Inorganic Chemistry Commons^™

Engineering Silicone Magnetic Fluids For Localized Radiation Attenuation During Ocular Melanoma Brachytherapy, Zachary L. Caprow

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Ocular melanoma is commonly treated using plaque brachytherapy; however, radiation-induced damage to healthy ocular tissues frequently results in partial or complete vision loss. This work investigates the development of an injectable, magnetically responsive silicone magnetic fluid designed to localize adjacent to the tumor and attenuate low-energy gamma radiation during treatment.

The material system consists of iron oxide nanoparticles surface-functionalized with a siloxane polymer, in which the nanoparticles provide magnetic responsiveness and radiation attenuation, while the polymer coating ensures colloidal stability, injectability, and biocompatibility. A one-pot synthetic approach was developed wherein a functionalized siloxane polymer containing iron-affinitive groups was reacted with …

Exploring Halogen Bonding Interactions In Cocrystals And Deep Eutectic Solvents, Madhushi Bandara

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Halogen bonding is a noncovalent intermolecular interaction analogous to hydrogen bonding that occurs between an electrophile and a nucleophile. This is often observed in compounds containing heavy halogens such as iodine and bromine. When these halogens are covalently bonded to another atom or molecule, preferably to an electron-withdrawing moiety, an electrophilic region called a sigma hole is created on the halogen atom on the extension of the covalent bond.

The first study of this dissertation presents a comprehensive characterization of eight newly synthesized triiodide salts using single-crystal X-ray diffraction, powder X-ray diffraction, thermal analysis (DSC and TGA), and Raman spectroscopy. …

Development Of Mixed O/S-Donor Imidazole Thione Ligands For Trivalent Lanthanide/Actinide Separations, Rhianna Wolsleger

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Separation of lanthanides and actinides is difficult due to their very similar size and charge. Increasing selectivity for actinides over lanthanides is possible by incorporating a softer, more polarizable donor atom into a chelating ligand, since the softer donor atom is capable of greater orbital overlap with the 5f orbitals of the actinides vs the 4f orbitals of the lanthanides. Sulfur-containing imidazole thione chelating ligands have not been investigated for this purpose but possess a resonance structure that puts significant negative charge on the sulfur, enabling it to form strong metal-sulfur bonds compared to other sulfur-containing ligands such as thioethers …

Synthesis And Characterization Of New Inorganic Materials In Different Length Scales; From Nanometer To Micrometer, Kirkland Sheriff

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In this dissertation there are a new series of Preyssler polyoxometalate (POM) crystalline solids created using electrochemical potential. It was found that using electrochemical potential, where nucleation and reduction occur simultaneously, was a convenient method for exploratory synthesis creating new crystalline solids in aqueous solution and at room temperature. The general structure feature reveals that Preyssler POM was covalently linked by various metals from the d and f block including Co²⁺, Ni²⁺, La³⁺, Nd³⁺, Gd³⁺ and Ho³⁺ where the POM was reduced by 2 to 4 electrons. The resulting solids …

Hydrothermal Synthesis Of Single-Crystal Magnetic Oxides, Bhakti Patel

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Multifunctional materials are systems that have two or more properties of interest. Some of these features are polar axes, chirality, magnetic ions, triangular arrangements, and/or magnetically silent building blocks. Various combinations of these properties can result in chiral ferromagnetism, multiferroic magnetoelectric behavior, antiferromagnetism, and quantum spin liquids and spin ices. By tuning these structure-property relations, quantum computing, memory, and sensors may be created. Large single crystals allow for a better understanding of the magnetic behavior of these crystals since they can be oriented in a magnetic field. Inorganic single crystals have a wide range of applications but growing high-quality single …

Hydrothermal Synthesis, Characterisation, And Magnetic Study Of First-Row Transition Metal Molybdates And First-Row Transition Metal Vanadates, Mahsa Foroughian Foroughian

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Growing high-quality single crystals of transitional metal oxides have been of interest over the last two centuries because of the many applications of these transparent materials in various industries, such as optics, magnetism, semiconductors, and batteries. During this period, a variety of crystal growth techniques have been utilized, each offering unique advantages and disadvantages to the solid-state community.

