Chemistry Commons^™

Low Speed Current Bearing Anti-Force Waves, M. Hemmati, W. P. Childs, H. Shojaei, H. Morris

Journal of the Arkansas Academy of Science

For theoretical investigation of electrical breakdown of a gas, we apply a one-dimensional, steady profile, constant velocity, three-component (electrons, ions and neutral particles) fluid model. Our fluid model consists of the equations of conservation of mass, momentum and energy, coupled with the Poison’s equation. The set of equations is referred to as the electron fluid dynamical equations (EFD). This investigation involves breakdown waves with a substantial current behind the wave front, and waves for which the electric field force on electrons is in the opposite direction of the wave propagation (anti-force waves – lightning return stroke). Therefore, the set of …

Uv Curable Coatings For Improved Gas Barrier Properties Of Poly(Ethylene Terephthalate), Ethem Kaya, Tara Smith, Lon J. Mathias

Faculty Publications

A new high-barrier coating based on methyl (alpha-hydroxymethyl)acrylate (MHMA) for poly(ethylene terephthalate) (PET) was developed along with the process for preform dipping and cure prior to blow molding into bottles. The UV curable coating gives excellent gas barrier improvement when coated onto PET biaxially oriented thin films. Blown bottle side walls from coated PET preforms also show 2-3 times improvement over uncoated side walls. The effect of photoinitiator concentration, initiator types, and temperature on photopolymerization kinetics of MHMA was investigated. Once the photoinitiator, lrgacure 819 (R), concentration became larger than 1 mol%, a decrease in rate of propagation was observed. …

Stop Rotating! One Substitution Halts The B19- Motor, Francisco Cervantes-Navarro, Gerarso Martínez-Guajardo, Edison Osorio, Diego Moreno, William Tiznado, Rafael Islas, Kelling J. Donald, Gabriel Merino

Chemistry Faculty Publications

The B₁₉^- anion and other boron species have been dubbed ‘Wankel motors’ for the almost barrierless rotation of inner and outer concentric rings relative to each other in these compounds. A single substitution in B₁₉^- is shown to shut down the well-established fluxionality in the anion. A carbon atom substituted in the structure to give a neutral CB₁₈ species is shown computationally to enforce bond localization.

Approximate Quantum Trajectory Method For Modeling Chemical Reaction Dynamics: Application To Enzymatic Proton Transfer, James William Mazzuca

Theses and Dissertations

Molecular dynamics simulations, providing a detailed picture of the reaction mechanism, is an essential tool for theoretical and experimental chemists. In these simulations the nuclei are typically treated as classical particles, but under some conditions (low energies and temperatures, processes involving multiple electronic states) a classical description is inappropriate. Quantum effects of nuclear motion, such as tunneling and zero-point energy can play an important role in determining a reaction mechanism, yet exact quantum dynamics methods are limited to reactive systems of just 3-4 atoms. Central to this work is the development and implementations of an efficient trajectory-based methodology, in which …

Synthesis, Structure, And Luminescent Properties Of 2 Novel 5-Chlorhydroxybenzoate-Imidazole Metal-Organic Complexes, Hong Chen, Si Yuan Luo, Xiuling Wu, Yongqian Wang, Bo Hu, Chao Hu, Gang Huang, Qiao Xin Du

Turkish Journal of Chemistry

Two novel Zn and Cu complexes with 5-chlorhydroxybenzoate and imidazole ligands, C_{41}H_{36}Zn_2N_8O_{13}Cl_4 (1) and C_{26}H_{22}Cl_2Cu_2N_8O_6 (2), were prepared by slow evaporation method. Single crystal X-ray diffraction analysis was used to determine their structures. The purity of the complexes was confirmed by powder X-ray diffraction analysis. In 1 the Zn^{2+} cation is tetracoordinated with 2 nitrogen atoms from 2 imidazoles and 2 oxygen atoms from the 2 carboxyl groups in 5-chlorhydroxybenzoate. In 2 the coordination polyhedrons of Cu^{2+} center can be described as distorted square pyramidal geometry sharing common edges, with an oxygen atom on the top of the pyramid. The …

Simulation Of Impedance Spectra Of Oxalic Acid Electroreduction To Glyoxylic Acid: Effect Of Chemical Activator, Ph, Activation Energy, And Reduction Potential, Ni̇yazi̇ Alper Tapan

