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2019

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Articles 1471 - 1500 of 1773

Full-Text Articles in Chemistry

One-Pot Enol Silane Formation-Mukaiyama Aldol Reactions: Crossed Aldehyde-Aldehyde Coupling, Thioester Substrates, And Reactions In Ester Solvents, C. Wade Downey, Grant J. Dixon, Jared A. Ingersoll, Claire A. Fuller, Kenneth W. Maccormac, Anna Takashima, Rohina Sediqui Jan 2019

One-Pot Enol Silane Formation-Mukaiyama Aldol Reactions: Crossed Aldehyde-Aldehyde Coupling, Thioester Substrates, And Reactions In Ester Solvents, C. Wade Downey, Grant J. Dixon, Jared A. Ingersoll, Claire A. Fuller, Kenneth W. Maccormac, Anna Takashima, Rohina Sediqui

Chemistry Faculty Publications

Trimethylsilyl trifluoromethanesulfonate (TMSOTf) and a trialkylamine base promote both in situ enol silane/silyl ketene acetal formation and Mukaiyama aldol addition reactions between a variety of reaction partners in a single reaction flask. Isolation of the required enol silane or silyl ketene acetal is not necessary. For example, crossed aldol reactions between α-disubstituted aldehydes and non-enolizable aldehydes yield b- hydroxy aldehydes in good yield. In a related reaction, the common laboratory solvent ethyl acetate functions as both an enolate precursor and a green reaction solvent. When thioesters are employed as enolate precursors, high yields for additions to non-enolizable aldehydes are routinely …

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First Generation Amperometric Biosensing Of Galactose With Xerogel-Carbon Nanotube Layer-By-Layer Assemblies, Najwa Labban, Mulugeta B. Wayu, Ciara M. Steele, Tess S. Munoz, Julie A. Pollock, William S. Case, Michael C. Leopold Jan 2019

First Generation Amperometric Biosensing Of Galactose With Xerogel-Carbon Nanotube Layer-By-Layer Assemblies, Najwa Labban, Mulugeta B. Wayu, Ciara M. Steele, Tess S. Munoz, Julie A. Pollock, William S. Case, Michael C. Leopold

Chemistry Faculty Publications

A first-generation amperometric galactose biosensor has been systematically developed utilizing layer-by-layer (LbL) construction of xerogels, polymers, and carbon nanotubes toward a greater fundamental understanding of sensor design with these materials and the potential development of a more efficient galactosemia diagnostic tool for clinical application. The effect of several parameters (xerogel silane precursor, buffer pH, enzyme concentration, drying time and the inclusion of a polyurethane (PU) outer layer) on galactose sensitivity were investigated with the critical nature of xerogel selection being demonstrated. Xerogels formed from silanes with medium, aliphatic side chains were shown to exhibit significant enhancements in sensitivity with the …

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Halogen Bonding Interactions For Aromatic And Non-Aromatic Explosive Detection, Arjun K. A. Jaini, Lillian B. Hughes, Michael K. Kitimet, Kevin John Ulep, Michael C. Leopold, Carol A. Parish Jan 2019

Halogen Bonding Interactions For Aromatic And Non-Aromatic Explosive Detection, Arjun K. A. Jaini, Lillian B. Hughes, Michael K. Kitimet, Kevin John Ulep, Michael C. Leopold, Carol A. Parish

Chemistry Faculty Publications

Improved sensing strategies are needed for facile, accurate and rapid detection of aromatic and nonaromatic explosives. Density functional theory was used to evaluate the relative binding interaction energies between halogen-containing sensor model molecules and nitro-containing explosives. Interaction energies ranged from –18 to –14 kJ/mol and highly directional halogen bonding interactions were observed with bond distances ranging between 3.0 and 3.4 Å. In all geometry optimized structures, the sigma-hole of electropositive potential on the halogen aligned with a lone pair of electrons on the nitro-moiety of the explosive. The computational results predict that the strongest interactions will occur with iodine-based sensors …

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Increased Utility Of Ph Sensitive Indicators As High Concentration Co2 Detectors Through The Use Of Polyelectrolyte Complexes As Stabilizing Media, Camden James Johnson Jan 2019

Increased Utility Of Ph Sensitive Indicators As High Concentration Co2 Detectors Through The Use Of Polyelectrolyte Complexes As Stabilizing Media, Camden James Johnson

All Master's Theses

Development of plastic materials which produce visible color change when exposed to different environments has recently attracted attention for many biomedical applications.1,2Many biomedical devices are packaged under high concentrations of carbon dioxide (CO2) which can lower the pH of the packaging environment. This is similar to the CO2 chemistry responsible for ocean acidification.3 Dye molecules that are sensitive to environmental changes in pH (known as pH indicators) can be encapsulated in plastics and produce a visible color change when a medical device is removed from the sterile CO2 environment. Plastics made from large …

