Chemistry Commons^™

An In-Situ Study Of The Aqueous Speciation Of Uranium (Vi) Under Hydrothermal Conditions, Diwash Dhakal

Graduate Theses/Dissertations

Rigorous study of the speciation distribution of uranyl-chloride bearing solutions under hydrothermal conditions is important to understand the transport mechanism of uranium underground, which is of uttermost interest to parties studying the geological uranium deposits and those studying the possibilities of geological repositories for spent nuclear waste. I report an in-situ Raman spectroscopic study of the speciation distribution of aqueous uranyl-chloride complexes upto 500°C conducted using a HDAC as the high PT spectroscopic cell. The samples studied contained the species UO₂²⁺, UO₂Cl⁺, UO₂Cl₂⁰ and UO₂Cl₃^{- …}

Synthesis, Characterization And Crystal Growth Of I2-Ii-Iv-Vi4 And I4-Ii-Iv2-Vi7 Diamond-Like Semiconductors With Potential In Ir-Nlo Applications, Jennifer Glenn

Electronic Theses and Dissertations

In this dissertation, several new and existing diamond-like semiconductors (DLSs) were synthesized and investigated for their potential in infrared nonlinear optical (IR-NLO) applications. In Chapter 2 growth of large single crystals of Li₂MnGeS₄ was carried out using iodine vapor transport and a newly created graphite-tube containment system. This crystallization method produced sizable single crystals on the scale of 2x1x1 mm³, that were used to determine the material’s magnetic properties. Magnetization data indicate that the compound is antiferromagnetic with a Néel temperature of 10 K and an effective magnetic moment of 5.6 /f.u.. The specific heat …

Lanthanum-Based Perovskites As An Effective Electrocatalyst For Water Splitting And Energy Storage Applications, Xavier Martinez

Electronic Theses & Dissertations

Recent changes in global weather patterns have accented the need a shift from fossil fuels to a cleaner energy option. As part of an overall plan, hydrogen production for fuel cells offer substantial power without carbon emissions. Overall water splitting, with the aid of a low cost electrocatalyst could prove to be an abundant green fuel source. Utilizing readily available transition metals, three perovskite nanostructures were studied as a multifunctional material for hydrogen production as well as an energy storage material. LaCoO₃ (LCO), LaFeO₃ (LFO)_, and LaMnO₃ (LMO) were synthesized and characterized by X-ray diffraction (XRD) …

Deposition Of Platinum Particles On Surface-Modified Carbon Ultramicroelectrodes, Caitlin Millsaps

Undergraduate Honors Theses

Nanoparticles are used as electrocatalysts due to their large surface area-to-volume ratios. Most studies of nanoparticle electrocatalysis are performed on collections of particles on a support, which represent ensemble average behavior influenced by spatial distribution of the nanoparticles. Therefore, recent emphasis has been placed on analyzing electrocatalytic behavior of single particles. The focus here is to develop carbon ultramicro- and nanoelectrode platforms for studying the electrocatalytic properties of single metal nanoparticles. Ultramicroelectrodes were prepared using chemical vapor deposition of carbon in pulled quartz capillaries. Electrode diameters were determined by cyclic voltammetry. Electrodes were modified using a soft nitriding technique to …

Gas Chromatography Analysis Of Co2 Reduction Photocatalysis With Zinc Dipyrrin Complexes, Alex Day

Undergraduate Honors Theses

Bis(1,3,7,9-tetramethyl-5-mesityldipyrrinato)zinc(II) (ZnDPY) was synthesized in the lab by the McCusker group and a procedure was created to analyze its ability as a photosensitizer, a molecule that provides the energy for the reaction to occur by capturing light energy and turning it into a form that can be used by the photocatalyst. While more work is needed, preliminary steps have been made to create a process that can analyze the amount of carbon monoxide produced by a photocatalytic CO₂ reduction reaction with ZnDPY as the photosensitizer. Progress has been made via the setup of a reaction apparatus, targeted gas chromatography …

Surface Immobilization Of Terpyridine Compounds, Elizabeth Hallett

Chemical Engineering Undergraduate Honors Theses

The deoxydehydration (DODH) of polyols to alkenes is a promising method of producing high-value chemical feedstocks from biomass-derived materials. Current catalytic systems for DODH require the use of costly reducing agents that generate stoichiometric amounts of chemical waste. Immobilizing catalysts on electrode surfaces using chemical linking groups eliminates the need for sacrificial reductants. In this work, glassy carbon electrodes were modified with 4’-(3,4-dihydroxyphenyl)-2,2’:6’,2’’-terpyridine to investigate o-benzoquinone as a potential linking group for DODH, and possibly for other reactions. Previous studies involving electrodes modified with quinone-containing compounds have primarily been focused on catalyzing the oxidation of NADH; the nature or …

