Chemistry Commons^™

The Potential Importance Of Microenvironment On Polymer Bound Chemical Reagents, Nathan Joseph Halsteter

Theses and Dissertations

In this thesis will provide a brief history of polymer bound reagents, their uses, and advancements. The importance of polymer microenvironments will be explored using a model kinetic resolution reaction utilizing polymer bound reagents to observe how changes in a polymer’s microenvironment effects the yield and selectivity of a reaction. It was found that there are copious factors that affect polymer bound reagents, and no direct conclusion could be drawn from the study.

Reactivity Of Redox-Active Carboranyl Diphosphines And Carboranyl Diphosphoniums: Metal-Free Pathways For Small Molecule Activations And Transformations, Amanda Lynn Humphries

Theses and Dissertations

Transition metal catalysis has been an integral part of synthetic chemistry for its ability to selectively activate strong substrate bonds, promoting numerous crucial transformations. Despite their utility, the precious metals that are often employed in these catalytic reactions suffer from several drawbacks (including high toxicity, low natural abundance, high costs, and low sustainability), increasing the motivation to design suitable metal-free alternatives. Towards this end, several ambiphilic main-group systems have been devised to show metal-like reactivity, such as carbenes, borylenes, and Frustrated Lewis Pairs. This manuscript will describe the ambiphilic reactivity of carborane-based phosphorus compounds, highlighting the unique metallomimetic reactivity that …

Characterizing Dissolved Organic Matter Composition In A Southeastern United States Watershed, Gwendolyn Marcelette Hopper

Theses and Dissertations

Dissolved organic matter (DOM) has important roles in many biogeochemical cycles. DOM is primarily composed of dissolved organic carbon (DOC), nitrogen, and phosphorus, and the processing of DOM is important for nutrient regulation and carbon cycling. In the coastal plains of the southeastern United States, there are many rivers and streams known as “blackwaters” with exceptionally high concentrations of chromophoric dissolved organic matter (CDOM) leached from terrestrial soils, coinciding with a region experiencing some of the nation’s highest rates of development. As changes in land use and climate continue to occur, DOM composition from natural to anthropogenically impacted systems can …

Determination Of Structure-Function Relationships In Hybrid Catalysts On Metal Oxide Supports, Joseph John Kuchta

Theses and Dissertations

Transition metal catalysis has revolutionized chemical synthesis, enabling efficient and selective transformations critical to the pharmaceutical, agricultural, and materials industries. However, traditional methods often rely on expensive, non-sustainable metals and harsh reaction conditions that generate significant waste. This dissertation explores a series of innovations aimed at bridging the gap between homogeneous and heterogeneous catalysis through the development of hybrid catalysts. These systems combine the molecular precision of homogeneous catalysts with the stability and practicality of heterogeneous supports, offering a pathway to more sustainable and scalable catalytic processes.

The first area of focus investigates nickel-based hybrid catalysts as a cost-effective and …

Rapid Charging Lithium-Ion Batteries: Structure, Morphology, And Methodology, Sean Cade Wechsler

Theses and Dissertations

The initial commercialization and subsequent development of the lithium-ion battery (LIB) in 1991 has revolutionized the way that humans power devices, cars, and homes and led to the advent of many technologies that seemed impossible just half a century ago. As LIBs are integrated into more of daily life through handheld devices, wearable medical devices, transportation, and grid-level energy storage, the demand for fast charging and high energy density increases rapidly. To design a battery with these favorable qualities, an understanding of the effect of electrode crystal structure and electrode morphology on the ionic/electronic transport and failure modes must be …

Exploring The Self-Assembly Of Functional Bis-Urea Macrocycles: M-Terphenyl Bis Urea Macrocycles And Triphenylamine Bis-Urea Macrocycles, Gamage Isuri Pramodya Wijesekera

Theses and Dissertations

Porous materials have gained significant attention due to their diverse applications in catalysis, separation, and molecular storage. Among them, self-assembled macrocycles represent a unique class of functional materials that leverage non-covalent interactions to form well-defined architectures with pores of controlled size. This thesis explores the design, synthesis, and self-assembly of bis-urea macrocycles in both solid-state and solution-phase environments, with a particular focus on supramolecular polymerization mechanisms and the emergence of kinetically trapped states.

The first chapter of this thesis presents a detailed overview of self-assembled porous materials, categorizing them based on pore dimensions and discussing their significance in catalysis, separation, …

In Vivo Analysis Of Fe-S Cluster Assembly And Iron Homeostasis In Escherichia Coli, Dexter Mclaurin Reasons

Theses and Dissertations

Iron-sulfur (Fe-S) clusters are an essential cofactor for a wide range of cellular processes, and their assembly and storage require tight regulation.

