Chemistry Commons^™

Templated Oligosaccharide Synthesis, Jia Guang Xiao

Dissertations

Glycosyl transfer within the active site of an enzyme involves the arrangement of the gly-cosyl donor and glycosyl acceptor in close proximity to each other. To mimic this pro-cess, intramolecular glycosylations are carried out where the donor and acceptor are linked together via a spacer. Correct orientation, rigidity and position of the spacer play a vital role in the selectivity and yield of reactions in this “molecular clamp method”. Though current methodologies show promising results in terms of yield and selectivity, the need to synthesize different complexes to ensure selectivities in all types of glycosidic linkages is a large deterrent …

Synthesis Of Cyclic Enolphosphonates And Enolphosphates As Inhibitors Of Serine Hydrolases, Benjamin Patrick Martin

Dissertations

Cyclophostin is a potent naturally occurring inhibitor of acetylcholinesterase with a novel bicyclic enolphosphate structure. The cyclipostins are a family of potent hormone-sensitive lipase inhibitors which share the same bicyclic enolphosphate core structure with cyclophostin which but differ primarily in that they are long-chain alkyl phosphate esters whereas cyclophostin is a methyl phosphate ester. Due to the novelty of the inhibitor structure, potency, and ability to select between two serine hydrolase enzymes with a simple change in the ester substituent, the ongoing structure activity relationship investigation of this family of inhibitors was continued. Methods of transesterification were investigated in order …

A Library Of Coumarin-Enaminone Chemodosimeters For The Detection Of Analytes, Aaron Berrell Davis

Dissertations

Many anions and metal ions are of biological and environmental importance. This work describes our attempts to synthesize molecular probes to specifically target cyanide, zinc, cadmium and mercury as these species can often result in negative effects to the environment and the human body.

The work in this dissertation, describes the synthesis of a family of coumarin-enamine chemodosimeters, in a straightforward synthetic procedure, the reaction between 7-(diethylamino)-4-hydroxycoumarin and a primary amine. The work presented in this dissertation demonstrates that these molecules can play dual roles and therefore the work is split into two distinct parts: Part 1 describes one role …

The Synthesis Of Chemosensors For Toxic Analytes, Johnathan Hugh Broome

Dissertations

A number of chemosensors have been designed and synthesized to target cations (Zn²⁺ions), neutral molecules (cathinones), charged molecules (aminoindanes), and anions. The Zn²⁺ ion sensor featured bistriazole designed binding unit and ferrocene signaling units. Characterization of Zn²⁺ ion binding was carried out with electrochemical techniques (CV and DPV), ¹H-NMR, mass spectrometry, and molecular modelling. It exhibited a 1:1 binding stoichiometry with Zn²⁺ and had an affinity for ZnCl₂ (Log K_1:1 = 4.1 ± 0.02) over other Zn²⁺ salts.

The cathinone probe was designed to selectively bind mephedrone over common street drugs …

Preparation And Characterization Of Singlet-Oxygen Generating Thiol-Ene Networks Containing Fullerene And Metallofullerene Derivatives, Emily Matthews Barker

Dissertations

This work explores the derivatization of C₆₀ and Sc₃N@C₈₀ with S-, P-, and C- centered radicals, and is the first exploration into the functionalization of Sc₃N@C₈₀ with sulfur and phosphorous. The number of addends bound to C₆₀, as a function of reaction time and molar ratios, as well as, structure-property relationships including thermal stability, solubility, and singlet oxygen generation were explored. Fullerene derivatives exhibiting enhanced solubility were incorporated into two different thiol-ene polymer matrices at varying thiol-ene monomer concentrations (1:1 or 1:0.75 molar equivalents) and at different C₆₀ loadings (0, …

Analysis Of The Intricacies Of Substrate Recognition Of High Mobility Group Proteins And Aminoacyl-Trna Synthetases Using Non-Cognate Substrates, Douglas Van Iverson Ii

