Open Access. Powered by Scholars. Published by Universities.®

Chemistry Commons™

Open Access. Powered by Scholars. Published by Universities.®

2005

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 541 - 562 of 562

Full-Text Articles in Chemistry

A General Synthesis Of Tris-Indole Derivatives As Potential Iron Chelators, R. Bryan Sears, Russell A. Carpenter, Christine R. Whitlock Jan 2005

A General Synthesis Of Tris-Indole Derivatives As Potential Iron Chelators, R. Bryan Sears, Russell A. Carpenter, Christine R. Whitlock

Chemistry: Faculty Publications (1990-2023)

The development of a novel route for the synthesis of a new class of compounds is described. The first tripodal, tris-indole amines are prepared by straightforward routes.

Go to article

Study Of The Electronic Structure Of Cafeo₃, Jinbo Yang, M. S. Kim, Qingsheng Cai, X.-D. Zhou, Harlan U. Anderson, William Joseph James, William B. Yelon Jan 2005

Study Of The Electronic Structure Of Cafeo₃, Jinbo Yang, M. S. Kim, Qingsheng Cai, X.-D. Zhou, Harlan U. Anderson, William Joseph James, William B. Yelon

Materials Science and Engineering Faculty Research & Creative Works

We have studied the charge disproportionation phenomenon in CaFeO3 using the local-spin density approximation with the on-site Coulomb interaction parameter U and exchange parameter J. The calculation reveals that the total number of the 3d electrons is about 5.1 for both Fe(1)(Fe5+) and Fe(2)(Fe3+) atoms, and that there are about 0.25 electron holes in the O-2p band. Therefore, the charge disproportionation can be more accurately described as 2d5L(Fe4+)=d5L2(Fe5+)+d5(Fe3+), where L denotes a hole in the oxygen 2p band, instead of 2d4(Fe4+)=d3(Fe5+)+d5(Fe3+). The hybridization between the Fe-3d and O-2p orbitals is stronger for Fe(1) than for Fe(2) due to the shorter …

Go to article

Environment Friendly Organic Synthesis Using Bismuth Compounds. An Efficient Method For Carbonyl-Ene Reactions Catalyzed By Bismuth Triflate, Ram Mohan, Erin Anderson, Justin Ernat, Mai Nguyen, Ann Palma Jan 2005

Environment Friendly Organic Synthesis Using Bismuth Compounds. An Efficient Method For Carbonyl-Ene Reactions Catalyzed By Bismuth Triflate, Ram Mohan, Erin Anderson, Justin Ernat, Mai Nguyen, Ann Palma

Scholarship

Bismuth triflate (0.1 mol %) is a highly efficient catalyst for the cyclization of citronellal 1, a reaction that yields a ratio of 80:20 of isopulegol 2 and neoisopulegol 3. This methodology has also been extended to the synthesis of substituted piperidines. The bismuth triflate catalyzed ene reaction of aldehyde 4 gives a 70:30 mixture of piperidines 5 and 6. The advantages of these methods include the use of a highly efficient catalyst that is relatively nontoxic, cheap and easy to handle.

Go to article

The Discovery-Oriented Approach To Organic Chemistry. 6. Selective Reduction In Organic Chemistry: Reduction Of Aldehydes In The Presence Of Esters Using Sodium Borohydride, Ram Mohan, Ashvin Baru Jan 2005

The Discovery-Oriented Approach To Organic Chemistry. 6. Selective Reduction In Organic Chemistry: Reduction Of Aldehydes In The Presence Of Esters Using Sodium Borohydride, Ram Mohan, Ashvin Baru

Scholarship

Chemoselective reductions are valuable in organic synthesis and are routinely discussed in a sophomore organic chemistry course. Yet, there are few examples of laboratory experiments that illustrate such chemoselectivity. A reaction that is routinely discussed in sophomore organic chemistry is the selective reduction of aldehydes and ketones using sodium borohydride. Esters are typically not affected by NaBH4. However, none of the lab experiments reported to date illustrate this chemoselectivity (1). We have developed a discovery-oriented lab experiment that illustrates the chemoselective nature of reductions using sodium borohydride. The experiments involve the reduction of vanillin acetate (Scheme I) …

Go to article

On-Road Emissions In Asia Measured By Remote Sensing (Presentation), Donald H. Stedman, Gary A. Bishop Jan 2005

On-Road Emissions In Asia Measured By Remote Sensing (Presentation), Donald H. Stedman, Gary A. Bishop

Fuel Efficiency Automobile Test Publications

No abstract provided.