Preparation Of Enantioenriched Alkyltin Species And Their Application In Stereospecific Transformations, Glenn O. Ralph

Dissertations, Theses, and Capstone Projects

Organometallic reagents containing the tin-carbon bond are used extensively in modern synthetic chemistry for the formation of new bonds to carbon. Over recent decades, transition metal catalyzed cross coupling reactions between two C(sp²) centers have been widely developed. However, the introduction of a C(sp³) center complicates the catalytic cycle, and opens unproductive chemical pathways which lead to isomerization, elimination, and racemization. Our lab has developed a modified-Stille reaction to combat the deleterious effects of β-hydride elimination. Our protocol enables unactivated 2° alkyl organotin nucleophiles to undergo efficient cross coupling reactions with C(sp²) electrophiles, avoiding …

A Pretargeted Spect Imaging Strategy Employing Technetium-99m Based On Bioorthogonal Diels-Alder Click Chemistry, Justin H. Walsh

Dissertations, Theses, and Capstone Projects

A series of related N₃S ^99mTc-peptide complexes were synthesized and tested for use in pretargeting SPECT imaging that utilizes the bioorthogonal Diels-Alder click reaction between tetrazine (Tz) and transcyclooctene (TCO). The objective was to optimize the excretory pathways of the ^99mTc-peptide complexes for maximum tumor targeting with the in vivo “click” and minimum non-target uptake. The ^99mTc–tetrazine constructs were prepared by reaction of ^99mTc-peptide complexes (^99mTc-FKC, ^99mTc-FKCR, ^99mTc-DKC, and ^99mTc-SKC) with Tz-NHS or Tz-PEG₅-NHS to form ^99mTc FK(Tz)C, ^99mTc-FK(PEG₅-Tz)CR, ^99mTc-DK(PEG₅-Tz)C, …

Synthesis And Characterization Of Dielectric And Multiferroic Nanocrystalline Transition Metal Oxide Materials And Nanocomposites, Frederick A. Pearsall

Dissertations, Theses, and Capstone Projects

Nanocrystalline transition metal oxides with unique chemical, physical, magnetic and dielectric properties have very broad applications, ranging from photocatalysis, capacitor energy storage and 4-state memory. Frequency stable, high permittivity nanocomposite capacitors produced under mild processing conditions offer an attractive replacement to MLCCs derived from conventional ceramic firing. In one project reported herein, 0-3 nanocomposites were prepared using BaTiO₃ (barium titanate, BTO) nanocrystals, suspended in a poly(furfuryl alcohol) matrix, resulting in a stable, high effective permittivity, low and stable loss dielectric. Effective medium approximations were used to compare this with similar nanocomposite systems. The use of synthesized BTO nanocrystal photocatalysts …

Development Of Granulated Adsorbent For Clean-Up Of Water Contaminated By Cesium, Esther Alorkpa

Electronic Theses and Dissertations

A study was conducted on sol-gel synthesis of an adsorbent (phosphotungstic acid embedded in silica gel, H-PTA/SiO­₂) of radioactive cesium. A novelty of this work is covalent bonding of PTA to the surface of solid support that prevents leaching from the surface of the material. The sample was granulated with a binder, aluminium oxide (γ-Al₂O₃). Solid-state NMR and FT-IR spectroscopy were used to confirm the presence of Keggin units of PTA in the bound materials. Thermal analysis of H-PTA/SiO­₂ - γ-Al₂O₃ (50 %) showed that the water content in the …

An Investigation Of Alkylboron Transmetallation In Palladium-Catalyzed Suzuki Reactions, Benjamin Murray

Dissertations, Theses, and Capstone Projects

Through the past 40 years, carbon-carbon cross-coupling reactions have greatly enhanced the ability of chemists to synthesize C(sp²)-C(sp²) bonds and more recently C(sp²)-C(sp³) bonds. In particular, the Suzuki reaction has proven to be invaluable with its high yields, good functional group tolerance, and low toxicity of reagents. One of the component steps of the catalytic cycle of this reaction is transmetallation, in which the nucleophilic species transfers its organic component to the metal center (generally palladium). The mechanism of transfer from primary alkylboron nucleophiles was studied in the 1990's via use of …

Effect Of A Coordinating Pyridine Moiety On The Sap And Tsap Isomer Populations Of Bimodal Lanthanide (Iii) Complexes, Marisa Poveda, Osasere M. Evbuomwan

