Chemistry Commons^™

Electrode And Electrolyte Additives For Lifetime Extension In Lithium-Ion Batteries, Kishore Anand Narayana

Theses and Dissertations--Chemistry

Lithium-ion batteries (LIBs) are the most commonly used type of rechargeable batteries with a global market estimated at $11 billion, which is predicted to grow to $60 billion by 2020. The global commercialization of Li-ion batteries is impeded by issues such as poor cycle life (5000 cycles achieved in some LIBs) in high energy and power density applications because of the rising internal resistance due to aging and safety concerns such as overcharge which ultimately leads to thermal runaway and explosions. A battery’s performance mainly depends on external factors such as electrode thickness and degree of compacting, and the type …

A Study Of Lignin Depolymerization By Selective Cleavage Of The Cα-Cβ Linkages In Lignin Model Compounds Via Baeyer-Villiger Oxidation & An Investigation Of The Channeling Reaction In Nitrogen-Doped Multiwalled Carbon Nanotubes (N-Mwcnts), Nikhil Dilip Patil

Theses and Dissertations--Chemistry

A STUDY OF LIGNIN DEPOLYMERIZATION BY SELECTIVE CLEAVAGE OF THE Cα-Cβ LINKAGES IN LIGNIN MODEL COMPOUNDS VIA BAEYER-VILLIGER OXIDATION

Lignin is amorphous aromatic polymer derived from plants and is a potential source of fuels and bulk chemicals. Herein, we present a survey of reagents for selective stepwise oxidation of lignin model compounds. Specifically, we have targeted the oxidative cleavage of Cα-Cβ bonds as a means to depolymerize lignin and obtain useful aromatic compounds. In this work, we prepared several lignin model compounds that possess structures, characteristic reactivity, and linkages closely related to the parent lignin polymer. We observed that selective …

Cross Photoreaction Of Pyruvic And Glyoxylic Acids In Model Aqueous Aerosols, Shasha Xia

Theses and Dissertations--Chemistry

Aerosols affect climate change, the energy balance of the atmosphere, and public health due to their variable chemical composition, size, and shape. Aerosols from natural and anthropogenic sources can be primary organic aerosols (POA), which are directly emitted to the atmosphere, or secondary organic aerosols (SOA) that are formed from chemical reactions of gas-phase precursors. At variance with the well investigated formation of SOA from gas phase precursors, the chemistry of aqueous SOAs that contribute to the total SOA budget remains unknown. Field measurements have revealed that carboxylic, dicarboxylic and oxocarboxylic acids are abundant species present in SOAs. This thesis …

Salen Aluminum Compounds In The Dealkylation And Detection Of Organophosphates, Rahul R. Butala

Theses and Dissertations--Chemistry

The focus of this dissertation is the use of aluminum Schiff base compounds, Salen(^tBu)AlBr (SAB), in the dealkylation and detection of organophosphates (OPs). Three SAB compounds, Salen(^tBu)AlBr (1), Salpen(^tBu)AlBr (2), and Salophen(^tBu)AlBr (3) were used to dealkylate a variety of trialkyl OPs. These reactions lead to unique organic-soluble aluminum phosphate compounds containing six-coordinate aluminum. Examples include [salen(^tBu)AlOP(O)(OCH₃)₂]_n (4), [salen(^tBu)AlOP(O)(OCH₂CH₃)₂]_n (5), [salen(^tBu)AlOP(O)(OPh)₂]_{n …}

Methods Development In Biological Mass Spectrometry: Application In Glycoproteomics, Sanja Trajkovic

Theses and Dissertations--Chemistry

Proteomics refers to global characterization of the full set of proteins present in a biological sample. Various analytical disciplines contribute to proteomics but mass spectrometry became method of choice for analysis of complex protein samples.

Mass spectrometry allows for high throughput analysis of the proteome but, moreover, it has the ability to acquire higher-order information such as post-translational modifications (PTM). Glycosylation is the most abundant PTM on eukaryotic proteins.

