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2018

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Articles 1321 - 1350 of 1672

Full-Text Articles in Chemistry

Enhanced Electrocatalytic Activity Of Copper Phthalocyanine/Multiwalled Carbon Nanotube Composite Electrode Via Pt Nanoparticle Modification For Oxygen Reduction, Çağri Ceylan Koçak, Zekerya Dursun Jan 2018

Enhanced Electrocatalytic Activity Of Copper Phthalocyanine/Multiwalled Carbon Nanotube Composite Electrode Via Pt Nanoparticle Modification For Oxygen Reduction, Çağri Ceylan Koçak, Zekerya Dursun

Turkish Journal of Chemistry

Enhanced electrocatalytic reduction of oxygen is achieved using Pt nanoparticle-modified copper phthalocya- nine-multiwalled carbon nanotube (PtNPs/CuPc-CNT) composite film on a glassy carbon electrode (PtNPs/CuPc-CNT/GCE). The PtNPs/CuPc-CNT/GCE surface is characterized by scanning electron microscopy, transmission electron microscopy, electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. The electrocatalytic activity of composite electrodes in the oxygen reduction reaction is investigated by cyclic voltammetry and rotating-disk electrode measurements. PtNPs/CuPc-CNT/GCE show higher catalytic activity than CNT/GCE, CuPc/GCE, and CuPc-CNT/GCE in oxygen reduction with four electron transfers.

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Anticorrosion Coating For Magnesium Alloys: Electrospun Superhydrophobic Polystyrene/Sio$_{2}$ Composite Fibers, Nesri̇n Horzum Polat, Özlem Kap, Ami̇r Farzaneh Jan 2018

Anticorrosion Coating For Magnesium Alloys: Electrospun Superhydrophobic Polystyrene/Sio$_{2}$ Composite Fibers, Nesri̇n Horzum Polat, Özlem Kap, Ami̇r Farzaneh

Turkish Journal of Chemistry

Superhydrophobic nanocomposite coatings for magnesium surfaces with remarkable corrosion resistance were fabricated by electrospinning in the presence of fluorosilane-functionalized silica (SiO$_{2})$ nanoparticles. The effects of surface-modified silica (mod-SiO$_{2})$ nanoparticles on the superhydrophobicity and corrosion resistance of polystyrene (PS)/mod-SiO$_{2}$ fiber coatings were evaluated. The incorporation of the SiO$_{2}$ nanoparticles endows PS fibers with rough surfaces exhibiting a water contact angle (WCA) of 165$^{\circ}$. The surface wettability, corrosion resistance, and their relation to the inorganic content in the PS fibers and the contact angle of the composite coatings were explored. Analysis of the corrosion results confirmed that the PS/mod-SiO$_{2}$ coating protected the …

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Synthesis And Characterizations Of Novel Thiazolyl-Thiadiazole Derivatives As Telomerase Activators, İsmai̇l Kayaği̇l, Ayşe Gül Mutlu, Ülkü Bayhan, İnanç Yilmaz, Şeref Demi̇rayak Jan 2018

Synthesis And Characterizations Of Novel Thiazolyl-Thiadiazole Derivatives As Telomerase Activators, İsmai̇l Kayaği̇l, Ayşe Gül Mutlu, Ülkü Bayhan, İnanç Yilmaz, Şeref Demi̇rayak

Turkish Journal of Chemistry

Pyridine-3/4-thiocarboxamide derivatives were used as starting materials for the synthesis of the target compounds. The pyridine-3/4-thiocarboxamide derivatives were reacted with ethyl 2-chloroacetoacetate in ethanol to give the thiazole derivatives (1, 2). The two ethyl thiazole-carboxylate derivatives (1, 2) thus obtained were treated with sodium hydroxide solution and ethanol and converted to carboxylic acids (3, 4). The carboxylic acid derivatives (3, 4) were reacted with thiosemicarbazide in phosphoroxy trichloride and aminothiadiazole rings (5, 6) were formed. Thus, two thiazolyl-thiadiazole amine derivatives (5, 6) were obtained. These two derivatives (5, 6) were converted into two chloroacetamidothiadiazole derivatives (7, 8) by reaction with …

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An Ionic Liquid/Bismuth Film-Modified Sensor For The Electrochemical Detection Of Cefixime, Yeşi̇m Tuğçe Yaman, Gülçi̇n Bolat, Ceren Yardimci, Serdar Abaci Jan 2018

An Ionic Liquid/Bismuth Film-Modified Sensor For The Electrochemical Detection Of Cefixime, Yeşi̇m Tuğçe Yaman, Gülçi̇n Bolat, Ceren Yardimci, Serdar Abaci

