Chemistry Commons^™

Recyclable Magnetite Nanoparticle Catalyst For One-Pot Conversion Of Cellobiose To 5-Hydroxymethylfurfural In Water, Anuja Bhalkikar, Zane C. Gernhart, Chin Li Cheung

Department of Chemistry: Faculty Publications

Environmentally benign and easily recoverable magnetite nanoparticles (Fe₃O₄ NPs) were demonstrated to catalyze the one-pot conversion of cellobiose, a glucose disaccharide, to 5-hydroxymethylfurfural (5-HMF).Theconversion was achieved in water under hydrothermal conditions.The catalytic activity of Fe₃O₄ NPs surpassed those of iron (II) and iron (III) chlorides in this reaction. Optimized cellobiose conversion reactions catalyzed with Fe₃O₄ NPs gave the highest 5-HMF yields of 23.4 ± 0.6% at 160^∘C for 24 hours. After three reuses, the Fe₃O₄ NP catalyst retained its catalytic activity with similar 5-HMF yields, demonstrating …

Simulation Evidence Of Hexagonal-To-Tetragonal Znse Structure Transition: A Monolayer Material With A Wide-Range Tunable Direct Bandgap, Lei Li, Pengfei Li, Ning Lu, Jun Dai, Xiao Cheng Zeng

Department of Chemistry: Faculty Publications

2D material with tunable direct bandgap in the intermediate region (i.e., ≈2–3 eV) is key to the achievement of high efficiency in visible-light optical devices. Herein, a simulation evidence of structure transition of monolayer ZnSe from the experimental pseudohexagonal structure to the tetragonal structure (t-ZnSe) under lateral pressure is shown, suggesting a possible fabrication route to achieve the t-ZnSe monolayer. The as-produced t-ZnSe monolayer exhibits highly tunable bandgap under the biaxial strains, allowing strain engineering of t-ZnSe’s bandgap over a wide range of 2–3 eV. Importantly, even under the biaxial strain up to 7%, the t-ZnSe monolayer still keeps its …

Affinity Chromatography: A Historical Perspective, David S. Hage, Ryan E. Matsuda

David Hage Publications

Affinity chromatography is one of the most selective and versatile forms of liquid chromatography for the separation or analysis of chemicals in complex mixtures. This method makes use of a biologically related agent as the stationary phase, which provides an affinity column with the ability to bind selectively and reversibly to a given target in a sample. This review examines the early work in this method and various developments that have lead to the current status of this technique. The general principles of affinity chromatography are briefly described as part of this discussion. Past and recent efforts in the generation …

Chromatographic Immunoassays: Strategies And Recent Developments In The Analysis Of Drugs And Biological Agents, Ryan E. Matsuda, Elliott Rodriguez, Doddavenkatanna Suresh, David S. Hage

David Hage Publications

A chromatographic immunoassay is a technique in which an antibody or antibodyrelated agent is used as part of a chromatographic system for the isolation or measurement of a specific target. Various binding agents, detection methods, supports and assay formats have been developed for this group of methods, and applications have been reported that range from drugs, hormones and herbicides to peptides, proteins and bacteria. This review discusses the general principles and applications of chromatographic immunoassays, with an emphasis being given to methods and formats that have been developed for the analysis of drugs and biological agents. The relative advantages or …

Snails From Heavy-Metal Polluted Environments Have Reduced Sensitivity To Carbon Dioxide-Induced Acidity, Hugh Lefcort, David A. Cleary, Aaron M. Marble, Morgan V. Phillips, Timothy J. Stoddard, Lara M. Tuthill, James R. Winslow

Biology Faculty Scholarship

Anthropogenic atmospheric CO2 reacts with water to form carbonic acid (H2CO3) which increases water acidity. While marine acidification has received recent consideration, less attention has been paid to the effects of atmospheric carbon dioxide on freshwater systems—systems that often have low buffering potential. Since many aquatic systems are already impacted by pollutants such as heavy metals, we wondered about the added effect of rising atmospheric CO2 on freshwater organisms. We studied aquatic pulmonate snails (Physella columbiana) from both a heavy-metal polluted watershed and snails from a reference watershed that has not experienced mining pollution. We used gaseous CO2 …

A Cu4S Model For The Nitrous Oxide Reductase Active Sites Supported Only By Nitrogen Ligands, Brittany J. Johnson, William E. Antholine, Sergey V. Lindeman, Neal P. Mankad

Chemistry Faculty Research and Publications

To model the (His)₇Cu₄S_n (n = 1 or 2) active sites of nitrous oxide reductase, the first Cu₄(μ₄-S) cluster supported only by nitrogen donors has been prepared using amidinate supporting ligands. Structural, magnetic, spectroscopic, and computational characterization is reported. Electrochemical data indicates that the 2-hole model complex can be reduced reversibly to the 1-hole state and irreversibly to the fully reduced state.

