chromenones) with 1,3-bis(silylenol ethers), radical mediated cyclization of arylbenzoates, metal or base catalyzed cyclization of phenyl-2-halobenzoates and 2-halobenzyloxyphenols, and benzoic acid coupling with benzoquinone using electrophilic metal-based catalyst. The efficient and simple procedures are those involving the reactions of Michael acceptor (chromenones and chalcones) with 1,3- and …
Characterization And Photocatalytic Properties Of Tio$_{2}$/Chitosan Nanocomposites Synthesized By Hydrothermal Process, Funda Okuşluk, Fatma Bi̇lge Emre
Characterization And Photocatalytic Properties Of Tio$_{2}$/Chitosan Nanocomposites Synthesized By Hydrothermal Process, Funda Okuşluk, Fatma Bi̇lge Emre
Turkish Journal of Chemistry
Nanocomposites of TiO$_{2}$/chitosan (nTC) were synthesized by hydrothermal process at 200 $^{\circ}$C. Photocatalytic activity of the nanocomposites was studied with degradation of malachite green (MG) in aqueous medium. Structural and physico-chemical properties of the obtained nanocomposites were characterized by XRD, SEM, BET, FTIR, and particle size analyzer. Complete photodegradation of MG was successfully achieved with the aid of the nanocomposites. The optimum photocatalytic degradation conditions, irradiation time, irradiation power, and amount of catalyst were studied. Photocatalytic activity of the synthesized nanocomposites in terms of degradation of MG was compared with that of undoped TiO$_{2}$ (synthesized by our team) and chitosan …
Synthesis And Photochromism Of New Asymmetrical Diarylethenes With A Variable Heteroaryl Ring And A Quinoline Unit, Hongyan Xu, Renjie Wang, Congbin Fan, Gang Liu, Shouzhi Pu
Synthesis And Photochromism Of New Asymmetrical Diarylethenes With A Variable Heteroaryl Ring And A Quinoline Unit, Hongyan Xu, Renjie Wang, Congbin Fan, Gang Liu, Shouzhi Pu
Turkish Journal of Chemistry
Three new asymmetrical photochromic diarylethenes containing a variable heteroaryl ring and a quinoline unit were synthesized and their structures were determined by single-crystal X-ray diffraction analysis. Their properties, including photochromism, acidichromism, and fluorescence, were investigated systematically. For these diarylethenes, the one with an indole moiety had the largest absorption maximum, cyclization quantum yield, photoconversion ratio, emission peak, and fluorescent modulation efficiency. In addition, these diarylethenes exhibited an evident dual switching behavior induced by the stimulation of acid/base and UV/Vis. Addition of trifluoroacetic acid to solution of the diarylethenes produced protonated derivatives with notable changes in their absorption spectra. These results …
Density Functional Study Of The Structure And Water Adsorption Activity Of An Al$_{30}$O$_{30}$ Star-Shaped Alumina Nanocage, Mehdi Zamani
Density Functional Study Of The Structure And Water Adsorption Activity Of An Al$_{30}$O$_{30}$ Star-Shaped Alumina Nanocage, Mehdi Zamani
Turkish Journal of Chemistry
Molecular and electronic structures of a novel Al$_{30}$O$_{30}$ star-shaped alumina nanocage (SANC) were studied using the recently developed CAM-B3LYP density functional method. Comparison of the stretching vibrational modes of this compound with the corresponding modes related to an Al$_{20}$O$_{30}$ perfect cage and Al$_{50}$O$_{75}$ tubular alumina nanomaterials showed a shift to lower frequencies, while the bending modes moved to higher frequencies. The highest occupied molecular orbital (HOMO) of the SANC had 65% nonbonding character, whereas the lowest unoccupied molecular orbital (LUMO) was 72% antibonding. The HOMO and LUMO of the SANC arose mostly from Al 3s and 2p atomic orbitals. The …
Synthesis And Evaluation Of A Novel N--P-Containing Oil-Based Fire-Retardant Plasticizer For Poly(Vinyl Chloride), Pu-You Jia, Guo-Dong Feng, Yun Hu, Yong-Hong Zhou
Synthesis And Evaluation Of A Novel N--P-Containing Oil-Based Fire-Retardant Plasticizer For Poly(Vinyl Chloride), Pu-You Jia, Guo-Dong Feng, Yun Hu, Yong-Hong Zhou
Turkish Journal of Chemistry
A novel N--P-containing soybean-oil-based fire-retardant plasticizer was synthesized using soybean oil methyl ester, 9,10-dihydro-9-oxa-phosphaphenanthrene-10-oxide (DOPO), and tris(2-hydroxyethyl) isocyanurate (THEIC). The structure was verified by Fourier transform infrared (FTIR) spectrometry and nuclear magnetic resonance (NMR) spectroscopy. The blends were characterized by thermogravimetric analysis (TGA), FTIR spectrometry, scanning electron microscopy (SEM), and dynamic mechanical analysis (DMA). TGA showed that the thermal stability of the blends were acceptable. DMA indicated that the plasticizer had good plasticity for PVC. The limiting oxygen index (LOI) of the blends ranged from 21.3 to 29.6. The flammability and thermal stability of PVC/THEIC-DOPO-ESOME was better than that of …