Dissertations

The studies presented in section 1 (Chapters I-IV) focus on the design and development of nucleic acid four-way junctions (4WJs) to target a member of the high mobility group (HMG) proteins, the proinflammatory cytokine high mobility group box 1 protein (HMGB1). In the present study, hybrid PNA-DNA 4WJs based on a model DNA 4WJ were constructed to improve the thermal stability of 4WJs while maintaining strong binding affinity toward HMGB1. An electrophoretic mobility shift assay (EMSA) was used to examine the binding affinity of an isolated DNA binding domain of HMGB1, the HMGB1 b-box (HMGB1b), toward a set of PNA-DNA …

Binding Properties Of Large Antiviral Polyamides (Pa1 And Pa25) And Natural Product Derivatives As Inhibitors Of Serine Hydrolases, Elena Vasilieva

Dissertations

Polyamides are a class of DNA minor groove binders that were developed from the natural product Distamycin A. PA25 (20-ring PA) showed better activity (3-fold) in the elimination of HPV16 episomes than PA1 (14-ring PA). Binding studies of PA1 and PA25 were performed in the long control region of HPV16 (7348-122 bp). PA1 showed similar binding affinity to perfect match and single mismatch binding sites. PA1 bound to double, triple, and quadruple mismatch sites with lower affinity. PA25 bound with similar binding affinity to perfect through triple mismatch binding sites. PA25 bound quadruple mismatch sites and nonspecifically. Therefore, it was …

N-Terminal Domains Of Copper Atpases In Plasmodium Falciparum, Dictyostelium Dicsoideum, Human Atp7b And A Chimera Of Atox1 With Metal Binding Domain Four Of Atp7b, Javan Kilango Kisaka

Dissertations

Copper transporting ATPases (Cu-ATPases) are essential for mediating copper uptake, maintaining cellular copper levels and prevention of accumulation of toxic copper. The most studied copper ATPases are the Menkes and Wilson proteins in eukaryotes, CopA and CopB found in bacteria. The precise interaction of the metal binding domains with their copper donor, the association of each metal binding domain within the N-terminal portion of the protein, how they communicate with each other, and the eventual metal ion translocation across the membrane, is little known. The variation in number of the cytosolic metal binding domains may also offer clues on the …

Thermochemical Properties Of Fluorinated Hydrocarbons, Hydroperoxides, And Fluorinated Hydroperoxides; Thermochemistry And Kinetics On Dissociation And Association Reactions Of Oxiranyl Radical, Heng Wang

Dissertations

Thermochemical properties on fluorinated hydrocarbons, alcohol, hydroperoxides, and alkyl hydroperoxides are determined. Reaction kinetics and modeling on the three member ring cyclic ether radical, oxiranyl radical, are studied under atmospheric and combustion environments.

Molecular geometries, vibration frequencies, internal rotor potentials, and thermo-chemical properties (ΔfHº298, S°(T) and C°p(T)) for fluorinated-hydrocarbons, thermochemical properties and bond energies, for alkyl and fluoro hydroperoxides and fluoro alcohols are determined with comparison of data from a number of different ab initio, density functional theory (DFT) and composite calculation methods, and basis sets.

Kinetic parameters for unimolecular decomposition and isomerization reactions of the oxiranyl radical are determined …

Studies On Purification And Functionalization Of Carbon Nanotubes And Their Aqueous Phase Behavior, Zheqiong Wu

Dissertations

Carbon nanotubes (CNTs) are known to have unique mechanical, thermal and electrical properties which make them attractive for a wide range of applications ranging from batteries to sensors. CNTs are rolled up graphene sheets where the single-walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs) are classified according to the number of concentric rings. In this dissertation, the focus is on several different aspects of MWCNTs. These include purification, functionalization and colloidal behavior.

MWCNTs are insoluble in solvents and therefore some degree of functionalization is required prior to their real-world applications. Oxidation debris is generated during carboxylation which is usually the first …

Applications Of Nanoporous Gold Monoliths As Substrates For The Capture And Release Of Lectins And Glycoproteins, Allan Jonson Alla

Dissertations

Nanoporous gold (np-Au) monoliths are a free-standing nanostructured material with typical pore dimensions in the tens of nanometers range. The microstructure of np-Au resembles those of macroporous monolithic materials being used in chromatographic separations. The surfaces of np-Au monoliths were modified via flow methods with different ligands to develop affinity substrates for separations. A carbohydrate-modified np-Au monolith was prepared by immobilizing thiolated saccharides and further used to separate lectins. The np-Au monolith surface was also functionalized with self-assembled monolayers (SAMs) of α-lipoic acid (LA) followed by activation of carboxyl terminal groups to create amine reactive esters. Concanavalin A (Con A) …

