Chemistry Commons^™

Boron-Doped Diamond As A Resilient Electrode Material In Molten Salts, Hannah Katherine Patenaude

UNLV Theses, Dissertations, Professional Papers, and Capstones

Molten salt chemistry has a range of applications within nuclear technology, including for the Molten Salt Reactors (MSRs) and pyroprocessing to recover valuable actinides for energy and national security needs. However, the high-temperature, corrosive nature of molten salts makes them particularly challenging to deploy on an industrial scale and study in benchtop measurements. Material accountability and corrosion monitoring of MSR fuels are essential components to the successful deployment of MSRs, and electroanalytical techniques like cyclic voltammetry (CV) and spectroelectrochemistry (SEC) can provide a wealth of information to describe salt systems in situ. To perform such measurements, it is imperative to …

Bridging The Gap Between Molecular Components And Functional Electronic Chemical Sensing Devices With 2d Layered, Conductive Metal–Organic Frameworks, Emma Katherine Ambrogi

Dartmouth College Ph.D Dissertations

Layered, conductive framework materials are a class of materials with properties that make them ideal sensing materials in electronic chemical sensors. My thesis is focused on the development of these materials for electrochemical sensing of liquid phase analytes, and on understanding the material–analyte and material–electrode interfaces, and their self-assembly and deposition onto surfaces.

Chapter 1 provides a summary of the use of layered conductive metal–organic frameworks (MOFs) and covalent organic frameworks (COFs) in electronic chemical sensors, detailing the materials and sensor architectures employed, and the analytes detected. Relevant performance metrics are compared, and investigations into material–analyte interactions are highlighted.

Chapter …

An Examination Of The Teaching And Learning Of Resonance In General Chemistry I And Organic Chemistry I Using Variation Theory, Sabrina Barakat

UNLV Theses, Dissertations, Professional Papers, and Capstones

Resonance is a fundamental chemistry concept first introduced to students in General Chemistry I, reintroduced in Organic Chemistry I, and then utilized throughout other higher-level chemistry courses. A molecule or ion can be said to exhibit resonance when it can be represented by two or more chemical structures (i.e., Lewis structures) that differ only in their arrangement of electrons. In other words, resonance represents the electronic structure of a molecule or ion when a single Lewis structure does not adequately depict the true distribution of electrons. The molecule or ion is best represented as a combination of all of the …

Performance Effects Of Dissociated Hydrogen In Nuclear Thermal Propulsion Engines, Richard Adam Gorrell

UNLV Theses, Dissertations, Professional Papers, and Capstones

Nuclear thermal propulsion (NTP) research considers hydrogen dissociation as negligible to design and analysis of propulsion engines. This study reintroduces chemically reacting flow to NTP engine analysis for investigation of the dissociation effect on engine performance. A first-principles approach observes the basic chemical mechanism and reaction within the high-speed, high-temperature NTP flow to baseline expected atomic hydrogen levels and validate equilibrium. A surface reaction study looks into hydrogen absorption through dissociation and its effect on the boundary layer, and bulk flow. For total performance, the resulting dissociated flow is analyzed through nozzle expansion and performance metrics calculated.

All historic reactor …

Ligand-Stabilized Sno2 As A High-Performance And Scalable Electron Transport Material For Inverted Perovskite Solar Cells., Sashil Chapagain

Electronic Theses and Dissertations

Over the past decade, perovskite solar cell (PSC) technology has attracted significant attention for its low material costs, simple fabrication processes, and impressive photovoltaic performance, with recent power conversion efficiencies (PCEs) surpassing 26%. This advancement marks PSCs as strong competitors to traditional silicon-based photovoltaics. Despite the high efficiency of PSCs, the path to commercialization is hindered by challenges in stability, scalability, and module efficiency. The stability and scalability of PSCs are primarily dependent on the successive charge transfer layers (CTLs) that are interfaced with the perovskite layer. Among CTLs, metal oxide (MO_x) CTLs are preferred for their cost-effectiveness, …

