Physical Sciences and Mathematics Commons^™

Studies Directed Toward The Synthesis Of Amphibian Alkaloids Via Iridium Catalyzed N-Heterocyclization Reactions, Kiran Kumar Thota

University of New Orleans Theses and Dissertations

The pyrrolidine and piperidine ring systems are present in a variety of different classes of amphibian alkaloids. We have found the iridium catalyzed N-heterocylization reaction of diols with amines to be very useful for the construction of novel pyrrolidine, piperidine and piperazine derivatives. The scope and utility of the iridium catalyzed N-heterocyclization reaction for the construction of novel anuran scaffolds using amino diols and triols are presented. Studies directed towards the total synthesis of 4,6-disubstituted quinolizidine and (±)-epiquinamide are discussed.

The second study is focused on the selective conversion of terminal dienes to primary diols. This conversion has always had …

Incorporation Of Charge Transfer Into Classical Molecular Dynamics Force Fields With Applications In Physical Chemistry., Marielle Soniat

University of New Orleans Theses and Dissertations

The presence of charge transfer (CT) interactions is clear in a variety of systems. In CT, some electron density is shifted from one molecule to another (non-bonded) molecule. The importance of this CT interaction is unclear. Previous attempts to look at the conse- quences of CT required the use of ab initio molecular dynamics (AIMD), a computationally intensive method. Herein, a method for including CT in force field (FF) simulations is described. It is efficient, produces charges in agreement with AIMD, and prevents long- ranged CT.

This CT MD method has been applied to monatomic ions in water. When solvated, …

Template-Assisted Fabrication Of Ferromagnetic Nanomaterials, Jagnyaseni Tripathy

University of New Orleans Theses and Dissertations

Abstract

Template assisted deposition was used to produce various nanomaterials including simple nanowires, nanorods, multi-segmented metal nanowires, core-shell nanowires, alloy and polymer wires and tubes. Anodized aluminum oxide (AAO) membranes were used as templates for the growth of the various structures using an electrochemical deposition method and also by wetting the porous templates. In the electrochemical deposition method, the pore size of the templates affects the rate of synthesis and the structures of the nanomaterials while in the wetting method, the viscosity and reaction time in the polymer solution influence the structures of the nanomaterials.

A conventional two-step anodization procedure …

Production And Applications Of Formaldehyde-Free Phenolic Resins Using 5-Hydroxymethylfurfural Derived From Glucose In-Situ, Yongsheng Zhang

Electronic Thesis and Dissertation Repository

The phenol-formaldehyde (PF) resin manufacturing industry is facing a growing challenge with respect to concerns over human health, due to the use of carcinogenic formaldehyde and sustainability due to the use of petroleum-based phenol in PF resin manufacture. Glucose and its derivative, 5-hydroxymethylfurfural (5-HMF), have proven to be potential substitutes for formaldehyde in the synthesis of phenolic novolac resins.

This thesis investigated a number of glucose and 5-HMF resin systems including the curing of phenol-glucose novolac resin (PG) with a bis-phenol-A type epoxy. The curing process was modeled according to the Sestak-Berggren equation (S, B) using Málek methods. This was …

The Effect Of Ph And Counterion On The Size Distribution And Luminescence Lifetime Of Terbium-Doped Lanthanum Nanocrystals, Sarah Baker

Undergraduate Honors Theses

In recent years, nanoparticles have been applied to and have gained prevalence in fields such as chemistry, biology, the medical sciences, and biotechnology,and have attracted the attention of medical researchers as potential microscopic drug delivery systems in the human body. In particular, nanoparticles made with the lanthanides have shown themselves to be useful to many biological applications due to their unique luminescent properties. It is crucial to determine optimum synthetic parameters so that nanoparticles are both small enough to pass through the kidneys and also have the ability to attach different functional groups so that they may be relevant to …

Study Of Ii-Vi Colloidal Semiconductor Magic-Size Nanoclusters And Crystalline Quantum Platelets, Yuanyuan Wang

Arts & Sciences Electronic Theses and Dissertations

The main objective of this project is to prepare and isolate the smallest, discrete, magic-size nanoclusters of cadmium selenide (CdSe) and to grow crystalline, wurtzite CdSe quantum platelets (QPs) at room temperature. The achievement of these goals enables us to provide a general synthesis of II-VI semiconductor magic-size nanoclusters and low-temperature routes to well-passivated nanocrystals having a range of compositions and morphologies.