Controlled Deposition Of Tin Oxide And Silver Nanoparticles Using Microcontact Printing, Joo C. Chan, Nicole Hannah-Moore, Shankar B. Rananavare

Chemistry Faculty Publications and Presentations

This report describes extensive studies of deposition processes involving tin oxide (SnO_x) nanoparticles on smooth glass surfaces. We demonstrate the use of smooth films of these nanoparticles as a platform for spatially-selective electroless deposition of silver by soft lithographic stamping. The edge and height roughness of the depositing metallic films are 100 nm and 20 nm, respectively, controlled by the intrinsic size of the nanoparticles. Mixtures of alcohols as capping agents provide further control over the size and shape of nanoparticles clusters. The distribution of cluster heights obtained by atomic force microscopy (AFM) is modeled through a modified …

Photoelectrons And Recombining Electrons In Atomic And Molecular Systems, Kristen D'Ann Fulfer

LSU Doctoral Dissertations

This work in this dissertation explores how photoelectrons enter and exit atoms and molecules. The electron rescattering events which may occur during photoionization or photorecombination processes play a dominant role in the understanding of how photoelectrons enter and exit molecules, which is intrinsically linked to how chemical reactions occur. Chapters 3-4 of this dissertation present evidence of vibrational mode specific breakdown of the Franck-Condon Principle in the photoionization of low symmetry molecules, acrolein and the singly halogenated thiophenes, due to resonant and non-resonant electron rescattering dynamics. In Chapters 5-6, the disentanglement of the valence electronic structure, as well as evidence …

Electrospun Titanium Dioxide And Silicon Composite Nanofibers For Advanced Lithium Ion Batteries, Kathleen Mccormac

College of Graduate Studies: Theses & Dissertations

A unique electrospinning method was implemented to fabricate composite nanofibers for lithium ion battery applications. The composite nanofibers were made of amorphous carbon, rutile phase TiO₂, and cubic phase Si nanoparticles. Sulfur was utilized as a template to form void structures within the TiO₂ nanofiber matrix. This provides the desired space for the Si expansion during the lithiation process. Phase, structure, composition, and morphology of the nanofibers were characterized using Raman spectroscopy, SEM, EDS, TGA, and powder XRD. Carbonized TiO₂ nanofibers showed a low but stable specific capacity. Si Nanoparticles demonstrated an initially high but fast …

Acylation Of Trans-2-Substituted Cyclohexanols: The Impact Of Substituent Variation On The Pyridine-Induced Reversal Of Diastereoselectivity, Sven Hackbusch, Andreas H. Franz

College of the Pacific Faculty Articles

Numerous methods for the stereoselective synthesis of chiral compounds exist in the literature, which use chiral templates or catalysts. Only in a limited number of cases have achiral catalysts been shown to significantly influence the stereochemical outcomes of reactions. Previous studies in our laboratories have revealed the achiral acyl-transfer catalyst pyridine to alter the stereochemical outcome of the reaction of racemic trans-2-substituted cyclohexanols with racemic 2-chloropropionyl chloride and cause a reversal of diastereoselectivity. The current paper presents the application of the reaction scheme to a wider number of substrates and reveals the importance of the heteroatom in the trans-2-substituent

The Dimerization Kinetics Of Ncad12 With A Mutated Cis-X-Pro Bond, Victoria Mcclearn

Honors Theses

VICTORIA RAE McCLEARN: DIMERIZATION KINECTICS OF NCAD12 P16A (Under the direction Dr. Susan Pedigo) Calcium binding causes a conformational change into a strand swapped dimer for the cadherins. However, regardless of the sequence similarity for Epithelial Cadherin (ECAD) and Neural Cadherin (NCAD), they respond to the presence of calcium differently. For NCAD, the rate of assembly and disassembly depends upon the presence of calcium, whereas for ECAD the rate of exchange is independent of calcium. Studies into a kinetic model to explain the differences between the rates have been recently conducted. It is believed that ECAD uses an X-dimer intermediate …

Biginelli Synthesis And Characterization Of Potentially Anti-Proliferative Dihydropyrimidinone Thione Analogs, Timothy K. Summers

Theses and Dissertations

No abstract provided.