Go to article

Nmr And Modulated Differential Scanning Calorimetry Of Adsorbed Poly(Methyl Acrylate) On Silica, Frank D. Blum, Burak Metin Jan 2005

Nmr And Modulated Differential Scanning Calorimetry Of Adsorbed Poly(Methyl Acrylate) On Silica, Frank D. Blum, Burak Metin

Chemistry Faculty Research & Creative Works

The interaction between polymers and solid substrates can be studied by a variety of techniques. The results from different experiments can be affected by the nature of the polymer, surface, polymer-surface interactions and, also, the experiment. A great deal has been learned about the behavior of polymers at interfaces, but there is also much to be learned about the interactions and how they affect the physical properties of adsorbed polymers. In the present study, we report both deuterium nuclear magnetic resonance (NMR) and modulated differential scanning calorimetry (MDSC) of poly(methyl acrylate) (PMA) adsorbed on Cab-O-Sil silica. The focus of this …

Go to article

Coupled Electrical And Magnetic Properties In (La,Sr)Feo3-Δ, X.-D. Zhou, Qingsheng Cai, Jinbo Yang, M. S. Kim, William B. Yelon, William Joseph James, Y.-W. Shin, B. J. Scarfino, Harlan U. Anderson Jan 2005

Coupled Electrical And Magnetic Properties In (La,Sr)Feo3-Δ, X.-D. Zhou, Qingsheng Cai, Jinbo Yang, M. S. Kim, William B. Yelon, William Joseph James, Y.-W. Shin, B. J. Scarfino, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

This article is aimed at studying the temperature dependence oxygen nonstoichiometry, magnetic moments, Fe3+ fraction, Néel temperature and conductivity of (La,Sr)FeO3-δ. It is found that the magnetic properties in La0.60 Sr0.40 Fe3-δ is determined by Fe3+ and its concentration, and the conductance is resulted from Fe4+ ions, which act as electron holes. Both of magnetic and electrical properties were directly governed by oxygen nonstoichiometry (δ). when δ=0.2, the compound has maximum Fe3+, the saturation magnetic moments and Néel temperature are 3.8 µB and 410 °C, both at the highest level, …

Go to article

Infrared And X-Ray Spectroscopic Studies Of The Copper(Ii) Oxide Mediated Reactions Of Chlorinated Aromatic Precursors To Pcdd/F, Steven L. Alderman Jan 2005

Infrared And X-Ray Spectroscopic Studies Of The Copper(Ii) Oxide Mediated Reactions Of Chlorinated Aromatic Precursors To Pcdd/F, Steven L. Alderman

LSU Doctoral Dissertations

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) are toxic compounds produced in combustion systems such as incinerators, and their emissions are an important environmental issue. Chlorinated phenols and benzenes form PCDD/F through heterogeneous reactions following adsorption onto fly-ash surfaces. Current research implicates transition metals in promoting formation of phenoxyl radicals that react to form PCDD/F, although this has not been studied extensively. This objective of this work is to better understand PCDD/F formation from chlorinated aromatic precursors. Using 2 chlorophenol as a model PCDD/F precursor and silica as a fly-ash surrogate, time-dependent chemisorption of 2 chlorophenol onto silica was studied in situ …

Go to article

Structure, Magnetic, And Transport Properties Of Ti-Substituted La₀.₇Sr₀.₃Mno₃, M. S. Kim, Jinbo Yang, Qingsheng Cai, X.-D. Zhou, William Joseph James, William B. Yelon, D. Buddhikot, Satish K. Malik, Paul Ernest Parris Jan 2005

Structure, Magnetic, And Transport Properties Of Ti-Substituted La₀.₇Sr₀.₃Mno₃, M. S. Kim, Jinbo Yang, Qingsheng Cai, X.-D. Zhou, William Joseph James, William B. Yelon, D. Buddhikot, Satish K. Malik, Paul Ernest Parris

