Chemistry Commons^™

Detection Of Cyanotoxins (Microcystins/Nodularins) In Hepatic Tissues And Epidermal Mats Of Stranded Bottlenose Dolphins (Tursiops Truncatus) In Northeast Florida, Amber Brown

UNF Graduate Theses and Dissertations

The St. Johns River (SJR; Jacksonville, FL, USA) is a large, brackish, estuarine system characterized by considerable anthropogenic pollution, recurrent harmful algal blooms (HABs), and diverse toxin-producing cyanobacteria. The most prevalent toxins in SJR water samples are microcystins/nodularins (MCs/NODs). Additionally, the SJR provides critical habitat for a genetically and behaviorally distinct estuarine community of bottlenose dolphins (Tursiops truncatus) that routinely uses and strands in low mesohaline and oligohaline areas of the river. This population has been subject to two unusual mortality events (UME) since 2010 and has since been described as having substantial declines in population health, characterized …

Targeting Metastatic Breast Cancer With Statin Drugs And Coq10, Jacob Thrasher

Honors Theses

Statin drugs are commonly prescribed to lower cholesterol levels in patients, but recently statins have been under investigation as a potential anti-cancer drug. Statins are HMG-CoA reductase inhibitors and subsequently inhibit the mevalonate pathway and cholesterol synthesis. Since cholesterol trafficking is vital in the growth and metastasis of cancer, statin drugs are being studied to explore their effects on cancer cells. CoQ10, one of the products from the mevalonate pathway, also has shown some potential anti-cancer properties, but its use to combat cancer is controversial. While some studies have shown that CoQ10 supplements can be synergistic with other cancer treatment …

Fabrication And Application Of Functional Polymer-Protein Coreshell Nanoparticles, Lin Lu

Theses and Dissertations

The study of polymer-protein nanoparticles is of increasing interest due to their various potential applications in biosensing, imaging, bioseparations, gene and drug delivery, etc. Synthetic polymers can be tailored with different functional groups and properties, therefore, they can serve as platforms to impart proteins with additional features and assist proteins to better perform biological functions. In this dissertation work, we were mainly focusing on the preparation of polymer-protein core-shell nanoparticles by synthesizing new functional polymers and assembling them with proteins for different applications. In chapter 1, a pyridine grafted diblock copolymer P(CL-g-Py)-b-PCL was prepared through ROP and CuAAC reactions. …

Structural Transformations Of Multimetallic Nanoparticles, Guangfang Li

Theses and Dissertations

Atomic-level understanding of the structural transformations of multimetallic nanoparticles (NPs) triggered by external stimuli is of vital importance to the enhancement of our capabilities to precisely fine-tailor the key structural parameters and thereby to fine-tune the catalytic properties of the NPs. In this work, I firstly show that Au-Cu bimetallic NPs demonstrate stoichiometry-dependent architectural evolutions during chemical dealloying processes and nanoporosity-evolving percolation dealloying only occurs for Au-Cu alloy NPs with Cu atomic fractions above the parting limit. The electrochemically active surface area and the specific activity of the dealloyed nanoframes can be systematically tuned to achieve the optimal electrocatalytic activity. …

Probing Solvent Effects In Aromatic Interactions Using Molecular Balances, Josef M. Maier

Theses and Dissertations

Aromatic interactions play a key role in many important processes, such as the formation and stability of biological and synthetic assemblies, facilitation of molecular recognition processes, and catalysis of chemical reactions. One of the key factors determining the strength of aromatic interaction is the solvent environment. Therefore, developing model systems that can accurately measure the influence or effects of solvents on non-polar interaction strengths is a task of great importance. Over the years, we have been approaching this challenge via designing and analyzing molecular devices that can quantitatively report aromatic interaction energies under various solvent and chemical environments. With this …

Synthesis Of Small-Molecule Fluorescent Probe And Polymers For Bioapplication: Bioimaging And Enzyme Stabilization, Yanmei Xu

