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Synthesis, Reactivity, And Nmr Trends Of Early Transition Metal Compounds, Tabitha Marie Cook

Doctoral Dissertations

This dissertation focuses of three different subjects. The first is the synthesis and characterization of heptacoordinate amidinate compounds. Heptacoordinate compounds are not common, but their structures have been studied. Group 4 amidinate compounds have been used as precursors in the CVD/ ALD processes. Ancillary ligands, such as amidinates, have been used to reduce air-sensitivity of complexes. Reactions of these complexes with water have been used to make metal oxide thin films.

In the first study, the complexes Zr[MeC(NⁱPr)₂]₃Cl [zirconium trisamidinate chloride], Hf[MeC(NⁱPr)₂]₃Cl [hafnium trisamidinate chloride], Zr[MeC(NⁱPr) …

The Effect Of Illumination On The Conformation And Thermodynamics Of Conjugated Polymers, Brian Frank Morgan

Doctoral Dissertations

This dissertation explores the effects which illumination has on the structure and conformation of conjugated polymers, both in solution and the bulk. Conjugated polymers are an important class of optoelectronic polymeric materials which make up the active layer of key organic electronic devices such as organic photovoltaics, transistors, and light emitting diodes. Considering the strong link between polymer chain structure and device efficiency in these materials, a comprehensive understanding of certain experimental conditions which may influence this conformation and thusly alter the functionality of the devices predicated upon them is of vital importance.

The first part of this dissertation provides …

Design And Synthesis Of Lipid Probes Used For Membrane Derivatization And Fusion, Stuart Allen Whitehead

Doctoral Dissertations

Lipids control a variety of complex biological processes. Bulk lipids such as phosphatidylcholine (PC), phosphatidylserine (PS), and phosphatidylethanolamine (PE) represent the major components of cellular membranes. In addition, unilamellar vesicles composed of lipids (liposomes) are valuable for delivery applications since they can encapsulate and transport drugs and other agents. In order to maximize delivery efficiency and target specific membranes, the ability to trigger and control vesicle-vesicle fusion is desirable. Such approaches generally seek to mimic the membrane fusion machinery present in nature while imparting specificity in the membranes that undergo fusion. The goal of this work is selective drug delivery …

Development Of An F-Element Separation Chemistry Using Solid Electrolytes, Kristian Guy Myhre

Doctoral Dissertations

The f‒elements (lanthanides and actinides) have numerous applications and are critically important to many industries, including the energy, security, and medical industries. One of the barriers to increased use and availability of the f‒elements is the difficulty in separating them from each other due to their similar chemistries. This is especially true of the trivalent f‒elements (lanthanides and minor actinides). The development of separation techniques that maximize the differences in the physicochemical properties of the f‒elements is therefore an important area of research. For these reasons, an effort was undertaken to explore the use of solid …

Catalytic Aziridination With A Borate-Containing N-Heterocyclic Tetracarbene Iron Complex, Preeti Pradip Chandrachud

Doctoral Dissertations

Aziridines, the nitrogen analog of epoxides, are an important class of compounds. They are present in many biologically active compounds having antibacterial and antitumor properties. Along with biological significance, it can also be considered as a synthetic tool for various functional group transformations. Being an important functional group we focused on the development of synthetic methodology using alkenes as substrates and organic azides as the nitrene source [C₂ (carbon2)+ N₁ (nitrogen1) addition reaction].

For the potential use as an aziridination catalyst a macrocyclic N-heterocyclic tetracarbene (NHC) ligand system was developed. First, the neutral NHC ligand was used …

Synthesis And Behavior Of Stimuli-Responsive Shape-Changing Linear Molecular Bottlebrushes, Daniel Mark Henn

Doctoral Dissertations

Molecular bottlebrushes are composed of polymer side chains densely grafted to a macromolecular backbone. The main focus of this dissertation work is the synthesis and behavior of linear molecular brushes that can undergo unimolecular size and shape changes in response to environmental stimuli in dilute aqueous solution. Chapter 1 provides an introduction to molecular bottlebrushes and stimuli-responsive polymers.

