Chemistry Commons^™

Investigation Of Spillover Effect To Enhance Hydrogen Storage, Sarah C. Corrigan, Lin Simpson, Thomas Gennett

STAR Program Research Presentations

Hydrogen is an attractive energy option because of its low
environmental impact, but a critical problem is its low energy
density, which makes it difficult to store. For example, the US
Department of Energy (DOE) hydrogen plan for fuel cell powered
vehicles requires a gravimetric density of 6.5 wt%. There are several
existing hydrogen storage methods, including compressed gas,
liquefaction, metal hydrides, and physisorption, but at present, none
of these technologies comes close to achieving the targets set by the
DOE. Although chemical storage methods have been claimed to be the
most promising hydrogen storage technology, and activated carbons the …

Preparation Of Copper-Based Oxygen Carrier Supported On Titanium Dioxide, Yaowen Cui

Masters Theses & Specialist Projects

Chemical-looping combustion is an indirect oxygen combustion strategy, considered to be the most cost-effective power generation technology with the CO2 inherently concentrated. In this process, a solid oxygen carrier is used to transfer oxygen from the air reactor to the fuel reactor, which completely isolates nitrogen in air to meet with fuels. The oxygen carriers in the combustion process are subjected to the severe environments, such as high temperatures, multi-cycle operations, and thermodynamic limitations. Thus, the preparation of an oxygen carrier with high durability and better kinetics under harsh environment could be an essential part of Chemical-looping combustion development. In …

Removal Of Heavy Metals From Drinking Water By Adsorption Onto Limestone With A Focus On Copper And Aluminum Applications, Swarna Latha Somasani

Masters Theses & Specialist Projects

Elevated levels of arsenic and other heavy metals like copper, aluminum, zinc, and selenium in drinking water are found to have deleterious effects on human health. Hence, finding methods for reducing their levels is critical. Iron-coated limestone is used as an adsorption material for the removal of heavy metals from drinking water. Removal of heavy metals by native or uncoated limestone was also observed and used for comparison to and evaluation of the improvement in removal efficiency from the ironcoated material. The removal efficiency with limestone was studied for different concentrations of heavy metals. Kinetic studies were done to determine …

Sillica Nanoporous Materials Adsorption And Release Study, Gang Wang

Chemistry - Dissertations

The lower efficiency of the current common ways of delivering drugs to humans like oral administration and injection make it necessary to find more efficient delivery systems. In this regard, a class of nanostructured materials called mesoporous silicates such as MCM-41, SBA-15 has attracted the attention of many scientists as drug delivery vehicles for their outstanding features like high surface area, high porosity, well-ordered, tunable nanometer pores and "non-cytotoxic" properties.

In this dissertation, comparative investigations of the adsorption capacity and drug release properties of these materials whose surfaces were functionalized with judiciously chosen organic groups via either post-grafting or co-condensation …

Origin Of Fluorescence In 11-Cis Locked Bovine Rhodopsin, Elena N. Laricheva, Samer Gozem, Silvia Rinaldi, Federico Melaccio, Alessio Valentini, Massimo Olivucci

Chemistry Faculty Publications

The excited state lifetime of bovine rhodopsin (Rh) increases from ca. 100 fs to 85 ps when the C11=C12 bond of its chromophore is locked by a cyclopentene moiety (Rh5). To explain such an increase, we employed ab initio multiconfigurational quantum chemistry to construct computer models of Rh and Rh5 and to investigate the shape of their excited state potential energy surfaces in a comparative way. Our results show that the observed Rh5 fluorescence (lambda(f)(max) = 620 nm) is due to a previously unreported locally excited intermediate whose lifetime is controlled by a small energy barrier. The analysis of the …

Department Of Chemistry News, Fall 2012, Illinois State University, Department Of Chemistry

Chem Letter

Newsletter of the Illinois State University Department of Chemistry

Understanding The Molecular Determinants Of Substrate And Inhibitor Specificities In The Carbapenemase Kpc-2: Exploring The Roles Of Arg220 And Glu276

Chemistry Faculty Publications

β-Lactamases are important antibiotic resistance determinants expressed by bacteria. By studying the mechanistic properties of β-lactamases, we can identify opportunities to circumvent resistance through the design of novel inhibitors. Comparative amino acid sequence analysis of class A β-lactamases reveals that many enzymes possess a localized positively charged residue (e.g., R220, R244, or R276) that is critical for interactions with β-lactams and β-lactamase inhibitors. To better understand the contribution of these residues to the catalytic process, we explored the roles of R220 and E276 in KPC-2, a class A β-lactamase that inactivates carbapenems and β-lactamase inhibitors. Our study reveals that substitutions …