This dissertation will focus on method development for structural proteomics that will be utilized to explain the glycoproteome of obligate intracellular protozoan parasite Toxoplasma gondii as a model system.

Optimization of …

Laser Spectroscopy Of Radicals Containing Group Iiia And Va Elements, Robert A. Grimminger

Theses and Dissertations--Chemistry

Radicals are interesting to study because of importance in so many processes such as semiconductor growth or stellar evolution. Laser induced fluorescence (LIF) and wavelength resolved emission spectra of jet cooled HPS, HAsO, AsD₂, H₂PS, and F₂BO have been measured using the pulsed discharge jet technique.

Several bands in the à ¹A′′ − X̃ ¹A′ transition of HPS were observed and assigned with the help of ab initio calculations. The ab initio geometries showed that HPS does not follow Walsh’s predictions for the angle change upon electronic excitation; Walsh predicts an increase …

Nuclear Structure In Transitional Regions: Studies Of ¹³²,¹³⁴Xe And Lifetimes In The Stable Zr Nuclei With The (N,N′Γ) Reaction, Erin Elizabeth Peters

Theses and Dissertations--Chemistry

Nuclei at closed shells tend to be spherical and are well-described by the shell model, while those between closed shells are deformed and better described by collective models. The nuclei which are in transitional regions between spherical and deformed may be studied to gain insight into the nature of this transition. The stable isotopes of zirconium and xenon span such transitional regions and are the subject of this dissertation. Gamma-ray spectroscopy following inelastic neutron scattering has been performed on the stable isotopes of Zr as well as ^132,134Xe at the University of Kentucky Accelerator Laboratory. Level lifetimes have been …

Applications Of Gas Chromatography/Mass Spectrometry And Capillary Electrophoresis For The Analysis Of Lignocellulosic Biomass Pretreatment, Dawn M. Kato

Theses and Dissertations--Chemistry

The focus of this dissertation centers on the development and applications of gas chromatography/mass spectrometry and capillary electrophoresis methodologies to quantify monomeric compositions of the β-O-4 linkages in lignin. Pretreatment is a required step in the utilization of lignocellulosic biomass for biofuels. Lignin is the target of pretreatment because it hinders the accessibility of enzymes and chemicals to cellulose. The effects of pretreatment are commonly assessed utilizing enzymatic saccharification and lignin assays. However, these techniques do not elucidate the effects of pretreatment on the monomeric make up of lignin.

The overarching hypothesis of this dissertation is that changes in individual …

Temperature-Dependent Tunable Photoluminescence Properties Of Carbon Nanodots Derived From Polyethylene Glycol, Sin Hea Yeom

Theses and Dissertations--Chemistry

Fluorescent carbon dots (C-dots) are well known for their low cell-cytotoxicity, biocompatibility, low preparation cost, excitation dependent photoluminescence, and excellent photostability. Typically, raw C-dots have low quantum efficiency and thus researchers have been utilizing biocompatible polymers such as polyethylene glycol (PEG) as a passivation agent in order to increase fluorescence signal. In this work, we report fluorescent self-passivated carbon nanodots (CNDs) synthesized from PEG by using it as a carbon source as well as a passivating agent. Importantly, the addition of graphene quantum dots (GQDs) during the synthesis of self-passivated CNDs can tune photoluminescence property. The results of bioimaging and …

Addressing Public Health Risks Of Persistent Pollutants Through Nutritional Modulation And Biomimetic Nanocomposite Remediation Platforms, Bradley J. Newsome

Theses and Dissertations--Chemistry

Due to their relative chemical stability and ubiquity in the environment, chlorinated organic contaminants such as polychlorinated biphenyls (PCBs) pose significant health risks and enduring remediation challenges. Engineered nanoparticles (NPs) provide a novel platform for sensing/remediation of these toxicants, in addition to the growing use of NPs in many industrial and biomedical applications, but there remains concern for their potential long-term health effects. Research highlighted herein also represents a transdisciplinary approach to address human health challenges associated with exposure to PCBs and NPs. The objectives of this dissertation research are two-fold, 1) to develop effective methods for capture/sensing and remediation …

