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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%).
Speciation Of Inorganic Selenium By Solid Phase Extraction Using Nanozirconium Oxide/Boron Oxide Composite Material, Hakan Erdoğan, Özcan Yalçinkaya, Ali̇ Rehber Türker
Speciation Of Inorganic Selenium By Solid Phase Extraction Using Nanozirconium Oxide/Boron Oxide Composite Material, Hakan Erdoğan, Özcan Yalçinkaya, Ali̇ Rehber Türker
Turkish Journal of Chemistry
The speciation and preconcentration of selenium were carried out by solid phase extraction using nanozirconium oxide/boron oxide (ZrO$_{2}$/B$_{2}$O$_{3})$. Electrothermal atomic absorption spectrometry (ETAAS) was used for detection. This preconcentration and/or speciation method depends on the retention of Se(IV) ions selectively as its ammonium pyrrolidine dithiocarbamate (APDC) complex on the sorbent. The effects of pH, flow rate, and volume of sample solution and eluent type were investigated for determining the optimum preconcentration and speciation conditions. The effects of other ions that may interfere with the determination and speciation of selenium were also investigated. Moreover, the analytical performance criteria of the method …
An Indirect Model For Sintering Thermodynamics, Yüksel Sarikaya, Müşerref Önal
An Indirect Model For Sintering Thermodynamics, Yüksel Sarikaya, Müşerref Önal
Turkish Journal of Chemistry
A model was proposed and used to calculated the changes in enthalpy $(\Delta H^{o})$, entropy $(\Delta S^{o}),$ and Gibbs energy $(\Delta G^{o})$, as well as equilibrium constant $(K)$ relating to the sintering of alumina compacts. Specific nanopore volume $(V)$ of the compacts was assumed as a thermodynamic variable. A hypothetical equilibrium constant $(K_{h})$ and corresponding Gibbs energy $(\Delta G_{h}^{o})$ were calculated depending on the $V$ value measured after each sintering. The thermodynamic relationships with the SI units were respectively evaluated for the initial-stage $(i)$ sintering between 1000 and 1200 $^{\circ}$C and final-stage $(f)$ sintering between 1200 and 1600 $^{\circ}$C in …
Zr(Iv) Complexes Of Some Heterocyclic Ligands: Synthesis, Characterization, And Ethylene Polymerization Activity, Hamdi Ali Elagab
Zr(Iv) Complexes Of Some Heterocyclic Ligands: Synthesis, Characterization, And Ethylene Polymerization Activity, Hamdi Ali Elagab
Turkish Journal of Chemistry
Thirty-one complexes of bis-(benzimidazole, benzothiazole, and benzoxazole) compounds with Zr(IV) metal centers were synthesized, characterized, activated with methylaluminoxane (MAO), and then tested for catalytic ethylene polymerization. The activities of the various catalysts were found to be functions of the heteroatoms in the ligand frameworks and the structure around the active metal center. The highest activity was obtained with 38/MAO (424 kg E/mol cat. h). The produced polyethylenes showed high molecular weights (41/MAO, 1.9 $\times$ 10$^{6}$ g/mol) and broad molecular weight distributions (38/MAO, M$_{w}$ = 9.64 $\times $ 10$^{5}$ g/mol, PD = 23). This could result from different interactions of the …
Bismuth(Iii)-Sio$_{2}$ Catalyzed Synthesis Of Polysubstituted Imidazoles With The Participation Of Azaaryl Derivatives Of Aniline In Four-Component Reactions, Zarrin Ghasemi, Ziba Zakeri, Maryam Allahvirdinesbat
Bismuth(Iii)-Sio$_{2}$ Catalyzed Synthesis Of Polysubstituted Imidazoles With The Participation Of Azaaryl Derivatives Of Aniline In Four-Component Reactions, Zarrin Ghasemi, Ziba Zakeri, Maryam Allahvirdinesbat
Turkish Journal of Chemistry
A series of novel polyaromatic derivatives of imidazole were synthesized by Bi(III) nitrate-SiO$_{2}$ catalyzed four-component reactions of benzil, ammonium acetate, aromatic aldehydes, and $N$-heterocyclic derivatives of aniline under solvent-free conditions.
