Inorganic Chemistry Commons^™

De Novo Protein Binding To Zinc Oxide Through Biomineralization Pathways, Jean-Mark A. Francis

Theses and Dissertations

De novo proteins are structurally distinct from proteins found in nature and thus capable of having their amino acid sequence modified to accomplish tasks such as increasing protein-nanoparticle binding without unfolding or decomposing. Zinc Oxide nanoparticles are functionally distinct from their bulk counterparts and are widely used as semiconductors in a variety of fields such as medicine and agriculture. With demand for these nanoparticles increasing, environmentally sustainable methods of Zinc Oxide nanoparticle synthesis are being investigated as an eco-friendly alternative to currently utilized but environmentally hazardous chemical and physical techniques. This research investigates the binding characteristics between Zinc Oxide nanoparticles …

Elucidation Of The Optical Properties Of Si And Si-Ge Alloy Nanostructures With Visible To Near-Ir Photoluminescence, Griffin Spence

Theses and Dissertations

Silicon and silicon-germanium alloy nanostructures have garnered increasing attention in the past 25 years due to their favorable optical properties, visible to near-IR luminescence, and inherently low toxicity. While many synthetic routes have been discussed in the literature, the high-temperature, solid-state disproportionation of hydrogen silsesquioxane (HSQ) has become the most popular way to produce highly crystalline, size-tunable Si and Si-based nanostructures (NCs). It has been shown in this work that maximum annealing temperature from 450°-1100°C and the addition of GeI₂or SnCl₄ precursors can be used to achieve different morphologies, alloying efficiency, and sizes. Directly annealing HSQ from …

Synthesis And Application Of Redox-Active Covalent Organic Frameworks In Rechargeable Batteries, Mohammad K. Shehab

Theses and Dissertations

Synthesis and Application of Redox-Active Covalent Organic Frameworks in Rechargeable Batteries

Mohammad K. Shehab

Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States

Abstract

In recent years, lithium-ion batteries (LIBs) have been considered the dominant energy storage devices for portable electronics and electric vehicles due to their high energy density, low self-discharge rate, and long cycle life. In LIBs, the traditional positive electrodes employed are mainly derived from metal-containing inorganic compounds composed of cobalt, iron, nickel, or manganese (LiCoO₂, LiMn₂O₄, and LiFePO₄) coupled with graphite as the negative electrode. Despite …

Synthesis And Modeling Of Manganese Ferrite Nanoparticles For Magnetic Hyperthermia Applications, Margaret E. Thornton

Theses and Dissertations

Biologically targeted magnetic hyperthermia (MH) is a promising cancer therapeutic that is both non-invasive and has the potential to serve as a single-modality cancer treatment. MH operates through the elevation of temperatures between 40-43 °C to induce apoptosis in malignant tumor cells, while the small size of the magnetic nanoparticles preserves the healthy surrounding tissue. At present, MH is limited by low heating efficiency and heterogenous outcomes, and treatment requires direct-injection of the nanoparticles, excluding deep-tissue and metastatic tumors from the therapy. The most popular candidates for MH are the spinel ferrites iron oxide and manganese iron oxide (MFO). These …

Antiviral Effects Of Metalloshielding: Differential Antiviral Activity Of Polynuclear Platinum And Cobalt Compounds, Mary Zoepfl

Theses and Dissertations

The majority of antiviral drug development has focused on virus-specific discovery targeting discrete steps in the individual life cycles. Although great strides have been made for a number of clinically relevant diseases such as human immunodeficiency virus, influenza virus, and hepatitis B, broad spectrum antivirals do not exist. Broad spectrum antivirals would offer (1) treatment for viruses without specifically-targeted antivirals, (2) treatment for viruses which have developed resistance to their available treatments, and (3) a rapidly deployable treatment option in viral epidemics. Many viruses including human cytomegalovirus (HCMV), HIV, and SARS-CoV-2. rely on heparan sulfate (HS), a highly sulfated glycosaminoglycan …

Conformational Modulation Of Α-Helical N-Acetylated Α-Synuclein, Ricardo Fernandez

Theses and Dissertations

Human N-acetylated α-synuclein (^NAcαSyn) has long been accepted as an intrinsically disordered protein (IDP) predominantly found in terminal nerve regions in healthy subjects. ^NAcαSyn structural fluidity enables the formation of transient or dynamic assemblies. Some of these assemblies may serve functional, yet undefined purposes. ^NAcαSyn is highly susceptible to the surrounding environment, leading to misfolding under high cytosolic oxidative stress conditions, which in turn assemble in the form of toxic oligomers or amyloid fibrils. These ^NAcαSyn inclusions along with their accretion and migration within neurons, are pathological hallmarks of Parkinson’s disease (PD), dementia, and multiple …