Theses and Dissertations

In chapter one, we designed, synthesized and characterized two cysteine sensors CCPAP and CCPAN, with improved water solubility, cell penetration ability, and potential targeting selectivity. Two types of positive charged groups, i.e. triphenylphosphonium and pyridinium were introduced respectively to the frame structure CCP by coupling carboxylic acid with amine to improve the cell permeability and cysteine selectivity. ESI-MS, NMR and IR were employed to characterize the molecular structures of the two novel probes. These probes have better water solubility than the parent molecule DCP, and better cell penetration capability than CEP, which could further distinguish the cysteine concentration differences in …

Mechanisms Of Decarboxylation In The Cyp152 Family Of Cytochrome P450s, José Armando Amaya

Theses and Dissertations

Intense interest has focused on the development of enzymes as next-generation catalysts for the production of molecules with biotechnological potential. OleTJE, a member of the cytochrome P450 CYP152 family is an excellent candidate for the generation of advanced biofuels. OleTJE catalyzes the hydrogen peroxide-dependent decarboxylation of Cn fatty acids to produce Cn-1 terminal alkenes. Despite the ability of this enzyme to yield long chain alkenes with nearly exclusive chemoselectivity, its reactivity towards shorter chain length substrates results in undesired levels of hydroxylated side-products, limiting its industrial potential. Previous transient kinetic studies have demonstrated that, despite its unusual chemistry, the reaction …

Instrumentation For, And Application Of, Novel Electrochemical Tools For In Vivo Analysis Of Neurotransmitters In The Context Of Psychiatric Disease, Rhiannon Robke

Theses and Dissertations

ABSTRACTSerotonin’s involvement in many physiological processes including anxiety, stress, compulsivity, and mood has been speculated for decades. Insufficient progress in our understanding of serotonin chemistry is due to the lack of effective tools to selectively measure this neurotransmitter on a neurotransmission-relevant time scale in vivo. An analytical technique for serotonin measurements, fast-scan cyclic voltammetry (FSCV), was pioneered in the last decade in anesthetized rodents and is beginning to shed light on the complexity of serotonergic activity on a sub-second timescale. Complementary, more recent technological innovations have enabled ambient neurotransmitter levels to be determined every few seconds using a method called …

Understanding The Adsorption And Nucleation Of Transition Metals On A Model Carbon Support, Grant S. Seuser

Theses and Dissertations

Heterogeneous catalysis plays a vital role in the commercial production of chemicals. However, much is still unknown about the fundamental surface chemistry involved in catalyst preparation and the surface chemistry of the catalysts themselves. In the first part of this work, a surface science approach was employed to develop a fundamental understanding of the surface chemistry of strong electrostatic adsorption (SEA) of metal precursors on a model carbon support, highly oriented pyrolytic graphite (HOPG). SEA is a wet impregnation method in which anionic/cationic metal precursors are adsorbed onto positively/negatively charged functional groups by adjusting the pH of the solution above …

Studies Of The Activation Of Carbon-Gold And Carbon-Hydrogen Bonds By The Pentaruthenium Carbonyl Cluster Ru5(Μ5-C)(Co)15, Jonathan Darrell Tedder

Theses and Dissertations

The current practical uses of hydrocarbons by industry are discussed in Chapter 1. Carbon-hydrogen (C-H) bond activation and selective functionalization by transition metal complexes is presented as a possible alternative for the upgrading of hydrocarbons. The comparison of carbon-gold (C-Au) bond activation to C-H bond activation based on isolobal principles by transition metal complexes is presented. The high nuclearity ruthenium cluster complexes Ru6C and Ru5C are presented and their early chemistry is discussed.