Turkish Journal of Chemistry

A highly sensitive and simple method based on an ionic liquid/ex situ bismuth film-modified single-use pencil graphite electrode (IL/Bi/PGE) was offered for the electrochemical detection of cefixime (CEF) for the first time. The synergistic effects of the ionic liquid and bismuth film combination as the surface modifier remarkably improved the electrochemical response of the modified sensor. Anodic oxidation of CEF was observed at 0.9 V vs. Ag/AgCl/3 M KCl as one well-defined irreversible oxidation peak. Under optimum experimental conditions, the IL/Bi/PGE exhibited a linear relationship for CEF concentrations in the range of 0.005--0.5 $\mu $M (R$^{2}$ = 0.996) with a …

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Synthesis And Evaluation Of Novel 1,3,4-Thiadiazole--Fluoroquinolone Hybrids As Antibacterial, Antituberculosis, And Anticancer Agents, Asli Demi̇rci̇, Kaan Gökçe Karayel, Esra Tatar, Si̇nem Öktem Okullu, Ni̇han Ünübol, Paki̇ze Nesli̇han Taşli, Zühtü Tanil Kocagöz, Fi̇kretti̇n Şahi̇n, İlkay Küçükgüzel Jan 2018

Synthesis And Evaluation Of Novel 1,3,4-Thiadiazole--Fluoroquinolone Hybrids As Antibacterial, Antituberculosis, And Anticancer Agents, Asli Demi̇rci̇, Kaan Gökçe Karayel, Esra Tatar, Si̇nem Öktem Okullu, Ni̇han Ünübol, Paki̇ze Nesli̇han Taşli, Zühtü Tanil Kocagöz, Fi̇kretti̇n Şahi̇n, İlkay Küçükgüzel

Turkish Journal of Chemistry

A series of 5-substituted-1,3,4-thiadiazole-based fluoroquinolone derivatives were designed as potential antibacterial and anticancer agents using a molecular hybridization approach. The target compounds 16-25 were synthesized by reacting the corresponding $N$-(5-substituted-1,3,4-thiadiazol-2-yl)-2-chloroacetamides with ciprofloxacin or norfloxacin. The purity and identity of the synthesized compounds were determined by the use of chromatographic and spectral techniques (NMR, IR, MS, etc.) besides elemental analysis. Antibacterial, antituberculosis, and anticancer activity of the target compounds were evaluated against selected strains and cancer cell lines. Compound 20 was appreciated as the most active agent representing antibacterial activity against Escherichia coli and Staphylococcus aureus with MIC values of 4 …

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Computational Investigation Of Intramolecular Reorganization Energy In Diketopyrrolopyrrole (Dpp) Derivatives, Şule Atahan Evrenk Jan 2018

Computational Investigation Of Intramolecular Reorganization Energy In Diketopyrrolopyrrole (Dpp) Derivatives, Şule Atahan Evrenk

Turkish Journal of Chemistry

Intramolecular reorganization energy (RE) of molecules derived from the diketopyrrolopyrrole (DPP) unit has been studied using B3LYP/6-31G(d,p) theory. It was found that the replacement of the oxygen atoms with sulfur in the DPP unit led to a smaller RE for both the hole and electron transfer processes. One disadvantage of the sulfur replacement is the twist of the conjugated backbone, which might impair the $\pi - \pi $ interactions in the solid state. The RE calculated from the adiabatic potential energy surfaces and that derived from the normal mode analysis agreed well for both systems. Electronic structure data showed that …

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One-Pot Multicomponent Synthesis Of Piperidinium 3,3'-(Arylmethylene) Bis (2-Hydroxynaphthalene-1,4-Diones): Nmr Spectroscopic And X-Ray~Structure Characterization, Maryam Fatahpour, Nourollah Hazeri, Malek Taher Maghsoodlou, Fatemeh Noori Sadeh, Mojtaba Lshkari Jan 2018

One-Pot Multicomponent Synthesis Of Piperidinium 3,3'-(Arylmethylene) Bis (2-Hydroxynaphthalene-1,4-Diones): Nmr Spectroscopic And X-Ray~Structure Characterization, Maryam Fatahpour, Nourollah Hazeri, Malek Taher Maghsoodlou, Fatemeh Noori Sadeh, Mojtaba Lshkari

Turkish Journal of Chemistry

A facile synthesis of piperidinium 3,3'-(arylmethylene) bis (2-hydroxynaphthalene-1,4-dione) analogs as organic salts is described by the one-pot pseudo-four-component reaction between 2-hydroxy-1,4-naphthoquinone, aromatic aldehydes, and piperidine. The single-crystal X-ray diffraction analysis of these systems confirms that the stabilized predominant interactions are N-H\... O and O-H\... O hydrogen bonds. Mild and clean reaction conditions, high atom economy, and operational simplicity of this one-pot multicomponent reaction coupled with excellent yields and no need for column chromatography have transformed this procedure to be a superior synthetic route for the efficient formation of families of naphthoquinone-derived compounds.