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Modular Synthesis And Hydroalkylation Of Vicinally Functionalized Ketopiperazines: A Solution To The Piperazine Problem, Antonio Moreno Jan 2019

Modular Synthesis And Hydroalkylation Of Vicinally Functionalized Ketopiperazines: A Solution To The Piperazine Problem, Antonio Moreno

All Master's Theses

The stereocontrolled synthesis of functionalized piperazines is of great interest to pharmaceutical companies owing to their multiple biological activities such as antidepressant, antiparasitic, anticancer and antiretroviral. Current methods towards functionalized piperazines include intramolecular cyclization of appropriately tethered on acyclic precursors as well as α-C–H functionalization of intact piperazine rings. Although effective for the most part, these methods suffer from drawbacks such as the use of expensive catalysts, potentially toxic reagents, limited scope and functional group compatibility. Seeking to side-step some of the aforementioned limitations, we herein describe a step-economical-, cost-effective-, transition metal-free-, and mild approach to highly functionalized piperazines, including …

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Optical Characterization Of Salt-Induced Swelling Behavior Of Poly($N$-Isopropylacrylamide) Terpolymer Hydrogel Layers, İlke Anaç, Anil Bozdoğan Jan 2019

Optical Characterization Of Salt-Induced Swelling Behavior Of Poly($N$-Isopropylacrylamide) Terpolymer Hydrogel Layers, İlke Anaç, Anil Bozdoğan

Turkish Journal of Chemistry

This study reports for the first time the effect of different sodium halide salts (NaClO$_{4}$, NaI, and Na$_{2}$CO$_{3})$ in the low concentration range (in the range of 10$^{-7}$-1 M) on the swelling behavior of photo-crosslinked, surface-immobilized poly($N$-isopropyl acrylamide) (PNIPAAm) terpolymer layers. PNIPAAm terpolymer (consisting of $N$-isopropylacrylamide, methacrylic acid, and 4-methacryloxybenzophenone) was synthesized via free radical polymerization. The PNIPAAm terpolymer layers were prepared on gold substrates via spin coating and crosslinked and surface attached via UV radiation. The swelling behavior of the layers in monovalent (NaClO$_{4}$ and NaI) and divalent (Na$_{2}$CO$_{3})$ solutions was monitored by surface plasmon/optical waveguide spectroscopy. The terpolymer …

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Targeting Human Telomeric Dna With Azacyanines, Ayça Küçükakdağ Doğu, Özgül Persi̇l Çeti̇nkol Jan 2019

Targeting Human Telomeric Dna With Azacyanines, Ayça Küçükakdağ Doğu, Özgül Persi̇l Çeti̇nkol

Turkish Journal of Chemistry

Small molecules targeting telomeric DNA or its interactions with telomerase have been an active area of cancer research. In the present study, we investigated the interactions of six benzimidazole compounds, called azacyanines, differing from each other in alkyl chain length and branching in the benzimidazole ring (azamethyl, azaethyl, azapropyl, azaisopropyl, azabutyl, and azaisobutyl) with human telomeric DNA (tel24) in 1:1 and 1:6 ratio (tel24:azacyanine) using UV-Vis, circular dichroism (CD), and fluorescence spectroscopy. All the compounds were binding to tel24 as indicated by the formation of the weak induced CD band between 320 nm and 360 nm. A substantial red shift …

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Amperometric Urea Biosensor Based On Immobilized Urease On Polypyrrole And Macroporous Polypyrrole Modified Pt Electrode, Maliheh Hosseinian, Ghasem Najafpour, Ahmad Rahimpour Jan 2019

Amperometric Urea Biosensor Based On Immobilized Urease On Polypyrrole And Macroporous Polypyrrole Modified Pt Electrode, Maliheh Hosseinian, Ghasem Najafpour, Ahmad Rahimpour

Turkish Journal of Chemistry

Biosensing of urea by a biosensor as a direct detection method at ambient temperature and pressure instead of chromatography leads to a significant reduction in processing costs. Amperometric biosensors based on urease immobilization on macroporous polypyrrole (MPPy) and pyrrole on the surface of a Pt electrode were developed. Applying cyclic voltammetry (CV), we demonstrated the synthesis of MPPy using monodispersed polystyrene spheres (460 nm) as a template. CV and chronoamperometric studies were conducted to evaluate the electrochemical current of the modified electrodes. For the electrode with polypyrrole (PPy), the biosensor response was linear in the range of 1.67--8.32 mM (R$^{2}$ …