The reactions of high nuclearity carbido cluster complexes, Ru6C(CO)17 and Ru5C(CO)15, with PhAuNHC are presented in Chapter 2. The reaction of Ru6C(CO)17 with PhAuNHC yields the π-arene …

Multiple C-H Bond Activations Of Aromatic Compounds By Unsaturated Dirhenium Carbonyl Complexes, Poonam Dhull

Theses and Dissertations

The background and importance of aromatic C-H bond activation by metal complexes are discussed in Chapter 1 with the help of various examples from the literature. Synthesis of the dirhenium complex Re2(CO)8(-C6H5)(-H) 1.1 is also discussed in detail. It also includes work done on C-H activation on arenes and heteroarenes by previous members of Dr. Adams’ group. The reactions of Re2(CO)8(-C6H5)(-H) with naphthalene and anthracene yielding the first multiply-CH activated arene products by the multiple oxidative-addition processes are presented in Chapter 2. The reaction of Re2(CO)8(-C6H5)(-H) with itself yielded the doubly-Re2-metalated C6H4 bridged compound Re2(CO)8(µ-H)(µ-1,µ-3- C6H4)Re2(CO)8(µ-H), 2.3. The reaction of …

Inorganic Nanocrystals And Their Applications In Hybrid 0d:2d Material Optoelectronics, Mathew Kelley

Theses and Dissertations

Functional nanomaterials have garnered great interest as candidates for use in next-generational optoelectronics such as solar photovoltaics, light-emitting diodes, and photodetectors. Among these low-dimensional materials, hybrid devices employing both 0D and 2D materials are of interest due to exploitation of the favorable characteristics of each component, and performances superior to standalone counterparts are achievable. This thesis is divided into two parts, as follows. The first two chapters will introduce lowdimensional materials and their favorable characteristics; our work on the formation of ligand-exchanged nanocrystal thin films purified by gel-permeation chromatography will also be discussed. In the second component, the formation and …

Hierarchical Corannulene-Based Materials, Allison M. Rice

Theses and Dissertations

Merging the intrinsic properties of fullerene (buckyball) and corannulene (buckybowl) derivatives with the inherent properties of crystalline metal- and covalentorganic frameworks (MOFs and COFs), including their modularity, porosity, versatility, high surface area, and structural tunability, opens a pathway to unlock a novel class of fulleretic materials. Despite the great interest in MOFs and COFs, as well as fullerene derivatives, this dissertation is focused on crystalline fullerene- and corannulenecontaining frameworks, highlighting their potential contributions in the fields of optoelectronic devices, electrodes, and photosensitizers. We have revealed a dual role of fullerene- and corannulene-containing building blocks showing their versatility to act as …

Sustainable Soybean Oil And Lignin Derived Monomers And Polymers For Potential Use In Polymeric Materials, Ryan Miskin

Theses and Dissertations

In this thesis project, high oleic soybean oil and lignin derived monomers and polymers are investigated. The properties of these monomers and polymers are characterized and discussed.

Chapter 1 details the potential impact of bio-based resources, monomers, and polymers on the environment. An introduction on polymerization techniques is given, and the overall objectives of my research are discussed.

In Chapter 2, attempts are made at modifying a soybean oil derived thermoplastic polymer into a vitrimer. The synthesis of thermoplastics is reviewed and the vitrimer trials outlined. Different scenarios that arose are examined and discussed.

Chapter 3 outlines the preparation of …

Cationic Metallocene-Containing Biomaterials For Antimicrobial Applications, Parasmani Pageni

Theses and Dissertations

Metal-containing polymers or metallopolymers, are one of the major classes of polymers which stand out independently because of a unique combination of organic and inorganic components in one macromolecular system. Among the variety 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. This dissertation is focused on the synthesis, characterization, and application of cationic metallocene-containing polymeric materials. Cationic-cobaltocenium was grafted in various inorganic nanoparticles using polymerization techniques such as reversible addition-fragmentation chain transfer polymerization.

In Chapter 1, the overall background …

Structural And Chemical Consequences Of High Oxygen Coverages On Rh(111), Rachael Gabrielle Farber

Dissertations

Partial oxidations of small molecules over metal surfaces are central to many heterogeneously catalyzed reactions. However, the identity of the actual surface species that promote or hinder these reactions has remained elusive for a variety of reasons. Recently, the understanding of the role of surface oxides in catalytic activity has changed. Instead of being thought of as poisons, they are now believed to be effective promoters of selective catalysis.