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Synthesis Of Novel Sn38-Aspirin Prodrugs For The Treatment Of Hepatocellular Carcinoma, Zhimin Chen, Yi Luo, Aiping Fang, Chen Fan, Chenjuan Zeng Jan 2018

Synthesis Of Novel Sn38-Aspirin Prodrugs For The Treatment Of Hepatocellular Carcinoma, Zhimin Chen, Yi Luo, Aiping Fang, Chen Fan, Chenjuan Zeng

Turkish Journal of Chemistry

Hepatocellular carcinoma (HCC) is the most common primary liver malignancy and is a leading cause of cancer-related death worldwide. However, there is no effective chemotherapeutic treatment for HCC and its prognosis remains poor. Consequently, it is urgent to find an efficient antitumor agent to treat HCC. In this study, 7-ethyl-10-hydroxycamptothecin (SN38), the bioactive metabolite of the anticancer drug irinotecan (CPT-11), which is 100-1000 times more potent than CPT-11, was coupled with aspirin to give 4 prodrugs. Their structures were characterized by $^{1}$H~NMR and elemental analysis. The in vitro anticancer activities of these compounds on two human hepatocellular carcinoma cell lines …

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One-Step Potentiostatic Codeposition And Electrochemical Studies Of Poly(1-Pyrenyl)-2,5-Di(2-Thienyl)Pyrrole-Co-Pyrrole) Film For Electrochemical Supercapacitors, Hakan Görçay, İlhami̇ Çeli̇k, Yücel Şahi̇n Jan 2018

One-Step Potentiostatic Codeposition And Electrochemical Studies Of Poly(1-Pyrenyl)-2,5-Di(2-Thienyl)Pyrrole-Co-Pyrrole) Film For Electrochemical Supercapacitors, Hakan Görçay, İlhami̇ Çeli̇k, Yücel Şahi̇n

Turkish Journal of Chemistry

In this paper, we report a simple, low-cost, and environmentally friendly electrochemical method to obtain a novel copolymer consisting of 1-pyrenyl-2,5-di(2-thienyl)pyrrole and pyrrole on a pencil graphite electrode (PGE). Poly(1-pyrenyl)-2,5-di(2-thienyl)pyrrole-co-pyrrole) that is P(PyrPy-co-Py) film was prepared by one-step potentiostatic codeposition in an ethanol solution containing PyrPy and Py monomers for supercapacitor applications. The electrodeposition of homopolymer and copolymer modified electrodes was carried out on the surface of the PGE via chronocoulometry. For comparison, P(Py)/PGE and P(PyrPy)/PGE were also electrochemically synthesized under the same reaction conditions. The surface morphologies of all the electrode materials were analyzed by field emission scanning electron …

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Solid-Phase Extraction Method For Preconcentration Of Cadmium And Lead In Environmental Samples Using Multiwalled Carbon Nanotubes, Ayman A. Gouda, Wael A. Zordok Jan 2018

Solid-Phase Extraction Method For Preconcentration Of Cadmium And Lead In Environmental Samples Using Multiwalled Carbon Nanotubes, Ayman A. Gouda, Wael A. Zordok

Turkish Journal of Chemistry

A new sensitive and accurate solid-phase extraction method for preconcentration of trace amounts of cadmium and lead in various environmental samples prior to flame atomic absorption spectrometry determination has been developed. The proposed method is based on the utilization of multiwalled carbon nanotubes in combination with 5-benzyl-4-[-chlororbenzylidene amine]-4H-1,2,4-triazole-3-thiol (BCBATT) as a solid-phase sorbent with the aid of ultrasonication. The effect of the preconcentration parameters was investigated. Good recoveries ranging from 95% to 102% with relative standard deviations of 3.2% and 2.8% for Cd$^{2+}$ and Pb$^{2+}$, respectively, were obtained, indicating high accuracy and precision. The limits of detection were 0.2 and …

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Differential Pulse Voltammetric Determination Of Dopamine Using Pd Nanoparticles Deposited On (3-Aminopropyl)Triethoxysilane Functionalized Ceo$_{2}$ Nanoparticles, Muhammet Güler Jan 2018