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Acetyl- And Butyrylcholinesterase Inhibitory Activity Of Selected Photochemically Synthesized Polycycles, Ivana Sagud, Irena Skoric, Dragana Vuk, Ana Ratkovic, Franko Burcul Jan 2019

Acetyl- And Butyrylcholinesterase Inhibitory Activity Of Selected Photochemically Synthesized Polycycles, Ivana Sagud, Irena Skoric, Dragana Vuk, Ana Ratkovic, Franko Burcul

Turkish Journal of Chemistry

Alzheimer's disease (AD) is a progressive neurodegenerative disorder and the main cause of dementia in the elderly population. Since the treatment of AD has been associated with the activity of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), their inhibitors remain the main focus of AD investigations. In this study we evaluated cholinesterase inhibitory activity of 14 bicyclo[3.2.1]octene/octadiene derivatives and naturally occurring sesquiterpene alcohol cedrol. These 14 compounds have been efficiently and ecologically prepared by a photochemical approach in batch photochemical reactors. Various compounds with the bicyclo[3.2.1]octene skeleton have already been successfully evaluated for treatment of central nervous system disorders and AD. Among …

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Reduced Graphene Oxide Supported Tin Oxide-Boron Oxide Flexible Paper Anodes For Li-Ion Batteries, Hi̇lal Köse, Şeyma Dombaycioğlu, Hatem Akbulut, Ali̇ Osman Aydin Jan 2019

Reduced Graphene Oxide Supported Tin Oxide-Boron Oxide Flexible Paper Anodes For Li-Ion Batteries, Hi̇lal Köse, Şeyma Dombaycioğlu, Hatem Akbulut, Ali̇ Osman Aydin

Turkish Journal of Chemistry

Freestanding tin oxide-boron oxide/reduced graphene oxide (SnO$_{2}$-B$_{2}$O$_{3}$/rGO) nanocomposite anode was produced for Li-ion cells. This binder-free flexible paper anode structure was fabricated by combining SnO$_{2}$-B$_{2}$O$_{3}$ composite and graphene oxide which were synthesized through the sol-gel method and Hummers' method, respectively. Field emission gun scanning electron microscopy, high-resolution transmission electron microscopy, energy dispersive X-ray spectrometer, Fourier transform infrared spectroscopy, Raman spectroscopy, and X-ray diffraction were utilized to characterize anode materials. The Williamson-Hall (W-H) analysis was applied using XRD data to determine crystal size and strain of the lattice. Electrochemical tests, cyclic voltammetry, and electrochemical impedance spectroscopy measurements were performed to determine …

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Extraction Of High-Purity Silica From Rice Husk Via Hydrochloric Acid Leaching Treatment, Seitkhan Azat, Zhanar Sartova, Kalampyr Bekseitova, Kydyr Askaruly Jan 2019

Extraction Of High-Purity Silica From Rice Husk Via Hydrochloric Acid Leaching Treatment, Seitkhan Azat, Zhanar Sartova, Kalampyr Bekseitova, Kydyr Askaruly

Turkish Journal of Chemistry

The present paper aimed at the investigation of the effect of preliminary acid treatment on the structure and purity of extracted silica. In this study, the acid leaching of rice husk (RH) in 2 M hydrochloric acid solution before the calcination process at 600 $^{\circ}$C was proposed to achieve completely white silica with high specific surface area and low content of impurities. RH, selected from the Almaty Region, Kyzylorda Region, and Turkestan Region was used as the main silica source. The results confirmed that the highest purity (98.2%-99.7%) amorphous silica with a specific surface area between 120 and 980 m$^{2}$ …

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The Effect Of Starting Material Types On The Structure Of Graphene Oxide And Graphene, Fi̇li̇z Boran, Sevi̇l Çeti̇nkaya Gürer Jan 2019

The Effect Of Starting Material Types On The Structure Of Graphene Oxide And Graphene, Fi̇li̇z Boran, Sevi̇l Çeti̇nkaya Gürer

Turkish Journal of Chemistry

In this study, the effects of starting material types on graphene oxide (GO) are reported with the aim of developing graphene (GR) synthesis. The GOs were prepared from natural graphite (NG) powder and graphite nanoplate (GNp) based on the Hummers method. Two kinds of GR were successfully synthesized using GOs, which were prepared from NG and GNp in the presence of hydrazine and ammonia for 24 h at a 100 $^{\circ}$C reaction temperature. The synthesized GOs and GRs were characterized by X-ray diffraction (XRD) techniques, Fourier transform infrared, high-contrast transmission electron microscopy (HCTEM), dispersive Raman spectroscopic analyses, and elemental analyses. …