Turkish Journal of Chemistry

The aim of this study was to examine qualitatively the effect of important electrochemical parameters on the faradaic impedance spectra of oxalic acid electroreduction. The impedance spectrum of a 3-step oxalic acid electroreduction mechanism was simulated by the solution of a faradaic impedance equation based on 3 state variables. Before the solution of the faradaic impedance equation, the electroreduction mechanism was analyzed and it was seen that this mechanism can be represented by an electrical circuit composed of 2 resistors and a capacitance or inductance. The effect of chemical activator on the impedance spectrum was determined by using the relation …

Fluorescence Quenching Study Of Moxifloxacin Interaction With Calf Thymus Dna, Yunkai Lv, Pan Li, Miao-Lun Jiao, Bao-Sheng Liu, Chao Yang

Turkish Journal of Chemistry

Moxifloxacin (MOX) is a fourth-generation synthetic fluoroquinolone antibacterial agent with many important therapeutic properties. Fluorescence quenching was used to study the interaction of MOX with calf thymus DNA (ct-DNA) in aqueous solution. The intercalative binding mode and a static quenching mechanism were confirmed by the Stern--Volmer quenching rate constant (K_q) of 3.48 \times 10^{11} M^{-1} s^{-1} at 298 K. The thermodynamic parameters (\Delta H = --118.4 KJ mol^{-1} and \Delta S = --299.4 J mol^{-1} K^{-1}) were calculated at different temperatures, and they indicate that the main forces between MOX and ct-DNA are hydrogen bonding and Van der Waals force. …

Platinum Or Nickel Nanoparticles Decorated On Silica Spheres By Microwave Irradiation Technique, Ayşe Bayrakçeken

Turkish Journal of Chemistry

Supported catalysts are of great interest because of their wide range of application possibilities. In this study, firstly silica spheres were synthesized and then platinum and nickel nanoparticles were incorporated on this silica by microwave irradiation, which is an efficient technique for catalyst preparation. Synthesized silica spheres and catalysts were characterized by BET, X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, and transmission electron microscopy techniques. Pt or Ni nanoparticles well dispersed over silica support were obtained using microwave irradiation.

In Vitro Effects Of Pesticide Exposure On The Activity Of The Paraoxonase-1 Enzyme From Sheep Liver Microsomes, Büşra Cebeci̇, Zuhal Alim, Şükrü Beydemi̇r

Turkish Journal of Chemistry

The organophosphate target enzyme paraoxonase-1 (PON1) has been extensively studied in toxicology. Pesticides are organophosphate compounds that are commonly used in agriculture. They are also used as nerve gases, such as sarin and soman. Therefore, the effects of these compounds on enzymatic activity are well known. In the present study, we investigated the in vitro effects of fenoxaprop-p-ethyl, lambda cyhalothrin, imidacloprid, and dichlorvos pesticides on sheep liver microsomal PON1. The enzyme was purified approximately 141-fold with a specific activity of 1822.22 EU/mg proteins. The pesticides inhibited sheep liver PON1 in vitro, and the IC_{50} values for these compounds were 0.0103, …

Synthesis Of Novel Triazoles Bearing 1,2,4-Oxadiazole And Phenylsulfonyl Groups By 1,3-Dipolar Cycloaddition Of Some Organic Azides And Their Biological Activities, Yaşar Dürüst, Hamza Karakuş, Muhsi̇ne Zeynep Yavuz, Ali̇ Akçahan Gepdi̇remen

Turkish Journal of Chemistry

1,3-Dipolar cycloaddition of 5-azidomethyl-3-p-substituted phenyl-1,2,4-oxadiazoles to phenyl vinyl sulfone and bismaleimide gives rise straightforwardly to 1-((3-(p-substituted) phenyl-1,2,4-oxadiazol-5-yl)methyl)-4-(phenylsul\-fonyl)-4,5-dihydro-1H-1,2,3-triazoles and bisdihydropyrrolo[3,4-d][1,2,3]triazole-4,6(3aH,5H)-diones. The structures of the new cycloadducts were elucidated by means of IR, NMR (^1H, ^{13}C, 2D), mass spectra, and physical characteristics (mp and R_f values). In addition, anticancer activities of the cycloadducts against MCF-7 cells were also investigated.