Rhodium (Rh) effectively promotes oxidation reactions and is a benchmark system for models of heterogeneously catalyzed chemistry. For this reason, Rh(111) was chosen as the model system for this dissertation work. …

The Enzymatic Activity And Inhibition Of Dape Encoded N-Succinyl-L,L-Diaminopimelic Acid Dessucinylase, Tahirah Heath

Dissertations

The bacterial enzyme DapE is a hydrolase in the late stage of the mDAP/lysine biosynthetic pathway that catalyzes the hydrolysis of N-succinyl-L,L-diaminopimelic acid (L,L-SDAP) to succinic acid and L,L-diaminopimelate (DAP). The product DAP is ultimately converted to m-DAP and then to lysine which is used in the construction of proteins, whereas for humans, lysine is an essential amino acid obtained through diet. DapE has been shown to be conserved across many strains of bacteria. The m-DAP produced through the succinylase pathway is used by both gram negative and gram-positive bacteria in the construction of the essential peptidoglycan cell wall. Because …

Crystal Structure Of (2-{[(8-Aminona­Phthalen-1-Yl)Imino]­Meth­Yl}-4,6-Di-Tert-Butyl­Phenolato-Κ3n,N′,O)Bromido­Nickel(Ii), Patrick O’Brien, Matthias Zeller, Wei-Tsung Less

Chemistry: Faculty Publications and Other Works

The title compound, [NiBr(C25H29N2O)], contains an NiII atom with a slightly distorted square-planar coordination environment defined by one O and two N atoms from the 2-{[(8-aminonaphthalen-1-yl)imino]methyl}-4,6-di-tert-butylphenolate ligand and a bromide anion. The Ni—O and Ni—N bond lengths are slightly longer than those observed in the phenyl backbone counterpart, which can be attributed to the larger steric hindrance of the naphthyl group in the structure of the title compound. The molecule as a whole is substantially distorted, with both the planar naphthalene-1,8-diamine and imino–methyl– phenolate substitutents rotated against the NiN2OBr plane by 38.92 (7) and 37.22 (8), respectively, giving the molecule …

Dna Lesions Produced From The Reaction Of Diols And 5-Formylcytosine And Their Effects On Dna Replication, Brock Allen

University of the Pacific Theses and Dissertations

Nucleic acids are complex macromolecules that are susceptible to both endogenous and exogenous damage. This study explored damage resulting from interactions with environmental nucleophilic toxins, such as a variety of diols and amines found in industry. These nucleophiles can react with electrophilic groups, such as 5-formylcytosine. 5-formylcytosine is an oxidation product of the epigenetic base 5-methylcytosine. It is typically removed by thymine DNA glycosylase (TDG) but is known to accumulate in the genome, making the formyl group susceptible to attack. In this study we used GC/MS and ESI-MS to show that DNA lesions from the nucleophilic addition reaction of toxins …

Principles Of Surface Chemistry Central To The Reactivity Of Organic Semiconductor Materials, Gregory J. Deye

Dissertations

Organic thin-films are rapidly becoming implemented as semiconducting materials in electronic devices and as a result, surface reactivity plays an increasingly important role in the improvement of semiconducting properties. My dissertation addresses how organic thin-films react with gaseous molecules. Previous reports of chemical reactions on organic surfaces claim, “phase rebuilding reaction mechanisms,” whereby reactions only proceed if chemisorbed adsorbate molecules are able to traverse through voids in the molecular lattice. The over-assumptions of this model and lack of correlation to reaction temperature make understanding of organic substrate reactivity incomplete. In contrast, I argue applied heat causes deformation of the molecular …

Targeting The Folate Receptor: Improving Efficacy In Inorganic Medicinal Chemistry, Pauraic Mccarron, Aisling Crowley, Denis O'Shea, Malachy Mccann, Orla L. Howe, Mary Hunt, Michael Devereux

Articles

The discovery of the high-affinity, high-specificity folate receptor in mamalian kidney cells, coupled with the ability of folate to enter cells by folate receptor-mediated endocytosis and the subsequent elucidation of the folate receptor’s overexpression in specific cancer cell types; heralded the arrival of the area of chemotherapeutic folate targeting. The application of purely organic folate-based small-molecule drug conjugates that selectively target the folate receptor, which is over expressed in several diseases such as cancer, is well established. The application of inorganic folate-targeted drugs offers significant potential to expand and enhance this therapeutic approach. From the data made available to date, …

