Inorganic Chemistry Commons^™

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 …

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, …

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 …

Syntheses, Characterization, And Preliminary Evaluation Of Potential Ruthenium Anticancer Complexes Containing Schiff Base Ligands, Stephen Mensah

Theses and Dissertations

Platinum-based drugs have over the years been administered in the treatment of tumours.

Unfortunately, platinum resistance and the severe side effects associated with the treatments has necessitated the research for new anti-cancer drugs. Ruthenium(II) and Ruthenium(III) complexes have shown promise as useful alternative anticancer agents. The lead candidates include the Ru(II) complex RAPTA-C, a ruthenium(II)-arene complex [Ru(η6-p-cymene)Cl2(1,3,5-triaza-7-phosphaadamantane)] and the Ru(III) complex NAMI-A [imidazoleH][trans-Ru(imidazole) (dimethyl sulfoxide)Cl4]. Both compounds have shown potent cytotoxic activity in several primary human tumor models. Unfortunately, NAMI-A could not advance in clinical evaluations due to limited efficacy in vivo, while the clinical evaluation of RAPTA-C is unknown. …

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 …

Oxidation Of Carbon Monoxide Over Ceria And Alumina Supported Palladium Catalysts, John Davis Gary

Theses and Dissertations

Palladium catalysts on both Al2O3 and CeO2, supports were studied for efficacy in low temperature carbon monoxide oxidation. Calcination temperatures were varied between 500-900°C for alumina supported catalysts and shown to have no significant difference in activity. X-Ray Photoelectron Spectroscopy studies revealed structural changes associated with palladium states and reacted catalysts and displayed a change from palladium oxide (PdO) to native palladium oxide (PdOx) and elemental palladium (Pd). Activity studies were conducted on all catalysts synthesized and indicated that Pd/Al2O3 achieved 100% CO conversion at 150°C when calcined at 500°C and pretreated with reduction process. Pd/CeO2 showed higher activity and …

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 …

Catalytic Oxidation Of Methane Over Alumina Supported Palladium Oxides, Jacqueline Michelle Mcguire

Theses and Dissertations

The objectives of this research include development and characterization of alumina supported palladium oxide catalysts for low temperature catalytic oxidation of methane. The catalysts were prepared by various methods and then characterized and screened to select the best catalyst for further studies. A 5% (wt/wt) Pd/y-AhCb catalyst prepared by an improved vortex-assisted incipient wetness method showed the best activity of 94% (mol/mol) methane conversion at 325 °C. The active surface species was found to be PdO and Pd native oxides (PdNtv) as confirmed by X-ray Photoelectron Spectroscopy and activity studies. The y-AhCb support played an integral role in the formation …

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 …

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 …

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 …

Iron Uptake And Accumulation Is A Target Of Nickel Toxicity During The Lag Phase In Escherichia Coli, Geoffrey Tuttle Ford

Theses and Dissertations

Various transition metals are essential to all forms of life, and are only required in trace amounts. But this dependence comes as a double-edged sword. All organisms must maintain a careful intracellular quota that does not traverse outside an acceptable range. One transition metal in particular is nickel. The importance of this transition metal has been debated widely and its function varies greatly between organisms, including bacteria. However, the adverse effects caused by over exposure to this metal have been the center of much experimentation in recent years. Still, the mechanisms of nickel toxicity and the subsequent effects on cellular …

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 …

Fabrication Of Multifunctional Nanostructured Porous Materials, Ahmed A. Farghaly

Theses and Dissertations

Nanostructured porous materials generally, and nanoporous noble metals specifically, have received considerable attention due to their superior chemical and physical properties over nanoparticles and bulk counterparts. This dissertation work aims to develop well-established strategies for the preparation of multifunctional nanostructured porous materials based on the combination of inorganic-chemistry, organic-chemistry and electrochemistry. The preparation strategies involved one or more of the following processes: sol-gel synthesis, co-electrodeposition, metal ions reduction, electropolymerization and dealloying or chemical etching. The study did not stop at the preparation limits but extended to investigate the reaction mechanism behind the formation of these multifunctional nanoporous structures in order …

Sol-Gel Assembly Of Metal Nanostructures Into Metallic Gel Frameworks And Their Applications, Xiaonan Gao

Theses and Dissertations

The advent of nanoscience and nanotechnology has sparked many research forefronts in the creation of materials with control over size, shape, composition, and surface properties.^1,2 However, for most of the applications, nanoscale materials need to be assembled into functional nanostructures that exhibit useful and controllable physical properties. Therefore, numerous efforts on the assembly of nanoparticles (NPs) using organic ligands, polymers and polyelectrolytes have been reported.^3,4 However, the interactions between NPs are mediated by intervening ligands, which are detrimental to charge transport and limit the thermal stability. Hence, developing a new method to produce solid …

Development Of Non-Traditional Platinum Anticancer Agents: Trans-Platinum Planar Amine Compounds And Polynuclear Platinum Compounds, Daniel E. Lee

Theses and Dissertations

Development of Non-Traditional Platinum Anticancer Agents: trans-Platinum Planar Amine Compounds and Polynuclear Platinum Compounds

By Daniel E. Lee, Ph.D.

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

Virginia Commonwealth University, 2015

Major Director: Nicholas P Farrell, Ph.D., Professor, Department of Chemistry

Platinum anticancer compounds with cis geometry, similar to cisplatin, have been explored to circumvent the cisplatin resistance; however, they were not considered broadly active in cisplatin cells due to exhibiting similar or same cell death mechanism as cisplatin. Platinum compounds with trans geometry were less studied …

Synthesis, Surface Functionalization, And Biological Testing Of Iron Oxide Nanoparticles For Development As A Cancer Therapeutic, Stanley E. Gilliland Iii

Theses and Dissertations

Iron oxide nanoparticles are highly researched for their use in biomedical applications such as drug delivery, diagnosis, and therapy. The inherent biodegradable and biocompatible nanoparticle properties make them highly advantageous in nanomedicine. The magnetic properties of iron oxide nanoparticles make them promising candidates for magnetic fluid hyperthermia applications. Designing an efficient iron oxide nanoparticle for hyperthermia requires synthetic, surface functionalization, stability, and biological investigations. This research focused on the following three areas: optimizing synthesis conditions for maximum radiofrequency induced magnetic hyperthermia, designing a simple and modifiable surface functionalization method for specific or broad biological stability, and in vitro and in …

Colloidal Synthesis And Optical Characterizations Of Semiconductor Nanocrystals From Nontoxic Elements, Minh Q. Ho

Theses and Dissertations

To date, the search efforts have shifted from the toxic II-VI, III-V and IV-VI semiconductors to more environmentally friendly materials. Among Group II-V semiconductors, Zn₃P₂ has shown to be a more benign option, similar to Group IV (Ge, Si) materials, for future applications in photovoltaics and optoelectronics. This work is dedicated to the development of wet-chemical synthetic routes of (1) Zn₃P₂ and (2) Group IV (Ge, Si, Si_1-xGe_x) nanocrystals with precise control over composition, crystal structure, size and dispersity by adjusting different reaction parameters such as temperature, time and solvent …