Graphene Oxide--Magnetite Nanocomposite As An Efficient And Magnetically Separable Adsorbent For Methylene Blue Removal From Aqueous Solution, Kadem Meral, Önder Meti̇n

Turkish Journal of Chemistry

We report a facile method to produce a magnetically separable graphene oxide--magnetite nanocomposite (GO--Fe_3O_4) and its adsorption performance in methylene blue (MB) removal from aqueous solution. The GO--Fe_3O_4 nanocomposite was synthesized by a solution-phase self-assembly method including the incorporation of monodisperse Fe_3O_4 nanoparticles (NPs) and GO in a dimethylformamide/chloroform mixture under sonication. The successfully decorating GO sheet with monodisperse Fe_3O_4 NPs was proved by TEM study. ICP--OES data of the GO--Fe_3O_4 nanocomposite show that the GO--Fe_3O_4 nanocomposite consists of 21 wt% Fe_3O_4 NPs, which is sufficient for its magnetic separation from aqueous solution. The spectroscopic studies reveal that the GO--Fe_3O_4 …

Study On Transportation Of Phenol Through A Nanotubule Membrane, Yue Liu, Li Xie, Xiaoxue Fan, Dingyan Fan, Shasheng Huang

Turkish Journal of Chemistry

Gold nanochannels were prepared by plating electrolessly gold within the pores of polycarbonate filter membranes (PCTMs). These PCTMs with cylindrical Au nanotubules of uniform radius and high density can be used as a convenient model system to investigate the mechanism of particle transport through nanotubules. The transport properties of phenol through a modified Au nanotubule membrane were studied. The permeate flux of phenol transport through the nanotubule membrane can be spatially and temporally manipulated by controlling the magnitude and direction of the current applied across the separation cell, and the electroosmotic flow (EOF) was investigated by measuring the flux of …

Calixcephems: Clustered Cephalosporins Analogous To Calixpenams As Novel Potential Anti-Mrsa Agents, Fazel Nasuhi Pur, Karim Akbari Dilmaghani

Turkish Journal of Chemistry

Two novel clusters of cephalosporin based on calixarene were synthesized directly or by ring expansion of the penicillin arms of calixpenams to the corresponding cephem arms via sulfoxide intermediates. Antibiotic tests showed that calixcephems have a noteworthy increase in antibacterial activity against methicillin-resistant strains of Staphylococcus aureus (MRSA) with respect to parent calixpenams and their corresponding single cephems.

Graphite Oxide As An Efficient Solid Reagent For Esterification Reactions, Maryam Mirzaaghayan, Rabah Boukherroub, Mahshid Rahimifard

Turkish Journal of Chemistry

Esterification of organic acids with alcohols under mild conditions in high yields using graphite oxide, a readily available and inexpensive material, as an effective reagent is described.

Convenient Method For Synthesis Of Various Fused Heterocycles Via Utility Of 4-Acetyl-5-Methyl-1-Phenyl-Pyrazole As Precursor, Sobhi Mohamed Gomha, Ahmad Sami Shawali, Abdou Osman Abdelhamid

Turkish Journal of Chemistry

A new, less expensive, solvent-free procedure was developed for the synthesis of some new derivatives of various fused heterocyclic ring systems, namely azolopyridazine, azolotriazine, azinotriazine, thienopyridine, and pyrazolopyridine. The structures of the products prepared were established by their spectral data and elemental analyses. Eight compounds were evaluated for their in vitro antimicrobial activity. Some of the tested compounds exhibited moderate to significant antibacterial and antifungal activities.

Boron-Containing Tetrapyrroles, Şennur Özçeli̇k, Ahmet Gül

Turkish Journal of Chemistry

The recent advances in the synthesis of carborane and boronic ester-substituted tetrapyrroles (porphyrins, porphyrazines, and phthalocyanines) are reviewed together with their possible utilization as agents for photodynamic therapy (PDT) and boron neutron capture therapy of cancer (BNCT) as well as dual PDT/BNCT sensitizers.