Streptococcus Sanguinis: The Good, The Bad, And The Metal-Binding Lipoprotein, Cody Murgas

Theses and Dissertations

Streptococcus sanguinis is an opportunistic bacterium living beneficially in the human mouth. When S. sanguinis gains access to the bloodstream, it can result in colonization on damaged tissue and generate heart valve vegetations that can develop into infective endocarditis. It has been suggested that Mn and Fe are cofactors in the pathogenic capacity of this bacterium, and that these redox active metals are imported by the metal binding lipoprotein S. sanguinis adhesin B (SsaB). The SsaB lipoprotein is an integral part of SsaACB, an ATP-binding cassette (ABC) transport system in S. sanguinis. When SsaB is deleted, the resulting strain displays …

The Rational Synthesis Of Lanthanum Manganite Nanomaterials For Magnetic Refrigeration Applications, Caitlin Hunt

Theses and Dissertations

Refrigeration systems for the cooling of commercial and residential buildings are a major drain on energy resources and source of greenhouse gas emissions. Magnetic refrigeration, which employs the magnetocaloric effect, has the potential to mitigate the energy drain and greenhouse gas emissions for air conditioning. In order to commercialize magnetic refrigerators, a material with a high magnetic entropy change, ΔS, near room temperature which is simple and inexpensive to create is needed.¹ Current options for this solid refrigerant are either expensive, difficult to synthesize, or have a ΔS or T_c (the Curie Temperature, where ΔS is maximized) below …

Development Of Supported Pd-Based Catalysts For Carbon-Carbon Cross-Coupling And Oxidation Reactions, Mrinmoy Das

Theses and Dissertations

Heterogeneous catalysts are a crucial part of chemistry used for various chemical synthesis stages, pharmaceutical, and environmental applications. The use of nanoparticles or rather nanocatalysts enhances the heterogeneous catalytic applications. Both chemical and physical methods can be used to synthesize nanocatalysts. Chemical synthesis methods require comparatively fewer instruments and can easily synthesize a large amount of nanocatalysts. Nevertheless, chemical synthesis methods require reducing agents and solvents that can be toxic or harmful materials. They often need harsh reaction conditions as well, like high temperature and pressure. On the other hand, physical synthesis methods often require complex instrument setup, but their …

Discerning The Spectroscopic Properties And Chemical Reactivity Of Bioinspired Metallocomplexes, Ashley K. Forney

Theses and Dissertations

In Nature, metalloenzymes catalyze a variety of thermodynamically demanding reactions with remarkable performance under mild, physiological conditions. This innate ability is a driving force for the development of nature inspired, synthetic analogues that are robust and can catalyze a variety of organic transformations. This work involves the successful syntheses of four coordinate, bioinspired complexes, [M^II(n-DOB)] (M = Ni, Co, and Cu; n = 12 and 13), which have been characterized by NMR, ESI-MS, UV/Vis, EPR, and CV. Spectroscopic evidence presents the generation of reactive metal-(di)oxygen species that display amphoteric reaction behavior, making these rarities among inorganic oxidants. These …

Heparan Sulfate. A Ligand For Coordination Compounds., Eric Ginsburg

Theses and Dissertations

Heparan sulfate (HS), a type of glycosaminoglycan (GAG), has been identified as a ligand for interactions with polynuclear platinum complexes (PPCs). HS is involved in numerous biological processes, and often considered to be extracellular DNA. PPCs interact with HS through the formation of a “sulfate clamp”, where multiple anionic sulfate groups cluster around the cationic PPC. The masking of HS results in the inhibition of enzymatic activity, protein-HS interactions, and other biological processes. PPCs use HS proteoglycans as an method of cellular internalization. By targeting sulfated-GAGs, PPCs can offer precision medicine not currently observed with the FDA approved platinum therapies. …

Electrocatalytic Cathodes For Advanced Lithium–Sulfur Batteries, Ahmed Abdelkader

Theses and Dissertations

Energy demands are anticipated to increase in the next decades with the consumption of fossil fuels predicted to grow from the current levels. This will place an enormous burden on the non–renewable reserves of our energy sources and add to the preexisting environmental crisis with the emission of greenhouse gases like carbon dioxide (CO₂). Electrical energy storage (EES) is considered one of the most crucial needs of modern society to circumvent this crisis and potential applications include electric vehicles and devices, as well as storage systems for solar and wind sources.Lithium–ion batteries (LIBs) have proven to be …