The magic-size nanocluster (CdSe)13 is grown in a lamellar-bilayer soft template at room temperature. The results described in this thesis strongly suggest that [(CdSe)13(n-octylamine)13] is the most thermodynamically stable nanocluster and serves as a key intermediate in the …

Universal Two-Electron Correlation Operator On Excited States, Bryan Thomas Nichols

Theses and Dissertations

Excited states of chemical systems are extremely important in understanding spectra, chemical phenomena, as well as how a particular compound behaves in reactions. Computationally, excited states are normally very expensive to calculate. The difficulty in calculating these states with wavefunction based methods can be mainly attributed to the calculation of large multi-determinant wavefunctions. One reason to use a complicated multi-determinant wavefunction is to include some of the effects of correlation energy. The quantity of correlation energy can most simply be defined as the reduction in energy caused by any two or more electrons trying to avoid each other. The most …

Synthesis And Characterization Of Pbs Quantum Sheets Through Lamellar Assembly, And Updates To The Cdse Quantum Wire Synthesis, Paul James Morrison

Arts & Sciences Electronic Theses and Dissertations

This dissertation reports the novel synthesis of PbS quantum plates (QPs) via a reaction executed at low temperatures. The PbS QPs are grown in a template-assisted mechanism, with the first excitonic peak observed in the visible region of light at ~620 nm (2.0 eV), at an energy radically different than the band gap of bulk PbS (~3000 nm, 0.42eV). The large energy shift is due to the extremely thin dimension of these nanoplates, which is determined to be ~1 nm in thickness. Thickness measurements are made in a powder X-ray diffractometer (XRD) at low angles (between 2-15º 2θ). These measurements …

Isotope Harvesting At Heavy-Ion Fragmentation Facilities, Tara Elise Mastren

Arts & Sciences Electronic Theses and Dissertations

Isotope harvesting from heavy-ion fragmentation facilities is a potential source of isotopes of interest for applications research. With the upgrade of the National Superconducting Cyclotron Laboratory (NSCL) to the Facility for Rare Isotope Beams (FRIB) usable quantities of many isotopes of interest will be produced and available for harvest from an aqueous beam dump. If available, these isotopes would be of interest to a broad range of applications such as medicine, geology, and stockpile stewardship. Preliminary experiments were performed at the NSCL in order to determine the feasibility of isotope harvesting at (FRIB).

A water target station that consisted of …

Toward The Combinatorial Development Of Hydrophobic-Tagged Antifolate-Directed Degradation Of Human Thymidylate Synthase, Daniel J. Menasco

Theses and Dissertations

Direct post-translational control over a protein of interest (POI) can be exploited by manipulating the cells protein quality-control systems responsible for either intracellular turnover through ubiquitination (POI half-life) or repairing and degrading misfolded proteins.1 In an effort to target and degrade a high value POI we selected the enzyme human thymidylate synthase (TS) for post-translational degradation through ligand-directed ubiquitination and hydrophobic tagging. Thymidylate synthase catalyzes the reductive methylation of 2’-deoxyuridine monophosphate (dUMP) to 2’-deoxythymidine monophosphate (dTMP). As the de novo source of dTMP the regulation of intracellular TS is strictly controlled by ubiquitinindependent proteasomal degradation mediated by an internal TS-degron …

Surface Functionalization Of Inorganic Substrates With Polymeric Ligands Using Raft Polymerization, Anand Viswanath