Synthesis And Characterization Of Tetra-Substituted Titanium(Iv) Phthalocyanines With Axial Ligand, Deni̇z Kutlu Tarakci, İlke Gürol

Turkish Journal of Chemistry

In this paper, the synthesis and characterization of peripheral tetra-2-(2-ethyloxyethyloxy)ethyloxy substituted oxo-titanium phthalocyanines (TiOPcs) are reported. The reaction of 2,2,3,3-tetrafluoropropoxy substituted and [2-(2-ethoxyethoxy)ethoxy] substituted TiOPcs (1 and 3) with 4-[(6-hydroxyhexyl)oxy]benzene-1,2-diol as a strongly chelating oxygen donor ligand is described. Compounds 1a and 3a bearing the hydroxyl group as an axial ligand of the bulky group are converted into a thiol group (1c and 3c). The new compounds are characterized by elemental analysis, FT-IR, ^1H NMR, and mass spectrometry. While the fluoropropoxy substituted TiOPc has good solubility in polar solvents such as acetone and THF, the other TiOPc is soluble in …

Microwave-Assisted Synthesis Of Novel Nonperipherally Substituted Metallophthalocyanines Bearing (7-(Trifluoromethyl)Quinolin-4-Yl)Oxy Groups, Di̇dem Evren, Hacer Yasemi̇n Yeni̇lmez, Ayfer Kalkan Burat

Turkish Journal of Chemistry

The synthesis, characterization, and spectroscopic properties of novel nonperipherally tetrasubstituted metallophthalocyanines (zinc, cobalt, copper, manganese, and indium) bearing 4 (7-(trifluoromethyl)quinolin-4-yl)oxy units has been reported. The new compounds have been characterized using UV-Vis, IR, ^1H NMR, ^{13}C NMR, ^{19}F NMR, and mass spectroscopic data. The absorption properties of these new complexes were compared to those of peripherally substituted phthalocyanine derivatives. Based on the structural, spectroscopic, and absorption studies, it was found that the substitution effect altered the electronic structures significantly. The results provide useful information to understand the effect of peripheral or nonperipheral substitution on the properties of this macrocyclic ring. …

Synthesis And Characterization Of Zinc Sulfide/Zinc Oxide Semiconductor Nanoparticles, Daniel Alan Hall

All Master's Theses

ZnS/ZnO semiconductor nanoparticles have been synthesized with L-cysteine and sodium polyphosphate capping agents using a colloidal synthesis method. The nanoparticles were characterized through the use of fluorescence spectroscopy, ultraviolet/visible (UV /Vis) spectroscopy, and X-ray diffraction (XRD) instrumentation. Introduction of oxygen during the synthesis reaction increases the intensity of the nanoparticle fluorescence and causes a blue shift in emissions which becomes more pronounced with longer exposure to oxygen. Growth of the ZnO shell around the ZnS particles alters the composition from a ZnS nanoparticle to a ZnS/ZnO nanoparticle as seen by an increase in absorbance from 350nm to 450nm which indicates …

The Synthesis Of A Bisbenzothiophene (Bbt) Based Organic Semiconductor With Increased Function And Increased Solubility, Mary England

Senior Honors Theses

Organic semiconductors are growing in applications for use in modern technology.¹ The main interest in these molecules can be attributed to their low cost (compared to silicon) and their ability to be used on flexible substrates. There are four features that make a good organic semiconductor. First, the molecule should be conjugated, having alternating single and double bonds (lone electron pairs act similarly to double bonds). Secondly, the molecule should be planar, or flat, in shape. Thirdly, the molecule should have a narrow band gap to increase the overall conductivity. Lastly, the molecule should be soluble to ease application. …

The Effects Of Coal Mining On Health In Appalachia : Global Context And Social Justice Implications, Adrienne Schmidt

Honors Theses

The purpose of this report is to investigate the environmental and health effects of coal mining in the Appalachian region of the United States in the context of global natural resource extraction, explore existing regulation for the reduction of negative environmental health effects of mining in Appalachia, and explore the social justice implications of current mining practices. The research for this report was limited to literature published in English. It was found that there are widespread negative health effects of mining in Appalachia due to environmental toxins, a toxic social environment of limited economic opportunity, and occupational health hazards. The …

The Role Of Potential Antioxidant In Medicinal Drug-Induced Oxidative Stress, Weili Fan