Differential Pulse Voltammetric Determination Of Dopamine Using Pd Nanoparticles Deposited On (3-Aminopropyl)Triethoxysilane Functionalized Ceo$_{2}$ Nanoparticles, Muhammet Güler

Turkish Journal of Chemistry

In this study, a novel and effective electrochemical sensor for determination of dopamine (DA) was successfully developed by the modification of a glassy carbon electrode (GCE) using Pd nanoparticles deposited on (3-aminopropyl)triethoxysilane functionalized nanoceria (Pd@CeO$_{2}$-APTES) and nafion used as a protective membrane. The synthesized nanocomposites were evaluated using X-ray diffraction, high-resolution transmission electron microscopy, and Fourier transform infrared spectroscopy. Moreover, the electrochemical properties of the modified electrodes were investigated using cyclic voltammetry, electrochemical impedance voltammetry, and differential pulse voltammetry (DPV). The Nf/Pd@CeO$_{2}$-APTES/GCE showed a linear range of 2.5--149.5 $\mu $M for DA by DPV with a notable sensitivity of 3.89 …

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A Sample Stacking-Capillary Electrophoresis Method For Simultaneous Determination Of Nitrate And Thiocyanate Ions Of Ultra-Heat-Treated Milk Samples, Fi̇li̇z Tezcan Jan 2018

A Sample Stacking-Capillary Electrophoresis Method For Simultaneous Determination Of Nitrate And Thiocyanate Ions Of Ultra-Heat-Treated Milk Samples, Fi̇li̇z Tezcan

Turkish Journal of Chemistry

Ultra-heat-treated (UHT) cow milk is mostly consumed in Turkey. Heating milk can cause some chemical and biochemical changes that affect different components of milk. However, studies on the constituents of UHT milk are scare. In the present study, nitrate and thiocyanate contents of commercial UHT~whole cow milk were determined simultaneously by sample stacking-capillary electrophoresis. The best separation of nitrate and thiocyanate ions was performed by reducing the electroosmotic flow at pH 4.0 using 30 mM formic acid and 30 mM sodium sulfate containing separation electrolyte. Analysis was completed in less than 3 min. The limits of detection obtained at a …

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The Interaction Between A Zinc(Ii) Phthalocyanine Compound Bearing Octakis Phenoxyacetamide Substituents And Calf Thymus Dna, Ali̇ Arslantaş, Mehmet Sali̇h Ağirtaş Jan 2018

The Interaction Between A Zinc(Ii) Phthalocyanine Compound Bearing Octakis Phenoxyacetamide Substituents And Calf Thymus Dna, Ali̇ Arslantaş, Mehmet Sali̇h Ağirtaş

Turkish Journal of Chemistry

In this study, a zinc(II) phthalocyanine compound (PcZn) substituted with octakis phenoxyacetamide was synthesized and characterized. Calf thymus DNA (CT-DNA) was used to determine the DNA binding properties of the zinc(II) phthalocyanine compound. This interaction of CT-DNA with PcZn was investigated using electronic absorption spectra, emission spectroscopy, a thermal melting temperature study, cyclic voltammetry, and viscosity measurements in a Tris-HCl buffer solution at a pH of 7.2. The findings showed that zinc(II) phthalocyanine interacts with calf thymus DNA via partial intercalative binding mechanisms. In addition to the techniques above, a gel electrophoresis study was also carried out to verify the …

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A New Cocrystal Explosive Trinitrotoluene (Tnt):1-Amino-4-Bromonaphthalene With Reduced Sensitivity, Ni̇lgün Şen Jan 2018

A New Cocrystal Explosive Trinitrotoluene (Tnt):1-Amino-4-Bromonaphthalene With Reduced Sensitivity, Ni̇lgün Şen

Turkish Journal of Chemistry

A 1:1 cocrystal of TNT and 1-amino-4-bromonaphthalene was prepared via solvent evaporation. The structure of the cocrystal was determined via single-crystal and powder X-ray diffraction. Crystal structure determination studies indicated that the main mechanism of cocrystallization originates from the intermolecular hydrogen bonding (amino-nitro), halogen bonding, and $\pi -\pi $ stacking. Investigation of intermolecular interactions by Hirshfeld surface and fingerprint plot analysis revealed that the structures were stabilized by H...H, O...H, C...C ($\pi -\pi )$ and Br...O interactions. Hirshfeld surfaces showed that these weak interactions were significant for crystal packing. We analyzed the crystal packing and showed how this may influence …