Synthesis Of Supported Metal Nanoparticles On High Surface Area Supports For Application In Energy Conversion And Heterogeneous Catalysis, Nazgol Norouzi

Theses and Dissertations

Precise control of metal nanoparticles’ size, composition, and dispersity over high surface area supports are highly desirable to address current challenges in energy storage and conversion as well as catalytic processes involving precious metals. Therefore, developing viable synthetic routes that enable new catalytic systems derived from inexpensive transition metals or limited use of precious metals is vital for clean energy applications such as fuel cells and rechargeable batteries or affordable drugs in the pharmaceuticals arena. In addition to metal components of heterogeneous catalysts, the catalyst support is an integral part of catalyst design as it can impart both physical stability …

Structure, Morphology And Composition-Property Elucidation Of Ni–Mo And Ni−Mo−P Nanocrystals For Water Splitting Reactions And Group Iv Alloy And Silicate Nanocrystals For Visible To Near Ir Optoelectronics, Ebtesam Hassan Abuelenein Eladgham

Theses and Dissertations

Abstract

Structure, Morphology and Composition-Property Elucidation of Ni–Mo and Ni−Mo−P Nanocrystals for Water Splitting Reactions and Group IV Alloy and Silicate Nanocrystals for Visible to Near IR Optoelectronics

by

Ebtesam Hassan Abuelenein Eladgham

A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University.

Advisor: Indika U Arachchige

Associate Professor, Department of Chemistry

Nanomaterials have gained a great attention because of their unique physical properties with size intermediate between molecular materials and extended solids. They have a large surface to volume ratio and display size tunable physical properties that was not …

Investigation Into The Reaction Profile Of A Bioinspired Nickel Complex, Denver Heitger

Theses and Dissertations

Metal complexes that can activate natural oxidants like H₂O₂ and O₂ have become a key research topic in many labs in hope of mimicking nature, by generating a bioinspired complex that can perform unique chemistry through green processes. To prepare the perfect catalyst, this has lead scientists to explore numerous avenues, including the use of both natural and artificial oxidants, to tease apart the reaction pathway taking place. A ligand system dear to the Lucas Lab (13-DOB) has been metalated with nickel, a cheap and earth abundant transition metal. Our bioinspired metal-(di)oxygen adducts can be formed …

Investigations Of Graphene-Supported Single-Atom Catalyst Model Ions In The Gas Phase, Michael Borrome

Theses and Dissertations

Recent developments in heterogeneous catalysis has led to the conception of single-atom catalysts (SACs), a class of catalysts based on isolated metal atoms anchored to a support scaffold. SACs are often much more reactive and can offer better selectivity when compared to nano-scale catalysts. In order to realize the full potential of SACs, a sound understanding of the underlying catalytic mechanisms is required. However, surface analysis tools can become less effective in studying catalytic mechanisms at the atomic scale. Mass spectrometry has proven to be a robust technique for studying organometallic catalytic mechanisms at the single-molecule level. Using mass spectrometry, …

Biometal-Induced Structural Consequences Of Α-Synuclein – The Parkinson’S Disease Protein, Dinendra L. Abeyawardhane

Theses and Dissertations

The pre-synaptic protein α-Synuclein (αS) is often linked to the pathology of Parkinson’s disease (PD), an age-related neurodegenerative disorder. Lewy bodies, the cytopathological hallmarks of PD, are found to be rich in aggregates of misfolded αS protein. Metal dyshomeostasis has also been linked to PD due to the accumulation of iron in the substantia nigra pars compacta, and diminished copper levels reported in this same region. Metal dyshomeostasis in the brain coupled with oxidative stress can enhance the aggregation of αS. Recently, it was confirmed that mammalian αS is universally acetylated at the N-terminus, a common post-translational modification in …

Metallic Systems At The Nano And Micro Scale: Bimetallic Nanoparticles As Catalysts And Mcraly Bond Coats In Thermal Barrier Coatings, Kenneth Kane

Theses and Dissertations

The dissertation is split into two parts. The first part will be focused on changes in material properties found at the nanoscale, as miscibility and electronic structure can change significantly with size. The formation of classically-immiscible bimetallic nanoparticles (BNPs) becomes favorable at the nanoscale and novel catalytic properties can emerge from the bimetallic alloying. The formation of alloyed and non-alloyed BNPs is achieved through pulse laser ablation (PLA) and a significant increase in catalytic activity is observed for both. Recently discovered, the increased activity in the non-alloyed BNPs, deemed multicomponent photocatalysis, is examined and the proposed mechanism discussed. The second …