Mcnair Research Journal - Summer 2015, Kelly Abuali, Starr Bailey, Krystal Courtney D. Belmonte, Brittaney Benson-Townsend, Jennifer Bolick, Mihaela A. Ciulei, Ashley Crisp, Daniel N. Erosa, Richard V. Foster, Gisele Braga Goertz, Michael A. Langhardt, Kara Osborne, Julienne Jochel Paraiso, Shawn M. Rosen, Bella V. Smith, Jeevake Attapattu, Ernesto H. Bedoy, Michael G. Curtis, Wanda Inthavong, Marielle Leo, Primrose Martin, Tamieka Meadows, Rosa Perez, Jessica Recarey, Shea Silver, Linda Tompkins

McNair Journal

Journal articles based on research conducted by undergraduate students in the McNair Scholars Program

Table of Contents

Biography of Dr. Ronald E. McNair

Statements:

Dr. Neal J. Smatresk, UNLV President

Dr. Juanita P. Fain, Vice President of Student Affairs

Dr. William W. Sullivan, Associate Vice President for Retention and Outreach

Mr. Keith Rogers, Deputy Executive Director of the Center for Academic Enrichment and Outreach

McNair Scholars Institute Staff

Synthesis, Surface Functionalization, And Biological Testing Of Iron Oxide Nanoparticles For Development As A Cancer Therapeutic, Stanley E. Gilliland Iii

Theses and Dissertations

Iron oxide nanoparticles are highly researched for their use in biomedical applications such as drug delivery, diagnosis, and therapy. The inherent biodegradable and biocompatible nanoparticle properties make them highly advantageous in nanomedicine. The magnetic properties of iron oxide nanoparticles make them promising candidates for magnetic fluid hyperthermia applications. Designing an efficient iron oxide nanoparticle for hyperthermia requires synthetic, surface functionalization, stability, and biological investigations. This research focused on the following three areas: optimizing synthesis conditions for maximum radiofrequency induced magnetic hyperthermia, designing a simple and modifiable surface functionalization method for specific or broad biological stability, and in vitro and in …

Quartz Crystal Microbalance Studies On Friction Modifiers For Lubricant Applications, Carey Lehner

Theses and Dissertations

Lubricants are used in numerous applications to control friction and protect moving parts from fatigue. These fluids consist of a variety of surface active chemistries competing for the surface to provide performance. In order to develop fluids that meet the ever-increasing requirements (from legislation and manufacturers), techniques that can provide insight into surface adsorption, in real time, and relate it back to performance are critical.

The objective of this work is to determine if Quartz Crystal Microbalance with Dissipation (QCM-D) is an effective technique to investigate surfactant adsorption in regimes that are common to the transportation lubricant industry. QCM-D is …

Potential Tau Directed Imaging Agents, Amanda Merrill Boyer

Browse all Theses and Dissertations

Given the ambident reactivity of oxindoles in terms of N- versus C-alkylation, realization of the three points of diversity available to (presumably benzenoid substituted) benzylidene oxindoles is normally achieved via a sequence involving initial N-alkylation of the corresponding isatin precursor, reductive deoxygenation to the N-alkylated oxindole, and finally aldol condensation to the desired target. Since benzenoid substituted isatins are generally more readily available than the corresponding oxindoles, an alternate but much less examined manifold involves reduction of the isatin to an oxindole, aldolization at the C-3 position followed by N-alkylation of the resultant benzylidene oxindole. Since benzylidene oxindoles have potential …

Cip10 Optimization For 4,4-Methylene Diphenyl Diisocyanate Aerosol Sampling And Field Comparison With Impinger Method, Silvia Puscasu, Simon Aubin, Yves Cloutier, Philippe Sarazin, Huu Van Tra, Sébastien Gagné

Études primaires

4,4-methylene diphenyl diisocyanate (MDI) aerosol exposure evaluation in spray foam insulation application is known as being a challenge because the spray foam application actually involves a fast-curing process. Available techniques are either not user-friendly or are inaccurate or not validated for this application. To address these issues, a new approach using a CIP10M was developed to appropriately collect MDI aerosol in spray foam insulation while being suitable for personal sampling. The CIP10M is a commercially available personal aerosol sampler that has been validated for the collection of microbial spores into a liquid medium. Tributylphosphate with 1-(2-methoxyphenyl)piperazine (MOPIP) was introduced into …

Comparison Between The Asset Ez4 Nco And Impinger Sampling Devices For Aerosol Sampling Of 4,4′-Methylene Diphenyl Diisocyanate In Spray Foam Application, Silvia Puscasu, Simon Aubin, Yves Cloutier, Philippe Sarazin, Huu Van Tra, Sébastien Gagné