Creative Activity and Research Day - CARD

Paramagnetic Chemical Exchange Saturation Transfer (PARACEST) agents are lanthanide complexes that generate contrast through the slow-to-intermediate exchange of paramagnetically-shifted protons or water molecules. Although PARACEST agents have shown promise as molecular imaging agents, in-vivostudies have been limited due to the masking of the CEST signal by spin-relaxation exchange (T_2ex) and Magnetization Transfer (MT) effects. The majority of PARACEST agents studied to date have been Ln(III)DOTA-tetraamides which can either adopt the square antiprismatic (SAP) or twisted square antiprismatic (TSAP) geometries in solution. The more compact nature of the SAP isomer, combined with its slower bound-water exchange kinetics, makes …

The Lowest-Energy Isomer Of C2Si2H4 Is A Bridged Ring: Reinterpretation Of The Spectroscopic Data Based On Dft And Coupled-Cluster Calculations, Jesse J. Lutz, Larry W. Burggraf

Faculty Publications

The lowest-energy isomer of C₂Si₂H₄ is determined by high-accuracy ab initio calculations to be the bridged four-membered ring 1,2-didehydro-1,3-disilabicyclo[1.1.0]butane (1), contrary to prior theoretical and experimental studies favoring the three-member ring silylsilacyclopropenylidene (2). These and eight other low-lying minima on the potential energy surface are characterized and ordered by energy using the CCSD(T) method with complete basis set extrapolation, and the resulting benchmark-quality set of relative isomer energies is used to evaluate the performance of several comparatively inexpensive approaches based on many-body perturbation theory and density functional theory (DFT). Double-hybrid DFT methods are found to …

G-Quadruplex Dynamics Contribute To Regulation Of Mitochondrial Gene Expression, M. Falabella, J. E. Kolesar, C. Wallace, D. De Jesus, L. Sun, Y. V. Taguichi, C. Wang, T. Wang, Irene M. Xiang , '18, J. K. Alder, R. Maheshan, W. Horne, Joshua R. Turek-Herman , '16, P. J. Pagano, C. M. St. Croix, N. Sondheimer, Liliya A. Yatsunyk, F. B. Johnson, B. A. Kaufman

Chemistry & Biochemistry Faculty Works

Single-stranded DNA or RNA sequences rich in guanine (G) can adopt non-canonical structures known as G-quadruplexes (G4). Mitochondrial DNA (mtDNA) sequences that are predicted to form G4 are enriched on the heavy-strand and have been associated with formation of deletion breakpoints. Increasing evidence supports the ability of mtDNA to form G4 in cancer cells; however, the functional roles of G4 structures in regulating mitochondrial nucleic acid homeostasis in non-cancerous cells remain unclear. Here, we demonstrate by live cell imaging that the G4-ligand RHPS4 localizes primarily to mitochondria at low doses. We find that low doses of RHPS4 do not induce …

Drug Improvement And Design Involving G-Protein Coupled Receptors, Gabriel Saliba

Chemistry & Biochemistry Student Projects

No abstract provided.

A Chemical Overview Of Opioid Receptors And Their Agonists, Noah Kuszak

Chemistry & Biochemistry Student Projects

This work is a brief overview of the three main opioid receptors and some current research of the ways we can change the agonists and how they affect the opioid receptor pathway.

Dentin Biomodification Potency Of Proanthocyanidins, David J. Ryker

Chemistry & Biochemistry Student Projects

No abstract provided.

Cationic Cobalt (Ii) Hydroformylation, Drew Michael Hood

LSU Doctoral Dissertations

While investigating a bimetallic cobalt hydroformylation catalyst a new class of monometallic cationic cobalt (II) hydroformylation catalyst were discovered. These newly discovered catalyst proved to be very unique with high hydroformylation activity under mild conditions. The pre-catalyst were characterized using various methods including NMR, EPR, MS, and X-ray crystallography. Similarly the active catalyst was also investigated using NMR, EPR, FTIR, and X-ray crystallography. Various catalyst modifications were investigated for their effects on hydroformylation activity. Likewise various reaction parameters were probed to determine their effect on hydroformylation activity. Finally the best cationic cobalt (II) catalyst were directly compared to industry standards …

Investigating Cationic Metal Centers For Hydroformylation, Ryan Alexander Johnson