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In Silico And In Vitro Evaluation Of The Biological Activity Of Some Organic Sulfur-Containing Compounds, Victoria Osipova, Maria Polovinkina, Anastasia Osipova, Yulia Gracheva, Andrey Okhlobystin Jan 2019

In Silico And In Vitro Evaluation Of The Biological Activity Of Some Organic Sulfur-Containing Compounds, Victoria Osipova, Maria Polovinkina, Anastasia Osipova, Yulia Gracheva, Andrey Okhlobystin

Turkish Journal of Chemistry

It was predicted, using the Prediction of Activity Spectra for Substances online software, that organic sulfur-containing compounds 2,6-di-tert-butyl-4-mercaptophenol (1), 2,6-di-tert-butyl-4-(3-mercaptopropyl)phenol (2), bis-3-[3,5-di-tert-butyl-4-hydroxyphenyl)propyl] sulfide (3), bis(3,5-di-tert- butyl-4-hydroxyphenyl) disulfide (4), diphenyl disulfide (5), dibenzyl disulfide (6), dibutyl disulfide (7), di-tert-butyl disulfide (8), diallyl disulfide (9), and methyl propyl trisulfide (10) could possess antioxidant activity and act as active scavengers of oxygen metabolites. The antiradical activity of these species was analyzed and it was shown that they were able to react with electrochemically generated the superoxide anion radical. The rate constants for reactions of 1-10 with the superoxide anion radical were calculated. The …

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Acetylene-Bridged Triazine Π-Conjugated Structures: Synthesis And Liquid Crystalline Properties, Ni̇hat Akkurt, Mohammed Hadi Ali Al-Jumaili, Belkiz Bi̇lgi̇n Eran, Hale Ocak, Lokman Torun Jan 2019

Acetylene-Bridged Triazine Π-Conjugated Structures: Synthesis And Liquid Crystalline Properties, Ni̇hat Akkurt, Mohammed Hadi Ali Al-Jumaili, Belkiz Bi̇lgi̇n Eran, Hale Ocak, Lokman Torun

Turkish Journal of Chemistry

We report the synthesis and liquid crystalline properties of a new type of tribranched compound built up from triazine as the central core and electron-rich triazine rings as peripheral groups. An equimolar mixture of the star-shaped compound based on the 1,3,5-triazine core with 4-dodecyloxybenzoic acid produced an organic salt exhibiting a columnar mesophase with a dendritic growing texture at low temperatures. The liquid crystalline properties of the triazine-based compound and organic salt were investigated by differential scanning calorimetry and polarizing optical microscopy.

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One-Pot Synthesis Of Quinazolin-4(3$H$)-Ones And 2,3-Dihydroquinazolin-4(1$H$)-Ones Utilizing $N$-(2-Aminobenzoyl)Benzotriazoles, İlbi̇lge Merve Şenol, İlhami̇ Çeli̇k, İlker Avan Jan 2019

One-Pot Synthesis Of Quinazolin-4(3$H$)-Ones And 2,3-Dihydroquinazolin-4(1$H$)-Ones Utilizing $N$-(2-Aminobenzoyl)Benzotriazoles, İlbi̇lge Merve Şenol, İlhami̇ Çeli̇k, İlker Avan

Turkish Journal of Chemistry

A convenient and efficient method has emerged for the one-pot synthesis of substituted quinazolin-4(3$H)$-ones and nonaromatic alkaloids. 2-Substituted quinazolin-4(3H)-ones, 2,3-disubstituted quinazolin-4(3$H)$-ones, and 2,3-dihydroquinazolin-4(1$H)$-ones were obtained at yields of 46% to 95% by a one-pot reaction of $N$-(2-aminobenzoyl) benzotriazoles with amines and orthoesters or aldehydes under catalyst-free conditions.