Long-Range Ordered Carbon Clusters: A Crystalline Material With Amorphous Building Blocks, Lin Wang, Bingbing Liu, Hui Li, Wenge Yang, Yang Ding, Stanislav V. Sinogeikin, Yue Meng, Zhenxian Liu, Xiao Cheng Zeng, Wendy L. Mao

Xiao Cheng Zeng Publications

Solid-state materials can be categorized by their structures into crystalline (having periodic translation symmetry), amorphous (no periodic and orientational symmetry), and quasi-crystalline (having orientational but not periodic translation symmetry) phases. Hybridization of crystalline and amorphous structures at the atomic level has not been experimentally observed. We report the discovery of a long-range ordered material constructed from units of amorphous carbon clusters that was synthesized by compressing solvated fullerenes. Using x-ray diffraction, Raman spectroscopy, and quantum molecular dynamics simulation, we observed that, although carbon-60 cages were crushed and became amorphous, the solvent molecules remained intact, playing a crucial role in maintaining …

Producing Data To Support The Detection And Understanding Of Early On-Set Corrosion In Accelerated Weathering, Stephanie Suzanne Messer

Master's Theses

The goal of the research reported herein was to generate data towards the development of methods and protocols for detecting, quantifying, and understanding early on-set corrosion events on and above aluminum 2024-T3. The studies focused on incorporating two main fluorescent probes into a few model epoxy and/or urethane coatings to detect X and Y axis specific pH changes occurring upon and above the substrate during pre-macroscopic corrosion. The primary fluorophore used was fluorescein, a pH sensitive probe capable of detecting the changes, mainly increases in pH that accompanies aluminum corrosion. The second molecular probe, rhodamine B, was utilized to better …

Electrospun Biocompatible Polyurethanes With The Addition Of Multi-Walled Carbon Nanotubes, Travis Cantu

Theses and Dissertations - UTB/UTPA

Three different Polyurethanes (PUs) Lycra®, HydroThaneTM, and BioSpan®, were electrospun and characterized using Scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform-infrared spectroscopy (FTIR), & Raman spectroscopy. Nanofiber composites were made by incorporating MWCNTs at three different concentration 0.1wt% 0.5wt% and 1.0wt% to the three PUs. These samples were characterized and mechanical and thermal test were done. The TEM images showed MWCNT bundling in the polymer matrix at the highest concentration, the FTIR showed shifts in characteristic urethane bands indicating an interaction with the polymer and MWCNTs. Mechanical test showed a decrease in the Young’s modulus (E’) in most …

Investigating The Biochemical Activity Of Some Flavonoids, Coumarins And Modified Gold-Nanoparticles As Anti-Breast-Cancer Agents, Amr Ezzat Mohamed Mahmoud

Dissertations

Polyphenols compounds are abundant natural products found in many plants as secondary metabolites. These compounds display many interesting pharmacological activities, which have motivated chemists over the years to explore them, and their synthetic derivatives, as potential drugs, especially anticancer drugs. Breast cancer is the most common cancer in women globally, and in the United States of America the estimated worldwide new breast cancer cases and the number of deaths are 1.38 million and 458 thousand, respectively. Currently in the USA there are 2.6 million women who have been treated for breast cancer, and the estimated number of deaths are 39,520 …

Reactions Of Methyl Perfluoroalkyl Ethers With Isopropyl Alcohol: Experimental And Theoretical Studies, Howard Knachel, Vladimir Benin, Chadwick Barklay, Janine C. Birkbeck, Billy D. Faubion, William E. Moddeman

Chemistry Faculty Publications

The reaction of an isomeric mixture of the methyl perfluoroalkyl ether, C4F9OCH3 (Novec-7100), in the presence of isopropyl alcohol (IPA) and/or water has been studied by measuring the rate of product formation using an ion-selective electrode (ISE) for fluoride ion, Karl Fisher coulometric titrations for water, and 1H and 19F NMR spectroscopy for product identification and rate studies. The results showed the methyl perfluoroalkyl ether to be very stable with products forming at the rate of ∼1 ppm per year at a laboratory temperature of 20 °C. Measurements over the temperature range of 6° to 100 °C were made on …

Eerc Laboratory Capabilities, University Of North Dakota. Energy And Environmental Research Center

EERC Brochures and Fact Sheets

Brochure about the Energy & Environmental Research Center (EERC) laboratory facilities, equipment, and capabilities. Includes information on Analytical Research Laboratory, Natural Materials Analytical Research Laboratory, Applied Geology Laboratory, and Environmental Chemistry Laboratory. [This item is an outdated or superseded version and retained for historical purposes only. It may no longer reflect current information, policies, or practices.]