Materials Science and Engineering Faculty Research & Creative Works

Ti-substituted perovskites La0.7Sr0.3Mn1-xTixO3 with 0 ≤ x ≤ 0.20, were investigated by neutron diffraction, magnetization, electric resistivity, and magnetoresistance (MR) measurements. All samples show a rhombohedral structure (space group R3c) from 10 K to room temperature. At room temperature, the cell parameters a,c and the unit cell volume increase with increasing Ti content. However, at 10 K, the cell parameter a has a maximum value for x = 0.10, and decreases for x > 0.10, while the unit cell volume remains nearly constant for x > 0.10. The average (Mn,Ti)-O bond length increases …

Go to article

Synthesis And Characterization Of Mercury Vapor Coordination Species Using 1,3-Benzenedioethanethiolate (Bdet), Elizabeth Zuchek, Harvest L. Collier Jan 2005

Synthesis And Characterization Of Mercury Vapor Coordination Species Using 1,3-Benzenedioethanethiolate (Bdet), Elizabeth Zuchek, Harvest L. Collier

Opportunities for Undergraduate Research Experience Program (OURE)

Mercury is a major pollutant in the air today. Some possible chelators that have been used are British anti-Lewisite (BAL) 2,3-dimercaptopropanol, dimercaptosuccinic acid (DMSA). diinercaptopropanesulfonic acid (DMPS). and 1,3-benzenediamidoethanethiolate (BDE'I1. All contain two thiol groups, which 'capture' the heavy mercury element. Due to their structure, they all differ in how well they bind to the mercury atom. BDET is the most recent and efficient chelate used. Statistics show that coal-fired power plants are the nation's largest mercury polluter. Steps have been taken to lower the emission of this toxic metal by the Clean Air Act. However, recently The Bush Administration's …

Go to article

Photocontrol Of Upper And Lower Rim Complexation Of Neutral And Cationic Species By P-Tert-Butylcalix[4]Arene Tetraethyl Ester, Mary Deasy, Bernadette Creaven, Brian A. Murray, Catherine Mckenna, Darren Tobin Jan 2005

Photocontrol Of Upper And Lower Rim Complexation Of Neutral And Cationic Species By P-Tert-Butylcalix[4]Arene Tetraethyl Ester, Mary Deasy, Bernadette Creaven, Brian A. Murray, Catherine Mckenna, Darren Tobin

Articles

A number of sodium salt complexes of p-tert-butylcalix[4]arene tetraethyl ester, 1, were isolated both with and without upper-rim encapsulated solvent. Selective decomplexation of lower rim bound sodium cations and upper rim encapsulated solvent molecules could be successfully achieved using low pressure light sources. Oxidation of the counter anion at the lower rim of p-tert-butylcalix[4]arene tetraethyl ester triggered both the upper and lower rim decomplexation process. The extent of decomplexation at both rims is controlled both by the nature of the counter-anionic species at the lower rim and by the fate of the photoproducts generated. The calixarene host …

Go to article

Characterization And Design Of A Molecular Imprinted Polymer For Cinchona Alkaloids, William P. Fish Jan 2005

Characterization And Design Of A Molecular Imprinted Polymer For Cinchona Alkaloids, William P. Fish

Seton Hall University Dissertations and Theses (ETDs)

.

Go to article

Synthesis And Characterization Of Membrane Anchored Peptides, Eugenia Christine Tsamis Jan 2005

Synthesis And Characterization Of Membrane Anchored Peptides, Eugenia Christine Tsamis

Honors Program Theses

ln KW ALP23 peptides containing Lysine and Trp, as the Trps were moved further in towards the center of the bilayer, Lys became the dominant anchoring residue (1). The goal of this project was to determine whether Arg exhibits snorkeling behavior similar to Lys, and is able to anchor the peptide in the membrane despite the repositioning of Trp in the RWALP peptides. Several candidate R W ALP23 peptides containing Tryptophan and Arginine with an alternating LeucineAlanine backbone were synthesized successfully. They were then studied by HPLC, CD, and MALDI-TOF Mass Spectrometry to investigate the anchoring roles of Arg and …

Go to article

Synthesis Of Nanomaterials: Magnesium Hydroxide Nanoparticles And Applications For The Catalyzed Decomposition Of Toxins, Travis Witte Jan 2005