Chapter 2 presents the development of a robust method for the synthesis of well-defined molecular brushes by a “grafting to” approach using copper-catalyzed azide-alkyne cycloaddition “click” reactions. Well-defined, new azide-containing backbone polymers with different lengths and high degrees of azide functionality were …

Synthesis And Characterization Of Novel Ligand For Use On Rhodium Paddlewheel Complexes, Gavin J. Rustin

Masters Theses

Dirhodium (II) paddlewheel complexes have proven to be useful catalysts in many transformations including C-H insertions, cyclopropanation, and silane insertion reactions. One deficiency of these catalysts is the inability to modulate the enantioselectivity with reactive diazo compounds. One avenue for potential improvement of paddlewheel complexes is coordinating ligands in the axial site to increase enantioselectivity. The axial site has been occupied by various ligands including Nheterocyclic carbenes, nitrogen compounds, and phosphorous compounds. This work examines compounds that can be used as ligands on dirhodium complexes that have a pendant chain containing a dibenzyl phosphite and dibenzyl phosphate, both of which …

Three Body Interactions Of Rare Gas Solids Calculated Within The Einstein Model, Dan D'Andrea

Masters Theses

Three body interactions can become important in solids at higher pressures and densities as the molecules can come into close contact. At low temperatures, accurate studies of three body interactions in solids require averaging the three-body terms over the molecules' zero point motions. An efficient, but approximate, averaging approach is based on a polynomial approximation of the three-body term. The polynomial approximation can be developed as a function of the symmetry coordinates of a triangle displaced from its average geometry and also as a function of the Cartesian zero point displacements from each atom’s average position. The polynomial approximation approach …

Synthesis And Characterization Of New Multifunctional Initiators For Anionic Polymerization And The Use Of Poly(4-Hydroxystyrene) As A Template For New Polymers, Christopher Michael Hurley

Doctoral Dissertations

This dissertation explores the synthesis and use of multifunctional anionic polymerization initiators for the purpose of opening the gateway to the synthesis of polymer architectures of greater complexity. First the multifunctional oxyanion initiator generated by reacting poly(4-hydroxystyrene) with sodium hydride was used to synthesize a previously unknown polymer containing an aryl halide functional group. The homopolymer solution self-assembly behavior of poly(4-hydroxystyrene) and the newly synthesized poly (4-bromo-phenyloxystyrene) were both investigated. This is followed by the synthesis and characterization of multifunctional alkyne core molecules and random copolymers of polystyrene-co-poly(4-hydroxystyrene) which served as templates for the synthesis of new random copolymers of …

A Generalized Method For Fissile Material Characterization Using Short-Lived Fission Product Gamma Spectroscopy, Justin Richard Knowles

Doctoral Dissertations

Characterizing the fissile content of nuclear materials is of particular interest to the safeguards and nuclear forensics communities. Short-lived fission product gamma spectroscopy offers a significant reduction in analysis time and detection limits when compared to traditional non-destructive assay measurements. Through this work, a fully generalizable method that can be applied to variations in fissile compositions and neutron spectra was developed for the modeling and measurement of short-lived fission product gamma-rays. This method uses a 238-group neutron flux that was characterized for two pneumatic tube positions in the High Flux Isotope Reactor using flux monitor irradiations. This flux spectrum was …

Hybrid Micellar Network Hydrogels Of Thermosensitive Hydrophilic Triblock Copolymers And Thermosensitive Hairy Nanoparticles, Bin Hu

Doctoral Dissertations

Hybrid micellar network hydrogels, composed of thermosensitive hydrophilic triblock copolymers and thermosensitive polymer brush-grafted nanoparticles (hairy NPs), exhibit intriguing rheological properties. This dissertation work studies thermosensitive hybrid hydrogels with NPs positioned either inside or outside the core of block copolymer micelles.