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An Evaluation Of The Adsorption Dynamics Of Phosphate Ions Onto Fe(Ii)-Montmorillonites, Dawei Qin, Shuhua Chang, Min Qiao, Xiaotong Yuan, Wei Liu, Gang Liu Jan 2019

An Evaluation Of The Adsorption Dynamics Of Phosphate Ions Onto Fe(Ii)-Montmorillonites, Dawei Qin, Shuhua Chang, Min Qiao, Xiaotong Yuan, Wei Liu, Gang Liu

Turkish Journal of Chemistry

Fe(II)-montmorillonites (Fe(II)-MMTs) were prepared by mixing solutions of Fe(II) and montmorillonite at pH 3.5. Two different Fe(II)-MMTs were prepared and the ferrous iron contents were 40 mg/L and 80 mg/L. All samples were characterized by XRD, FT-IR, TGA, DSC, and nitrogen adsorption. By nitrogen adsorption, the pore size can be obtained in the pore diameter curve with average pore widths of 6.67 nm, 9.96 nm, and 17.07 nm, respectively. The removal rate of phosphate increased rapidly during the first 40 min, in which Fe(II)-MMT (1) and Fe(II)-MMT (2) were stronger adsorption systems than MMT. The maximum adsorption was 48.38 mg/g …

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Synthesis Of Highly Active Crystalline Carbon Nitride Prepared In Various Salt Melts For Photocatalytic Degradation Of Phenol, Mohd Hayrie Mohd Hatta, Hendrik Oktendy Lintang, Siew Ling Lee, Leny Yuliati Jan 2019

Synthesis Of Highly Active Crystalline Carbon Nitride Prepared In Various Salt Melts For Photocatalytic Degradation Of Phenol, Mohd Hayrie Mohd Hatta, Hendrik Oktendy Lintang, Siew Ling Lee, Leny Yuliati

Turkish Journal of Chemistry

Crystallinity could have a decisive influence on photocatalytic performance. In this study, the synthesis of crystalline carbon nitride (CN) was studied via an ionic melt polycondensation of urea precursor in the presence of various salt melts, which were KCl-LiCl, KCl-NaCl, and KCl-ZnCl$_{2}$. While all the salt melts helped to improve the optical properties of the CN, only KCl-LiCl salt melt could form crystalline CN as evidenced by its X-ray diffraction pattern. Furthermore, the specific surface area of CN (72 m$^{2}$/g) was maintained when using KCl-LiCl (73 m$^{2}$/g), but it was decreased in the presence of KCl-NaCl (22 m$^{2}$/g) or KCl-ZnCl$_{2}$ …

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Synthesis, Characterization, And Kinetic Studies Of Multifunctionalized Mesoporous Silica For Adsorption Of Zinc, Ali̇me Çitak Jan 2019

Synthesis, Characterization, And Kinetic Studies Of Multifunctionalized Mesoporous Silica For Adsorption Of Zinc, Ali̇me Çitak

Turkish Journal of Chemistry

The aim of this study is to evaluate the utilization of bifunctional mesoporous silica with a platinum and propylsulfonic acid group (Pt/SBA15-PrSO$_{3}$H) as an adsorbent for the removal of Zn(II) ions from aqueous solutions. The SBA15-functionalized organosulfonic acid material was synthesized with a one-step cocondensation synthesis route. The second step was Pt loading during reduction and deposition into the aqueous suspension of the bifunctional mesoporous silica synthesized by an aqueous solution of formaldehyde as the reducing agent. The propylsulfonic acid and platinum functionalized mesoporous silica were characterized by BET, thermogravimetric analysis, and X-ray diffraction methods. The adsorption properties and thermodynamic …

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Characterization And Purification Of 1,2,4-Triazole-Containing Phthalocyanines Synthesized By Microwave Method And Structure Elucidation By Spectroscopic Techniques, Asi̇ye Nas, Ümi̇t Demi̇rbaş, Nurhan Gümrükçüoğlu, Hali̇t Kanteki̇n Jan 2019

Characterization And Purification Of 1,2,4-Triazole-Containing Phthalocyanines Synthesized By Microwave Method And Structure Elucidation By Spectroscopic Techniques, Asi̇ye Nas, Ümi̇t Demi̇rbaş, Nurhan Gümrükçüoğlu, Hali̇t Kanteki̇n

Turkish Journal of Chemistry

The complexes of peripherally tetra-substituted metal-free (8), lead(II) 9), and zinc(II) (10) phthalocyanine derivatives were synthesized for the first time in this work. The structures of these new complex compounds have been elucidated using many spectral methods such as electronic absorption, FT-IR, $^{1}$H NMR, $^{13}$C NMR, elemental analysis, and mass spectra. The thermogravimetric behavior of compounds 8-10 was determined by thermogravimetric analysis method in addition to these spectral methods.