Synthesis Of Nanomaterials: Magnesium Hydroxide Nanoparticles And Applications For The Catalyzed Decomposition Of Toxins, Travis Witte

Presidential Scholars Theses (1990 – 2006)

Utilizing a modified sol-gel process, a series of Mg(OH)2 nanoparticles will be produced. Each series synthesized will utilize six different toluene/methanol solvent ratios to yield six samples of nanoparticles. each with a different surface area. The surface area is expected to increase as the toluene/methanol ratio is increased. After preparation is completed, the nanoparticles will be characterized by BET method nitrogen adsorption measurement, IR spectroscopy and thermal gravimetric analysis. The Mg(OH)2 will then be utilized in a simple photocatalysis experiment to determine its possible use as catalyst for the degradation of toxic substances.

Go to article

(Μ-Diazenediyldiphenyl-Κ2c2, N2: Κ2c2′, N1) Bis [(3, 5-Dimethylphenyl) Tellurium (Ii)]., Prabodhika R. Mallikaratchy, Richard E. Norman, Frank R. Fronczek, Thomas Junk Jan 2005

(Μ-Diazenediyldiphenyl-Κ2c2, N2: Κ2c2′, N1) Bis [(3, 5-Dimethylphenyl) Tellurium (Ii)]., Prabodhika R. Mallikaratchy, Richard E. Norman, Frank R. Fronczek, Thomas Junk

Publications and Research

The title compound, C28H26N2Te2, prepared by reduction of (3,5-dimethylphenyl)(2-nitrophenyl)tellurium(II), is the first structurally characterized example of an azo group bridging two TeII centers. The compound is centrosymmetric and the Te—N distance [2.6916 (19) A ° ] is longer than in non-bridging azo compounds.

Go to article

Modifications Of Human Βa1/Βa3-Crystallins Include S-Methylation, Glutathiolation, And Truncation, Veniamin N. Lapko, Ronald Cerny, David L. Smith, Jean B. Smith Jan 2005

Modifications Of Human Βa1/Βa3-Crystallins Include S-Methylation, Glutathiolation, And Truncation, Veniamin N. Lapko, Ronald Cerny, David L. Smith, Jean B. Smith

Ronald Cerny Publications

Disulfide bonding of lens crystallins contributes to the aggregation and insolubilization of these proteins that leads to cataract. A high concentration of reduced glutathione is believed to be key in preventing oxidation of crystallin sulfhydryls to form disulfide bonds. This protective role is decreased in aged lenses because of lower glutathione levels, especially in the nucleus. We recently found that human [1]-crystallins undergo S-methylation at exposed cysteine residues, a reaction that may prevent disulfide bonding. We report here that βA1/A3-crystallins are also methylated at specific cysteine residues and are the most heavily methylated of the human lens crystallins. Among the …

Go to article

Scope And Mechanistic Study Of The Ruthenium-Catalyzed Ortho-C−H Bond Activation And Cyclization Reactions Of Arylamines With Terminal Alkynes, Chae S. Yi, Young Yun Jan 2005

Scope And Mechanistic Study Of The Ruthenium-Catalyzed Ortho-C−H Bond Activation And Cyclization Reactions Of Arylamines With Terminal Alkynes, Chae S. Yi, Young Yun

Chemistry Faculty Research and Publications

The cationic ruthenium hydride complex [(PCy3)2(CO)(CH3CN)2RuH]+BF4- was found to be a highly effective catalyst for the C−H bond activation reaction of arylamines and terminal alkynes. The regioselective catalytic synthesis of substituted quinoline and quinoxaline derivatives was achieved from the ortho-C−H bond activation reaction of arylamines and terminal alkynes by using the catalyst Ru3(CO)12/HBF4·OEt2. The normal isotope effect (kCH/kCD = 2.5) was observed for the reaction of C6H5NH2 and C …

Go to article

Grouping Www Image Search Results By Novel Inhomogeneous Clustering Method, Gu Xu, Zhiwei Li, Mingjing Li, Wei-Ying Ma, Hong-Jiang Zhang Jan 2005