Chapter 1 is an introduction. Chapter 2 examines the effect of NP’s location on properties of hybrid hydrogels of a thermosensitive ABA triblock copolymer and hairy NPs. Two batches of thermoresponsive polymer brush-grafted silica NPs and an ABA triblock copolymer with thermosensitive outer blocks were prepared. When the lower critical solution temperature (LCST) of hairy NPs was similar to …

Synthesis And Application Of Polymer Brush-Grafted Nanoparticles As Hydrogel Gelators And Lubricant Additives, Roger Anthony Emory Wright

Doctoral Dissertations

This dissertation describes the synthesis of polymer brush-grafted nanoparticles (hairy NPs) and an analysis of their behavior or utility in multiple areas. The hairy NPs were synthesized from silica NPs functionalized with initiating moieties by surface-initiated atom transfer radical polymerization. A brief introduction to hairy NPs, with a focus on the synthesis and behavior of stimuli-responsive polymer brush-grafted particles, is given in Chapter 1 to provide context for this work.

Chapters 2 and 3 present the synthesis of thermosensitive diblock copolymer brush-grafted nanoparticles designed as hairy NP analogues in place of thermosensitive block copolymers micelles for the construction of hybrid, …

Actinium-225 Production Via Proton Irradiation Of Thorium-232, Justin Reed Griswold

Doctoral Dissertations

High energy proton spallation reactions on natural thorium metal targets have been utilized to produce multi mCi [milliCurie] quantities of Actinium-225. Theoretical cross sections for actinium and thorium isotopes as well as for a select number of the fission products produced in these reactions were generated by the Monte Carlo radiation transport code PHITS to simulate the experimental data obtained from sixteen irradiations of thorium metal targets with 25-210 µA [microampere] proton beams ranging in energies from 77 to 192 MeV. Irradiations were conducted at Brookhaven National Laboratory (BNL) and Los Alamos National Laboratory (LANL), while target dissolution and processing …

Interaction Between Charge-Transfer States Studied By Magnetic Field Effects, Mingxing Li

Doctoral Dissertations

Organic semiconducting materials, consisting mostly of carbon and hydrogen atoms, provide remarkable promise for electronic applications due to their easy processing, chemical tenability, low costs and environmental-friendly characteristics. For realizing electronic applications such as light emitting diodes and photovoltaic cells, charge-transfer states act as an important intermediate state for recombination and dissociation. Interestingly, magnetic field effects on semiconducting materials have been realized based on the suppression of spin mixing in the charge-transfer states. Although lots of studies have been carried out on investigating the properties of charge-transfer states, little has been done to consider the interaction between them. This thesis …

Metabolomics Approaches To Decipher The Antibacterial Mechanisms Of Yerba Mate (Ilex Paraguariensis) Against Staphylococcus Aureus And Salmonella Enterica Serovar Typhimurium, Caroline Sue Rempe

Doctoral Dissertations

The increasing prevalence of drug-resistant pathogens is an urgent problem that requires novel methods of bacterial control. Plant extracts inhibit bacterial pathogens and could contain antibacterial compounds with novel mechanisms of action. Yerba mate, a common South American beverage made from Ilex paraguariensis, has antibiotic activity against a broad range of bacterial pathogens. In this work, an attempt was first made to characterize the antibacterial source of an aqueous yerba mate extract by generating a series of extract fractions, collecting GC-MS and antibacterial activity profiles, and then ranking the hundreds of compounds by their presence in fractions with high antibacterial …

Development Of Instrumentation For The Analysis Of Photoconductivity In Functional Materials, Brandon L. Chapman 9741174

Chancellor’s Honors Program Projects

No abstract provided.