Synthesis And Characterization Of Magnetic Cabides And Oxides Nanomaterials, Hei Man Tsui

Theses and Dissertations

The design and development of nanoparticles is of great interest in the current energy and electronic industry. However, based on the current materials available the production cost can be high with insignificant magnetic and mechanical properties. Specifically, rare-earth magnetic materials composed of neodymium and samarium are known for their high magnetic performance, however, due to the cost of development there is a need to develop a versatile and cost effective material. Alternatively, cobalt carbide nanomaterials have shown to be a promising alternative for rare-earth free magnets as they exhibit comparable properties as hexaferrite magnetic materials. The primary goal of this …

Investigation Of Gold(Iii) Complexes With Hiv-Ncp7 And Models, James Beaton

Theses and Dissertations

The medicinal uses of gold date as far back as 2500 B.C. in China. In modern times, gold has been used in the treatment of a number of different human diseases including rheumatoid arthritis, cancer, and viral infections. This dissertation will focus on the development of gold complexes for the purpose of selective inhibition of HIV NCp7, a 55 amino acid zinc finger protein with two Cys₃His zinc binding domains.

NCp7 is involved in a number of viral life cycle processes including activation of reverse transcription, integration, DNA recognition, RNA packaging, and formation of the viral envelope. The …

Colloidal Synthesis And Photophysical Characterization Of Group Iv Alloy And Group Iv-V Semiconductors: Ge1-Xsnx And Sn-P Quantum Dots, Venkatesham Tallapally

Theses and Dissertations

Nanomaterials, typically less than 100 nm size in any direction have gained noteworthy interest from scientific community owing to their significantly different and often improved physical properties compared to their bulk counterparts. Semiconductor nanoparticles (NPs) are of great interest to study their tunable optical properties, primarily as a function of size and shape. Accordingly, there has been a lot of attention paid to synthesize discrete semiconducting nanoparticles, of where Group III-V and II-VI materials have been studied extensively. In contrast, Group IV and Group IV-V based nanocrystals as earth abundant and less-non-toxic semiconductors have not been studied thoroughly. From the …

Heteroatom Doped Porous Carbon For Alternative Energy Conversion And Storage Systems, Fatema A. Choudhury

Theses and Dissertations

Abstract

The electrocatalysis of oxygen plays a significant role in several electrochemical energy storage and conversion systems including metal−air batteries, fuel cells, electrocatalytic and photocatalytic water splitting. The sluggish kinetics and complex reaction mechanism of this cathodic oxygen reduction reaction (ORR) affect the performance and practical application of such renewable energy technologies. To address this limiting factor, a suitable electrocatalyst is required for ORR. In general, platinum or highly dispersed Pt-based nanoparticles on carbon black are considered as the best ORR catalyst. But platinum being very scarce and expensive tends to increase the cost. Moreover, platinum-based catalysts are prone to …

The Investigation Of Oxidative Addition Reactions Of Metal Complexes In Cross-Coupling Catalytic Cycles Based On A Unique Methodology Of Coupled Ion/Ion-Ion/Molecule Reactions, Mariah L. Parker

Theses and Dissertations

Popular catalytic cycles, such as the Heck, Suzuki, and Negishi, utilize metal centers that oscillate between two oxidation states (II/0) during the three main steps of catalysis: reductive elimination, oxidative addition, and transmetallation. There has been a push to use less toxic, cheaper metal centers in catalytic cycles, leading to interest in first-row transition metals, such as nickel and cobalt. With these metals, the cycles can potentially pass through the +1 oxidation state, which acts as reactive intermediates, undergoing oxidative additions to form products, potentially with radical characteristics. The oxidative addition steps of catalytic cycles are critical to determining overall …

Development Of Photocatalysts Supported On Graphitic Carbon Nitride For The Degradation Of Organic Water Pollutants, Atanu Giri

Theses and Dissertations

Graphitic carbon nitride (g-C₃N₄) heterojunction composites with the semiconducting metal oxides, CeO₂, ZnO and TiO₂ are prepared in situ by co-calcination of the precursor materials or by a solvothermal method. The structural, morphological and the optical properties of the prepared materials are studied using various microscopy and spectroscopy techniques. The synthesized composite materials, CeO₂/g-C₃N₄, ZnO/g-C₃N₄ and TiO₂/g-C₃N₄ are more efficient in the photocatalytic degradation of the water pollutants indigo carmine (IC) and atrazine than the pure metal oxide, g-C …