Synthesis Of 1,1-Dialkyhydrazines And Their Hydroxyl Radical Degradation In Aqueous Environments, Benjamin F. Strong

Masters Theses

Determination of hydroxyl radical rate constants are essential to ensure adequate degradation of contaminants in wastewater. Hydrazines are an important class of organic contaminants and are the focus of this research. Ten 1,1-dialkylhydrazines are synthesized by the zinc reduction of the corresponding N-nitrosamines. Their hydroxyl radical rate constants are determined using the linear accelerator at the Notre Dame Radiation Laboratory at pH 4, 7, and 10.

Their rate constants are found to depend on the protonation state of the molecule. At pH 4 the molecules are fully protonated and hydrogen atom abstraction is favored from the alkyl chains. At …

En Route Towards Α-Benzotriazoyl Nitroso Derivatives, Jean-Christophe M. Monbaliu, Lucas K. Beagle, Judit K. Beagle, Matthias Zeller, Christian V. Stevens, Alan R. Katritzky

Chemistry Faculty Publications

A new class of geminally-substituted nitroso compounds, i.e., α-benzotriazoyl nitroso derivatives, is presented. These compounds display a rather different behavior than other related nitroso compounds bearing a geminal electron-withdrawing group. An unexpected and spontaneous oxidation to the nitro analog is observed in solution.

Insights On Cytochrome P450 Enzymes And Inhibitors Obtained Through Qsar Studies, Jayalakshmi Sridhar, Jiawang Liu, Maryam Foroozesh, Cheryl Stevens L. Klein Stevens

Faculty and Staff Publications

The cytochrome P450 (CYP) superfamily of heme enzymes play an important role in the metabolism of a large number of endogenous and exogenous compounds, including most of the drugs currently on the market. Inhibitors of CYP enzymes have important roles in the treatment of several disease conditions such as numerous cancers and fungal infections in addition to their critical role in drug-drug interactions. Structure activity relationships (SAR), and three-dimensional quantitative structure activity relationships (3D-QSAR) represent important tools in understanding the interactions of the inhibitors with the active sites of the CYP enzymes. A comprehensive account of the QSAR studies on …

The Effect Of Poss Modified Montmorillonite On Elastomer Nanocomposites, Elana Celeste Lewis

Master's Theses

The goal of this thesis was to define the structural factors that determine performance in clay/rubber nanocomposites when polyhedral oligomeric silsesquioxane (POSS) is used as a dispersant. POSS has been shown previously to enhance clay, metal oxides, and carbon nanotube dispersion in thermoplastics matrices, but their performance in rubber systems has not yet been explored. There is little fundamental understanding of how POSS interacts with clay and how these modified fillers react with rubber matrices. This thesis aims to develop a greater understanding of the mechanisms of POSS-clay modification through the examination of two different POSS-clay systems and their effect …

Experimental And Theoretical Studies In Nuclear Magnetic Resonance, John D. Persons

Department of Chemistry: Dissertations, Theses, and Student Research

Nuclear Magnetic Resonance (NMR) has proven to be an excellent tool to probe the structure of molecules by gaining insight into nuclear interactions. Used in conjunction with theoretical calculations, NMR has the potential to elucidate these nuclear interactions and how they affect structure, bonding and dynamics on a molecular scale. The first two projects presented herein study the peroxide explosive hexamethylene triperoxide diamine (HMTD). In the first project, we use the characteristics of the solid-state NMR lineshape to determine the ¹⁴N quadrupole coupling constant (C_Q). The second project uses multi-dimensional solution-state NMR and chiral shift reagents …

Experimental And Theoretical Studies In Solid-State Nuclear Magnetic Resonance, Monica N. Kinde