The Use Of Sodium Persulfate In Hydraulic Fracturing Fluids: A Degradation Study Based On Furfural, Katherine Elizabeth Manz

Masters Theses

Hydraulic fracturing has allowed natural gas to become a viable energy source via extraction of unconventional shale reserves, but this process requires an enormous amount of water. To ensure a productive fracture, a proprietary blend of chemical additives is added to the water. In this research, a hydraulic fracturing chemical additive – an enzyme breaking agent – is analyzed for organic components using gas chromatography mass spectrometry. The chemical changes that occur over the course of a fracture are also investigated using one model chemical found in the additive, furfural, in order to help assess the environmental risk that hydraulic …

Mining Uranium From Seawater: A Coordination Chemistry Approach, Nada Mehio

Doctoral Dissertations

Poly(acrylamidoxime) fibers are the current state-of-the-art adsorbent for mining uranium from seawater. However, the amidoxime group is not perfectly selective towards the uranyl cation, in particular, competition with transition metal cations remains a major challenge. In order for subsequent generations of chelating polymer adsorbents to be improved, the coordination chemistry of amidoxime-uranyl and -transition metal cation complexes needs to be better understood. While the coordination mode of amidoxime-uranyl complexes has been established in the literature, a number of amidoxime-transition metal cation complex binding motifs can be observed on the Cambridge Structrural Database. Likewise, the formation constants, or log K values, …

Novel Methods And Sensors For The Analysis Of Trace Chemicals With Potential Environmental Applications, Samuel Mason Rosolina

Doctoral Dissertations

The work in this dissertation focuses on the detection and analysis of trace chemicals in biological and environmental samples. Methods for the electrochemical detection of heavy metals Cd(II) [cadmium] and Pb(II) [lead], and the catalytic metal Pd(II) [palladium] in pharmaceutical ingredients have been optimized without the necessity of sample pretreatment. The metals can be analyzed simultaneously as well as individually, and the study includes the first known instance of the use of anodic stripping voltammetry (ASV) to detect metals in dimethyl sulfoxide (DMSO) solutions. Another method, based on ASV, has been optimized and evaluated for the purpose of mercury(II) analysis …

Development Of Novel Analytical Methods With The Aim Of Forensic Analyte Detection Using Ultra-Thin Layer Chromatography, Surface Enhanced Raman Spectroscopy, And Magneto-Elastic Wire Sensing, Nichole Ann Crane

Doctoral Dissertations

The purpose of this dissertation is to develop analytical methods that aid in the detection of forensic analytes. Forensic analytes require methods with increased sensitivity and low limit of detection capabilities. Improvements in separation techniques, surface enhanced Raman spectroscopic techniques, and wire-less gas sensing can each assist in the detection of trace evidence.

When surface enhanced Raman is coupled with thin-layer chromatography a mixture of compounds can be separated and transferred to a metal substrate to be detected using Raman spectroscopy. Surface enhanced Raman scattering enhances the Raman signal intensity by placing a metal substrate in close proximity to an …

A Characterization Study On Catalyst Layers In Proton Exchange Membrane Fuel Cells, Luyue Li

Doctoral Dissertations

This thesis describes the work for the catalyst layer (CL) characterization study of proton exchange membranes (PEM) for fuel cells. In particular, both the structure and performance of catalyst layers with alternative ionomers were studied. Structure wise, the morphology, surface area and pore size distribution studies were accomplished with scanning electron microscopy (SEM), transmission electron microscope (TEM) and nitrogen adsorption processed through Brunauer–Emmett–Teller (BET) and Barrett-Joyner-Halenda (BJH) theory. Water uptake isotherms of the CLs have been developed under well controlled relative humidity (RH) levels. The performance characterization focuses on polarization study, catalyst layer proton conductivity measurement and estimation of the …

Thermodynamics Of Short Chain Perfluoroalkanes Adsorbed On The Surfaces Of The Graphite Basal Plane And Mgo (100), Nathaniel Keenan Bass

Doctoral Dissertations

Molecular adsorption of short-chain linear perfluoroalkanes was studied by volumetric isotherm and by molecular dynamics simulation. Isotherms of perfluoroethane, perfluoropropane, and perfluorobutane gas were measured on clean surfaces of the graphite basal plane nanometer-scale cubic magnesium oxide (100). Each system was measured over a range of temperatures, and thermodynamic determinations of the entropies, enthalpies, and heats of adsorption were determined as a result. Potential phase transitions between the surface structures were identified, and the constant-coverage heats of adsorption for each system were determined. Comparisons to molecular dynamics simulations provided guidance in the assignment of phase diagrams, giving insights to the …

Improving And Understanding Inter-Filament Bonding In 3d-Printed Polymers, Madeline S. Stark

Chancellor’s Honors Program Projects

No abstract provided.