In Escherichia coli (E. coli), there are two pathways of Fe-S cluster assembly, the Isc and the Suf pathways. The Isc pathway is used under good growth conditions, and the Suf pathway is used under iron starvation and oxidative stress conditions. Once the cluster has been assembled on the scaffold protein of either pathway, it is transferred to Fe-S cluster trafficking proteins. In E. coli, the monothiol glutaredoxin GrxD and the BolA-type proteins BolA and IbaG …

Advances In And Applications Of Capillary Scale Liquid Chromatography, Samuel William Foster

Theses and Dissertations

Analytical-scale high performance liquid chromatography (HPLC) is one of the most widely used analytical techniques in the world. Efforts have been made to reduce the mobile phase consumption of HPLC by reducing the inner diameter (I.D.) of the column. By using capillary-scale columns (< 0.5 mm I.D.), separations can be performed with orders of magnitude less solvent consumption. This work describes advances made to capillary scale instrumentation as well as applications enabled by these advances. A compact capillary-scale LC was used for the analysis of numerous pharmaceutical and illicit drug compounds for point of need analysis. A miniaturized mass spectrometer was coupled to this instrument for on-line reaction monitoring within a standard chemical fume hood. Kinetic profiles of commercially available capillary columns were developed in order to provide guidance to others during column selection. The implementation of a column oven improved the analysis of large biopharmaceuticals. Several critical quality attributes of monoclonal antibodies including fragmentation, charge variants, and glycosylation profiles were able to be determined on the capillary scale. These results will help to make capillary-scale liquid chromatography a more viable solution for chromatographic analysis.

Enhancing Chemical Synthesis For Sustainability And Process Monitoring Utilizing Group Ten Metal Catalysis, Amanda M. Perkins

Theses and Dissertations

This thesis explores two sustainable methodologies by modifying established catalytic processes using group ten metal complexes from nickel and palladium. Efforts were made to provide alternatives for processes that often do not follow the principles of green chemistry. In the first project, a nickel(II) N-heterocyclic carbene complex was used to perform catalytic hydrogenation of 2-acetylpyridine under mild conditions. The complex was synthesized and characterized with techniques including mass spectrometry and 1H-NMR. Following this, the reactions were carried out to optimize conditions and yield moderate conversions. For the second project, the Suzuki-Miyaura cross coupling of 7-chlorotryptophan occurred utilizing a palladium complex …

Investigations Into Fluorescence Of Fluorene Dimers: Linker Impacts And Tuning Potential Through Substituent Addition, Abigail R. Ressler

Theses and Dissertations

Fluorene-based fluorescing conjugated polymers are being used to develop sensors that show great sensitivity and selectivity, however, important questions about the photophysics of these systems remain unanswered. For example, a fluorescence intensity difference was observed between fluorene dimers linked with either an acetylene (diFA) or phenyl (diFP). The polymers diFA and diFP have similar structures and extinction coefficients, yet diFA yielded a five times higher fluorescence intensity than diFP. In project one, Density Functional Theory (DFT) and Time-Dependent DFT (TD-DFT) were used to calculate the ground and excited states of diFA and diFP. A python code was developed to solve …

Investigation Into The Effectiveness Of G-C3n4 For The Degradation Of Indigo Dye In Aqueous Solution Via Electrocatalysis, Rolando R. Barron Jr

Theses and Dissertations

Indigo dye (IUPAC 2-(3-hydroxy-1H-indol-2-yl)indol-3-one) is one of the most used dyes in the textile industry worldwide with more than 40,000 tons produced each year. It can elicit adverse physiological responses in humans including vomiting, diarrhea, and other gastrointestinal conditions, and it is toxic in large amounts. There is also evidence to suggest that indigo is a teratogen and genotoxic in aquatic life. Environmentally, the enormous amount of indigo used in the textile industry has caused rivers and waterways to run blue as well as severely impacting aquatic and plant ecosystems. The chemicals used in its synthesis are also …

Understanding The Through-Space Intermolecular Interactions Of Isothiourea Catalysts In Acylation/Silylation Reactions Of Secondary Alcohols, Ziyuan Gong

Theses and Dissertations

Through space interactions, including cation-π interaction, lone pair-πinteraction, steric hinderance etc. play a central role in organocatalytic reaction. They can control the reactivity or the selectivity of an organic reaction. Previous work in our group has already shown that the chiral isothiourea compounds can catalyze the acylation as well as silylation reaction of secondary alcohol with the possible cation-πinteraction between the catalyst and substrate. However, there is lack of study to understand how the delocalization of the positive charge would affect the reaction rate and whether some unexpected inter- or intramolecular interaction could help stabilize …