Development Of A High-Resolution Mid-Infrared Spectroscopy Apparatus For The Study Of Methane And Other Astrochemical Molecules., S M Shah Riyadh

Electronic Theses and Dissertations

This research documents steps towards building a novel spectroscopic technique, namely, cavity-enhanced double-resonance (CEDR) spectroscopy, for investigating methane (CH₄) and other molecules with significance in astrochemistry. These efforts focus on tackling the complexities of their ro-vibrational energy levels and the inefficiencies in analyzing vibrational spectra, particularly for molecules with high symmetry and strong intramolecular interactions. In the CEDR spectroscopy, the first photon, generated by a continuous-wave optical parametric oscillator (CW-OPO) locked to a Doppler-free saturation absorption line, excites the molecule from its ground level to a selected excited ro-vibrational (rotational-vibrational) level, e.g., that of the asymmetric CH-stretch mode. …

Utilizing Metal Ligand Cooperativity To Activate Small Molecules., Christine Burgan

Electronic Theses and Dissertations

The problems created from the excessive use of fossil fuels can be approached from two directions: capture the CO₂ from the atmosphere or develop alternative energy sources. The current industrial standards for these are environmental and/or health hazards and utilize precious metals, respectively. Metal ligand cooperativity (MLC) has emerged as a promising alternative to using precious metals to activate small molecules. In this dissertation, we focus on a series of metal complexes based on the ligand diacetyl-2-(4-methyl-thiosemicarbazone)-3-(2-hydrazinopyridine) (H₂L¹) for either hydrogen evolution or CO₂ capture. The novel complexes were characterized by ¹H NMR, …

Electrochemical Modulation Of Surface Plasmon Wave To Investigate Dna-Based Sensing Platforms And Detection Of Sars-Cov2., Anil Sharma

Electronic Theses and Dissertations

This study offers a thorough comparative analysis of optical and electrical signaling strategies for assessing the electrochemical properties of different redox-labeled DNA-based biosensing platforms. In addition, it illustrates the development of an optical interrogation technique with electrochemical modulation of surface plasmon waves (ECM-SPW) as a route for analyzing and implementing DNA-based hybridization sensors. For those quantitative analyses, we chose a model sensing platform composed of a methylene blue (MB)-modified single-stranded DNA (ssDNA) signaling probe and an unlabeled capture ssDNA probe that complements the signaling probe. Two types of signaling probes were employed in this work: one with MB attached to …

Revealing The Three-Dimensional Arrangement Of Polar Topology In Nanoparticles, Chaewa Jeong, Juhyeok Lee, Hyesung Jo, Jaewhan Oh, Hionsuck Baik, Kyoung-June Go, Junwoo Son, Si-Young Choi, Sergey Prosandeev, Laurent Bellaiche, Yongsoo Yang

Physics Faculty Publications and Presentations

In the early 2000s, low dimensional ferroelectric systems were predicted to have topologically nontrivial polar structures, such as vortices or skyrmions, depending on mechanical or electrical boundary conditions. A few variants of these structures have been experimentally observed in thin film model systems, where they are engineered by balancing electrostatic charge and elastic distortion energies. However, the measurement and classification of topological textures for general ferroelectric nanostructures have remained elusive, as it requires mapping the local polarization at the atomic scale in three dimensions. Here we unveil topological polar structures in ferroelectric BaTiO₃ nanoparticles via atomic electron tomography, which …

Development Of Chiral Lewis Base Catalysts For Chlorosilane-Mediated Asymmetric C-C Bond Formations, Changgong Xu

Theses and Dissertations

The chiral hydrazine is a crucial structural motif that serves as pivotal structural elements in numerous natural products and biologically significant molecules. We are particularly interested in the catalytic asymmetric reduction of hydrazones, as well as the catalytic asymmetric propargylation and allenylation of hydrazones, because they provide direct pathways to these enantio-enriched chiral building blocks. In this work, we will explore the potential of two different categories of chiral Lewis base catalysts in the said transformations.