Traditionally, metal oxides such as molybdates and vanadates are produced using high-temperature techniques (700 to 1200 °C). These methods can cause oxygen to be expelled, resulting in the creation of lattice defects and lower-valence metal ions and complicate precise measurements of physical …

Studying The Chemistry-Property Relationship In Magnetic And Optical Materials: Spin S = 3/2 Systems Of Neodymium, Manganese, And Cobalt Oxyanions, Xudong Huai

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This dissertation describes the design and tunability of new magnetic and optical materials, emphasizing the intricate relationship between their crystal structures and their optical, electronic, and magnetic properties.

Two new frustrated magnets, ANd(SO₄)₂ (A = Rb, Cs), were designed and synthesized to examine the influence of the the counter cation A site in Nd lanthanide materials featuring a distorted triangular magnetic lattice with S = 3/2. This work demonstrates how the tunability of magnetic and photoluminescent properties can be achieved through the A sites, with findings validated through density functional theory calculations.

AMnTeO₆ (A = Ca, …

Engineering Multifunctional Silicon Nanostructures From Biorenewable Cellulose Nanocrystals, Nancy Chen

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The imperative search for alternative materials to address the pressing demand for advance energy storage is underscored by the escalating environmental predicaments. Lithium-ion batteries (LIBs) with graphite anodes have become the benchmark in energy storage; however, they are approaching a saturation point in terms of energy density. Silicon emerges as a promising contender to supplant graphite, owing to its profuse availability, cost-effectiveness, and impressive specific capacity of 4200 mAh g^-1. By integrating silicon anodes, LIBs stand to undergo a radical transformation, markedly diminishing in weight and size, thus heralding a novel wave of compact, lightweight energy storage systems. …

Structure-Property Relationship Studies Of Electrically Conductive Metal-Organic Framework Materials, Shiyu Zhang

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Electrically conductive metal-organic frameworks (EC-MOFs) are among the most promising materials due to their tunable structures, properties, and diverse functions. However, the lack of comprehensive understanding of their structure-property relationship hinders the development of EC-MOFs. My dissertation focuses on the design, construction, and structure-property relationship studies of EC-MOFs.

Chapter 1 describes how MOFs' structural features and compositions affect the electronic properties and demonstrates conductive mechanisms and the corresponding design strategies to develop EC-MOFs.

Chapter 2 describes the synthesis, characterization, electronic and optical properties of four novel alkali-metal-based (Na, K, Rb, and Cs) 3D-MOFs with continuous tetrathiafulvalene tetracarboxylate (TTFTC) π-stacks, systematicly …

Hydrothermal Synthesis Of First-Row Transition Metal Polyanions Towards The Design Of Frustrated Magnetic Materials, Megan Smart

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Novel modern materials are constantly being discovered as humanity seeks constantly better improvement to the optics and electronics around us, from lasers used in medical therapies to the magnets and supercomputing chips in our phones. Inorganic oxides commonly draw inspiration from naturally occurring minerals to template new discoveries through substitution of similarly behaving elements with the goal of inducing certain desired properties, such as ferroelectricity or creating the elusive quantum spin liquid. While many minerals are silicates, its periodic table neighbor germanium(IV) has a rich and under-explored crystal chemistry that could contain many new structures and magnetic materials. Another common …

Supramolecular Pi-Donor/Acceptor Arrays Based On Redox-Active Metal-Organic Coordination Assemblies, Paola Benavides

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Coordination-driven self-assembly is an attractive strategy for constructing thermodynamically stable supramolecular coordination complexes, ranging from discrete metallacycles and cages to infinite coordination polymers and metal-organic frameworks for a variety of applications.

Chapter 1 discusses strategies for preparing supramolecular charge-transfer π-donor/acceptor assemblies and their potential applications.

Chapter 2 demonstrates that tricomponent self-assembly method, which was believed to yield 3D-cages, based on tetrapyridyl porphyrin (M’TPP, M’ = Zn or H₂), dicarboxylate ligands (XDC), and caped cis-Pt(II) corners, actually yields 2D-bowties featuring an M’TPP core and two parallel XDC linkers held together by four heteroligated PtII(N,O) corners. The 2D-bowties showed …

Designing Noncentrosymmetric Multifunctional Materials, Ebube Oyeka

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Noncentrosymmetric (NCS) materials with crystal lattices lacking spatial inversion symmetry display a wide range of exciting functionalities. This dissertation covers two classes of functional NCS materials: magnetic skyrmion-host compounds and multifunctional materials. Magnetic skyrmion and multifunctional materials combining optical and magnetic responses are providing avenues for developing and optimizing the performance of electronic devices that can have uses in memory storage, laser technology, medicine, sensors, etc. The formation of skyrmions is driven by asymmetric Dzyaloshinskii–Moriya (DM) interaction facilitated by broken spatial inversion symmetry and large spin-orbit coupling (SOC), while multiple functionalities arise when spin carriers and optical chromophores are optimally …