Cd Transport In Eutectic Licl-Kcl And Contamination Of Zr Metal And Thermal Dehydration Of Bulk Licl-Kcl, Nicholas Azoy Earle

Masters Theses

Researchers at Idaho National Labs have noted unexpectedly high Cd content in empty cladding hulls after processing in the Mark-IV ER. It has been theorized that Cd metal is transporting from the LCC pool through the eutectic LiCl-KCl salt bath to the anode baskets containing the empty hull where it is retained as a Zr-Cd intermetallic. This study sought to replicate the Cd contamination in a dry Ar glovebox using small-scale analogue of the Mark-IV ER salt-Cd metal system.

Anhydrous eutectic LiCl-KCl was an essential regent in this research and experiments were conducted to investigate the feasibility of dehydrating nominally …

Incorporating Carbon Nanotubes Into Carbon Fiber Via Surface Modification, Robert Benjamin Ripy

Masters Theses

Ever more advanced materials need to be designed to further the exploration of avenues of science and engineering. Metals and traditional composites are not meeting the needs of today’s stringent demands for lightweight and strong materials. There is a need for advanced materials that are lighter and stronger to replace conventional materials; carbon fiber composites became the obvious choice because of their outstanding mechanical properties. Polyacrylonitrile (PAN) based carbon fiber has reached its apex in terms of its strength to weight ratio. Carbon nanotubes (CNTs) offer a lightweight and potentially stronger alternative to PAN based fibers. However, it is difficult …

Synthesis Of A Novel Cox-2 Inhibitor Analog For Pet Scan Imaging, Rebecca Neighbor

Chancellor’s Honors Program Projects

No abstract provided.

Magnetron Sputtering And Corrosion Of Ti-Al-C And Cr-Al-C Coatings For Zr-Alloy Nuclear Fuel Cladding, Devin Alan Roberts

Masters Theses

The disaster at the Fukushima Daiichi Nuclear Power Plant in March 2011 bought renewed focus to the issue of corrosion in nuclear fuel cladding applications. This thesis reports on the background behind these issues, the investigation strategy, and the analysis of experiments focused on mitigating oxidation of Zr-alloy fuel cladding. This thesis seeks to develop magnetron sputtered Ti-Al-C and Cr-Al-C coatings for Zr-alloy substrates and characterize the as-deposited and corroded samples.

Ti-Al-C and Cr-Al-C coatings were deposited onto ZIRLO, Si, and Al₂O₃ [Aluminum Oxide] substrates under various sputtering conditions. A combinatorial sputtering method was employed to refine …

Developing Synthetic Methods To Prepare Discrete Metal-Organic Nanotubes, Derek L. Mull

Masters Theses

Metal-organic nanotubes (MONTs) are an emerging class of discrete materials that are the 1D variant of metal-organic frameworks (MOFs). MONTs have potential to become an alternative 1D material to carbon nanotubes, metal oxide nanotubes, and boron nitride nanotubes because they possess an organic ligand that can be functionalized and tuned for specific applications. Despite this potential, only a handful of structures have been reported and only two examples of discrete MONTs exist in the literature. It is thus imperative to develop general methods to prepare and characterize discrete MONTs to bring them to the forefront of the scientific literature.

Efforts …

Optical Sensors For The Analysis Of Alcohols In Fuels, Kendhl Kate Witt

Masters Theses

This thesis reports the development of optical sensors to analyze alcohols in fuel samples. One optical sensor enables the analysis of phenol in aviation fuels and cellulosic biofuels. It is critical to monitor the concentration of phenols in fuels because they increase the presence of solid oxidative deposits and lower the thermal stability of fuels. Preliminary studies of another optical sensor have been conducted to detect ethanol in E10 gasoline samples. Gasoline containing ethanol is widely available and used, but the exact percentage of ethanol is not specified and varies between samples and regions. Higher concentrations of ethanol in gasoline …