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 …
Production, Purification, And Characterization Of A Thermo-Alkali Stable And Metal-Tolerant Carboxymethylcellulase From Newly Isolated Bacillus Methylotrophicus Y37, Yonca Duman, Yonca Yüzügüllü Karakuş, Arzu Sertel, Fi̇kri̇ye Polat
Production, Purification, And Characterization Of A Thermo-Alkali Stable And Metal-Tolerant Carboxymethylcellulase From Newly Isolated Bacillus Methylotrophicus Y37, Yonca Duman, Yonca Yüzügüllü Karakuş, Arzu Sertel, Fi̇kri̇ye Polat
Turkish Journal of Chemistry
A carboxymethylcellulose (CMC)-degrading bacterium was isolated from soil, identified as Bacillus methylotrophicus according to the physiological properties and analyses of 16S rRNA and a partial sequence of the gyrase A (gyrA) gene, and named as B. methylotrophicus Y37. The CMCase enzyme was purified to homogeneity by 20.4-fold with 21.73% recovery using single-step hydrophobic interaction chromatography and biochemically characterized. CMCase showed a molecular weight of approximately 50 kDa as determined by SDS-PAGE. The activity profile of the CMCase enzyme exhibited optimum activity at 45 $^{\circ}$C and pH 5.0. The activity was highly stable at alkaline pH levels. More than 90% of …
Speciation Of Trace Metals And Metalloids By Solid Phase Extraction With Spectrometric Detection: A Critical Review, Ali̇ Rehber Türker
Speciation Of Trace Metals And Metalloids By Solid Phase Extraction With Spectrometric Detection: A Critical Review, Ali̇ Rehber Türker
Turkish Journal of Chemistry
Considerable interest is continuing to be shown in the speciation of metals, metalloids, and organometals due to the dependence of their toxicity and mobility on their chemical form. This review focuses on the speciation analysis of metals, metalloids, and organometals by solid phase extraction before spectrometric detection, and all aspects of analytical speciation such as determination of oxidation states and organometallic compounds. Some applications of speciation of metals and metalloids are also presented and discussed in this review. Fractionation, which is used sometimes as speciation, and chromatographic detection are not discussed. This review covers approximately the last four years (2012-March …
Synthesis, ($E)$/($Z)$-Isomerization, And Dna Binding, Antibacterial, And Antifungal Activities Of Novel Oximes And $O$-Substituted Oxime Ethers, Hati̇ce Başpinar Küçük, Ayşe Sergüzel Yusufoğlu, Leyla Açik, Betül Aydin, Leyla Arslan
Synthesis, ($E)$/($Z)$-Isomerization, And Dna Binding, Antibacterial, And Antifungal Activities Of Novel Oximes And $O$-Substituted Oxime Ethers, Hati̇ce Başpinar Küçük, Ayşe Sergüzel Yusufoğlu, Leyla Açik, Betül Aydin, Leyla Arslan
Turkish Journal of Chemistry
A series of novel positional oximes (2a-2d), $O$-methyl oxime ethers (3a-3d), and $O$-benzyl oxime ethers (4a-4d) were synthesized in high yields starting from their corresponding methyl 3-, 4-, 6-, and 13-keto tetradecanoates. The synthesized compounds were characterized by $^{1}$H NMR, $^{13}$C NMR, FT-IR, mass, and elemental analyses for their structures and $(E)$/$(Z)$ isomerizations. Their DNA binding abilities were investigated in vitro by agarose gel electrophoresis. The antibacterial and antifungal activities were tested also in vitro against eleven bacterial strains and three fungal strains. The relationship between the structure and the mentioned biological activities was discussed. Compound 2a showed good antibacterial …
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 …
Determination Of Hexavalent Chromium In Aqueous And Alkaline Soil Extracts, Tsvetomil Voyslavov, Stefan Tsakovski, Sonya Ganeva
Determination Of Hexavalent Chromium In Aqueous And Alkaline Soil Extracts, Tsvetomil Voyslavov, Stefan Tsakovski, Sonya Ganeva
Turkish Journal of Chemistry