Developed by another student in our group, axial-chiral 3,3’-triazolyl biisoquinoline N,N’-dioxides derived catalysts are tested and demonstrated its capability in activating various hydrazone …

Characterizing The Role Of Chemo-Mechanical Couplings In The Activation Process Of Proteins That Undergo Conformational Changes, Ugochi Isu

Graduate Theses and Dissertations

Proteins are not static entities; rather, they are dynamic macromolecules that undergo conformational changes to perform their biological functions. These structural transitions are often coupled to chemical events such as lipid interactions, or changes in the cellular environment. Understanding the intricate interplay between chemical perturbations and the resulting mechanical response is crucial for elucidating the activation mechanisms of proteins. This dissertation aims to characterize the role of chemo-mechanical couplings in the activation process of two G protein-coupled receptors (GPCRs): Cannabinoid Receptor 1 (CB1) and Metabotropic Glutamate Receptor 1 (mGluR1). We employ molecular dynamics simulations to investigate the conformational landscapes of …

Two Studies: Aromatization-Driven Ring Opening Functionalization Of Unstrained Cycloalkanones Through Visible Light Catalysis, And Synthesis Of Amino Endoperoxides Using Self-Doped Titanium Dioxide (Ti3+@Tio2) As A Photocatalyst, Enoch Kudoahor

Graduate Theses and Dissertations

The pharmaceutical industry has been focused on discovering new innovative drugs over the last decade, but the syntheses are either inefficient or the approach to environmental sustainability raises significant concerns. Photochemistry and photocatalysis have found widespread applications in organic synthesis as a result of this pressing issue. Our role as organic chemists is to improve environmental quality by creating a "greener" world through the development of efficient synthetic methods and strategies. Solar energy is now one of the most abundant and renewable natural resources. The emergence of environmental sustainability concerns has led to the development of new techniques for harnessing …

Student Self-Efficacy And Attitude In Organic Chemistry: A Comparison Of Two Pedagogical Approaches, Matthew Autry

Arts & Sciences Graduate Student Theses and Dissertations

No abstract provided.

Learning, Optimizing, And Simulating Fermions With Quantum Computers, Andrew Zhao

Physics & Astronomy ETDs

Fermions are fundamental particles which obey seemingly bizarre quantum-mechanical principles, yet constitute all the ordinary matter that we inhabit. As such, their study is heavily motivated from both fundamental and practical incentives. In this dissertation, we will explore how the tools of quantum information and computation can assist us on both of these fronts. We primarily do so through the task of partial state learning: tomographic protocols for acquiring a reduced, but sufficient, classical description of a quantum system. Developing fast methods for partial tomography addresses a critical bottleneck in quantum simulation algorithms, which is a particularly pressing issue for …

Biotinylated Protein Capture And Tween-20 Assisted Exosome Isolations Via Capillary Chanelled Polymer Fiber, Md Khalid Bin Islam

All Theses

In the past two decades, Marcus and colleagues have led the advancement of capillary-channeled polymer (C-CP) fiber stationary phases for biomacromolecule separations, including proteins and nanovesicles. These stationary phases offer notable advantages, including low cost ($5/column), straightforward column fabrication, and the capacity for on-column surface modification, enabling high chemical selectivity. This study examines a C-CP fiber modification strategy for capturing target proteins and develops a Tween-20-assisted C-CP-based hydrophobic interaction chromatography (HIC) method for the isolation and quantification of exosomes from human urine.

The quest for higher-throughput and cost-effective protein isolation techniques remains a key focus in a variety of end …

Modelling Terrestrial And Potential Extraterrestrial Photopigments Via Density Functional Theory, Dorothea Illner

Theses and Dissertations

In the search for extraterrestrial life, biosignatures play a crucial role in identifying its putative traces. A commonly known and robust biosignature is the Vegetation Red Edge (VRE), which can be described as a sharp increase of reflectance observed from a planet and stems from the light absorption of photopigments in specific regions in the electromagnetic spectrum. For Earth, this VRE is known to occur around 700 nm, however, if the photopigments absorb light in different regions and have different structures the VRE could experience a wavelenght shift.