Impacts Of Preferential Flow On Tc-99and Np-237 Vadose Transport In Soils At The Savannah River Site, Josh Parris

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Since the 1950s, the United States has produced approximately 90,000 metric tons of spent nuclear fuel (SNF) (Office of Nuclear Energy, 2022); however, no long-term storage solutions are available. Technecium-99 and neptunium-237, two fission products found in SNF, readily form highly mobile species in oxidizing conditions (Hu, 2008; Bondietti, 1979) and have respective half-lives of 2.13 x 10⁵ and 2.14 x10⁶ years (Hu, 2010). Considering these characteristics, ⁹⁹Tc and ²³⁷Np are two risk-driving isotopes found in SNF storage. The process of macropore-facilitated preferential flow, transport through cracks within a soil matrix, has been recognized to increase …

Hydrothermal Synthesis Of Frustrated Lanthanide Pyrochlores And Transition Metal Double Perovskites And Germanates, Matthew S. Powell

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Magnetically frustrated materials hold promise of unique behavior allowing for the novel study of quantum phenomena. Such materials are poised to become an integral foundation for technological advancement in the post-Silicon Age. Crystalline materials are given special focus where the rigid lattice allows more detailed study of these quantized effects and frustration behavior. As opposed to polycrystalline powders, large single crystals can be preferentially aligned enabling the study of anisotropic behavior. Two cubic structure types have garnered significant interest due to their 3-D tetrahedral arrangement of symmetry-related metal centers with the potential for magnetic frustration: pyrochlores and perovskites.

The supercritical …

Computational And Experimental Investigations Of Alkali Cation Interactions At The Rutile – Water Interface, Isaac Johnston

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Overall, the objective of this dissertation was to investigate the degree of sorption for the alkali cations on rutile to ascertain the impact of different cation properties, such as ion size and charge density, on sorption mechanics as well as probe how the ion may alter the surface – aqueous interface. Initial molecular dynamic simulations and batch experiments showed minimal surface sorption for any alkali cation at relatively low concentrations while simultaneously suggesting the enthalpy of deprotonation shifts slightly in the presence of the alkali cations at different ionic strengths. The cations are likely causing small reorientations of the near-surface …

Competition Between Halogen And Chalcogen Bonding And Their Role In Probing Organic Transformations, Andrew Peloquin

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Halogen bonding, the attractive interaction of an electrophilic region on a halogen atom with a nucleophilic region on another atom or molecule, provides a highly directional tool in forming solid-state motifs. This interaction, along with the related chalcogen bonding interactions, forms powerful synthons, which, when combined with other typical intermolecular attractions such as hydrogen bonding, allow for the design of supramolecular structures and inputs to crystal engineering. This dissertation research serves two primary purposes: (1) to catalog halogen and chalcogen bonding interactions with various donor molecules and (2) to utilize these interactions to probe interesting organic transformations.

In order to …

Light Harvesting And Electrically Conducting Metal-Organic Frameworks, Monica Gordillo Varela

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Composed of metal clusters nodes and organic linkers, metal-organic frameworks (MOFs) have emerged as versatile platforms with unparalleled chemical and structural tunability, synthetic facility, permanent porosity, and size-selective guest encapsulation capability. These features make them potential candidates for a variety of applications such as gas storage,drug delivery, catalysis,and sensing. In recent years, the introduction of redox- and photoactive components have yielded stimuli-responsive electronic and photonic MOFs and expanded their utility in molecular electronics and energy storage devices/technologies.

Chapter one describes the light-harvesting ability of a porphyrin-based MOF. Herein, we have demonstrated spontaneous solvothermal growth of [100]-oriented uniform pillared-porphyrin framework-11 (PPF-11) …

A Performance Evaluation Of Architectural Coatings To Preserve Aerosol Paint On Concrete, Riley Morris

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The growing movement of assigning cultural and heritage value to graffiti and street art is one without a preservation solution to ensure the longevity of these works in-situ in an outdoor environment. The goal of this thesis was to provide a comprehensive evaluation of six architectural topcoats’ performance when applied as a conservation treatment to outdoor aerosol graffiti and street art on concrete substrate. An artist’s quality, durable, color-fast spray-paint was applied to twenty-eight concrete test panels to mimic the application of graffiti or street art. Six topcoats, Prosoco SC-1, Prosoco Gloss n’ Guard WB, Keim Faceal Oleo HD®, Keim …