Explorations Of Multi-Carboranyl Thiols And Phosphines, Jared Ross Riffle

Theses and Dissertations

In order to ascribe the impact of substituent groups on the bis-ortho-carborane, closo-{C2B10}-closo-{C2B10} multi-cluster system, the first sulfur-containing biscarborane derivatives were synthesized. Biscarborane dithiol, disulfide, bis(methyl)thioether, as well as multiple dithiolate salts were structurally characterized. The exceedingly long C–C bonds and shortened C–S bonds in biscarborane dithiol and its doubly deprotonated dithiolate salts are indicative of significant delocalization of electron density from the sulfur atoms into the cluster. Additionally, a new concept of ligand ambiphilicity is described where, instead of the involvement of only a single center in a ligand, this amphiphilicity relies on the redox behavior of the indirectly …

Building A Framework For Analyzing Non-Linear And Multidimensional Kinetics, Mainak Dhar

Theses and Dissertations

Many materials exhibit multiple rates of molecular relaxation due to structural complexities. Standard linear and one-dimensional kinetic cannot extract all the necessary dynamic information about these systems. This dissertation contributes to an overarching scheme to develop new non-linear and multidimensional kinetic experiments to obtain this information. The studies span computation and experiments, picosecond to second timescales, and both single-molecule and pulsed-laser kinetics

Single-molecule kinetics experiments yield time series that contain information about unique structural and dynamic properties of materials. However, these time series are noisy, and data analysis is challenging. Parametric methods are computationally intensive and require strong, unverifiable assumptions …

Expanding Tailored Nanomaterials With Precise Spatial And Morphological Control, Mengxue Zhang

Theses and Dissertations

Multicomponent nanocomposites with precise spatial control are important for diverse fields spanning from energy conversion to optoelectronics and catalysis. Traditional methods using hydrophilic interactions alone are limited to random mixtures when multiple nanoparticle (NP) types are combined. To improve capabilities, a new strategy for polymer micelle design combining orthogonal hydrophilic (H) and fluorophobic (F) interactions to independently control two distinct NP populations was developed.

Initial research aimed at understanding F-interaction adjustments, which further enabled the switchability of FNP distribution states (dispersion vs aggregation) within polymer films through immersion annealing. Next, dual-NP assembly was examined using a diblock poly (H-b-F) where …

The Design And Optimization Of Optical Systems For The Detection And Characterization Of Phytoplankton, Caitlyn M. English

Theses and Dissertations

Phytoplankton are among the smallest organisms found in marine and freshwater ecosystems. Despite their small size, phytoplankton play a vital role in sustaining life on Earth as primary producers. Through oxygenic photosynthesis phytoplankton are also responsible for large scale carbon fixation and oxygen production. The distribution of phytoplankton in a given water resource can exhibit a high degree of variability across time and space, and this is in large part due to their varying sensitivities to environmental conditions such as resource availability and grazing by predator organisms. As such, phytoplankton community structure is widely used as an investigative tool for …

Thermodynamic Study Of Ligand Coordination On Lead Halide Perovskite Quantum Dots, Bishal Adhikari

Theses and Dissertations

Inorganic lead halide perovskite (ILHP) has been extensively studied in thin films and bulk crystals as promising materials for their photovoltaic and optoelectronic properties. These are stable enough to be prepared as colloidal quantum dots that can be dispersed, deposited and used to achieve quantum confinement; however, selection of the suitable surface passivating ligand remains challenge for long term stability of the colloidal quantum dots. Several ligand coordination chemistries used to achieve greater stability or specific functions: these can be installed at time of synthesis in some cases they can also be installed to preexisting quantum dots by ligand exchange …

Evaluating Dry Air Personnel Decontamination Of Methyl Salicylate As A Chemical Agent Surrogate In Extreme Cold Environments To Reduce Airborne Risks Using A Manikin, Lance E. Campbell

Theses and Dissertations

This research investigated a mobile air shower as an alternative to water washing for personnel chemical decontamination in Arctic environments, where traditional methods like disrobing and rinsing are impractical. Interest in Arctic operations has grown with recent U.S. military focus on strategic advancements by Russia and China, yet research on air shower effectiveness for chemical decontamination remains limited. This study examined whether a commercial off-the-shelf air shower could effectively decontaminate methyl salicylate (MES), a surrogate for chemical warfare blister agents, from a manikin outfitted in military cold-weather gear. Researchers used a ppbRAE 3000 photo-ionization detector to measure MES concentrations following …