Wetlands And Greenhouse Gas Fluxes: Causes And Effects Of Climate Change – A Meta-Analysis, Robert E. Ventura

Pomona Senior Theses

Climate change is one of the largest problems facing this generation. Anthropogenically caused increases of greenhouse gas emissions is a significant culprit to this problem. Although the obvious problems such as cars, industry, and urbanism garnish a significant amount of the criticism, natural sources such as wetlands are also beginning to contribute to this issue. This is becoming increasingly significant as wetlands shift from being sinks of greenhouse gases to becoming sources as various anthropogenic impacts, including global warming itself, begin to affect the health of the wetlands. The aim of this project is to look at four common types …

Mercury In Fish In North Mississippi Reservoirs: Statistical Analysis And Risk Assessment, Stacy Wolff

Honors Theses

Mercury (Hg) is a pollutant of particular concern because it is wide-spread, persistent, and poses a serious risk to human health. Once released into the atmosphere, it cycles through the environment by a series of complex biogeochemical processes. Upon deposition to aquatic ecosystems, inorganic mercury can be transformed to methylmercury by microorganisms. Methylmercury is a known human neurotoxin that can bioacculmulate in fish tissue and biomagnify up aquatic food chains. Consumption of contaminated fish is the primary route of human exposure to methylmercury. The Mississippi Department of Health has issued fish consumption advisories for Grenada and Enid Lakes in the …

Domain-Specific Probes For Calcium Binding To Neural Cadherin, Charles Ryan Humphries

Honors Theses

Cadherin is a major mediator of cell adhesion whose adhesive function is dependent upon calcium binding. However, the binding of calcium is not completely understood. The binding of calcium can be monitored using an abbreviated construct that contains only the first two extracellular domains (EC12) which includes two tryptophan residues, W2 and W113. Single tryptophan mutants were created which contain only W113 (W2A) and W2 (W113F). Fluorescence spectra were obtained of W2A, W113F, and WT in the presence and absence of calcium. Calcium titration data were collected for each protein. In both experiments, calcium binding increased the fluorescence signal of …

Investigation Into The Synthesis Of Dodecahydro-3a,9a-Diazaperylene, Andrew Palmer

Honors Theses

Dodecahydro-3a,9a-diazaperylene (DHDAP) may serve as a potential donor for use in a donor-sigma-acceptor complex for unimolecular rectification. In order to use DHDAP as a donor, its synthesis must first be studied and altered in such manners as to add a synthetic handle. Other things of important include increasing the yield and better understanding the mechanism by which DHDAP forms. Numerous experiments were conducted in various manners such as testing various solvents among various temperatures to even adding in extra reagents to push the reaction one way or another. In the end the yield of the synthesis was found to improve …

Non-Covalent Interactions, Dative Bonding, And Electron Affinities: A Multi-Method Computational Study Of Boron Tetrahalides, Lance R. Ezell

Honors Theses

This study focuses on boron tetrahalides of the form BFXClY, where X + Y = 4, using the B3LYP, M06-2X, and MP2 methods with the aug-cc-pVTZ basis set. The various neutral and anionic species were constructed and optimized using the Gaussian 09 software package, and the equilibrium geometries, harmonic vibrational frequencies, and energetics (specifically the electron affinity, vertical attachment and detachment energies, and stability with respect to dissociation) of each system are presented. The anionic species, due to their closed-shell electron configurations, have relatively high symmetry: Td for BF4- and BCl4-, C3v for BF3Cl- and BFCl3-, and C2v for BF2Cl2-. …

On Harmonic Vibrational Frequency Convergence To The Complete Basis Set Limit In Water Dimers And Hydrogen Fluoride Dimers, Amanda Hardwick