Valorization Of Biopolymers And Biomass To Produce Materials For A More Circular Economy, Moira Lauer

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With a globally increasing population and largely unchecked consumption of raw materials, human society is on track for devastating consequences. Two industries responsible for utilizing massive amounts of raw materials and generating equally gargantuan quantities of waste are the packaging and infrastructure sectors. In 2017 in Europe, for example, packaging reached a record 173 kg of packaging waste per capita. One of the largest packaging consumers is the food industry, in which 40% of packaging is made of petroleum-derived single-use plastic, leading to a massive carbon imbalance. “The Built Environment,” on the other hand, is responsible for about 50% of …

Hydrothermal Synthesis Of Organically-Linked Polyoxometalates, Riyadh Alshammari

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One of the thrust areas of our research deals with exploratory synthesis of new inorganic-organic hybrid materials for energy storage. It is well-known that relevant to the research described later in this thesis, inorganic-organic hybrid solids studied thus far are largely made of coordination complexes where the organic molecules are acting like a ligand to coordinate around metal cations. In this research, we will employ polyoxometalate (POM) anions as an inorganic building block to replace otherwise oppositely charged metal cations in hopes to synthesize extended hybrid frameworks with rich redox chemistry. POM clusters are made of aggregates of transition-metal (TM) …

Synthesis And Characterization Of Extended Solids Containing Nano-Sized Transition Metal Oxide Lattices, Matthew Williams

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In this research, focus has been placed on the study of magnetic anomalies due to geometric frustration of magnetic ions. The goal of the study presented in this dissertation was to synthesize pseudo&ndashlow&ndashdimensional (PLD) compounds, those structures showing zero (dot), one (chain), and two (sheet) dimensional lattices observed in extended (3D) host frameworks with enhanced anisotropic physical properties, in an attempt to elucidate some structure&ndashproperty correlations arising from magnetic spin confinement. The scope of this research involved 1) exploratory synthesis of novel, low&ndashdimensional transition metal oxide lattices, specifically Mn and V, embedded in non&ndashmagnetic oxyanion frameworks, either Ge, P, or …

Synthesis Of Meta-Terphenyl Scaffolded Molecules For Catalysis And Sensor Applications, Brad Morgan

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The utility of the m-terphenyl has been observed in a wide variety of applications since its first discovery. The tunable conformational flexibility contributes to the unique properties and resulting applications thereof. Chapter 1 goes into detail about the concepts used throughout and defines the tools needed to understand the chemistry in the
resulting chapters.
The primary use of the m-terphenyl herein is as a canopy that shields a pocket created underneath the central ring. Functionalization within this pocket allows metal binding in defined coordination environments. with the use of donor ligands attached to the flanking rings. The applications of these …

Synthesis And Characterization Of Magnetic Solids Containing Periodic Arrays Of Transition Metal Oxide Nanostructures, Wendy Queen

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The ultimate goal of the research presented in this dissertation was to explore new systems containing low–dimensional magnetic nanostructures in hopes of finding new extended solids exhibiting novel magnetic properties due to the confined magnetic lattices. The scope of this research is threefold: 1) to explore new solids containing low–dimensional magnetic nanostructures in the A–M–X–O system, where A is an alkali or alkalinendash;earth metal cation, M is a first–row transition metal cation, and X is P, As, or V, 2) to characterize these new materials and, through chemical substitution, fine tune (and optimize) magnetic and electronic properties of solids that …

Synthesis Of Complex Fluorides For Optical Applications, Seth Stepleton

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Large single crystals of alkali metal fluorides are desirable for many reasons. Fluoride laser crystals have a wide transmission range and on account of their low phonon energies, many efficient laser emissions have been obtained from 285 nm to 4.34 µm.1,2 Inorganic fluoride single crystals feature large bandgaps, very wide optical transmittance ranges from vacuum-ultraviolet (VUV) to mid-IR wavelength regions, lower refractive indices than those of oxides, and typically lower phonon energies (which drastically reduce multiphonon relaxation rates of rare earth ions).3
The main goal of this work was to investigate the hydrothermal synthesis of alkali metal fluorides. Melt techniques …

Hydrothermal Crystal Growth Of Tetravalent And Pentavalent Metal Oxides, James Mann