In this work, Chlorophyll a and a potential photopigment precursor called Phot0 …

Earth Abundant Catalyst For Evironmental Sustainability Applications, Javier Hernandez

Open Access Theses & Dissertations

The development of experimental methodologies for synthesizing a diverse range of metallic and metal oxide nanoparticles tailored for sustainable water treatment applications was investigated. These nanoparticles are prepared using environmentally friendly and scalable synthesis methods, underscoring their potential for large-scale production. Synthesized nanoparticles are harnessed for various processes, including catalysis and electrocatalysis, with a primary objective of degrading and removing organic pollutants from water. Key to this research is the encapsulation of nanoparticles within solid supports. Multiple methodologies are explored to engineer supports that ensure nanoparticle stabilization, monodispersion, and prevent unintended release into the environment. Two alternative approaches were evaluated …

Computational Study Of Fluorescent Molecular Probes For The Early Detection Of Alzheimer's Disease, Gabriela Elizabeth Molina Aguirre

Open Access Theses & Dissertations

Alzheimer's disease is a debilitating brain disorder that affects memory, thinking, and behavior. It is the most prevalent form of dementia and the seventh leading cause of death in the United States. As, researchers have identified biomarkers that can indicate the presence of the disease many years before the first symptoms appear, so there is an opportunity for early detection and treatment follow-ups, which could significantly improve the quality of life for those affected by this disease.This dissertation investigates the relationship between molecular structure and optical properties of donor-bridge-acceptor (DBA) fluorescent molecular probes designed for detecting Amyloid-β and p-Tau protein …

Combining Green Analytical Methods And Machine Learning To Develop Urinary Fatty Acid Models For Cancer Detection, Elizabeth Noriega Landa

Open Access Theses & Dissertations

This study aimed to explore fatty acids (FAs) as non-invasive biomarkers for prostate cancer (PCa) detection and prognosis, and their potential applications in other cancers. The objectives of this study were: 1) Develop a non-invasive urinary FAs-based model for diagnosing PCa; 2) Develop a FAs-based liquid biopsy model for non-invasive monitoring of PCa progression; 3) Investigate FAs composition in periprostatic adipose tissue (PPAT) collected from PCa positive patients; 4) Investigate the potential of urinary FAs biomarkers for diagnosing clear cell renal cell carcinoma (ccRCC) and ovarian cancer (OC).For the PCa diagnostic model, urine samples from 334 biopsy-confirmed PCa-positive and 232 …

Produced Water: Characterization And Treatment, Ramon Antonio Sanchez Rosario

Open Access Theses & Dissertations

In recent years, environmental concerns have urged companies in the energy sector to modify their industrial activities to facilitate greater environmental stewardship. For example, the practice of unconventional oil and gas extraction has drawn the ire of regulators and various environmental groups due to its reliance on millions of barrels of fresh water for hydraulic fracturing well stimulation, which is generally withdrawn from natural sources and public water supplies. Additionally, this process generates two substantial waste streams, which are collectively characterized as flowback and produced water. Whereas flowback water is comprised of various chemical additives that are used during hydraulic …

Synthesis Of Neoglycoproteins As Potential Biomarkers For Chagas Disease And Cutaneous Leishmaniasis Caused By Leishmania (Viannia) Braziliensis, Eileni Rodriguez Gil