Études primaires

4,4′-methylene diphenyl diisocyanate (MDI) aerosol exposure evaluation in spray foam insulation application is known to be a challenge. Current available techniques are either not user-friendly or are inaccurate or are not validated for this application. A new sampler has recently been developed to address the user-friendliness issues with other samplers: the ASSET EZ4-NCO, but the use of this sampler in spray foam insulation applications has not been demonstrated or validated. Because of this, the current work was undertaken to provide a comparison of the ASSET sampler with an impinger method, considered to be the best available method in the context …

One-Pot Silyl Ketene Acetal-Formation-Mukaiyama–Mannich Additions To Imines Mediated By Trimethylsilyl Trifluoromethanesulfonate, C. Wade Downey, Jared A. Ingersoll, Hadleigh M. Glist, Carolyn M. Dombrowski, Adam T. Barnett

Chemistry Faculty Publications

In the presence of trimethylsilyl trifluoromethanesulfonate and trialkylamine base, thioesters are readily converted to silyl ketene acetals in situ and undergo Mukaiyama–Mannich addition to N-phenylimines in one pot. The silyl triflates appears to play two roles, activating both the thioester and the imine. This process also works well when thioesters are replaced with amides, esters, or ketones. Products are isolated as desilylated anilines without the necessity of a deprotection step. Yields range from 65-99%.

Morphological And Surface Chemistry Characteristics Of Silica Nanoparticle Based Cryogels From Specific Processing Parameters, Ben Walusiak

Masters Theses

The goal of this research was to determine the effects of processing conditions on the morphology and surface chemistry of silica nanoparticle based cryogels. All processing conditions resulted in a change in morphology or surface chemistry compared to the starting material, CAB-O-SIL HS5 fumed silica. N₂ adsorption isotherms were used to characterize surface area and pore size distributions of fumed silica and silica cryogels. TGA (thermogravimetric analysis) was performed on all samples in order to characterize the adsorbed water and hydroxyl group content of the silica surface. Solid state ²⁹Si NMR was also used to evaluate surface chemistry …

Icp-Oes Analysis Of The Chemical Composition Of Hypergolic Mixtures, Monique Jones

Undergraduate Research Posters

Hypergolic mixtures involve a chemical reaction between an oxidant and a fuel source. These reactions are self-igniting and can be performed using common household materials. The ease of access to the reactants, and delayed ignition have increased the occurrence of hypergolic mixtures in arson-related crimes and incendiary devices. Currently, few chemical signatures exist to link hypergolic residues to a perpetrator. This makes it difficult to obtain forensically relevant information from evidence during an investigation. A hypergolic reaction of interest to forensic laboratories involves combustion between a glycol-based fuel source and potassium permanganate. Past studies have determined that one can distinguish …

(3+2)-Cycloaddition Reactions Of Oxyallyl Cations, Jimmy Wu, Hui Li

Dartmouth Scholarship

The (3+2)-cycloaddition reaction involving oxyallyl cations has proven to be a versatile and efficient approach for the construction of five-membered carbo- and heterocycles, which are prevalent frameworks in natural products and pharmaceuticals. The following article will provide a brief summary of recent disclosures on this process featuring chemo-, regio- and diastereoselective oxyallyl cycloadditions with both electron-rich and electron-deficient 2π partners.

Grazing Incidence X-Ray Fluorescence Measurements Of Genesis Sample 30580 For Determination Of Manganese And Nickel Fluences, Martina Schmeling, J. Davidson, P.J. Eng, J.E. Stubbs, A.J.G. Jurewicz, D.S. Burnett

Chemistry: Faculty Publications and Other Works

Genesis flight sample 30580 was analyzed by grazing incidence X-ray fluorescence spectrometry for subsequent calculation of Mn and Ni fluences.

Preparation Of Scanning Tunneling Microscopy Tips Using Pulsed Alternating Current Etching, Victor A. Valencia, Avesh A. Thaker, Johnathan Derouin, Damian N. Valencia, Rachael G. Farber, Dana A. Gebel, Daniel Killelea

Chemistry: Faculty Publications and Other Works

An electrochemical method using pulsed alternating current etching (PACE) to produce atomically sharp scanning tunneling microscopy (STM) tips is presented. An Arduino Uno microcontroller was used to control the number and duration of the alternating current (AC) pulses, allowing for ready optimization of the procedures for both Pt:lr and W tips using a single apparatus. W tips prepared using constant and pulsed AC power were compared. Tips fashioned using PACE were sharper than those etched with continuous AC power alone. Pt:lr tips were prepared with an initial coarse etching stage using continuous AC power followed by fine etching using PACE. …