A fast, simple, and reliable method for determination of hexavalent chromium species in soil aqueous and alkaline extracts has been developed. The procedure is based on the ion-pair extraction of Cr(VI) with methyltrioctylammonium chloride (Aliquat 336) into xylene. The extract is analyzed by flame (FAAS) or electrothermal atomic absorption spectrometry (ETAAS). The method allows the detection of up to 2 mg kg$^{-1}$ Cr(VI) by FAAS and up to 25 $\mu $g kg$^{-1}$ Cr(VI) by ETAAS. The relative standard deviation varied in the range 2%-12% depending on the Cr(VI) levels in the samples. The analysis of certified reference material CRM041-30G Chromium …
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 …
Spectrophotometric Determination Of Mercury Using Vortex-Assisted Liquid-Liquid Microextraction, Tatiana Antolova, Serhii Zaruba, Jana Sandrejova, Livia Kocurova, Andriy B. Vishnikin, Yaroslav Bazel, Vasil Andruch, Ioseph S. Balogh
Spectrophotometric Determination Of Mercury Using Vortex-Assisted Liquid-Liquid Microextraction, Tatiana Antolova, Serhii Zaruba, Jana Sandrejova, Livia Kocurova, Andriy B. Vishnikin, Yaroslav Bazel, Vasil Andruch, Ioseph S. Balogh
Turkish Journal of Chemistry
A novel method for the determination of mercury(II) is suggested. The procedure is based on the formation of an ion associate between the bromide complex of Hg(II) and Astrazon Red 6B dye and vortex-assisted liquid-liquid microextraction of the ion associate formed, with subsequent spectrophotometric detection. The variables that affect the procedure, such as pH, the concentration of ligand and dye, the type and volume of extraction solvent, and the rate and time of vortex mixing, were optimized. Under optimum conditions (pH 2.0, 0.01 mol L$^{-1}$ KBr, 2 $\times $ 10$^{-4}$ mol L$^{-1}$ AR6B, 50 $\mu $L of the extraction mixture …
A Simple And Efficient Approach For Preconcentration Of Some Heavy Metals In Cosmetic Products Before Their Determinations By Flame Atomic Absorption Spectrometry, Nai̇l Altunay, Ramazan Gürkan
A Simple And Efficient Approach For Preconcentration Of Some Heavy Metals In Cosmetic Products Before Their Determinations By Flame Atomic Absorption Spectrometry, Nai̇l Altunay, Ramazan Gürkan
Turkish Journal of Chemistry
In the current study, a simple and efficient analytical method for preconcentration and determination of Cd(II), Pb(II), and Sn(II) in some cosmetic samples, using ultrasonic assisted-cloud point extraction and flame atomic absorption spectrometry, was developed. The method is based on the ternary complex formations of Sn(II), Pb(II), and Cd(II), which are available in the form of neutral and/or anionic hydroxo complexes (Sn(OH)$_{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 …
Remediation Of Cr(Vi) Via Combined Self-Reduction And Adsorption Bychemically Modified Carbon Sorbents, Mohamed E. Mahmoud, Amr. A. Yakout, Asmaa M. Halbas, Maher M. Osman
Remediation Of Cr(Vi) Via Combined Self-Reduction And Adsorption Bychemically Modified Carbon Sorbents, Mohamed E. Mahmoud, Amr. A. Yakout, Asmaa M. Halbas, Maher M. Osman
Turkish Journal of Chemistry
Hexavalent chromium, Cr(VI), is a highly toxic species, while trivalent chromium, Cr(III), is an essential trace element for humans and other organisms. In the present work, a simple, rapid, and efficient procedure for water treatment of Cr(VI) is described. Active carbon (AC) was chemically treated with HCl and NaOH for the formation of surface modified Acidic-AC and Basic-AC sorbents, respectively. In addition, AC sorbent was treated with HNO$_{3}$ as an oxidizing agent and sodium sulfite as a reducing agent for the formation of Ox-AC and Rd-AC sorbents, respectively. The modified AC sorbents were tested to identify their potential applications in …
An Application Of Coacervate-Based Extraction For The Separation And Preconcentration Of Cadmium, Lead, And Nickel Ions Prior To Their Determination By Flame Atomic Absorption Spectrometry In Various Water Samples, Anies Awad Satti, İlknur Durukan Temuge, Sema Bektaş, Çi̇ğdem Arpa Şahi̇n
An Application Of Coacervate-Based Extraction For The Separation And Preconcentration Of Cadmium, Lead, And Nickel Ions Prior To Their Determination By Flame Atomic Absorption Spectrometry In Various Water Samples, Anies Awad Satti, İlknur Durukan Temuge, Sema Bektaş, Çi̇ğdem Arpa Şahi̇n