Honors Theses

This work focuses on the convergence of harmonic vibrational frequencies in the water dimer (H2O)2 and the hydrogen fluoride dimer (HF)2 to the complete basis set (CBS) limit. It also evaluates the effect of counterpoise (CP) correction procedures and the effect of sequentially removing diffuse functions from specific basis sets on the harmonic vibrational frequencies of these dimers. Computations were run using second-order Møller-Plesset perturbation theory (MP2) with large, flexible correlation consistent basis sets. This research aims to determine if removing diffuse functions can increase the speed of harmonic vibrational frequency computations without sacrificing accuracy. Results indicate that CP-correction procedures …

Raman Spectroscopic And Computational Analysis Of The Effects Of Noncovalent Interactions On Dmso, Ashton T. Nicholson

Honors Theses

Dimethyl sulfoxide (DMSO) is a widely used chemical in synthetic chemistry and also has unique and important biological applications. In the pure liquid, DMSO forms chain like structures of alternating sulfur and oxygen atoms due to its high self-association. However, it is known that DMSO/water mixtures form solutions with unique physical characteristics depending on the mole ratio. For instance, at a 1:2 ratio of DMSO/water a eutectic mixture forms with a freezing point of-70 C. Vibrational spectroscopy allows us to study the effects of noncovalent interactions when water and DMSO interact in solution. Spectral shifts can be analyzed in order …

Synthesis Of An Unsymmetrical Ccc-Nhc Pincer Ligand Precursor, Brian Spurlock

Honors Theses

The purpose of this study was to synthesize a 3-butyl-1-(3-(3-butyl-1H-imidazol-3-ium-1-yl)phenyl)-4,5-dichloro-1H-imidazol-3-ium salt using an Ullmann-type copper coupling reaction. This salt would subsequently be metallated and evaluated for C-H bond activation and luminescence. However, NMR and MS spectra did not show evidence of conversion to the desired product under standard conditions so a model reaction was designed making use of recent findings concerning the Ullmann-type coupling of imidazoles to aryl halides. Specifically, an activated aryl halide with a larger leaving group was used with a more soluble base and a ligand for the copper. The desired product appears by ESI-MS to have …

Energy Drinks And Caffeine: The Science Behind The Billion- Dollar Industry, Eric Villarreal

Honors Theses

Ask any college student how he or she gets through long study sessions, all-nighters, and the always grueling finals week and he or she will most likely reference some caffeine-containing beverage as the antidote, with energy drinks becoming an ever increasing option. The effects, both physiological and psychological, of the ingredients in energy drinks (caffeine and, to a lesser degree, glucose) dictate their usefulness to consumers. A review of the available research literature from http://scholar.google.com using the following keywords: caffeine, energy drink, Red Bull, caffeinated beverage, caffeine drink, energy drink industry, energy drink company, and glucose yielded the references that …

Concern-Driven Integrated Toxicity Testing Strategies For Nanomaterials - Report Of The Nanosafety Cluster Working Group 10, Hugh Byrne, Agnes G. Oomen, Peter M.J. Bos, Teresa F. Fernandes, Kerstin Hund-Rinke, Diana Boraschi, Karin Aschberger, Stefania Gottardo, Frank Von Der Kammer, Dana Kühnel, Danail Hristozov, Antonio Marcomini, Lucia Migliore

Articles

Bringing together topic-related European Union-(EU)-funded projects, the so-called “NanoSafety Cluster” aims at identifying key areas for further research on risk assessment procedures for nanomaterials (NM). The outcome of NanoSafety Cluster Working Group 10, this commentary presents a vision for concern-driven integrated approaches for the (eco-)toxicological testing and assessment (IATA) of NM. Such approaches should start out by determining concerns, i.e. specific information needs for a given NM based on realistic exposure scenarios. Recognized concerns can be addressed in a set of tiers using standardized protocols for NM preparation and testing. Tier 1 includes determining physico-chemical properties, non-testing (e.g. structure …