Theses and Dissertations

This work focused on using polymers to modify the surface of various inorganic substrates, ranging from TiO2, ITO, CDSe and CdS nanostructures to micron sized silica particles. The synthesis of the polymers using the RAFT technique and the characterization of the functionalized substrates were analyzed in detail to provide insights into their use for various applications. In the first part of this work, novel phosphate based RAFT agents and phosphate containing polymers, including poly(methyl methacrylate) (PMMA), poly(glycidyl methacrylate) (PGMA) and poly(dimethyl siloxane) (PDMS) were synthesized. Alkyne functionalized PGMA was used to click to ITO surfaces in a grafting-to method, and …

Kinetic Analysis And Inhibition Studies Of Iron-Dependent Histone Demethylases, Barbara Gordon Cascella

Arts & Sciences Electronic Theses and Dissertations

The research presented herein focuses on the kinetics and inhibition of the KDM4 subfamily of Jumonji C (JmjC) domain-containing histone demethylases (HDMs). Belonging to the larger class of alpha-ketoglutarate (alpha-KG)-dependent, non-heme iron monooxygenases, the JmjC-HDMs remove methyl groups from mono-, di-, and tri-methylated histone lysine residues through an Fe(IV)-oxo-catalyzed hydroxylation reaction. JmjC-HDMs have been found to play integral roles in the maintenance of genomic integrity as well as in the regulation of transcription. Three KDM4 members were studied: the mixed H3K9/H3K36 demethylases KDM4A and KDM4C, and the pure H3K9 demethylase KDM4E. KDM4C is a hypoxia-inducible factor 1 (HIF-1) target gene …

Polyol Synthesis Of Silver Nanowires By Heterogeneous Nucleation And Mechanistic Aspects Influencing Its Length And Diameter, Waynie M. Schuette

Arts & Sciences Electronic Theses and Dissertations

Various additives are employed in the polyol synthesis of silver nanowires (Ag NWs), which are typically halide salts such as NaCl. A variety of mechanistic roles have been suggested for these additives. My research showed that the early addition of NaCl in the polyol synthesis of Ag NWs from AgNO3 in ethylene glycol results in the rapid formation of AgCl nanocubes, which induce the heterogeneous nucleation of metallic Ag upon their surfaces. Ag NWs subsequently grow from these nucleation sites. The conclusions are supported by studies using ex-situ generated AgCl nanocubes.

Additionally, the final mean silver nanowire diameter is found …

Cationic Metallocene-Containing Polymers: From Synthesis To Applications, Jiuyang Zhang

Theses and Dissertations

Metallopolymers, with the combination of metals and polymeric framworks, have attracted a lot of attention during the past decades. The development of metallopolymers has been largely driven by the desire to combine the synthetic efficiency and versatility of an organic polymer framework with the unique redox, responsive and catalytic properties of inorganic metals. Among different kinds of metallopolymers, metallocene-containing polymers， have been widely utilized for applications ranging from electrochemical sensors to templates for advanced inorganic catalysts to battery materials, due to their unique physicochemical properties. In the first part of my thesis, we showed controlled/living polymerization strategies to prepare well-defined …

Polyglyoxylates: A New Class Of Triggerable Self-Immolative Polymers, Bo Fan

Electronic Thesis and Dissertation Repository

Self-immolative polymers, which degrade by an end-to-end depolymerization mechanism in response to the cleavage of a stabilizing end-cap from the polymer terminus, are of increasing interest for a wide variety of applications ranging from sensors to controlled release. However, the preparation of these materials often requires expensive, multi-step monomer syntheses and the degradation products such as quinone methides or phthalaldehydes are potentially toxic to humans and the environment. We demonstrate here that polyglyxoylates can serve as a new and versatile class of self-immolative polymers. Polymerization of the commercially available monomer ethyl glyoxylate, followed by end-capping with a 6-nitroveratryl carbonate provides …