Turkish Journal of Chemistry
Cloud point extraction (CPE), which is the most popular coacervate-based extraction method, was utilized for the separation and preconcentration of trace amounts of cadmium, lead, and nickel. Quinalizarin was used as complexing agent and Triton X-114 was used as surfactant. After extraction, analyte ions were determined by flame atomic absorption spectrometry. The detection limits (3$s)$ of 1.8 $\mu $g L$^{-1}$ for Cd(II), 3.2 $\mu $g L$^{-1}$ for Pb(II), and 2.8 $\mu $g L$^{-1}$ for Ni(II) were obtained using 50 mL of solutions. The relative standard deviation was calculated as 4.3% for 10 $\mu $g L$^{-1}$ Cd(II), 4.9% for 50 $\mu …
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 …
Separation And Preconcentration Of Pb(Ii) And Cu(Ii) Ions Via Carrier Element-Free Coprecipitation Using An Acetohydrazide Derivative, Süreyya Oğuz Tümay, Murat Yazar, Duygu Özdeş, Hakan Bektaş, Celal Duran
Separation And Preconcentration Of Pb(Ii) And Cu(Ii) Ions Via Carrier Element-Free Coprecipitation Using An Acetohydrazide Derivative, Süreyya Oğuz Tümay, Murat Yazar, Duygu Özdeş, Hakan Bektaş, Celal Duran
Turkish Journal of Chemistry
A new method based on the combination of carrier element-free coprecipitation and flame atomic absorption spectrometric determination has been investigated for simultaneous separation and preconcentration of Pb(II) and Cu(II) ions in some environmental solid and liquid samples. The 2-{3-(4-methylbenzyl)-4-[2-(1H-indol-3-yl)ethyl]-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl} -N'-(phenylmethylene) acetohydrazide (MITA) was utilized as an organic coprecipitating agent without using a carrier element for coprecipitation of the analyte ions. The effects of experimental conditions including aqueous solution pH, MITA quantity, sample volume, standing time, and centrifugation rate and time were investigated in detail and optimized. The influences of some foreign ions were also evaluated on the quantitative recoveries of …
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})$, relative standard …
Biosorption Potential Of Surface-Modified Waste Sugar Beet Pulp For The Removal Of Reactive Yellow 2 (Ry2) Anionic Dye, Si̇bel Tunali Akar, Sema Çeli̇k, Di̇lek Tunç, Yasemi̇n Yeti̇moğlu Balk, Tamer Akar
Biosorption Potential Of Surface-Modified Waste Sugar Beet Pulp For The Removal Of Reactive Yellow 2 (Ry2) Anionic Dye, Si̇bel Tunali Akar, Sema Çeli̇k, Di̇lek Tunç, Yasemi̇n Yeti̇moğlu Balk, Tamer Akar
Turkish Journal of Chemistry
Tetra-$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 …
Ionic Liquid Based Microextraction Combined With Derivatization For Efficient Enrichment/Determination Of Asulam And Sulfide, Habibollah Eskandari, Mahnaz Shahbazi-Raz
Ionic Liquid Based Microextraction Combined With Derivatization For Efficient Enrichment/Determination Of Asulam And Sulfide, Habibollah Eskandari, Mahnaz Shahbazi-Raz
Turkish Journal of Chemistry
This study reports 2 new simple derivatization-based dispersive liquid-liquid microextraction (DLLME) methods for spectrophotometric ultratrace determination of asulam and sulfide. 1-Naphthol (in the presence of nitrite) and N,N-diethyl-p-phenylenediamine (in the presence of Fe(III)) were used to derivatize asulam and sulfide, respectively. In the enrichment methods, the formed derivatives were preconcentrated into microdroplets of the in situ formed water insoluble ionic liquid (IL), 1-hexyl-3-methylimidazolium hexafluorophosphate. Monitoring was performed at 526 nm for asulam and at 664 nm for sulfide, after dissolution of the IL-rich phases into the basic ethanolic solution and ethanol for asulam and sulfide, respectively. Beer's law was obeyed …
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}$. The …
Characterization And Photocatalytic Properties Of Tio$_{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 …
Comparative Study For The Separation, Preconcentration, And Determination Of Copper And Cadmium In Real Samples By Using Two Different Ligands, Hami̇de Elvan Bayrak, Volkan Numan Bulut, Mehmet Tüfekçi̇, Hacer Bayrak, Celal Duran, Mustafa Soylak