Grouping Www Image Search Results By Novel Inhomogeneous Clustering Method, Gu Xu, Zhiwei Li, Mingjing Li, Wei-Ying Ma, Hong-Jiang Zhang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper, a novel inhomogeneous clustering method is proposed for grouping web images. It is used to re-organize the search result of web image search engines into a hierarchical structure so that the users can conveniently browse the search result. This method takes into account various features associated with web images, and treats them in different ways. For the surrounding text extracted from the containing web pages, co-clustering approach is adopted; for low-level features of the image content and other features, one-way clustering approach is adopted. The clustering results of different approaches are combined together to produce the final …

Go to article

Synthesis Of Symmetric And Asymmetric Water-Soluble Porphyrin Derivatives, Caroline Owendi Ongayi Jan 2005

Synthesis Of Symmetric And Asymmetric Water-Soluble Porphyrin Derivatives, Caroline Owendi Ongayi

LSU Doctoral Dissertations

Novel symmetric and asymmetric water-soluble tetrabenzoporphyrin are synthesized in relatively good yields. These compounds are synthesized by the condensation of butanopyrrole with several aldehydes that contain masked water solubilizing groups followed by metal insertion, oxidation and demetallation and deprotection of the masked solubilizing groups. The biological evaluation (in vitro and in vivo) studies are described in addition to the photophysical evaluations of the corresponding compounds. A novel versatile route to the syntheses of novel free-bases and metallo-benzoylbiliverdin is discussed. The treatment of metal free-dodecasubstituted porphyrin with sodium nitrite and trifluoroacetic acid at room temperature in the presence of oxygen affords …

Go to article

Measurement Of Lipid Peroxidation In Biology Models Using Gas-Chromatography-Aass Spectrometry, Madhavi Lokireddy Jan 2005

Measurement Of Lipid Peroxidation In Biology Models Using Gas-Chromatography-Aass Spectrometry, Madhavi Lokireddy

Master's Theses and Doctoral Dissertations

C2C12 mouse myoblast cells, grown in glass vials, were connected to a cryofocusing unit to trap volatile organic compounds (VOCs). The VOCs were eluted from the trap by capacitive discharge into a gas chromatograph with time-of-flight mass spectral capabilities (GC-TOFMS) and were found to include the lipid peroxidation product hexanal. The pro-oxidant cumene hydroperoxide elevated the levels of these lipid peroxidation products, whereas the anti-oxidant butylated hydroxy toluene (BHT) impaired their production. Derivatization of the aldehyde products of lipid peroxidation in the same myoblast cells with pentafluorobenzyl hydroxylamine hydrochloride (PFB) provided evidence for formation of non-volatile products of lipid peroxidation …

Go to article

Deuterium Nmr Studies Of Segmental Dynamics Of Anopore-Adsorbed Poly(Methyl Acrylate), Macduff O. Okuom, Frank D. Blum Jan 2005

Deuterium Nmr Studies Of Segmental Dynamics Of Anopore-Adsorbed Poly(Methyl Acrylate), Macduff O. Okuom, Frank D. Blum

Chemistry Faculty Research & Creative Works

Studies of segmental dynamics of polymers at interfaces provide a basis for understanding the properties of composite materials. Interfacial phenomena in multi-phase systems need to be understood as devices made from multi-phase polymeric systems become smaller. Various techniques have been used to investigate interfacial polymers at the air-polymer-solid interface; for example, ellipsometry,1 X-ray,2 and neutron reflectometry.3 These techniques typically characterize the structure (often the thickness) of the polymer layer and are normally used to determine the glass-transition temperature (Tg) through a break in the thicknesstemperature curve. There have been a few reports where the dynamics of polymers at the surface-air …

Go to article

Oceanic Uptake And The Global Atmospheric Acetone Budget, Christa Marandino, Warren J. De Bruyn, Scott Miller, M. J. Prather, Eric S. Saltzman Jan 2005

Oceanic Uptake And The Global Atmospheric Acetone Budget, Christa Marandino, Warren J. De Bruyn, Scott Miller, M. J. Prather, Eric S. Saltzman

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

In this study, direct measurements of the air/ sea flux of acetone were made over the North Pacific Ocean. The results demonstrate that the net flux of acetone is into, rather than out of the oceans. The extrapolated global ocean uptake of 48 Tg yr(-1) requires a major revision of the atmospheric acetone budget. This result is consistent with a recent reevaluation of acetone photodissociation quantum yields.

Go to article

First Prev