Open Access Theses & Dissertations

Protozoan parasites are responsible for causing numerous diseases in humans and mammals worldwide. Among them are Chagas disease (CD), caused by the parasite Trypanosoma cruzi (T. cruzi), and tegumentary leishmaniasis (TL), caused by the parasite Leishmania (Viannia). Both diseases coexist in many regions of Latin America, and current hurdles to differentially diagnose them and determine chemotherapy success need to be overcome. CD can be diagnosed by traditional serological tests and polymerase chain reaction (PCR), but disadvantages of these methods are that they may produce false negatives because the antigens used in commercial CD kits are not conserved across all T.cruzi …

Computational Investigation Of Transition Metal Photoredox Catalysis: Redox Property Tuning Via Ligand Modification, Christian Fernando Sandoval Pauker

Open Access Theses & Dissertations

In the last decade, photoredox catalysis has become a powerful tool in synthetic chemistry. It relies on the ability of catalytic systems that facilitate energy-demanding redox reactions thanks to photoinduced electron transfer processes. This dissertation focuses on the computational investigation of the redox properties of transition metal photoredox catalysts using density functional theory (DFT) calculations. The research systematically explores the effects of altering redox-active ligands on the thermodynamics of electron transfer events in the photoredox cycle. The electronic structure changes throughout oxidative and reductive quenching cycles are analyzed, with a particular focus on Cu(I) complexes. Through computational techniques, insights into …

Studies Of Novel And Well-Defined Dinickel Architectures Utilizing An N-Atom Bridge, David Anthony De Los Santos

Theses and Dissertations

There has been a growing interest in organometallic chemistry to utilize late Earth-abundant metals towards challenging molecular functionalization of abundant feedstocks to value-added products. There is precedent of utilizing cooperativity to try and address some of the shortcomings of traditional mononuclear complexes by integrating metal-metal and or metal-ligand cooperativity to facilitate multi-electron transformations. The utility of a redox-noninnocent scaffold allows for the metal centers to be stable over a range of oxidation states, using the ligand to store electrons. Despite recent progress, complexes harnessing cooperative states towards challenging transformations is still an emerging field. Our group has synthesized a multinucleating …

Synthesis And Characterization Of Indole-Based Zinc Dipyrrin Photosensitizers, Jean-Pierre Sanza

Electronic Theses and Dissertations

Metal complexes of dipyrromethene (dipyrrins) used as sensitizers in photocatalysis offer a way to harness solar energy in chemical bonds to create new fuels. This offers the dual role of reducing fossil fuel dependence and atmospheric CO₂ levels. Traditionally, metal dipyrrin complexes are synthesized using substituted pyrroles, aldehydes, and transition metals. Indoles have a more expanded pi-electron system and their dipyrrin-type complex may exhibit visible light absorption, suggesting that they can act as photosensitizers for CO₂ reduction processes. A novel indoledipyrromethene was synthesized using unsubstituted indole and mesitaldehyde. The complex exhibits visible light absorption at 422 nm. Its …

Electrochemiluminescence Using Pencil Graphite Electrodes And Screen-Printed Carbon Electrodes Interfaced With A Simple Imaging System, Sandra Ehigiator

Electronic Theses and Dissertations

Electrochemiluminescence (ECL) is a phenomenon whereby electrochemical reactions generate a product that is capable of emitting light. ECL’s high sensitivity, selectivity, extremely low background, and relatively simple instrumentation make it particularly well-suited for chemical sensing and biosensing strategies. Here we report a simple ECL imaging system based on a camera interfaced with a zoom lens to compare pencil graphite electrode (PGE) and screen-printed carbon electrode (SPCE) arrays as ECL platforms. With this system, ECL signals generated from tris(2,2′- bipyridine)ruthenium(II) chloride hexahydrate ([Ru(bpy)3]2+) using co-reactant tri-n-propylamine (TPA) were linear with respect to [Ru(bpy)3]2+ concentrations from 9 to 450 μM. Detection limits …

Magnetic Properties Of Zgnrs With Nitrogen And Fluorine Adsorbates, A Computational Study, Justin Petit