Colloidal And Biological Properties Of Triscationic Amphiphiles With One Or Two Tails, John N. Marafino

Masters Theses, 2010-2019

The decline in the development of novel antimicrobials, combined with the misusage and over prescription of antibiotics, has contributed to the increasing prevalence of antimicrobial-resistant infections. Thus development of effective novel disinfectants could reduce the transmission of pathogens and decrease the risk of infection by antibiotic resistant organisms. The antimicrobial activity of amphiphiles, compounds with hydrophobic and hydrophilic regions, was first reported in 1935, and has influenced the synthesis of amphiphiles with variations in structure. In this study, three series of amphiphiles were synthesized by two subsequent Menshutkin reactions. Each amphiphile contains one or two hydrocarbon tails ranging from 8 …

Exploring The Reactivity Of Donor-Acceptor Cyclopropanes And The Synthesis Of (+/-)-Quebrachamine, Huck K. Grover

Electronic Thesis and Dissertation Repository

The development and utility of cyclopropanes is an ever-growing field within organic chemistry. In particular, donor-acceptor cyclopropanes have been used in a vast array of methods to access a variety of different hetero and carbocyclic molecular scaffolds. Recently, we have developed a Zn(NTf2)2 catalyzed tandem reaction consisting of a nucleophilic ringopening of 1,1-cyclopropanediesters by 2-alkynyl indoles followed by a Conia-ene ring closure, resulting in the efficient one-step synthesis of tetrahydrocarbazoles. These adducts may be further elaborated to carbazoles. The scope and limitations of this method were determined along with a mechanistic study into the function of the zinc catalyst. In …

New 4-Aminoquinoline Compounds To Reverse Drug Resistance In P. Falciparum Malaria, And A Survey Of Early European Antimalarial Treatments, Katherine May Liebman

Dissertations and Theses

Intermittent fevers caused by Plasmodium parasites have been known for millennia, and have caused untold human suffering. Today, millions of people are afflicted by malaria each year, and hundreds of thousands die. Historically, the most successful synthetic antimalarial drug was chloroquine, as it was safe, inexpensive, and highly efficacious. However, plasmodial resistance to chloroquine now greatly limits its utility. Previously in our laboratories it has been shown that attachment of a "reversal agent moiety" to the side chain of chloroquine can result in the restoration of activity against chloroquine-resistant strains of P. falciparum malaria. In the first part of the …

Poly(Ester Amide) And Poly(Ethyl Glyoxylate) Nanoparticles For Controlled Drug Release, Amira Mohamed Moustafa

Electronic Thesis and Dissertation Repository

The objective of this research was to develop polymeric nanoparticles (NPs) having improved drug release properties for drug delivery. Poly(ester amide)s (PEAs) are promising biodegradable polymers. PEA NPs were prepared via emulsification-evaporation and salting-out methods and optimized through by varying different processing parameters. Polymer-model drug conjugates based on PEAs containing L-aspartic acid and rhodamine B were synthesized and used for NP preparation. Release behavior was studied and compared to a control system with physically encapsulated rhodamine B. It was shown that the release of rhodamine B from the covalent system did not show the burst effect and exhibited a slower …

Electrochemical Synthesis Of Nanostructured Noble Metal Films For Biosensing, Jay Kishan Bhattarai

Dissertations

Nanostructures of noble metals (Au and Ag) are of interest because of their important intrinsic properties. Noble metals by themselves are conductive, physically robust, chemically inert, and strongly bind to thiols. However, when the nanostructures are formed, they in addition possess high surface area and unique optical properties tunable by adjusting the shape and size. All of these properties make nanostructures of noble metals suitable candidates to be used as a transducer for biosensing. Individual nanostructures might be easier to prepare but difficult to handle to be used as a transducer. Therefore, we prepared and analyzed nanostructured films/coating of noble …

Bidentate Ferrocenyl-Dithiol Reagents For Nanocluster Surface Functionalization, Yiyi Liu

Electronic Thesis and Dissertation Repository

Previous work using monodentate ferrocenyl-chalcogen reagents for nanocluster surface functionalization has indicated an effective way to involve ferrocene moieties onto the surface of these frameworks. However, the abilities of the large polynuclear nanocluster with ferrocene rich surface to form crystalline materials suitable for single crystal X-ray analysis proved to be limited. New bidentate ferrocenyl-chalcogen reagents have been synthesized and characterized in order to probe their ability in this case.