LSU Doctoral Dissertations

Bimetallic cooperativity can potentially increase activity of reactions. This concept is another way to increase reactivity besides simply focusing on the steric and electronic effects of a ligand. A binucleating tetrasphosphine ligand has been developed to showcase bimetallic cooperativity between two rhodium metal centers. Hydroformylation is a widely used industrial process to produce aldehydes from alkenes, H₂, and CO. The dirhodium catalyst, [Rh₂(μ-CO)(CO)₃(rac-et,ph-P4-Ph)](BF₄)₂,is highly active leading to favorable results when using a DMF/water solvent system, 1-hexene, 90 psi 1:1 H₂/CO, and 90° C: initial turnover frequency …

Facile And Efficient Synthesis Of Thiosemicarbazone Derivatives With Functionalized Pendant Amines., Anna E Davis

College of Arts & Sciences Senior Theses

Bis-thiosemicarbazones are an important class of ligands for the synthesis of transition metal complexes with applications in medicine and electrochemistry.^1,2 Among the most studied of these complexation ligands is diacetyl-2,3-bis(N⁴-methyl-3-thiosemicarbazone) (denoted as ATSM, 1, Figure 1).^2,3 Derivatives of 1 with various amines in place of the methylamine of ATSM have previously been reported, including diacetyl (N⁴-methylthiosemicarbazone-N⁴′-dimethylthio-semicarbazone) (denoted as ATSM/DM, 2).⁴ In this work, we pursue the development of a library of ATSM derivatives with a variety of functionalized pendant amines with a range of electronic and steric …

Metal-Assisted Hydrolysis Reactions Involving Lipids: A Review, Dominique E. Williams, Kathryn B. Grant

Chemistry Faculty Publications

This report covers major advances in the use of metal ions and complexes to hydrolyze ester and phosphate ester lipid bonds. These metal-based Lewis acids have been investigated as catalysts to isolate fatty acids from biological sources, as probes to study phospholipid bilayer properties, as tools to examine signal transduction pathways, and as lead compounds toward the discovery of therapeutic agents. Metal ions that accelerate phosphate ester hydrolysis under mild conditions of temperature and pH may have the potential to mimic phospholipase activity in biochemical applications.

Functionalized Carbon Nanotube Adsorption Interfaces For Electron Transfer Studies Of Galactose Oxidase, Mulugeta B. Wayu, Michael J. Pannell, Najwa Labban, William S. Case, Julie A. Pollack, Michael C. Leopold

Chemistry Faculty Publications

Modified electrodes featuring specific adsorption platforms able to access the electrochemistry of the copper containing enzyme galactose oxidase (GaOx) were explored, including interfaces featuring nanomaterials such as nanoparticles and carbon nanotubes (CNTs). Electrodes modified with various self-assembled monolayers (SAMs) including those with attached nanoparticles or amide-coupled functionalized CNTs were examined for their ability to effectively immobilize GaOx and study the redox activity related to its copper core. While stable GaOx electrochemistry has been notoriously difficult to achieve at modified electrodes, strategically designed functionalized CNT-based interfaces, cysteamine SAM-modified electrode subsequently amide-coupled to carboxylic acid functionalized single wall CNTs, were significantly more …

Toward The Impact Of Particulate Matter On Human Health: Evaluation Of Fluorescent Environmentally Persistent Free Radical (Epfr) Surrogates, Ansonia Badgett

LSU Doctoral Dissertations

Environmentally persistent free radicals (EPFRs)—a newly discovered pollutant associated with particulate matter (PM)—form during combustion and thermal processes, such as the incineration of hazardous waste. Various chlorine- and hydroxy-substituted benzenes chemisorb on the surface of metal oxides (e.g., NiO, CuO, and Fe₂O₃) and then form EPFRs, stabilized radical species, as the result of the transfer of electrons between the adsorbate and the metal ion of the metal oxide. Previous studies have shown direct correlations between ultra-fine (d < 0.1 mm) particulate matter (PM_0.1) exposure and adverse pulmonary health effects. PM_0.1 has the potential …

Palladium Complexes Bearing Κ²-N,N And Κ³-N,N,O Pendant Amine Bis(Phenolate) Ligands, Brendan J. Graziano, Eric M. Collins, Nathaniel C. Mccutcheon, Claire L. Griffith, Nicole M. Braunscheidel, Trilisa M. Perrine, Bradley M. Wile

Chemistry and Biochemistry Faculty Scholarship

The synthesis and characterization of ten new palladium(II) amine bis(phenolate) complexes is reported. Solution and single-crystal X-ray diffraction studies reveal the presence of both κ²-N,N and κ³-N,N,O binding modes in these square planar complexes. For complexes with sterically less demanding phenolate donors, addition of external acidic or basic reagents allows for the selective masking of a coordination site at Pd. Complexes bearing bulky cumyl substituents on phenolate donors exhibited unusual ¹H NMR spectroscopic features that are consistent with an anagostic interaction with the palladium center. Computational analysis …