Atmospheric Water Generation: Bacterial And Inorganic Chemical Quality, Garrett E. Stanley

Theses and Dissertations

This study investigated the quality of untreated water collected from a vapor compression-based atmospheric water generator (AWG) operated outdoors in Dayton, Ohio. The concentrations of bacterial and chemical constituents were determined. The concentration of culturable bacteria was between 200 and 2300 CFU/mL, significantly higher than the reference levels described in recreational and drinking water quality guidance. Three discrete bacteria phenotypes were visually identified; two were yellow in color, rod-shaped and gram-negative while the third was milky white, circular, and gram-positive. Chemical analysis on 15 randomly selected samples revealed the presence of Barium (average = 0.16 mg/L), Magnesium (0.08 = mg/L), …

Air-Based Chemical Patient Decontamination Methodologies For Arctic Regions Using Methly Salicylate As A Chemical Agent Surrogate On A Litter-Bound Manikin, Marcus D. Shadd

Theses and Dissertations

This study evaluated a mobile air shower for patient decontamination without disrobing or rinsing, an alternative for Arctic conditions where water is scarce. A manikin in extreme cold weather gear was exposed to 10 µL of methyl salicylate (MeS), a sulfur mustard surrogate, and placed in a horizontal chamber on a military litter. Airborne MeS was measured using a ppbRAE 3000 detector to assess inhalation risk for the patient and decontamination team. Three methods were tested: an air-knife system, paper towels, and no decontamination, with 10 trials each (30 total). ANOVA analysis showed significant reductions in airborne MeS with air-knife …

Molecular Scale Investigations Of Interactions Between Pfas And Concrete, Eric E. Keeler

Theses and Dissertations

Per- and polyfluoroalkyl substances (PFAS), widely referred to as “forever chemicals,” exhibit high environmental persistence and potential health risks due to their robust carbon-fluorine bonds. These substances are prevalent in aqueous film-forming foams (AFFF), used in industrial and military applications, and are known to contaminate environmental surfaces, including concrete. This study aims to characterize the molecular-level interaction energies of six PFAS species—PFOA, PFOS, PFHxS, PFHxA, 6:2 FTS, and PFBS—with calcium silicate, a key component of concrete, using density functional theory (DFT) calculations. Change in Gibbs free energy (ΔG) was determined for each of the interactions, revealing negative ΔG values for …

Tailor-Designed Oxalic Acid-Crosslinked Poly(Vinyl Alcohol)/Chitosan Biodegradable Films For Active Food Packaging Applications, Reem Hazem Fathy Anwar Elaasar

Theses and Dissertations

Food packaging plastic waste is posing great threats to ecosystems, human health, and the planet's overall sustainability; therefore, research has been directed towards the fabrication of biodegradable food packaging materials. In this study, active and biodegradable oxalic acid (OA) crosslinked poly(vinyl alcohol) (PVA)/chitosan (CS) composite films of different weight ratios were synthesized via the solvent casting technique and their food packaging properties were investigated. Owing to its water resistance and antibacterial superiority, the composite film with the ratio of OA chemically crosslinked PVA/CS 80:20 was elected to be coated with green tea extract (GTE) to ameliorate its antibacterial and antioxidant …

Mechanism Of Napthenic Acid Binding To Dissolved Organic Matter, Clarissa Jules

Theses and Dissertations

The oil sands in Alberta, Canada are being destroyed by oil extraction because remediation methods have proven largely ineffective. One toxic byproduct of oil extraction is a family of cyclical surfactant organic acids known as naphthenic acids (NAs). They are toxic to aquatic life, including fish, frogs, and aquatic birds. It is suspected that NAs bind to humic acid, a major organic component of soil, in dissolved organic matter in natural water, making them difficult to remove by conventional remediation methods. This problem prompts the following question: what is the binding mechanism between NAs and humic acid when dissolved in …

Protein-Metal Interactions Of A-Synuclein And Bioactive Transition Metals Via Molecular Dynamics, Gonzalo R. Vazquez

Theses and Dissertations

Parkinson’s Disease (PD) is a neurodegenerative movement disorder which has been found to target the dopaminergic neurons of the substantia nigra. It is characterized by the formation of masses known as Lewy Bodies, formed by aggregates of the intrinsically disordered protein (IDP) -synuclein (asyn). Research suggests that alpha synuclein can undergo aggregation in the presence of heavy metals, which may accumulate in the body through a variety of mechanisms. To study how metals may play a role in wildtype (WT) asyn aggregation, MD simulation of the protein was performed in the presence of bioactive transition metals including Fe2+, Fe3+, Cu+, …