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A Novel Core-Shell-Based Chromatographic Method Supported By Ratio Derivative Spectrophotometry For The Simultaneous Determination Of Perindopril, Indapamide, And Amlodipine Ternary Mixtures, Leyla Karadurmuş, Mehmet Gümüştaş, Sevi̇nç Kurbanoğlu, Bengi̇ Uslu, Si̇bel Ayşil Özkan Jan 2018

A Novel Core-Shell-Based Chromatographic Method Supported By Ratio Derivative Spectrophotometry For The Simultaneous Determination Of Perindopril, Indapamide, And Amlodipine Ternary Mixtures, Leyla Karadurmuş, Mehmet Gümüştaş, Sevi̇nç Kurbanoğlu, Bengi̇ Uslu, Si̇bel Ayşil Özkan

Turkish Journal of Chemistry

}In this work, ratio spectra of the first derivative spectrophotometric and liquid chromatographic methods have been described for the first time for the simultaneous determination of perindopril (PER), indapamide (IND), and amlodipine (AML) in dosage forms. For chromatographic separations several mobile phase compositions were tested for efficient separation with the use of a new column technology related to superficially porous particles. Optimum chromatographic separation was achieved using a Kinetex C18 column (150 $\times $ 4.6 mm I.D. 5 $\mu $m) at a flow rate of 1.5 mL min$^{-1}$. The separation was carried out at 30 $^{\circ}$C and the diode array …

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Fabrication And Electrochemical Performance Of La$_{0.595}$V$_{0.005}$Sr$_{0.4}$Mno$_{3-\Delta }$ (Lv05sm) Cathode Material For Solid Oxide Fuel Cells, Ayşenur Eslem Kisa, Oktay Demi̇rcan Jan 2018

Fabrication And Electrochemical Performance Of La$_{0.595}$V$_{0.005}$Sr$_{0.4}$Mno$_{3-\Delta }$ (Lv05sm) Cathode Material For Solid Oxide Fuel Cells, Ayşenur Eslem Kisa, Oktay Demi̇rcan

Turkish Journal of Chemistry

This study reports the effect of vanadium on the crystal structure and electrical and electrochemical properties of La$_{0.6-x}$V$_{x}$Sr$_{0.4}$MnO$_{3-\delta \, }(x =$ 0.005--0.1) perovskite-based cathode materials in solid oxide fuel cells. Crystal structure, morphology, and porosity of prepared cathode materials are characterized by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy. Using XPS analysis it was established that the La$^{3+}$ cation is exchanged by the V$^{4+/5+}$ cation in the perovskite structure. This ion replacement improves the ionic conductivity and catalytic activity for oxygen reduction reaction in the perovskite structure, presumably due to the smaller size of the V$^{4+/5+}$ cation …

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Determination Of Morin On An Electrochemically Activated Carbon-Paste Electrode, Alexander Chebotarev, Konstantin Pliuta, Denys Snigur Jan 2018

Determination Of Morin On An Electrochemically Activated Carbon-Paste Electrode, Alexander Chebotarev, Konstantin Pliuta, Denys Snigur

Turkish Journal of Chemistry

In this paper, the possibility of using an electrochemically activated carbon-paste electrode (ECA-CPE) for the determination of morin has been studied. It is established that the oxidation current increases 1.85 times in comparison with untreated CPE. The adsorption nature of the anodic current and the number of electrons taking part in the oxidation of morin on ECA-CPE was established. The optimal conditions for the determination of morin (pH $=$ 4, E$_{ads\, }=$ 200~mV, t$_{ads\, }=$ 180 s) were established. Using square-wave voltammetry (A $=$ 35 mV, $\nu =$ 25 Hz, $\upsilon =$ 100 mV/s) it is possible to determine morin …

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Metal Nanoparticles/Carbon Nanotube Modified Electrodes For Voltammetric Determination Of Boron, Lokman Li̇v, Zekerya Dursun, Nuri̇ Naki̇boğlu Jan 2018

Metal Nanoparticles/Carbon Nanotube Modified Electrodes For Voltammetric Determination Of Boron, Lokman Li̇v, Zekerya Dursun, Nuri̇ Naki̇boğlu

Turkish Journal of Chemistry

This study describes a sensitive and accurate voltammetric method for determination of boron using metal nanoparticles/carbon nanotube modified electrodes. The oxidation peak of Alizarin Red S (ARS) at -0.59 V in the boron-ARS complex formed in ammonium/ammonia buffer solution (pH 8.5) was evaluated as a response. The electrode modification conditions and experimental parameters affecting the peak height were optimized. The characteristics of modified electrodes were investigated using cyclic voltammetry, electrochemical impedance spectroscopy, scanning electron microscope, energy dispersive X-ray spectroscopy, high resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. The limits of detection (3s$_{y/x})$ and the analytical ranges for gold nanoparticles/carbon …