Passive Sampling For Quality Monitoring Of Irish Marine Waters, Philip White

Doctoral

This study details the steps involved in fabrication, deployment and retrieval of mainly polydimethyl siloxane (PDMS) passive sampling devices deployed in a number of locations in and around Ireland in an attempt to derive dissolved water concentrations of contaminants in-situ. PDMS samplers were initially deployed in the Burrishoole catchment, Co. Mayo in conjunction with the collection of biological tissues and sediment to investigate the source of elevated dioxins in the catchment. Passive samplers were used to generate dissolved water concentrations of persistent organic pollutants (POPs) and also to successfully screen for the presence of dioxins in the water column. The …

A Study On The Elementary School Teachers’ Awareness Of Students’ Alternative Conceptions About Change Of States And Dissolution, Chanho Yang, Taehee Noh, Lawrence C. Scharmann, Sukjin Kang

Department of Teaching, Learning, and Teacher Education: Faculty Publications

Knowledge about students’ conceptions is one of the requisite components of pedagogical content knowledge. A keen awareness of students’ alternative conceptions provides teachers with information about prospective difficulties students may incur as they make attempts to learn more accurate scientific representations of critical concepts. In this study, we investigated elementary school teachers’ understanding of their students’ alternative conceptions about change of states and dissolution. The subjects were 152 elementary school teachers and 529 sixth graders in Korea. A conceptions test and the test of the understanding about students’ conceptions were administered in order to examine students’ alternative conceptions and the …

Biochemical Characterization Of Four Distinct Proteins, Gustavo A. Avila

Open Access Theses & Dissertations

Proteins are ubiquitous in all living organisms, executing the majority of cellular functions in distinct ways. Understanding a protein's role necessitates investigating its structure and function, which are closely related. My research couples these two aspects by delving into the biochemical and structural characterization of proteins in four distinct systems, all playing central roles in numerous significant disease progressions. These four original research endeavors were all targeted for structural studies with a unifying relationship to establish our new structural biochemistry lab. These four systems are: (1) Gam1, an early adenovirus protein globally inhibiting host SUMOylation; (2) Anthrax toxin complexed with …

Synthesis And Characterization Of Platinum(Ii) Complexes Of Electron Donor And Acceptor Ligands, Namrata Khanal

Open Access Theses & Dissertations

Pt(II) complexes of N,N-diphenylpyridineamine or 4-diphenylphosphino derivatized triphenylamine as novel electron donors and alkynyl derivatized benzothiadiazole as electron acceptors were synthesized. All the complexes were characterized by 1H and 13C nuclear magnetic resonance spectroscopy, electronspray ionization mass spectrometry, infrared spectroscopy, and 31P nuclear magnetic resonance spectroscopy for the complexes of 4-diphenylphosphino derivatives. The electronic properties studied using UV/vis spectroscopy exhibit ᴫ-ᴫ* transition, metal to ligand charge transfer, and optical highest occupied molecular orbital-lowest unoccupied molecular orbital bandgaps from 2.62-2.65 eV. The electrochemical study performed using cyclic voltammetry have shown the highest occupied molecular orbital-lowest unoccupied molecular orbital bandgaps from 2.70-2.74 …

Application Of Stir Bar Sorptive Extraction Thermal Desorption Gas Chromatography Mass Spectrometry For The Study Of Water Accommodated Fractions Of Fossil Fuels And Biodiesel, Ricardo Mccreary

Open Access Theses & Dissertations

Even though measures are taken to decrease accidental release of crude oil and refined fuels into the aquatic environment, continued demand of such fuels--particularly in the transportation sector--pose a continued threat to the aquatic environment throughout their handling, processing, and consumption. Even though measures can be taken to remove the visible layers of fuel in water, it has been shown that constituents of these fuels--that partition into water--can have adverse health effects on the aquatic organisms at low concentrations that are not necessarily predictable through the study of the actual fuel's original composition. Consequently, this renders the need for an …

Structural Investigation Of The Molecular Chaperonin Tf55 From Thermophilic Archaeon Sulfolobus Solfataricus, Sanjay Kumar Molugu