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Preparation Of $\Alpha $-Hydroxyphenylacetic Acid With Cyclodextrins As An Effective Phase-Transfer Catalyst And Its Reaction Mechanism, Bing Ren Tian, Rui Xia Zhang, Hui Min Chu, Qing Huang, Zhi Zhong Wang Jan 2019

Preparation Of $\Alpha $-Hydroxyphenylacetic Acid With Cyclodextrins As An Effective Phase-Transfer Catalyst And Its Reaction Mechanism, Bing Ren Tian, Rui Xia Zhang, Hui Min Chu, Qing Huang, Zhi Zhong Wang

Turkish Journal of Chemistry

An effective procedure for the synthesis of $\alpha $-hydroxyphenylacetic acid with cyclodextrin (CD) catalysts was developed. The phase-transfer catalyst types, catalyst loadings, reaction times, reaction temperatures, and substrate molar ratios were investigated to optimize the reaction conditions. In addition, the factors that affect the reaction were studied, and the relationship between benzaldehyde and $\beta $-cyclodextrin ($\beta $-CD) was analyzed through 2D-ROESY. The equilibrium constant when $\beta $-CD was used as the catalyst was calculated. The results indicated that $\beta $-CD is the optimal catalyst for the reported reaction (yield: 69.08%). Furthermore, the mechanism underlying the reported reaction was proposed.

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Progress In The Chemistry Of 3-Amino-9-Ethylcarbazole, Samir Bondock, Salwa Alqahtani, Ahmed M. Fouda Jan 2019

Progress In The Chemistry Of 3-Amino-9-Ethylcarbazole, Samir Bondock, Salwa Alqahtani, Ahmed M. Fouda

Turkish Journal of Chemistry

Generally, 3-amino-9-ethylcarbazole is considered a versatile compound not only for its unique electronic properties but also for its significance as a building block in synthetic, pharmaceutical, and material chemistry. The synthesis, chemical reactivity, and applications of 3-amino-9-ethylcarbazole are described in this review. The presence of the amino group at position 3 exhibits a unique reactivity with both C-2 and C-4. The reactions of 3-amino-9-ethylcarbazole are divided into three categories, reactions that involve the amino group and cyclization reactions that involve the amino group and C-2 and/or C-4. In this review, relevant and appropriate applications of the synthesized, isolated, and condensed …

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Why Protein Conformers In Molecular Dynamics Simulations Differ From Their Crystal Structures: A Thermodynamic Insight, Fi̇li̇ppo Pullara, Mao Wenzhi, Mert Gür Jan 2019

Why Protein Conformers In Molecular Dynamics Simulations Differ From Their Crystal Structures: A Thermodynamic Insight, Fi̇li̇ppo Pullara, Mao Wenzhi, Mert Gür

Turkish Journal of Chemistry

Conformers generally deviate structurally from their starting X-ray crystal structures early in molecular dynamics (MD) simulations. Studies have recognized such structural differences and attempted to provide an explanation for and justify the necessity of MD equilibrations. However, a detailed explanation based on fundamental physics and validation on a large ensemble of protein structures is still missing. Here we provide the first thermodynamic insights into the radically different thermodynamic conditions of crystallization solutions and conventional MD simulations. Crystallization solution conditions can lead to nonphysiologically high ion concentrations, low temperatures, and crystal packing with strong specific protein--protein interactions, not present under physiological …

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Removal Of Cr(Vi) From Wastewater Through Glycine Assisted Synthesis Of Tio$_{2}$, Bi̇lsen Kurtteki̇n, Demet Özer, Nurşen Altuntaş Öztaş Jan 2019

Removal Of Cr(Vi) From Wastewater Through Glycine Assisted Synthesis Of Tio$_{2}$, Bi̇lsen Kurtteki̇n, Demet Özer, Nurşen Altuntaş Öztaş

Turkish Journal of Chemistry

In this study, titanium dioxide was synthesized via solution combustion method. Titanium(IV) oxysulfate was used as a titanium source. The fuel type, reaction time, and reaction temperature were tested for optimization. The glycine was set as a suitable fuel. Structural properties of the final product were characterized by p-XRD. Scanning electron microscopy (SEM) and BET techniques were used to examine the morphology. The synthesized products were compared to the commercial TiO$_{2}$ and it was found that the titanium dioxide with the high surface area (63.628 m$^{2}$/g) has been successfully synthesized by solution combustion method with time and energy saving. In …

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Chiral 1,4-Aminoalkylphenols For Enantioselective Diethylzinc Addition To Aldehydes, Ömer Di̇lek, Mustafa Ali̇ Tezeren, Tahi̇r Ti̇lki̇, Erkan Ertürk Jan 2019

Chiral 1,4-Aminoalkylphenols For Enantioselective Diethylzinc Addition To Aldehydes, Ömer Di̇lek, Mustafa Ali̇ Tezeren, Tahi̇r Ti̇lki̇, Erkan Ertürk

Turkish Journal of Chemistry

Starting from a chiral secondary alcohol, novel enantiopure 1,4-aminoalkylphenols (AAPs) were prepared by exploiting conventional organic transformations such as the Mitsunobu reaction, Eschweiler--Clarke N-methylation, and demethylation of anisoles. The catalytic activity of the 1,4-AAPs was investigated in enantioselective Et$_{2}$Zn addition to benzaldehyde. They were found to accelerate the Et$_{2}$Zn addition to benzaldehyde. High yields and enantioselectivities (e.g., 95% yield and 82% ee) were achieved.