Efficient Integration Of Plasmonic And Excitonic Properties Of Metal And Semiconductor Nanostructures Via Sol-Gel Assembly, Dilhara Liyanage

Theses and Dissertations

Research in nanoscience has gained noteworthy interest over the past three decades. As novel chemical and physical properties that are vastly different from extended solids are realized in nanosized materials, nanotechnology has become the center of attention for material in research community. Much to our amazement, investigations in the past two decades revealed that the nanocrystalline semiconductors are “THE PRIME CANDIDATES” to meet the growing energy demand, sensor development, cellular imaging and a number of other optoelectronic applications. Nonetheless, synthesis of nanostructures with control over physical parameters is not sufficient, yet assembling them into functional nanoarchitectures with unique and tunable …

Synthesis And Characterization Of Metallic Nanoparticles For Catalytic Applications, Sarah Smith

Theses and Dissertations

In recent years, research has focused on reducing the cost of catalysts in a variety of ways including using less expensive materials, improving the synthetic method, and increasing the catalytic activity, recovery, and recyclability. Typically with nanoparticles, the size, shape, composition, and surface coating have an effect on catalytic activity.^1-2 In this work, we focused on reducing the cost of precious metal based catalysts by altering the synthetic methods.

One way to lower the cost of synthesizing precious metal nanoparticles is by debasing the precious metal with a second cheaper more abundant metal. CuPd nanoparticles were synthesized in oleylamine …

Sol-Gel Chemistry: An Advanced Technique To Produce Macroscopic Nanostructures Of Metal And Semiconductor Colloids, Lamia Nahar

Theses and Dissertations

The fascinating physical properties that arise in materials limited to dimensions of 1-100 nm have gained noteworthy interest from the scientific community. Accordingly, there has been a lot of attention paid to the synthesis of discrete nanoparticles (NPs) and they are being investigated for a range of advanced technologies. Nonetheless, efficient use of nanomaterials in device applications require them to be assembled into solid state macro-structures while retaining their unique, nanoparticulate properties. To date, most commonly investigated assembling techniques include: covalent coupling of NPs surface groups, control evaporation of the solvent to produce ordered supercrystals or non-ordered glassy films, and …

The Dawn Of New Quantum Dots: Synthesis And Characterization Of Ge1-Xsnx Nanocrystals For Tunable Bandgaps., Richard J. Esteves

Theses and Dissertations

Ge_1-xSn_x alloys are among a small class of benign semiconductors with composition tunable bandgaps in the near-infrared spectrum. As the amount of Sn is increased the band energy decreases and a transition from indirect to direct band structure occurs. Hence, they are prime candidates for fabrication of Si-compatible electronic and photonic devices, field effect transistors, and novel charge storage device applications. Success has been achieved with the growth of Ge_1-xSn_x thin film alloys with Sn compositions up to 34%. However, the synthesis of nanocrystalline alloys has proven difficult due to larger discrepancies (~14%) in …

Electronic Structure And Stability Of Ligated Superatoms And Bimetallic Clusters, William H. Blades

Theses and Dissertations

Quantum confinement in small metal clusters leads to a bunching of states into electronic shells reminiscent of shells in atoms. The addition of ligands can tune the valence electron count and electron distribution in metal clusters. A combined experimental and theoretical study of the reactivity of methanol with Al_nI_m⁻ clusters reveals that ligands can enhance the stability of clusters. In some cases the electronegative ligand may perturb the charge density of the metallic core generating active sites that can lead to the etching of the cluster. Also, an investigation is conducted to understand how the bonding …

Non-Conventional Approaches To Syntheses Of Ferromagnetic Nanomaterials, Dustin M. Clifford

Theses and Dissertations

The work of this dissertation is centered on two non-conventional synthetic approaches to ferromagnetic nanomaterials: high-throughput experimentation (HTE) (polyol process) and continuous flow (CF) synthesis (aqueous reduction and the polyol process). HTE was performed to investigate phase control between Fe_xCo_1-x and Co_3-xFe_xO_y. Exploration of synthesis limitations based on magnetic properties was achieved by reproducing M_s=210 emu/g. Morphological control of Fe_xCo_1-x alloy was achieved by formation of linear chains using an H_ext. The final study of the Fe_xCo_1-x chains used DoE to …