Comparative Study For The Separation, Preconcentration, And Determination Of Copper And Cadmium In Real Samples By Using Two Different Ligands, Hami̇de Elvan Bayrak, Volkan Numan Bulut, Mehmet Tüfekçi̇, Hacer Bayrak, Celal Duran, Mustafa Soylak
Turkish Journal of Chemistry
Two new solid phase extraction methods have been developed for simultaneous separation and preconcentration of Cu(II) and Cd(II) in some food and environmental samples before their determination by flame atomic absorption spectrometry (FAAS). One of these methods is based on the absorption of the Cu(II) and Cd(II) complexes with [3-(cyanomethyl)-5-(4-methylphenyl)-4$H$-1,2,4-triazol-4-yl]carbamate (L1) and the other is based on the absorption of the Cu(II) and Cd(II) complexes with 4-(4-methylphenyl)-5-{[pyridine-4-yl-4$H$-1,2,4-triazole-3-yl)thio]methyl}-4$H$-1,2,4-triazole-3-thiol (L2) on Amberlite XAD-1180 resin. The metal complexes are retained on resin at pH 6.0 and eluted with 1.0 mol L$^{-1}$ HCl in acetone in both methods. After the optimum conditions were determined, …
Durability Of Carbon/Conducting Polymer Composite Supported Pt Catalysts Prepared By Supercritical Carbon Dioxide Deposition, Gamze Bozkurt, Fulya Memi̇oğlu, Ayşe Bayrakçeken Yurtcan
Durability Of Carbon/Conducting Polymer Composite Supported Pt Catalysts Prepared By Supercritical Carbon Dioxide Deposition, Gamze Bozkurt, Fulya Memi̇oğlu, Ayşe Bayrakçeken Yurtcan
Turkish Journal of Chemistry
Polypyrrole (PPy)/carbon (C) composites were synthesized by oxidative chemical polymerization and used as support material for Pt nanoparticles. PPy/C supported Pt nanoparticles were prepared by using a promising catalyst preparation method, supercritical carbon dioxide (scCO$_{2})$ deposition. The prepared materials were characterized by using BET, TGA, XRD, and TEM techniques. Cyclic voltammetry was used in order to determine the electrocatalytic activity of the prepared catalyst for hydrogen oxidation and oxygen reduction reactions that occur in proton exchange membrane fuel cells (PEMFCs). The Pt loading obtained over the composite material was around 10{\%}. TEM results showed highly dispersed and small nanoparticles over …
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 …
Pfam Catalyzed Enantioselective Diethylzinc Addition To Imines, Özdemi̇r Doğan, Eda Çağli
Pfam Catalyzed Enantioselective Diethylzinc Addition To Imines, Özdemi̇r Doğan, Eda Çağli
Turkish Journal of Chemistry
Chiral amines are important starting materials for the synthesis of biologically important compounds. Enantioselective addition of dialkylzinc reagents to imines is a reliable method for the synthesis of these compounds. Different chiral catalysts were developed and used for this method. Phosphorous based PFAM catalysts were tried for the first time in the enantioselective synthesis of amines by reacting diethylzinc with N-sulfonyl imines and N-diphenylphosphinoyl imines. Chiral amines were isolated with moderate to acceptable yields and enantioselectivities.
Gaseous And Dissolved Oxygen Sensing With Stabilized Pyrene In Ionic Liquid Modified Electrospun Slides, Özlem Öter, Gülhan Sabanci Şahi̇n
Gaseous And Dissolved Oxygen Sensing With Stabilized Pyrene In Ionic Liquid Modified Electrospun Slides, Özlem Öter, Gülhan Sabanci Şahi̇n
Turkish Journal of Chemistry
Pyrene dye has many superior characteristics for oxygen sensing studies such as long fluorescence lifetime, high quantum yield, and good sensitivity. It is preferred in some cases over ruthenium dyes for its more lipophilic character and higher sensitivity. However, easy photodegradation of pyrene is a challenging problem. In this study, pyrene dye was for the first time immobilized in an ethyl cellulose matrix and used for oxygen sensing in the form of thin films and electrospun sensing slides. The hydrophobic ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate was used as additive for the first time for dissolved oxygen sensing studies. The oxygen sensitivity …