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Investigation Of Sulfuric Acid-Treated Activated Carbon Properties, Neda Asasian Kolur, Seyedmehdi Sharifian, Tahereh Kaghazchi Jan 2019

Investigation Of Sulfuric Acid-Treated Activated Carbon Properties, Neda Asasian Kolur, Seyedmehdi Sharifian, Tahereh Kaghazchi

Turkish Journal of Chemistry

A granulated type of commercial activated carbon (GAC) with surface area of 828 m$^{2}$/g was treated with a strong solution of sulfuric acid (98% wt.) at a temperature of 30 $^{\circ}$C . The physicochemical and porous properties and the surface chemistry of the sorbents were investigated and compared in detail. It was established that the lower temperatures of impregnation and the higher concentration of H$_{2}$SO$_{4}$ solution resulted in the introduction of higher percentages of sulfur-containing groups and smaller porosity loss. The results of EDS, FTIR, and XPS tests confirmed the introduction of sulfone groups and acidic oxygenated ones, which increased …

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Synthesis And Antimicrobial Activity Of 1-(Benzo[B]Thiophen-4-Yl)-4-(2-(Oxo, Hydroxyl, And Fluoro)-2-Phenylethyl)Piperazine And 1-(Benzo[D]Isothiazole-3-Yl)-4-(2-(Oxo, Hydroxy, And Fluoro)-2-Phenylethyl)Piperazine Derivatives, Vaibhav Mishra, Tejpal Singh Chundawat Jan 2019

Synthesis And Antimicrobial Activity Of 1-(Benzo[B]Thiophen-4-Yl)-4-(2-(Oxo, Hydroxyl, And Fluoro)-2-Phenylethyl)Piperazine And 1-(Benzo[D]Isothiazole-3-Yl)-4-(2-(Oxo, Hydroxy, And Fluoro)-2-Phenylethyl)Piperazine Derivatives, Vaibhav Mishra, Tejpal Singh Chundawat

Turkish Journal of Chemistry

Twenty-two compounds in a series of 1-(benzo[$b$]thiophen-4-yl)-4-(2-(oxo, hydroxy, and fluoro)-2-phenylethyl) piperazine and 1-(benzo[$d$]isothiazole-3-yl)-4-(2-(oxo, hydroxy, and fluoro)-2-phenylethyl)-piperazine derivatives were synthesized through nucleophilic substitution reaction of phenacyl bromides with hetero arylpiperazine, reduction, and then fluorination. Compound K2 showed potent activity against gram-negative bacterial stain P. aeruginosa with minimum inhibitory concentration (MIC) value of 12.5 μg/mL. This compound showed better inhibitory activity than the standard drug chloramphenicol. K4 against S. aureus, H2 against P. aeruginosa, and F4 against E. coli showed good inhibitory activity with MIC values of 62.5 μg/mL. Compounds K1, K2, K4, K8, F1, and F3 showed good inhibitory activity against …

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Determination Of Triacylglycerols And Fatty Acid Composition Of Chilopsis Linearis Seed Oil By Reverse-Phase High-Performance Liquid Chromatography, Anh Van Nguyen, Victor Ivanovic Deineka, Lyudmila Aleksandrovna Deineka, Anh Thi Ngoc Vu Jan 2019

Determination Of Triacylglycerols And Fatty Acid Composition Of Chilopsis Linearis Seed Oil By Reverse-Phase High-Performance Liquid Chromatography, Anh Van Nguyen, Victor Ivanovic Deineka, Lyudmila Aleksandrovna Deineka, Anh Thi Ngoc Vu

Turkish Journal of Chemistry

In the present work, the compositions of the 27 triacylglycerols (TAGs) as well as fatty acid composition of Chilopsis linearis seed oil were determined by reverse-phase high-performance liquid chromatography (RP-HPLC) with diode array and mass spectrometric detections. It was shown that the main conjugated acid in the seed oil is a catalpic acid, (9E,11E,13Z)-octadeca-9,11,13-trienoic acid, while two unusual fatty acids have the parameters satisfying the literature data for (10E,12E)-octadeca-10,12-dienoic and (9E,12E)-octadeca-9,12-dienoic acids. For the two conjugated acid substituents the isosbestic point (at 234 nm) was found and was used to calculate the ratios of TAGs with different chromophores in the …