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Synthesis And Antimicrobial And Antioxidant Activities Of Hybrid Molecules Containing Benzotriazole And 1,2,4-Triazole, Mahesh Chand, Reena Kaushik, Subhash Chand Jain Jan 2018

Synthesis And Antimicrobial And Antioxidant Activities Of Hybrid Molecules Containing Benzotriazole And 1,2,4-Triazole, Mahesh Chand, Reena Kaushik, Subhash Chand Jain

Turkish Journal of Chemistry

Eleven novel 1,2,4-triazolylbenzotriazoles have been prepared using 1-(hydrazinylcarbonylmethyl)-1$H$-benzot- riazole (3) as a potent intermediate. Compound 3, however, was obtained from benzotriazole in two steps. All synthesized compounds were characterized by detailed spectral studies like IR, $^{1}$H NMR, $^{13}$C NMR, and mass spectrometry. All synthesized compounds were evaluated for their \textit{in vitro} antimicrobial activity against seven strains of bacteria and four strains of fungi. Compounds 13, 17, 19, 20, and 21}were found to possess antibacterial activity comparable to that of ciprofloxacin against a Klebsiella pneumoniae strain. Except for compounds2 and 13, all compounds showed good antifungal activity against an Aspergillus niger …

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Voltammetric Determination Of Glycopyrrolate In A Pharmaceutical Formulation, Muneer Fadr, Abdulaziz Nabil Amro, Sami Ben Aoun, Samer Ratrout, Fadi Asfour Jan 2018

Voltammetric Determination Of Glycopyrrolate In A Pharmaceutical Formulation, Muneer Fadr, Abdulaziz Nabil Amro, Sami Ben Aoun, Samer Ratrout, Fadi Asfour

Turkish Journal of Chemistry

The electrochemical activity of glycopyrrolate was studied. Different voltammetric techniques were applied in this study, including cyclic voltammetry (CV), differential pulse voltammetry (DPV), and linear sweep voltammetry (LSV). Glassy carbon and platinum working electrodes were utilized. CV indicated that glycopyrrolate has a reversible redox reaction on the working electrode surface, with an anodic peak current at approximately 1.05 V and a cathodic peak at 0.80 V. Several parameters that affect the sensitivity of these methods were optimized for the quantitation of glycopyrrolate. LSV showed a better correlation coefficient than DPV did, with a value of ca. 0.9990 in the range …

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Determination Of Hydrogen Peroxide With An Enzymeless Amperometric Sensor Based On Poly(Vinylferrocene)-Supported Ag Nanoparticles, Mutlu Sönmez Çelebi̇, Kübra Öztürk, Mehmet Dumangöz, Fi̇li̇z Kuralay Jan 2018

Determination Of Hydrogen Peroxide With An Enzymeless Amperometric Sensor Based On Poly(Vinylferrocene)-Supported Ag Nanoparticles, Mutlu Sönmez Çelebi̇, Kübra Öztürk, Mehmet Dumangöz, Fi̇li̇z Kuralay

Turkish Journal of Chemistry

An enzymeless electrochemical sensor for detection of low amounts of H$_{2}$O$_{2}$ with the aid of Ag nanoparticles supported on conducting poly(vinylferrocene) (PVF) film was developed. Experimental results revealed that contribution of Ag nanoparticles led to remarkable improvement by means of reduction potential and reduction current. Influence of experimental parameters (i.e. polymeric film thickness, concentration of Ag precursor, immersion time in precursor solution, reduction time, and reduction potential) were investigated. The Ag/PVF-modified electrode system was characterized physically by scanning electron microscopy. The results revealed that the sensor developed was easy-to-prepare, economic, selective, and sensitive, with a fast response time of 3 …

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Cascade Annulation And Ring-Opening Reactions Of Castagnoli-Cushman-Derived Allylic And Benzylic Thiomorpholinonates, Abdikani Omar Farah Jan 2018

Cascade Annulation And Ring-Opening Reactions Of Castagnoli-Cushman-Derived Allylic And Benzylic Thiomorpholinonates, Abdikani Omar Farah

All Master's Theses

Sulfur-containing compounds are prevalent in antibiotics, essential amino acids, bacterial RNA, food flavors, and enzymes. The divalent sulfur atom introduces a metabolic liability from a drug discovery standpoint. Indeed, it is quite telling that all the top ten best-selling drugs in 2012 contained sulfur. In this context, there is a growing need for the synthesis of sulfur-containing compounds in ways that are practical and cost-effective. One approach taken to achieve this goal is to employ diversity-oriented synthesis (DOS), which produces diverse complex molecules with similar core structures from a common precursor. When a DOS features a cascade or domino reaction …