The preparation of new bidentate ferrocenyl chalcogen reagents 1,1’-fc(C{O}OCH₂CH₂SH)₂ (fc = ferrocenyl) and 1,1’-fc(C{O}NHCH₂CH₂SH)₂ are presented. Furthermore, the preparation of silylated …

Scale-Up Methodology For Bench-Scale Slurry Photocatalytic Reactors Using Combined Irradiation And Kinetic Modelling, Patricio J. Valades Pelayo

Electronic Thesis and Dissertation Repository

The present study focuses on developing a predictive methodology to scale-up a slurry annular photoreactor using a TiO₂ Degussa P25 from the bench-scale to a pilot-plant scale. The bench-scale photoreactor is a Photo-CREC-Water II, a 2.65 L internally-irradiated slurry annular photocatalytic reactor. The pilot-plant scale photoreactor is a Photo-CREC Water Solar Simulator, a 9.8 L pilot-plant photoreactor, externally irradiated by eight lamps.

The adopted methodology allows the independent validation of radiative and kinetic models avoiding cross-correlation issues. The proposed approach involves two Monte Carlo methods, to model the Radiative Transfer Equation (RTE) inside each photoreactor. With this end, a …

Continuous Polymer Reactor Design, David Sujay Kingsley

Dissertations

Twin screw extruders can be used as continuous polymer reactors to process polymers, which are conventionally made through batch reactors. Batch processes have certain undesirable qualities such as improper mixing and the inability to precisely control the reaction, which leads to variation between batches and potential exotherms. The work presented in this dissertation investigates the use of continuous polymer reactor designs to efficiently process renewable sourced thermoplastic polyurethanes (TPU), and prepreg epoxy matrix prepolymers.

The overall goal of this research is to highlight the modularity of twin screw extruders as continuous polymer reactors to synthesize the relevant polymers. Chapter I …

Enzyme, Cosolvent, And Substrate Interactions In Ple Hydrolysis Reactions And Evaluation Of The Stability Of An Unnatural Glutathione Analogue, Maureen Elizabeth Smith

Dissertations

Prochiral diester malonates have been hydrolyzed in the presence of Pig Liver Esterase (PLE). Several of the diesters produced the respective half-ester in moderate to high enantioselectivity. A series of cosolvent assays were performed to evaluate the ability of the cosolvent to influence the enantioselective outcome of the hydrolysis reactions. Ethanol produced the largest changes in enantioselectivity of all solvents evaluated. The isoenzymes of PLE were also evaluated and provided very different enantioselective outcomes than that of crude PLE. A series of NMR titrations was performed to explore the interactions between the substrates and ethanol cosolvents.

Improvements to our previously …

Investigations Into Ambient Ionization Mechanisms: Electrospray Ionization And Direct Analysis In Real Time Mass Spectrometry, Stephen Colin Gibson

Doctoral Dissertations

Mass spectrometry (MS) is an important tool for chemical analyses. Despite the MS requirement for generation of analyte gas-phase ions, many ion source designs afford little-to-no fragmentation, allowing characterization of intact molecules. However, this does not assure that detected ions are representative of the analytes’ natural state. Ionization mechanisms are generally complex and rarely fully understood. Fundamental research into these mechanisms provides greater insight into the relationship between solution chemistry and mass spectra. Work herein addresses aspects of two ambient ionization mechanisms: electrospray ionization (ESI) and Direct Analysis in Real Time (DART).