Doctoral Dissertations

"Most medicinal drugs have adverse effects. Among the most commonly used of these drugs are several types, known as "oxidative drugs". These are believed to cause adverse effects that induce oxidative stress, an imbalance of generation and detoxification of reactive oxygen species. So it is a reasonable assumption that the antioxidant might alleviate the toxicity induced by these drugs. N-acetylcysteine (NAC), a synthetic thiol, is a free-radical scavenger and a precursor of glutathione (the main endogenous antioxidant). However, the negative charge of NAC at physiological pH limits its bioavailability. N-acetylcysteineamide (NACA) is neutral in charge and is believed to have …

Gold-Magnetite Nanoparticle-Biomolecule Conjugates: Synthesis, Properties And Toxicity Studies, Akshay Pariti

Masters Theses

"This thesis study focuses on synthesizing and characterizing gold-magnetite optically active magnetic nanoparticle and its conjugation with biomolecules for biomedical applications, especially magnetic fluid hyperthermia treatment for cancerous tissue. Gold nanoparticles have already displayed their potential in the biomedical field. They exhibit excellent optical properties and possess strong surface chemistry which renders them suitable for various biomolecule attachments. Studies have showed gold nanoparticles to be a perfect biocompatible vector. However, clinical trials for gold mediated drug delivery and treatment studied in rat models identified some problems. Of these problems, the low retention time in bloodstream and inability to maneuver externally …

Hollandites As A New Class Of Multiferroics, S. Liu, A.R. Akbashev, X. Yang, X. Liu, Wanlu Li, L. Zhao, X. Li, A. Couzis, M.-G. Han, Y. Zhu, L. Krusin-Elbaum, J. Li, L. Huang, S.J.L. Billinge, J.E. Spanier, S. O'Brien

Department of Chemistry and Biochemistry Faculty Scholarship and Creative Works

Discovery of new complex oxides that exhibit both magnetic and ferroelectric properties is of great interest for the design of functional magnetoelectrics, in which research is driven by the technologically exciting prospect of controlling charges by magnetic fields and spins by applied voltages, for sensors, 4-state logic and spintronics. Motivated by the notion of a tool-kit for complex oxide design, we developed a chemical synthesis strategy for single-phase multifunctional lattices. Here, we introduce a new class of multiferroic hollandite Ba-Mn-Ti oxides not apparent in nature. BaMn₃Ti₄O_14.25, designated BMT-134, possesses the signature channel-like hollandite structure, …

Generation Of Diverse Molecular Complexity From Cyclooctatetraene, Mohamed Fawzy El Mansy

Dissertations (1934 -)

ABSTRACT

GENERATION OF DIVERSE MOLECULAR COMPLEXITY

FROM CYCLOOCTATETRAENE

Mohamed F. El Mansy, B.Sc, M.Sc.

Marquette University, 2014

The use of simple hydrocarbons as starting materials for the synthesis of complex molecules relies on efficient methods for oxidation, functionalization or rearrangement. For example, various researchers have explored cyclopentadiene or cycloheptatriene as precursors for the preparation of a wide variety of drug candidates, natural products and synthetic products. The purpose of this research is to explore methods to transform the simple hydrocarbon, cyclooctatetraene (COT) into complex target molecules.

Tricarbonyl (cyclooctatetraene)iron, readily prepared from COT, reacts with a variety of electrophiles to form …

Metabolomic Analysis Of Liver Tissue From The Vx2 Rabbit Model Of Secondary Liver Tumors, R. Ibarra, J. E. Dazard, Y. Sandlers, F. Rehman, R. Abbas, R. Kombu, G. F. Zhang, H. Brunengraber, J. Sanabria

Chemistry Faculty Publications

Purpose. The incidence of liver neoplasms is rising in USA. The purpose of this study was to determine metabolic profiles of liver tissue during early cancer development. Methods. We used the rabbit VX2 model of liver tumors (LT) and a control group consisting of sham animals implanted with Gelfoam into their livers (LG). After two weeks from implantation, liver tissue from lobes with and without tumor was obtained from experimental animals (LT+/LT-) as well as liver tissue from controls (LG+/LG-). Peaks obtained by Gas Chromatography-Mass Spectrometry were subjected to identification. 56 metabolites were identified and their profiles compared between groups …