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Determination Of The Oxidative Capacity Of Soot Toward Gsh And Characterization Of Soot Physicochemical Properties, Kaylee Troth Jan 2018

Determination Of The Oxidative Capacity Of Soot Toward Gsh And Characterization Of Soot Physicochemical Properties, Kaylee Troth

All Master's Theses

Fine atmospheric particulate matter (PM2.5) emitted during the combustion of fossil and biomass fuels is known to adversely affect human health. While the underlying mechanisms are thought to be driven by the generation of reactive oxygen species (ROS), specific particle characteristics responsible for this detrimental effect are not well understood. In this research, the quantitative determination of the biologically relevant antioxidant, glutathione (GSH), was optimized for use as an indicator of oxidative stress to shed light on relevant particle characteristics. This was accomplished via fluorescent spectroscopy for GSH determination by way of reaction with o-phthalaldehyde (OPA), a …

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Characterization Of Coacervate Systems Using Redox Sensitive Dyes, Caleb Kaiser Jan 2018

Characterization Of Coacervate Systems Using Redox Sensitive Dyes, Caleb Kaiser

All Master's Theses

Coacervates are systems that spontaneously form when two oppositely charged polyelectrolytes are mixed in a concentrated salt solution. When coacervates form, a biphasic equilibrium occurs in the sample with two phases present in the solution. The two phases are described as the dense phase and the lean phase, named after the amount of polyelectrolyte material in each phase. Coacervates have been topics of interest to researchers in a variety of fields including biomedical applications, drug delivery devices, and more. This thesis worked towards the characterization of coacervate systems on the molecular level by investigating the interaction of the polyelectrolytes and …

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Paracest Agents Encapsulated In Reverse Nano-Assembled Capsules (Racs): How Slow Molecular Tumbling Can Quench Cest Contrast, Annah Farashishiko, Jacqueline R. Slack, Mauro Botta, Mark Woods Jan 2018

Paracest Agents Encapsulated In Reverse Nano-Assembled Capsules (Racs): How Slow Molecular Tumbling Can Quench Cest Contrast, Annah Farashishiko, Jacqueline R. Slack, Mauro Botta, Mark Woods

Chemistry Faculty Publications and Presentations

Although paraCEST is a method with immense scope for generating image contrast in MRI, it suffers from the serious drawback of high detection limits. For a typical discrete paraCEST agent the detection limit is roughly an order of magnitude higher than that of a clinically used relaxation agent. One solution to this problem may be the incorporation of a large payload of paraCEST agents into a single macromolecular agent. Here we report a new synthetic method for accomplishing this goal: incorporating a large payload of the paraCEST agent DyDOTAM3+ into a Reverse Assembled nano-Capsule. An aggregate can be generated between …

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Theoretical Circular Dichroism Spectra Of The Α-Helical Protein Calexitin With The Dipole Interaction Model Including The N-Π* Transition, Akongnwi C. Jungong, Tsvetan Aleksandrov, Rahul Nori, Justin Erickson, Kathryn A. Thomasson, Igor V. Uporov, Ethan R. Austhof, Emily Holt, Felix N. Ngassa Jan 2018

Theoretical Circular Dichroism Spectra Of The Α-Helical Protein Calexitin With The Dipole Interaction Model Including The N-Π* Transition, Akongnwi C. Jungong, Tsvetan Aleksandrov, Rahul Nori, Justin Erickson, Kathryn A. Thomasson, Igor V. Uporov, Ethan R. Austhof, Emily Holt, Felix N. Ngassa

Chemistry Faculty Publications

Circular dichroism (CD) is an important structural biology technique used to study protein dynamics, and most especially the secondary structure of peptides and proteins. Although CD is a technique that is relatively easy to introduce to undergraduate students, the high cost of obtaining a conventional CD instrument and the time required for sample preparation prevents a good number of students from having hands-on experiments demonstrating the principle of CD. Herein, theoretical circular dichroism with the dipole interaction model, DInaMo, is proposed as a tool for introducing students to CD. Using the dipole interaction model, the CD spectra of an α-helical …

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Research And Development Of Optically Transparent Join With Low Processing Temperatures, Eric Kevin Muskovin Jan 2018

Research And Development Of Optically Transparent Join With Low Processing Temperatures, Eric Kevin Muskovin