Ions produced by ESI are dispersed into a …

Synthesis And Thermodynamic Analysis Of Volatile Beta-Diketone Complexes Of Select Lanthanides Via Gas-Phase Separations, Daniel Hanson

Doctoral Dissertations

Rapid separation techniques for fission and activation products have long been desired to supplant the slow solution-based methodologies currently used. In this work, rare earth elements were derivatized with β [beta]-diketones to synthesize rare earth complexes with high volatility suitable for gas-phase separations. Rare earth elements samarium and dysprosium were combined with hfac (1,1,1,5,5,5-hexafluoro-2,4-pentadione) and fod (6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedione) and analyzed using a gas-phase separation technique. Rare earth elements praseodymium and europium were combined with dpm (2,2,6,6-tetra-methyl-3,5-heptanedione) and similarly analyzed. Employing the data from the separations, the entropy (Δ [delta] S) and enthalpy (Δ [delta] H) of adsorption were evaluated mathematically based …

Photo-Switchable Control Of Membrane Properties Of Liposomes And Biochemical Processes, Andrew Michael Bayer

Doctoral Dissertations

Liposomes are promising agents for drug delivery. They have the ability to encapsulate therapeutic drugs, resulting in decreased toxicity and prolonged circulation time. However, many obstacles to achieving broad utility in liposomal drug delivery still exist, including the ability to control release of therapeutic drugs and modulate surface reactivity. A primary focus of this dissertation involves the development of synthetic photocleavable lipids for controlled release from membranes.

Phosphatidylcholine (PC) is a natural lipid that comprises the majority of structural membranes. It contributes heavily to the formation of lipid bilayers in cell membranes, and modifications to the bilayer can induce membrane …

Computational Studies For Optimization And Design Of Extracting Agents For Separation Of Lanthanides And Actinides, Deborah Andrea Penchoff

Doctoral Dissertations

Rare earths and actinides are of great interest given their varied applications in energy conversion and storage, such as in catalysis and batteries, and for advanced technological applications related to optical and magnetic properties (including electronics and automotive), amongst others. Many of the rare earth elements are considered endangered species due to their unique properties which have no clear alternatives that will maintain performance for important applications. The optimal approach is to find readily available alternatives for critical materials to ensure a certain standard of living and quality of life for future generations, but it is very likely that reusing …

Design And Implementation Of A Near-Field Scanning Optical Module For Inverted Microscopes, Taher Ababneh

Theses and Dissertations

This dissertation describes the design and implementation of a home-built near-field scanning optical microscope (NSOM) module for inverted microscopes. In this design, the NSOM module is built atop an inverted fluorescence microscope. This is particularly well suited for applications in which the normal imaging modes of the inverted microscope are still required to locate and study the sample before performing NSOM experiments. This module is used as a near-field instrument for nanostructure investigation of various samples including plane-ruled reflection gratings, AFM calibration standards, nanospheres and gold nanoparticles. In addition, we will demonstrate the ability to achieve nanometer-scale surface modification of …

Oxidative Damage To Dna 2´-Deoxyribose By Carbonate Radicals: Reaction Mechanisms And Products, Terence J. Moore

Electronic Theses and Dissertations

The carbonate radical anion (CO₃^•-, CR) is an important reactive oxygen species produced in vivo by one-electron oxidation of CO₂ or bicarbonate, constituents of the major physiological buffer. It was demonstrated for the first time by using an HPLC-based analysis of low-molecular products of DNA damage that CRs react with DNA 2΄-deoxyribose by the hydrogen abstraction mechanism. CRs exhibit a ~ 800-fold preference for one-electron oxidation of guanine over hydrogen abstraction from DNA sugar, in sharp contrast with •OH. CRs also have, as compared to •OH, an increased preference for the H1΄ abstraction, which is the …