Phthalimide-Based Π-Conjugated Small Molecules With Tailored Electronic Energy Levels For Use As Acceptors In Organic Solar Cells, Arthur D. Hendsbee, Seth M. Mcafee, Jon-Paul Sun, Theresa M. Mccormick, Ian G. Hill, Gregory C. Welch

Chemistry Faculty Publications and Presentations

The design, synthesis, and characterization of seven phthalimide-based organic π-conjugated small molecules are reported. The new materials are based on a phthalimide–thiophene–CORE–thiophene–phthalimide architecture. The CORE units utilized were phthalimide (M2), diketopyrrolopyrrole (M3), isoindigo (M4), naphthalene diimide (M5), perylene diimide (M6), and difluorobenzothiadiazole (M7); they were specifically selected to progressively increase the electron affinity of the resulting compound. A small molecule with no core (M1) was synthesized for comparison. Each material was synthesized through optimized direct heteroarylation cross-coupling procedures using bench top solvents in air. Combinations of …

Aggregation Of Squaraine Dye Derivatives In Solid State Spin-Coated Thin Films, Mohammed Daoudi

Electronic Theses and Dissertations

Squaraine dyes have been the subject of intensive studies due their unusual electronic properties that make them good candidates for a wide range of applications in various technological fields. They are particularly promising in nonlinear optics, bioimaging for labeling and sensing of biomolecules, as sensitizers for solar energy harvesting in solar cells and organic photovoltaics, two-photon absorbing materials, near-infrared (NIR) emitting fluorescent probes, second harmonic generation organic dyes, and sensitizers for photodynamic therapy among others. In this dissertation, the aggregation behaviors and features of several squaraine dye derivatives in solid state thin films were studied and reported. In the first …

Chemical Analysis, Databasing, And Statistical Analysis Of Smokeless Powders For Forensic Application, Dana-Marie Dennis

Electronic Theses and Dissertations

Smokeless powders are a set of energetic materials, known as low explosives, which are typically utilized for reloading ammunition. There are three types which differ in their primary energetic materials; where single base powders contain nitrocellulose as their primary energetic material, double and triple base powders contain nitroglycerin in addition to nitrocellulose, and triple base powders also contain nitroguanidine. Additional organic compounds, while not proprietary to specific manufacturers, are added to the powders in varied ratios during the manufacturing process to optimize the ballistic performance of the powders. The additional compounds function as stabilizers, plasticizers, flash suppressants, deterrents, and opacifiers. …

Synthesis Of Fluorene-Based Derivatives, Characterization Of Optical Properties And Their Applications In Two-Photon Fluorescence Imaging And Photocatalysis, Grace Githaiga

Electronic Theses and Dissertations

The two-photon absorption (2PA) phenomenon has attracted attention from various fields ranging from chemistry and biology to optics and engineering. Two of the common NLO applications in which organic materials have been used are three-dimensional (3D) fluorescence imaging and optical power limiting. Two-photon absorbing materials are, therefore, in great demand to meet the needs of emerging technologies. Organic molecules show great promise to meet this need as they can be customized through molecular engineering, and as the development of two-photon materials that suit practical application intensifies, so does research to meet this need. However, there remains some uncertainty in the …

Quantum Chemical Studies For The Engineering Of Metal Organic Materials, Hector Javier Rivera Jacquez

Electronic Theses and Dissertations

Metal Organic Materials (MOM) are composed of transition metal ions as connectors and organic ligands as linkers. MOMs have been found to have high porosity, catalytic, and optical properties. Here we study the gas adsorption, color change, and non-linear optical properties of MOMs. These properties can be predicted using theoretical methods, and the results may provide experimentalists with guidance for rational design and engineering of novel MOMs. The theory levels used include semi-empirical quantum mechanical calculations with the PM7 Hamiltonian and, Density Functional Theory (DFT) to predict the geometry and electronic structure of the ground state, and Time Dependent DFT …

Biological Materials: Part A. Temperature-Responsive Polymers And Drug Delivery And Part B. Polymer Modification Of Fish Scale And Their Nano-Mechanical Properties, Xu Xiang

Dissertations, Master's Theses and Master's Reports - Open

This research has three parts. Two parts deal with novel nanoparticle assemblies for drug delivery, and are described in Part A, while the third part looks at properties of fish scales, an abundant and little-used waste resource, that can be modified to have value in medical and other areas.

Part A describes fundamental research into the affects of block sequence of amphiphilic block copolymers prepared from on a new and versatile class of monomers, oligo(ethylene glycol) methyl ether acrylate (OEGA) and the more hydrophobic di(ethylene glycol) methyl ether methacrylate (DEGMA). Polymers from these monomers are biologically safe and give polymers …