Department of Chemistry: Dissertations, Theses, and Student Research

Solid-state nuclear magnetic resonance (SSNMR) has proven to be a powerful tool for probing molecular structure and dynamics. Deuterium SSNMR is particularly useful due to the presence of anisotropic interactions whose motional averaging contributes structural and dynamical insight. The magnitude and type of molecular motion can be determined from analysis of solid echo deuterium lineshapes and/or relaxation studies. This work uses various applications of solid-state NMR as well as ab initio and density functional computational methods to study three different areas of physical chemistry: biophysical chemistry, materials science and fundamental concepts of physical chemistry. The first project addressed the dynamics …

Synthesis And Characterization Of Biodegradable Electrospun Polyurethanes For Biomedical Applications, Xujun Zhang

Theses and Dissertations - UTB/UTPA

Two types of polyesters [(Poly(ε-caprolactone) and Poly(δ-valerolactone)] were synthesized by ring-opening polymerization with diethylene glycol as a initiator and stannous octate as a catalyst. The corresponding polyurethanes were synthesized by two-step polymerization with 1,4-diisocyanate butane (BDI) and reacted with 1,4-diamino butane (Putrescine) chain extender. The polymers were characterized by Proton Nuclear Magnetic Resonance (1H NMR), Fourier Transform Infrared Spectroscopy (FT-IR), Raman Spectroscopy, Size-exclusive Chromatography (SEC), Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). The resulting polyurethanes were fabricated into nanofibers using an electrospinning technique. The morphological, structural characterizations and thermal properties of the bulk polyurethanes and electrospun polyurethanes nanofibers were …

Synthesis Of Novel Bis-Β-Lactams, Jocabed Marquez

Theses and Dissertations - UTB/UTPA

This study presents the synthesis and structure of newly discovered β-lactams and the mechanism of their synthesis via the Staudinger reaction. β-lactams known as 2-azetidinones, are four membered cyclic amides that have been extensively used and recognized as the central motif of the β-lactam antibiotics, the most widely employed family of antimicrobial agent to date. The Staudinger reaction involves the cycloaddition between an acid chloride with an imine, in presence of a tertiary base. The possibility of cooperative effects from two therapeutic functionalities in drug molecules, has prompted interest in the synthesis of Bis-β-lactams. The synthesis of 2 novel Bis-β-lactams …

Microwave-Induced Bismuth Nitrate-Catalyzed Multicomponent Reaction Toward Heterocycles, Ashwini Bobbala

Theses and Dissertations - UTB/UTPA

The microwave-induced reaction for the synthesis of nitrogen containing heterocyclesis very important in medicinal chemistry. The synthesis of various other valuable compounds is also done by employing this reaction. The aza Diels-Alder reaction is one of the most powerful synthetic tools for the synthesis of nitrogen containing heterocycles. The main goal of the research is to synthesize the nitrogen containing heterocycles using Bismuth nitrate as the catalyst in the presence of microwave irradiation. In the present study we explore the catalytic activity of bismuth nitrate and the role of microwave reactor in the synthesis of 2, 3-diaryl substituted bicyclic octanone …

A Mechanistic Study Of Catalytic Promiscuity In Protein Phosphatase 1, Yuan Chu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

"Catalytic promiscuous" enzymes, which possess additional activities besides their "native" activity, albeit with a lower efficiency than the main reaction, have become a new frontier for biochemistry and have received considerable attention. Catalytic promiscuity has been suggested to contribute to enzyme evolution through the mechanism of gene duplication followed by specialization of one of the two copies for the new function. Mimicking this evolutionary shortcut could also provide a more efficient route to changing the function of proteins by directed evolution.

The promiscuous phosphatase PP1 is a member of the phosphoprotein phosphatase (PPP) gene family, which is critical for the …

Synthesis, Characterization, Functionalization And Optical Properties Of Silver Nanostructures, Zachary Koontz

All Theses

The interaction between light and silver nanoparticles via the excitation of plasmon resonances which are the collective oscillation of the free electron density represents the most efficient interaction between light and matter. This alone makes plasmonic silver nanoparticles of great interest for both fundamental studies as well as practical applications. In this thesis, silver nanoparticles of various shapes and sizes and organized clusters were synthesized and investigated for their optical properties.