Surface And Interfacial Design And Control Of High Performing Thermoplastics: Polysulfones And Beyond, Katrina Marie Knauer

Dissertations

The study of a class of materials almost always begins with the development of an understanding of properties in the bulk state. However, it is the study of surface critical phenomena that has led to a number of new important insights into polymer behavior. A systematic understanding of physical properties in the immediate vicinity of surface and interfacial layers, which cannot be deduced by simple extrapolation of bulk properties, is of significant importance for advancements in polymer applications where the interface drives performance, such as in membranes, coatings, drug-delivery systems, medical devices, and composites.

First, the surface and interfacial modification …

Energy Management Mechanisms Employed At The Human-Material Interface Of Traditional And Minimalist Shod Running, Nadine M. Lippa

Dissertations

From recreational to elite athletes, greater than 50% of runners sustain overuse injuries each year, prompting substantial research efforts to identify causes of—and solutions to—the high injury rate. Different shoe types and material property degradation have been related to injury. Two popular footwear types are traditional shoes with thick graded soles and minimalist running footwear with thinner foam and/or non-graded soles. Notwithstanding 45 years of significant modifications to shoe design features, gained knowledge in kinesiology, and advanced technologies in polymer science, runner injury rates have not decreased and EVA foam has remained the primary running shoe midsole material since the …

Curing Of Polymer Thermosets Via Click Reactions, Mark Richard Brei

Dissertations

In the first project, an azide functional resin and tetra propargyl aromatic diamines were fabricated for use as a composite matrix. These systems take already established epoxy/amine matrices and functionalize them with click moieties. This allows lower temperatures to be used in the production of a thermoset part. These new systems yield many better mechanical properties than their epoxy/amine derivatives, but their T_gs are low in comparison.

The second project investigates the characterization of a linear system based off of the above azide functional resin and a difunctional alkyne. Through selectively choosing catalyst the linear system can show …

Synthesis And Characterization Of "Click Inspired" Thiol-Ene-Fullerene Nanocomposites, Amber Danielle Windham

Dissertations

This work explores the covalent incorporation of C₆₀ and Sc₃N@C₈₀ fullerenes into thiol-ene networks by a facile, one-pot photochemical reaction with multifunctional thiol and alkene monomers. Synthesis of disulfide bonds within the tri-functional thiol monomer served to photochemically initiate the reaction when cleaved. This was followed by thermal curing of the pre-polymer for preparation of fullerene-containing thiol-ene films. Films were characterized by standard techniques including infrared spectroscopy, gel percent, and thermogravimetric analysis. The role of C₆₀ and Sc₃N@C₈₀ as suitable alkenes for free-radical reaction with multifunctional thiols was investigated by preparing a …

Addressing The Issues Of Drug Delivery Via Advanced Macromolecular Design, Brooks Allen Abel

Dissertations

The work described in this dissertation focuses on the development of synthetic approaches toward novel polymer architectures that specifically address the issues of in vivo drug delivery. Successful implementation of the synthetic methodologies described herein required fundamental investigations into the underlying chemistries in ways that now provide greater insights into the nature of the these chemical reactions.

In Section I, the synthesis of tunable pH- and CO₂-responsive sulfonamide-containing polymers using reversible addition-fragmentation chain transfer (RAFT) polymerization is described. Initially, poor polymerization control of methacryloyl sulfonamide (MSA) monomers was observed using traditional RAFT polymerization conditions. Ultimately, reducing the polymerization …

The Utilization Of Liquid Chromatography Tandem Mass Spectrometry And Related Techniques For The Analysis And Identification Of Emerging Contaminants In Aqueous Matrices, Matthew Reichert

Dissertations

Environmental pollutants can be found in many ecosystems and cover many different compound classes. The Environmental Protection Agency is responsible for monitoring and regulating several of these classes of compounds which daily enter the environment. However, there are still hundreds, if not thousands, of compounds present in the environment which have yet to be regulated or even identified. The discovery and identification of these unknown emerging pollutants is crucial for the prevention of potential human health risks and irreversible ecological damage.