Electrochemical And Conformational Patterns Of S-Glycosides And The Synthesis Of Schistosoma Mansoni Antigens, Bhavesh Rajendra Deore

Theses and Dissertations

This thesis dives into two relevant fields in carbohydrate science: reactivity and conformation. We centered our attention on S-glycosides, a common class of glycosyl donors and glycomimetics, to study the influence exerted by the structural architecture over the conformational properties about flexible bonds and the reactivity towards electrochemical activation. Studying the conformational properties of sugars is key to understanding the molecular recognition mechanisms underlying their biological functions. Moreover, a well understanding of how the molecular components affect free rotation about bonds can be valuable information to design improved glycomimetic drug candidates. On the other hand, electrosynthesis is a promising application …

Synthesis And Characterization Of Novel Coumarin Derivatives, Jeanmeil M. Nestor

Theses and Dissertations

An optimized approach toward the synthesis of representative coumarin derivatives is described. In addition to standard heat application methods, microwave-assisted coupling has proven beneficial in generating the targeted molecular hybrids which will serve as key templates in the development of new drugs to address resistance and specificity challenges. The coumarin moiety is a fantastic scaffold for molecular hybridization and has gained much warranted attention due to its efficacy in anticancer, antibacterial, and antitumor activity. In this research, novel molecular hybrids of umbelliferone were synthesized and fully characterized as new potential players in the anticancer, antitumor and antibiotic race, as well …

Adsorption And Recovery Studies Of Cadmium And Lead Ions Using Biowaste Adsorbents From Aqueous Solutions, Liang Feng

Theses and Dissertations

The use of low-cost biowaste adsorbents for the removal of toxic metal ions from aqueous solutions offers significant environmental benefits and demonstrates strong potential. This study evaluated luffa peels and chamomile flowers as low-cost biosorbents for the adsorption and recovery of Cd2+ and Pb2+ ions in both batch and column modes. To enhance adsorption capacity, the biosorbents were treated with 0.4 M HNO3 or 0.4 M NaOH. Fourier transform infrared spectroscopy (FTIR) characterization showed that surface OH, C=O, CO and COO groups played a role in the adsorption process. Batch adsorption studies indicated an order of adsorption capacity as follows: …

Biological And Chemical Evaluation Of Amide-Based Cjoc42 Derivatives As Potential Gankyrin-Inhibitors For The Treatment Of Breast, Lung, And Liver Cancer, Benita Britton-George

Theses and Dissertations

Gankyrin is an ankyrin-repeat protein overexpressed in certain cancers and is responsible for cell growth and proliferation. Gankyrin is important to the development of many types of cancer, including breast, lung, and liver cancer. Consequently, gankyrin and its various protein-protein interactions, are prospective therapeutic targets for inhibiting the progression of certain cancers. In 2016, the first small molecule inhibitor of gankyrin, cjoc42, was discovered and subsequently demonstrated modest antiproliferative activity against liver cancer cells. Previous work from our lab demonstrated that replacing the sulfonate ester of cjoc42 with an amide group significantly improved gankyrin binding while enhancing antiproliferative activity against …

Investigation Of The Binding Mechanisms Between Naphthenic Acids And Humic Acid Using Raman Spectroscopy And Computational Modeling, Jaelyn N. Palmer

Theses and Dissertations

The oil sand regions in Alberta, Canada have proven to be costly to the environment despite its economic benefits. The toxins produced during oil processing are sent to tailing ponds to be recycled, though often leaking into nearby waterways and soil. Naphthenic acids, NAs, are one of the most common toxins produced and have shown to be toxic to aquatic life, animals, and humans. As there is dissolved organic matter in tailing ponds and surrounding environments, tailing ponds often lead to NAs coming in contact with organic material. Humic acid, HA, is a major soil component that has been suspected …

Qualitative Analysis Via Network Models Of Human Dynamin-1 Throughout Gtp Hydrolysis, Kevin Brian Schulman

Theses and Dissertations

This thesis aims to elucidate the molecular mechanisms by which nucleotide binding dictates the intrinsic dynamics and to understand the functional conformational changes of Human Dynamin-1 during the GTP hydrolysis cycle through the use of Elastic Network Models (ENM). A comprehensive understanding of this process is crucial given dynamin's role in clathrin-mediated endocytosis (CME). The research utilized both experimentally derived crystal structures and AlphaFold-predicted structures of dynamin, specifically examining the GTPase and Bundle Signaling Element (BSE) domains across nucleotide-free, GTP-bound, GDP-bound, and transition states. The essential features of the research methodology involved a multi-scale computational approach. Qualitative analyses were performed …