Masters Theses

The purpose of this study was to investigate durable solar cell cover glass joins produced by diffusion bonding with deep eutectic solvents (DES) and to develop a novel process of joining optically transparent materials at low temperatures. A joined PV cell-glass specimen was characterized using Raman, μ-FTIR, SEM-EDS, and thin-film XRD. DESs were created with malonic acid (MAL) and choline chloride (ChCl) of varying composition factors (CF; CF=MAL/ChCl). Joining borosilicate glass coupons was attempted using DESs with CF = 0.65 and 1 at temperatures between 100-150 °C for 20 hours. Joining the glass coupons failed at all temperatures and oxygen …

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Simultaneous Determination Of Azithromycin And Levooxacin In Pharmaceuticalsby Charge Transfer Complexation With Alizarin Red S Using An Absorption-Factormethod, Vijay D. Chavada, Nejal M. Bhatt, Mallika Sanyal, Pranav S. Shrivastav Jan 2018

Simultaneous Determination Of Azithromycin And Levooxacin In Pharmaceuticalsby Charge Transfer Complexation With Alizarin Red S Using An Absorption-Factormethod, Vijay D. Chavada, Nejal M. Bhatt, Mallika Sanyal, Pranav S. Shrivastav

Turkish Journal of Chemistry

A new approach based on a selective charge transfer reaction with alizarin red S is described for the simultaneous determination of azithromycin and levo oxacin in their binary mixtures using an absorption-factor spectrophotometric method. Native absorbance was used for the determination for levo oxacin, while a charge transfer complexation of alizarin red S served as the basis for the quantitation of azithromycin. The reaction of azithromycin with alizarin red S was possible in methanol under neutral conditions within 15 min at 25 ℃. The conditions were suitably optimized for selective complexation of azithromycin with minimal interference from levo oxacin. The …

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One-Pot Synthesis Of New N-(1-Methylpyridin-4(1h)-Ylidene)Amine Ligands Forpalladium-Catalyzed Heck Coupling Reaction, Muhammad Zafar, Sabeen Zahra, Muhammad Tahir, Ehsan Mughal, Muhammad Nazar, Hummera Rafique Jan 2018

One-Pot Synthesis Of New N-(1-Methylpyridin-4(1h)-Ylidene)Amine Ligands Forpalladium-Catalyzed Heck Coupling Reaction, Muhammad Zafar, Sabeen Zahra, Muhammad Tahir, Ehsan Mughal, Muhammad Nazar, Hummera Rafique

Turkish Journal of Chemistry

A series of new derivatives of N-(1-methylpyridin-4(1H)-ylidene)amines, [L1]-[L5], were synthesized and characterized by FTIR, NMR, MS, and XRD analysis. These targeted compounds were synthesized by the melt reaction between N-methylated-4-chloropyridinium triflate and corresponding amines (1-naphthyl amine, o-ansidine, 2-nitroaniline, p-ansidine, and cyclohexyl amine) followed by the addition of sodium hydride in dichloromethane in the same pot. These highly electron-donating N-(1-methylpyridin-4(1H)-ylidene)amine ligands considerably improve the catalytic activity of palladium acetate towards Heck-Mizoroki carbon-carbon cross-coupling reactions.

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Synthesis And Antioxidant, Aggregation, And Electronic Properties Of6-Tert-Butyl-1,4-Benzodioxine Substituted Phthalocyanines, Mehmet Sali̇h Ağirtaş, Beyza Cabi̇r, Selçuk Gümüş, Sadi̇n Özdemi̇r, Abdurrahman Dündar Jan 2018

Synthesis And Antioxidant, Aggregation, And Electronic Properties Of6-Tert-Butyl-1,4-Benzodioxine Substituted Phthalocyanines, Mehmet Sali̇h Ağirtaş, Beyza Cabi̇r, Selçuk Gümüş, Sadi̇n Özdemi̇r, Abdurrahman Dündar

Turkish Journal of Chemistry

As a starting material, 7-tert-butyldibenzo [b,e] [1,4] dioxine-2,3-dicarbonitrile was prepared by the reac- tion of 4-tert-butylcatechol with 4,5-dichlorophthalonitrile. Metallophthalocyanine complexes 4-7 were obtained by cyclotetramerization of 7-tert-butyldibenzo [b,e] [1,4] dioxine-2,3-dicarbonitrile. All compounds were characterized by elemental analysis and other spectroscopic methods (IR, UV/Vis, and $^{1}$H NMR). Phthalocyanine compounds remained nonaggregated in tetrahydrofuran at the studied concentration ranges. Metallophthalocyanines 4-7 were tested for their antioxidant activities. The antioxidant activity processes included evaluation of radical-scavenging activity, chelat- ing activity, and reducing power. These compounds were compared to standard antioxidant ascorbic acid. The electronic data of the new compounds were obtained by computational …

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