Chemical Modifications Of Lipids And Proteins By Nonthermal Food Processing Technologies, Juan M. PéRez-AndréS, CléMentine Charoux, Patrick J. Cullen, Brijesh K. Tiwari

Articles

A range of nonthermal techniques have demonstrated process efficacy in ensuring product safety, extension of shelf life, and in general a retention of key quality attributes. However, various physical, chemical and biochemical effects of nonthermal techniques on macro and micro nutrients are evident, leading to both desirable and undesirable changes in food products. The objective of this review is to outline the effects of nonthermal techniques on food chemistry and the associated degradation mechanisms with the treatment of foods. Oxidation is one of the key mechanisms responsible for undesirable effects induced by nonthermal techniques. Degradation of key macromolecules largely depends …

Unprecedented In Vitro Antitubercular Activitiy Of Manganese(Ii) Complexes Containing 1,10- Phenanthroline And Dicarboxylate Ligands: Increased Activity, Superior Selectivity, And Lower Toxicity In Comparison To Their Copper(Ii) Analogs, Pauraic Mccarron, Malachy Mccann, Michael Devereux, Kevin Kavanagh, Ciaran M. Skerry, Petros C. Karakousis, Ana Carolina Aor, Thaís P. Mello, Dos Santos, André Luis Souza Dos Santos, André Luis Souza, Débora Leite Campos, Fernando R. Pavan

Articles

Mycobacterium tuberculosis is the etiologic agent of tuberculosis. The demand for new chemotherapeutics with unique mechanisms of action to treat (multi)resistant strains is an urgent need. The objective of this work was to test the effect of manganese(II) and copper(II) phenanthroline/dicarboxylate complexes against M. tuberculosis. The water-soluble Mn(II) complexes, [Mn2(oda)(phen)4(H2O)2][Mn2(oda)(phen)4(oda)2]·4H2O (1) and ([Mn(3,6,9-tdda)(phen)2]·3H2O·EtOH)n (3) (odaH2 = octanedioic acid, phen = 1,10-phenanthroline, tddaH2 = 3,6,9-trioxaundecanedioic acid), and water-insoluble complexes, [Mn(ph)(phen)(H2O)2] (5), [Mn(ph)(phen)2(H2O)]·4H2O (6), [Mn2(isoph)2(phen)3]·4H2O (7), ([Mn(phen)2(H2O)2])2(isoph)2(phen)·12H2O (8) and [Mn(tereph)(phen)2]·5H2O (9) (phH2 = phthalic acid, isophH2 = isophthalic acid, terephH2 = terephthalic acid), robustly inhibited the viability of M. tuberculosis strains, H37Rv …

Construction Of Supramolecular And Coordination Compounds From Pyridyl Bis-Urea Macrocycles, Bozumeh Som

Theses and Dissertations

The self-assembly of macrocyclic molecules in solution and in the solid state modulates and in many cases enhances their properties for applications in sensing, catalysis and optoelectronics. The self-assembled structures are typically organized by non-covalent interactions such as hydrogen bonding, π-π stacking and dipole-dipole interactions. Our group has focused on the design and synthesis of bis-urea macrocycles that can self-assemble into solid cylinders or tubular structures affording crystalline materials. These macrocycles consist of two urea groups and two rigid C-shaped spacers. Easy functionalization of this system enables access to bis-urea macrocycle structures that could serve as molecular reactors, coordinating ligands …

Design, Synthesis, Characterization, And Applications Of Matrix Free Polymer Nanocomposites, Yucheng Huang

Theses and Dissertations

This dissertation focuses on the design, synthesis, characterization and application of matrix free polymer nanocomposites. Reversible addition-fragmentation chain transfer (RAFT) polymerization was used to synthesize block copolymers and polymer grafted silica nanoparticles with precise control over architectures.