Selective Catalytic Reduction Of Sulfur Dioxide By Carbon Monoxide Over Iron Oxide Supported On Activated Carbon, Guangjian Wang, Liancheng Bing, Zhijian Yang, Jiankang Zhang

Turkish Journal of Chemistry

The selective reduction of sulfur dioxide with carbon monoxide to elemental sulfur was studied over AC-supported transition-metal oxide catalysts. According to the study, Fe_2O_3/AC was the most active catalyst among the 4 AC-supported catalysts tested. By using Fe_2O_3/AC, the best catalyst, when the feed conditions were properly optimized (CO/SO_2 molar ratio = 2:1; sulfidation temperature, 400 °C; Fe content, 20 wt%; GHSV = 7000 mL g^{-1} h^{-1}), 95.43% sulfur dioxide conversion and 86.59% sulfur yield were obtained at the temperature of 350 °C. Catalyst samples were characterized by X-ray powder diffraction in order to relate the phase composition to the …

Speciation Of Chromium By The Combination Of Dispersive Liquid--Liquid Microextraction And Microsample Injection Flame Atomic Absorption Spectrometry, Yunusemre Ünsal, Mustafa Tüzen, Mustafa Soylak

Turkish Journal of Chemistry

A microextraction procedure was established for the speciation of total Cr, Cr(III), and Cr(VI). Sudan blue II was used as a ligand for speciation works. Some factors affecting the recoveries of chromium species, including type of extraction and dispersive solvents, pH, ligand amount, extraction time, and matrix ions, were examined. Optimum values for the dispersive liquid--liquid microextraction method were pH 6, LOD 0.34 \mu g L^{-1}, and preconcentration factor 400. Chromium(III) was quantitatively recovered under optimal conditions, while the recovery of chromium(VI) was below 10%. The relative standard deviation for Cr(III) determinations for the 10-replicate measurement of 0.3 \mu g …

Synthesis, Biological Evaluation, And Molecular Docking Of N'-(Aryl/Alkylsulfonyl)-1-(Phenylsulfonyl) Piperidine-4-Carbohydrazide Derivatives, Hira Khalid, Aziz Ur Rehman, Muhammad Athar Abbasi, Rashad Hussain, Khalid Mohammad Khan, Muhammad Ashraf, Syeda Abida Ejaz, Muhammad Qaiser Fatmi

Turkish Journal of Chemistry

A series of new N'-[(alkyl/aryl)sulfonyl]-1-(phenylsulfonyl)piperidine-4-carbohydrazide derivatives were synthesized. Starting from ethyl piperidine-4-carboxylate (a), first ethyl 1-(phenylsulfonyl)piperidine-4-carboxylate (1), second 1-(phenylsulfonyl)piperidine-4-carbohydrazide (2), and finally N'-[(alkyl/aryl)sulfonyl]-1-(phenylsulfonyl)piperidine-4-carbohydrazides (4a--n) were synthesized by reacting 2 with alkyl/aryl sulfonyl chlorides (3a--n). The structures of the synthesized compounds were characterized by IR, ^1H-NMR, and EI-MS spectra and all were screened in vitro for their acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzyme inhibition activities. Molecular docking was accomplished for these compounds to examine their binding interactions with AChE and BChE human proteins. The strategy we applied for this purpose was a direct receptor-based approach. The binding modes of the inhibitors …

Preparation Of A Lead Sensor Based On Porous Multiwalled Carbon Nanotubes/Thiolated Chitosan Composite Materials, Jun Wan, Ling Xing, Wei Wang

Turkish Journal of Chemistry

Thiolated chitosan (CS--TGA) was prepared using chitosan (CS) and thioglycolic acid (TGA). Then MWCNTs were added to the mixture of CS--TGA and CS to prepare the CS/CS--TGA/MWCNs porous composite by freeze-drying method and this composite was used to modify an indium tin oxide glass electrode. The electrode was used as a sensor for Pb^{2+}. The morphology and structure of the composite were characterized by infrared spectroscopy and scanning electron microscope, and their electrochemical behavior was also studied. Under the optimized experimental conditions, the sensor showed a linear range of 2.0 \times 10^{-9}\sim 2.0 \times 10^{-8} mol L^{-1} for Pb^{2+} with …