Open Access Theses & Dissertations

Chaperonins are ubiquitous multi-subunit macromolecules that mediate the folding and assembly of certain proteins that cannot fold properly in vivo. The Archaea bacterium Sulfolobus solfataricus encodes for three chaperonin complexes formed from three different, but closely related subunits named alpha,betaand Gamma. These subunits form a homo-18mer composed of all beta subunits at temperatures ranging between 80oC-85oC, a hetero-16mer composed of alpha and beta subunits at temperatures ranging between 70oC-75oC and a hetero 18mer composed of alpha, beta and gamma subunits at temperatures of 60oC. Structures exist for the chaperonin TF55 all-beta complex and for the TF55 alpha-beta complex but not …

Isomerase Activity Of Candida Rugosa Lipase In Conversion Of Racemic Ibuprofen To (S)-Ibuprofen, Saideh Sadat Mortazavi

Open Access Theses & Dissertations

The Candida rugosa lipase-catalyzed Dynamic Kinetic Resolution of racemic ibuprofen methyl ester was optimal at pH 7.6 to produce (S)-ibuprofen in 72 hours. The concentration of various buffers for these reactions ranged from 0.2 to 0.5 M. The commercial lipase was found to be acidic altering the final pH of the reaction mixtures. Dimethylformamide co-solvent maintained the reaction pH better than dimethylsulfoxide, with evidence of the latter functioning as an oxidizing agent. Lower concentrations of ibuprofen methyl ester and higher stirring rates led to faster conversions. The minimal amount of lipase needed was 20 mg/mL buffer. Reaction of (R)-ibuprofen methyl …

Impact Of Zinc Oxide Nanoparticles On Green Pea Plant & Seed Quality And Effects On Physiological Traits Of Green Peas, Corn, And Zucchini By Silver Nanoparticles, Arnab Mukherjee

Open Access Theses & Dissertations

The production and use of numerous engineered nanomaterials (ENMs) have increased exponentially over the past decade. Nanoparticles (NPs), ENMs possessing diameter between 1-100 nm, (NPs), are widely used in many applications. Worldwide consumption of NPs has increased their possible release into the environment. This, in turn, has elevated the extent of the potential impacts of NP exposure to living and non-living organisms. This is why the assessment of the impact of NPs on different environmental components, especially on plants, the producer in the food web, has become a very important aspect of nano-ecotoxicology. However, studies focusing on phytotoxicity and effects …

Alkali Promoted Molybdenum (Iv) Sulfide Based Catalysts, Development And Characterization For Alcohol Synthesis From Carbon Monoxide And Hydrogen, Belinda Delilah Molina

Open Access Theses & Dissertations

For more than a century transition metal sulfides (TMS) have been the anchor of hydro-processing fuels and upgrading bitumen and coal in refineries worldwide. As oil supplies dwindle and environmental laws become more stringent, there is a greater need for cleaner alternative fuels and/or synthetic fuels. The depletion of oil reserves and a rapidly increasing energy demand worldwide, together with the interest to reduce dependence on foreign oil makes alcohol production for fuels and chemicals via the Fischer Tropsch synthesis (FTS) very attractive. The original Fischer-Tropsch (FT) reaction is the heart of all gas-to-liquid technologies; it creates higher alcohols and …

Synthesis And Characterization Of Fluorophores For The Detection Of Lanthanides And Actinides, Robinson I. Roacho

Open Access Theses & Dissertations

A series of fluorophores based in the boron dipyrromethene (BODIPY) family were synthesized and characterized. These fluorophores have the capacity of being introduced to a carbamoyl methyl phosphine oxide (CMPO) lanthanide/actinide extractant. These blue, green and red emission fluorophores show high thermal/moisture stability and high fluorescence efficiencies. The fluorescence intensity seems to be dependent on the restricted rotation about the C(8)-C bond in 8-Ph-BODIPY. By taking advantage of this feature, a hydroxyl- containing BODIPY with high fluorescence intensity was synthesized to be incorporated to a CMPO carboxylic acid via esterification. Unfortunately, we did not observe an optical response upon the …