In the first chapter, thermoplastic elastomer (TPE) grafted nanoparticles were prepared by grafting block copolymer poly(styrene-block-(n-butyl acrylate)) onto silica nanoparticles (NPs) (~15nm) via surface initiated RAFT polymerization. The effects of polymer chain length and graft density on the mechanical properties were investigated using films made solely from the grafted NPs. The ultimate tensile stress and elastic modulus increased with the increase of PS …

Synthesis And Reactivity Of Carborane Backbone Pincer Complexes, Bennett J. Eleazer

Theses and Dissertations

In organometallic chemistry, boron-centered ligand systems represent a powerful synthetic strategy for the promotion of a variety of catalytic transformations. These ligands offer a versatile array of bonding motifs, which can function as borane, boratrane, boryl, borate, or borylenes type ligands, and are likely the strongest σ-donors in the anionic series of ligands based on boron, carbon, nitrogen, and oxygen. Carboranes, which are icosahedral boron clusters of the type C2B10H12, offer unique potential as metal ligands, such as their bonding to exohedral metal centers being dominated by two-center-two-electron σ-bond interactions, their three-dimensional cluster structure providing considerable steric shielding to a …

Designed Polymer Brush Interfaces For Plutonium Separations And Polyethylene Nanocomposites, Julia G. Pribyl

Theses and Dissertations

Modification of surfaces with polymer brushes has become an important area of research for developing materials with a variety of advanced properties. Flat or continuous surfaces modified with polymer brushes can serve as surfaces where chemical reactions or separations take place, and discrete nanoparticles covered in a polymer brush can disperse within a miscible surrounding polymer, generating a composite which retains the processability of the polymer but becomes endowed with the properties of the filler as well. Presented herein are new synthetic approaches to modify both continuous surfaces as well as discrete particles with polymer brushes for complex applications. In …

Synthesis And Characterization Of Polydiene-Grafted Nanoparticles, Zaid Mohammed Abbas Alajeeli

Theses and Dissertations

This dissertation presents the design, synthesis, and characterization of polydiene grafted nanoparticles as a way to tailor nanocomposite interfaces and properties via interface design. The polymerization of dienes was done via reversible addition fragmentation chain transfer (RAFT) polymerization. The grafting of polymer chains on the surface of silica nanoparticles can be controlled through the molecular design of the RAFT agents attached to the nanoparticles surface. The properties of the nanocomposites largely depended on the interface between the particles and the polymer matrix. In the first part of this work, the polymerization of diene monomers was done on 15 nm diameter …

Development Of A High-Resolution Spatial Heterodyne Libs Spectrometer, Kevin A. Dudley

Theses and Dissertations

Laser-Induced Breakdown Spectroscopy (LIBS) is an atomic emission technique that uses a pulse laser to ablate a sample and form a plasma. Atomic emissions from the plasma provide unique elemental characteristics regarding the composition of the sample. The technique produces valuable qualitative results, but the accuracy of quantitative analyses is hindered by spectral line broadening mechanisms and laser pulse reproducibility, among other factors. The Spatial Heterodyne Spectrometer (SHS) is a high-resolution spectrometer with very high light throughput, and its use to LIBS is currently limited to two peer-reviewed publications. In the following work a high resolution SHS is developed and …

Mechanistic Investigations Of The Iron(Iii)-Catalyzed Carbonyl-Olefin Metathesis Reaction, Susan Phan

Master's Theses

Iron(III)-catalyzed carbonyl-olefin ring-closing metathesis represents a new approach toward the assembly of molecules traditionally generated by olefinˆ’olefin metathesis or olefination. Herein, we report detailed synthetic, spectroscopic, kinetic, and computational studies to determine the mechanistic features imparted by iron(III), substrate, and temperature to the catalytic cycle. These data are consistent with an iron(III)-mediated asynchronous, concerted [2+2]-cycloaddition to form an intermediate oxetane as the turnover-limiting step. Fragmentation of the oxetane via Lewis acid-activation results in the formation of five- and six-membered unsaturated carbocycles.