Square Wave Voltammetric Determination Of Valproic Acid In Pharmaceutical Preparations, Ebru Türköz Acar, Ati̇ye Nur Onar
Square Wave Voltammetric Determination Of Valproic Acid In Pharmaceutical Preparations, Ebru Türköz Acar, Ati̇ye Nur Onar
Turkish Journal of Chemistry
The electrochemical behavior of valproic acid (VAL) was investigated using square wave voltammetry, cyclic voltammetry, and sampled direct current polarography and a new square wave voltammetric method was developed for determination of VAL in pharmaceutical preparations. VAL showed two reduction peaks at about --0.2 V and --0.8 V vs. Ag/AgCl 3 M KCl with a hanging mercury drop electrode in 0.05 M pH 3.3 Britton--Robinson (BR) buffer. These peaks were named peak I and peak II, respectively. The types of limiting current of both peaks were determined as diffusion controlled based on cyclic voltammetry studies. A linear calibration graph was …
Systematic Optimization Of Chemical Deposition Conditions For Synthesis Of Vanadium(V) Oxide Xerogels, Aksu Samet, Metodija Najdoski, Igor Kuzmanovski
Systematic Optimization Of Chemical Deposition Conditions For Synthesis Of Vanadium(V) Oxide Xerogels, Aksu Samet, Metodija Najdoski, Igor Kuzmanovski
Turkish Journal of Chemistry
We performed the optimization of conditions in chemical bath deposition using the design of experimental methodology. Factorial design (2$^{3})$ was used for finding the optimal conditions of preparing vanadium(V) oxide xerogel thin films with better electrochromic properties suitable for electrochemical applications. The thin films were prepared by acidification of NH$_{4}$VO$_{3}$ aqueous solution with chemical bath deposition. The factors and selected values we considered were as follows: the deposition time (10 and 20 min), the deposition temperature (70 and 80 $^{\circ}$C), and the mass of ammonium metavanadate (0.3 and 0.5 g). UV-vis spectrometry was used for recording the transmittance variance, $\Delta …
Adsorptive Features Of Polyacrylamide--Aluminosilicate Composites For Methylene Blue, Demet Baybaş, Ulvi̇ Ulusoy
Adsorptive Features Of Polyacrylamide--Aluminosilicate Composites For Methylene Blue, Demet Baybaş, Ulvi̇ Ulusoy
Turkish Journal of Chemistry
Polyacrylamide--montmorillonite (PAAm-Mt) and polyacrylamide--clinoptilolite (PAAm-Z) composites were prepared by cross-linked polymerization of acrylamide in dispersions of Mt and Z. The composites were characterized by FT-IR, SEM, XRD, CEC, and PZC analysis. The adsorptive features of PAAm-Mt and PAAm-Z for methylene blue (MB) were investigated by their relevance to initial dye concentration, temperature, contact time, PZC, and pH. The monolayer adsorption capacities were 0.14 and 0.08 mol kg$^{-1}$ for PAAm-Z and PAAm-Mt, respectively. The changes in pH of MB solution had an insignificant influence on their adsorption capacities. The values of enthalpy and entropy changes were positive ($\Delta $H$_{PAAm-Mt}$ = 7.6 …
Liquid State $^{15}$N Nmr Studies Of $^{15}$N Isotope Labeled Phthalocyanines, Armağan Atsay, Ahmet Gül, Makbule Koçak
Liquid State $^{15}$N Nmr Studies Of $^{15}$N Isotope Labeled Phthalocyanines, Armağan Atsay, Ahmet Gül, Makbule Koçak
Turkish Journal of Chemistry
$^{15}$N labeled soluble metallo- and metal-free phthalocyanines are described for the first time. The complexes were synthesized starting from phthalic anhydride derivatives using 98{\%} $^{15}$N enriched urea. The effects of the substitution pattern, aggregation, and coordinated metal on $^{15}$N chemical shifts in liquid state NMR were studied.
Purification And Characterization Of Mitochondrial Thioredoxin Reductase Enzyme From Rainbow Trout (Oncorhynchus Mykiss) Liver And Investigation Of The In Vitro Effects Of Some Metal Ions On The Enzyme, İlknur Özgençli̇, Mehmet Çi̇ftci̇
Purification And Characterization Of Mitochondrial Thioredoxin Reductase Enzyme From Rainbow Trout (Oncorhynchus Mykiss) Liver And Investigation Of The In Vitro Effects Of Some Metal Ions On The Enzyme, İlknur Özgençli̇, Mehmet Çi̇ftci̇
Turkish Journal of Chemistry
Thioredoxin reductase (E.C 1.6.4.5.; TrxR) is an enzyme belonging to the flavoprotein family of pyridine nucleotide-disulfide oxidoreductases. In this study, mitochondrial TrxR enzyme was purified from rainbow trout mitochondria. Thanks to the 2 consecutive procedures (preparation of homogenate and 2',5'-ADP Sepharose 4B affinity chromatography), the enzyme, having the specific activity of 11.9 EU mg protein-1, was purified with a yield of 2.38{\%} and 672-fold. The purity of the enzyme was monitored and the molecular weight of its subunits was calculated as 70 kDa by SDS-PAGE. The native molecular mass of the enzyme was found to be approximately 151 kDa by …