Synthesis And Applications Of Novel Silver Nanoparticle Structures, Kyle Dukes

All Theses

ABSTRACT
The field of nanotechnology is rapidly expanding across disciplines as each new development is realized. New exciting technologies are being driven by advances in the application of nanotechnology; including biochemical, optical, and semiconductors research. This thesis will focus on the use of silver nanoparticles as optical labels on cells, methods of forming different small structures of silver nanoparticles, as well as the use of silver nanoparticles in the development of a photovoltaic cell.
Silver nanoparticles have been modified with self-assembled monolayers of hydroxyl-terminated long chain thiols and encapsulated with a silica shell. The resulting core-shell nanoparticles were used as …

Part I - A Study Of The Formation Of Carbenes By Elimination Of Α-Bromosilanes And Application Toward The Synthesis Of Transition Metal Complexed Quinone Methide Analogs. Part Ii - Development Of Novel 7-Membered Ring Carbene Ligands For Palladium Catalyzed Cross Coupling Reactions., Christian Michael Loeschel

Graduate Theses and Dissertations

In part I, we wish to report our approaches toward transition metal complexed ortho-quinone methide analogs. ortho-Quinone Methides are a class of highly reactive compounds with a wide range of chemical and biological applications. Previously, a stable iron complexed benzannulated 5-membered ring quinone methide analog was reported by Allison and Neal27. Herein, we report our approaches to improve the reactivity of that system by removing benzannulation as well as changing the metal from iron to manganese and rhenium.

Furthermore, a methodological study on generating carbenes under mild conditions by elimination of α-halosilanes and its application towards metal complexed quinone methide …

Environmental Implications And Applications Of Nanomaterials, Priyanka Bhattacharya

All Dissertations

Recent advances in material science and nanotechnology have given rise to a myriad of developments, while in the meantime call for research into the impacts of nanomaterials on the environment and human health. Although considerable progress has been made in the past decade concerning the behavior of nanomaterials in biological systems, such understanding is critically lacking with respect to the fate of nanomaterials in ecosystems.
Accordingly, this dissertation addresses the interactions between nanomaterials and algae--the major constituent of the aquatic food chain (Part I, Chapter two), and exploits the physicochemistry of nanoscaled synthetic dendritic polymers for environmental applications, especially for …

Synthesis And Characterization Of Magnetic Solids Featuring 3d-4f Heterometallic Oxides Comprised Of Spin Chains And 3d-6p Noncentrosymmetric Oxides Templated By Acentric Salt Units, Jennings West

All Dissertations

The studies and syntheses presented in this dissertation were primarily aimed at exploring new magnetic solids comprised of special framework oxides with novel magnetic properties. Low-dimensional magnetic behavior has been of great interest, especially pertaining to molecular solids having single magnetic domains where slow relaxation and quantum properties of magnetization are evident. In attempts to mimic molecular magnets and achieve reduced dimensionality of, in this case 3d-;4f magnetic sublattices, diamagnetic oxyanions, XO_mn-, and A-site cations (A = alkali and alkaline-earth metals) were used as nonmagnetic spacers in hopes of disrupting or confining magnetic interactions in certain dimensions. The …

Evaluating Actinide Sorption To Graphite With Regards To Triso Repository Performance, Corey Christopher Keith

UNLV Theses, Dissertations, Professional Papers, and Capstones

Graphite has the potential for inclusion in nuclear waste for disposal in waste repository settings. Implementation of High Temperature Gas-cooled Reactors contributes to this potential through use of TRISO fuel, if direct disposal of the graphite matrix surrounding the fuel is employed. The inclusion of the large mass and volume in the TRISO fuel waste form differs significantly from used light water reactor fuel waste forms, requiring new performance models to describe the behavior in a repository setting. The purpose of this study is to evaluate the potential for the graphite to improve actinide, specifically uranium and neptunium, retardation from …

Semiconductor Nanocrystals: From Quantum Dots To Quantum Disks, Zheng Li

Graduate Theses and Dissertations

The bottom-up colloidal synthesis opened up the possibility of finely tuning and tailoring the semiconductor nanocrystals. Numerous recipes were developed for the preparation of colloidal semiconductor nanocrystals, especially the traditional quantum dots. However, due to the lack of thorough understanding to those systems, the synthesis chemistry is still on the empirical level. CdS quantum dots synthesis in non-coordinating solvent were taken as a model system to investigate its molecular mechanism and formation process, ODE was identified as the reducing agent for the preparation of CdS nanocrystals, non-injection and low-temperature synthesis methods developed. In this model system, we not only proved …