Coordination Chemistry Of N,N’- Azodoxides, Lakshmi Balaraman

ETD Archive

The coordination chemistry of nitric oxide (NO) with transition metals has been extensively investigated, but that of organic NO derivatives as ligands less so. Some nitrosoalkanes RNO and nitrosoarenes ArNO are in equilibrium with dimeric species known as N,N'–azodioxides, R(O)NN(O)R or Ar(O)NN(O)Ar. The cis diastereomers of azodioxides have been proposed to act as bidentate chelating ligands for both main-group and transition metals, but only three azodioxide complexes, a dicationic iron (II) complex, a neutral scandium (III) complex, and a dicationic calcium (II) complex, have thus far been structurally characterized before our work in this area. The delocalized π system of …

Novel Dna Origami Based Lateral Flow Assay Development, Adrienne Walker

Theses, Dissertations and Capstones

Lateral flow assays (LFA) are used for point-of-care qualitative diagnostics of an analyte of interest, often in non-laboratory environments. Traditionally, the format of a lateral flow assay is to utilize immobilized antibodies on a membrane as the capture probe in conjunction with a reporting immunological recognition system for an analyte captured between them in a sandwich format. However, there are several shortcomings of antibodies which recommend their replacement with other recognition elements, if possible. The research described in this thesis was directed toward using several of the inherent properties of DNA based Origami nanostructures to enable the construction of DNA …

Acue Reflection From A Stem Perspective, Ashley Vizenor

Q2S Enhancing Pedagogy

The following document contains reflections from various activities of the ACUE workshop. Activities pertain to syllabus editing, classroom conduct, and effective teaching practices.

Reactivity Of Molybdenum And Tungsten Sulfido Complexes With First-Series Transition Metals, Khalil Mudarmah

ETD Archive

Ammonium tetrathiomolybdate (ATTM) is an important compound in bioinorganic chemistry, with medicinal applications. Metal complexes of sulfur-containing ligands have been widely used as building block in biology and inorganic chemistry. This project aims to increase the number of Mo-S and W-S complexes that may contribute to fields such as bioinorganic and medicinal chemistry, by the preparation of heterometallic complexes containing both Mo or S and a metal of the first transition series. The homobimetallic complex anion salts (Et4N)2[Mo2(S)2(μ-S)2(edt)2] (1) and (Et4N)2[W2(S)2(μ-S)2(edt)2] (2) have been prepared from ATTM and ammonium tetrathiotungstate (ATTW) in order to start our work. The overnight treatment …

Electro- And Photocatalytic Carbon Dioxide Reduction And Thermal Isomerization Of Highly Strained Tricyclocompounds, Weiwei Yang

Electronic Theses and Dissertations

Anthracene-bridged dinuclear rhenium complexes are reported for electrocatalytic and photocatalytic carbon dioxide (CO2) reduction to carbon monoxide (CO). Related by hindered rotation of each rhenium active site to either side of the anthracene bridge cis and trans conformers have been isolated and characterized. Electrochemical studies reveal distinct mechanisms whereby the cis conformer operates via cooperative bimetallic CO2 activation and conversion and the trans conformer reduces CO2 through well-established single-site and bimolecular pathways analogous to Re(bpy)(CO)3Cl. Higher turnover frequencies are observed for the cis conformer (35.3 s−1) relative to the trans conformer (22.9 s−1) with both outperforming Re(bpy)(CO)3Cl (11.1 s−1). Photocatalytic …

Rare-Earth-Activated Group Vi D0 Metal Oxides As Thermosensitive Phosphors, Samarage Sameera Perera

Wayne State University Dissertations

ABSTRACT

RARE-EARTH-ACTIVATED GROUP VI d0 METAL OXIDES AS

THERMOSENSITIVE PHOSPHORS

by

SAMARAGE SAMEERA PRASAD PERERA

AUGUST 2019

Advisor: Dr. Federico A. Rabuffetti

Major: Chemistry

Degree: Doctor of Philosophy

Thermosensitive phosphors are solid-state materials that demonstrate distinct dependence of luminescence emission on temperature. These materials enable optical temperature sensing in environments where conventional thermometry is not possible (e.g., gas turbines, combustion engines, surface temperature distributions). However, the design of thermosensitive phosphors that show adequate sensitivity and low thermal quenching in the intermediate temperature range (i.e., 500–1000 K) remains challenging. This challenge can be addressed by understanding how to rationally manipulate the …