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Over the past two hundred years synthetic growth of crystals has become vital to the technological advancement of our society. A variety of crystal growth techniques have been developed during this time, with each having its own nuances. These differences have enabled the growth of a wide spectrum of crystalline materials that can be used for many applications which include solid state lasers, semiconductors, and communication devices. Despite these techniques there are entire classes of materials which have thus far proved quite difficult to prepare as single crystals. In particular, crystal growth of the tetravalent and pentavalent metal oxides has …

Understanding The Antioxidant Mechanism Of Inorganic Selenium, Oxo- Sulfur, And Polyphenol Compounds, And The Biological Implications Of Functionalized Nanoparticles, Ria Ramoutar

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Inorganic selenium, oxo-sulfur, and polyphenol compounds are found in foods and dietary supplements, and are recognized for their nutritional benefits and their potential to treat or prevent diseases caused by oxidative stress. In our experiments to determine the effects of inorganic selenium compounds on iron-mediated DNA damage, Na₂SeO₃3 and SeO₂ exhibit antioxidant and pro-oxidant activities depending on concentrations of both the compound and hydrogen peroxide. Additional experiments demonstrate that iron coordination is a novel mechanism responsible for the observed activities. In similar experiments, oxo-sulfur compounds prevent Cu+/ H₂O₂-mediated DNA damage significantly …

Synthesis Of Ionic Liquid Monomers Using Fluorinated Sulfonyl Imide Anions And The 1,3-Dialkylimidazolium Cation, Thomas Hickman

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With their unique material and solvent properties, ionic liquids have seen an amazing, exponential increase in interest. After a brief introduction of select areas of interest for these compounds, this thesis mainly focuses on the development of novel polyfunctional ionic liquids and polymeric ionic liquids.
One of the preferred anions for ionic liquids is the bis((trifluoromethyl)sulfonyl) imide anion, first introduced by our group in 1982. It shows excellent thermal stability and the desired resonance delocalization of a negative charge for ionic liquids. A series of monofunctional, difunctional, and multi-functional bis(perfluoroalkylsufonyl)imides, along with 1,3-dialkylimidazolium cations were prepared by direct methylation of …

Synthesis, Structure And Magnetic Properties Of Oxy-Anion Based Magnetic Solids Containing Transition Metal Oxide Nanostructures, Kulugammana Gedera Ranmohotti

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Inline with the focus of our research, my goal for this dissertation study is to further explore new classes of magnetic insulators exhibiting novel properties. The scope of this work is twofold: 1) the exploratory synthesis of polyanion-based mixed-framework compounds containing transition metal oxide magnetic nanostructures, and 2) the investigation of the structure/property correlation with respect to the spin couplings in confined lattices. These studies are of fundamental and technological importance regarding the long-term development of low-dimensional magnetic solids for device applications in especially information storage and quantum computing. Several interesting and significant transition metal based silicate, phosphate arsenate and …

The Role Of Metal Coordnation In The Inhibition Of Iron(Ii)- And Copper(I)-Mediated Dna Damage By Organoselenium And Organosulfur Compounds, Erin Battin

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Copper and iron are two widely-studied transition metals associated with hydroxyl radical (OH) generation: Fe2+/Cu+ + H2O2 = Fe3+/Cu2+ + OH + OH-. Metal-mediated oxidative damage is a major cause of cellular DNA damage and death, and has been implicated in cancer, neurodegenerative, and cardiovascular diseases. Because sulfur and selenium antioxidants ameliorate oxidative damage, the ability of twenty biological sulfur- and selenium-containing compounds to inhibit metal-mediated DNA damage caused by hydroxyl radical has been quantified. In the Cu+/H2O2 system, six sulfur compounds and three selenium compounds inhibited DNA damage with IC50 values ranging from 3.3 to 25.5 μM. Several sulfur …

Effects Of Polyphenol Compounds On Iron-And Copper-Mediated Dna Damage: Mechanisms And Predictive Models, Nathan Perron

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Polyphenol compounds are widely recognized for their antioxidant activity; however, under some conditions these compounds can also exhibit prooxidant activity. This work examined the interactions of polyphenols with iron and copper to improve understanding of both their antioxidant and prooxidant effects. Polyphenols with catechol and gallol groups effectively inhibit iron-mediated oxidative DNA damage by chelating iron, with IC₅₀ values ranging from 1-59 µM. Gallate compounds are more potent than their catecholate analogues in every instance, and their antioxidant potencies correlate to pK_a values for the most acidic phenolic hydrogen. This correlation represents the first predictive model of …