Electronic Theses and Dissertations

Imposing dimensional restrictions on graphene sheets and adding impurities can give rise to carbon nanostructures with magnetic properties. In this work, zigzag graphene nanoribbons, zGNRs, with nitrogen and fluorine adatoms are investigated for magnetic properties of interest for spin devices. Geometry optimizations were done determining which position along a zGNR electrode that N and F would favorably attach to. Edge positions were determined as the most stable attachment site. M-cell zGNR electrodes (M = 1-3) edge-functionalized by N and F adatoms were investigated with respect to their band structures and spin densities in antiferromagnetic and ferromagnetic, AFM and FM, configurations. …

Electrocatalytic Degradation Of Bisphenol A Using Nickel Sulfide Supported On Graphene Oxide And Cobalt Sulfide Supported On Graphene Oxide Composite Materials, Katherine Ellynn Wright

Theses and Dissertations

The degradation of bisphenol A (BPA) by nickel sulfide supported on graphene oxide (NiS/GO) and cobalt sulfide supported on graphene oxide (CoS/GO) composite materials was investigated. The catalysts were studied to determine the optimal conditions for BPA degradation using electrocatalysis. Electrocatalytic trials were performed using varying parameters, which included electrolyte concentrations of 1.0 g/L, 2.0 g/L, and 4.0 g/L Na2SO4, pHs of 2, 4, and 6, and constant currents of either 0.100 A or 0.200 A. During the reaction samples were taken before the current was applied and 30 minutes and 60 minute intervals to observe the degradation of …

Synthesis Of Thermoresponsive Poly(N-Isopropyl Acrylamide) Based Core-Shell And Hollow Shell Nanogel With Tunable Core And Shell Thickness, Mohamad Hijazi, Molla R. Islam

Student Scholar Symposium Abstracts and Posters

Nanogels have emerged as a notably safer and more effective means for drug delivery, primarily due to their adjustable drug-loading capabilities. Hollow-core nanoparticles offer some unique properties that are desirable for drug delivery applications. Initially, silica core nanoparticles were synthesized using the Stöber process at different temperatures where Tetraethoxysilane (TEOS) undergoes hydrolysis in the presence of ethanol and then a condensation reaction to form silica nanoparticles. Scanning Electron Microscopy (SEM) and Optical Microscopy (OM) analysis revealed that the size of silica core particles varied with the synthesis temperature (300 nm at 30°C to 150 at 60°C). The core silica particles …

A Comparative Analysis Of Field Electron Emission From Carbon Black Embedded Within Insulated Copper Hollowed Wires And Glass Tubes, Hatem A. Al-Braikat, Ahmad M D Jaber, Adel M. Abuamr, Mazen A. Madanat, Aseel A. Al-Jbarart, M-Ali H. Al-Akhras, Marwan S. Mousa

Karbala International Journal of Modern Science

In this study, two different methods are used to investigate carbon black as a cold field electron emitter. The first method is to incorporate carbon black into a specially designed insulated copper hollowed wire. The wire has a cup-shaped structure created by electrochemical etching. The second method involves the incorporation of carbon black into narrow glass tubes. A Comparative analyses is carried out to evaluate the effectiveness of each method. To evaluate the performance of the samples, the current-voltage characteristics will be examined using field electron microscopes. This analysis will provide an understanding of the emission of the carbon black …

Reply To: On The Statistical Foundation Of A Recent Single Molecule Fret Benchmark, Dorothy A. Erie, Lydia Kisley, Dushani Dunukara

Faculty Scholarship

In their ‘Matters Arising’ manuscript, Saurabh et al. discuss two issues related to single-molecule Förster resonance energy transfer (smFRET) experiments: the use of the Gaussian noise approximation and spectral crosstalk. Their arguments are based on simulations obtained with parameters that differ significantly from the typical conditions measured experimentally, and, thus, from the regime included in the original study (Götz et al.1). In addition, they make claims about our multi-lab blind study that we would like to rectify. In Table 1, we provide a list of specific statements made by Saurabh et al. with our respective explanations.