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Synthesis, Characterization, And Nonlinear Optical Properties Of Some New Series Of S-(5-Aryl-1,3,4-Oxadiazol-2-Yl) 2-Chloroethanethioate Derivatives, Zahra Dono Ghezelbash, Hamideh Motiei, Miri Mahmoody, Karim Akbari Delmaghani Jan 2019

Synthesis, Characterization, And Nonlinear Optical Properties Of Some New Series Of S-(5-Aryl-1,3,4-Oxadiazol-2-Yl) 2-Chloroethanethioate Derivatives, Zahra Dono Ghezelbash, Hamideh Motiei, Miri Mahmoody, Karim Akbari Delmaghani

Turkish Journal of Chemistry

In the present investigation, some novel S-(5-aryl-1,3,4-oxadiazol-2-yl)2-chloroethanethioate (3a-3e) derivatives were synthesized and their impact on optical properties was studied. They have also been characterized by elemental analysis and various spectroscopic methods including FTIR, $^{1}$H NMR, $^{13}$C NMR, and UV-Vis techniques. The nonlinear refractive indexes of 3a-3e were also measured in dichloromethane via Z-scan method using a continuous wave diode-pumped laser at 532 nm wavelength. The nonlinear refractive coefficient of compounds was obtained from ${10}^{11}\, \, {m}^{{2}}{/W}$ order. Regarding the appropriate nonlinearity of these compounds, they could be considered good candidates for biooptical and photonic applications. All the synthesized compounds (3a-3e) …

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Enhanced Uptake Capacities And Isosteric Heats Of Co$_{2}$ And Ch$_{4}$ Adsorption On Spent Coffee Ground Activated Carbons Loaded With Metal Ions, Çi̇sem Kirbiyik, Burak Zafer Büyükbekar, Mahmut Kuş, Mustafa Ersöz Jan 2019

Enhanced Uptake Capacities And Isosteric Heats Of Co$_{2}$ And Ch$_{4}$ Adsorption On Spent Coffee Ground Activated Carbons Loaded With Metal Ions, Çi̇sem Kirbiyik, Burak Zafer Büyükbekar, Mahmut Kuş, Mustafa Ersöz

Turkish Journal of Chemistry

Low-cost activated carbon (AC) samples obtained from waste coffee grounds were used for CO$_{2}$ and CH$_{4}$ adsorption. ACs were prepared by chemical activation and carbonized at three different temperatures. AC carbonized at 800 $^{\circ}$C showed a relatively high surface area (582.92 m$^{2}$ g$^{-1})$ and high adsorption capacities of 2.6 mmol g$^{-1}$ and 1.1 mmol g$^{-1}$ at 25 $^{\circ}$C for CO$_{2}$ and CH$_{4}$, respectively. Adsorbent samples were prepared by loading of Fe$^{3+}$ metal ions onto ACs and their adsorption capacities were compared with those of nonloaded ACs. As expected, the loading of Fe$^{3+}$ metal ions increased the adsorption capacities at all …

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Conformational Communication Mediates The Reset Step In T6a Biosynthesis, Amit Luthra, Naduni Paranagama, William Swinehart, Susan Bayooz, Phuc Phan, Vanessa Quach, Jamie M. Schiffer, Boguslaw Stec, Dirk Iwata-Reuyl, Manal A. Swairjo Jan 2019

Conformational Communication Mediates The Reset Step In T6a Biosynthesis, Amit Luthra, Naduni Paranagama, William Swinehart, Susan Bayooz, Phuc Phan, Vanessa Quach, Jamie M. Schiffer, Boguslaw Stec, Dirk Iwata-Reuyl, Manal A. Swairjo

Chemistry Faculty Publications and Presentations

The universally conserved N 6-threonylcarbamoylade nosine (t 6 A) modification of tRNA is essential for translational fidelity. In bacteria, t 6 A biosynthesis starts with the TsaC/TsaC2-catalyzed synthesis of the intermediate threonylcarbamoyl adenylate (TC-AMP), followed by transfer of the threonylcarbamoyl (TC) moiety to adenine-37 of tRNA by the TC-transfer complex comprised of TsaB, TsaD and TsaE sub-units and possessing an ATPase activity required for multi-turnover of the t 6 A cycle. We report a 2.5-˚ A crystal structure of the T. maritima TC-transfer complex (TmTsaB 2 D 2 E 2) bound to Mg 2+-ATP in the AT-Pase site, and substrate …

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