The research presented is divided into two projects. The first part of this research investigates the disinfectant 3-Bromo-1-chloro-5,5-dimethylhydantoin, which …

Atomic Oxygen Adsorption And Absorption On Rh(111) And Ag(111), Jonathan Derouin

Dissertations

A central question in the field of heterogeneous catalysis is how surface structure and subsurface species influence catalytic behavior. One key to answering that question is determining which surface structures and subsurface species are present under catalytically relevant conditions. This dissertation presents results of Auger electron spectroscopy, low energy electron diffraction, temperature programmed desorption, and scanning tunneling microscopy experiments on oxidized Rh(111) and Ag(111) crystals. Exposing Rh(111) to O2 produced a predominately (2 × 1) adlayer, but even after extended dosing, (2 × 2) domains were also present. Exposing Rh(111) to atomic oxygen yielded O coverages greater than 0.5 ML …

Development Of Folate Directed, Protein Based Photodynamic Therapy Agents, Rojenia Jones

Dissertations

To attack cancer cells in a specific manner, we have developed a folate-targeted, photodynamic therapy (PDT) agent. The folate (FA) and the chlorin e6 (Ce6) photosensitizer were attached to bovine serum albumin (BSA) using carbodiimide chemistry. Since over 50% of cancers overexpress folate receptors, FA-BSA-Ce6 can be taken up by them and is an effective PDT agent. Hela cells exposed to FA-BSA-Ce6 in the dark showed no cytotoxicity. Upon exposure to light, the conjugate was dose (time and concentration) dependent. Concentrations less than or equal to 2 µM were not effective at killing Hela cells but concentrations of at 5 …

Exploring Conditions For The Enhancement Of Acene Semiconductors Through The Use Of The Diels-Alder Reaction, Brittni Qualizza Qualizza

Dissertations

This dissertation demonstrates the application of SAMs to the surface of acene crystals, specifically of tetracene and rubrene, using the Diels-Alder reaction. The second chapter details preliminary reaction results and two analytical methods which were employed to confirm adsorption of the dienophile on the surface of single crystals, tetracene and rubrene. These were mass spectrometry and X-ray photoelectron spectroscopy (XPS). Mass spectrometry experiments distinguish the chemical identity of adduct on the crystals and also it discerned chemi- and physisorbed molecules from one another. XPS was used to prove face selectivity of the reaction by the detection of dichloromaleic anhydride. From …

Assessment And Comparison Of The Electronic Properties Of Group 10 Bimetallic Nanoparticles Relative To Their Monometallic Counterparts, Ali Bolandi

Dissertations

Group 10 transition metals with nanoscale dimensions offer significant advantages over their bulk counterparts. Significant work has been devoted toward studying the benefits of their catalytic efficiencies, however, less has been dedicated toward understanding their electronic properties and how such changes influence charge storage and sensor efficiency. The dissertation work focuses on designing metallic and bimetallic nanoparticles consisting of nanoscale Group 10 transition metals with welldefined structures, prepared using a facile synthetic procedure. The nanoparticles were characterized by electron microscopy, spectroscopic and x-ray techniques. The efficiency of monometallic and bimetallic nanoparticles toward electron storage was investigated electrochemically and by optical …

Design And Synthesis Of New Non-Steroidal Anti-Inflammatory Drugs With Anti-Cancer Activity On Colon Rectal Cancer Cell Lines Hct-116 And Caco-2, Wanda Ivette Rodríguez Rivera

Dissertations

Colon rectal cancer is one of the most common types of cancer and is the third leading cause of cancer related deaths among western countries. Current chemotherapy treatments are highly toxic and mostly result in only a low percentage of tumor reduction; therefore an effective treatment with low toxicity is needed.

In this study, different innovative new COX-2 inhibitors were synthesized using the frame of biologically active chalcones to which active COX-2 pharmacophores SO₂CH₃, SO₂NH₂, SO₂NHCOCH₃ were added. Additionally, the effect of different alkyl chain lengths and the effect …

Hybrid Aryl-Ether-Ketone And Hyperbranched Epoxy Networks, John Misasi

Dissertations

In this dissertation, relationships between chemical structures, cure kinetics and network architectures are correlated to bulk mechanical properties for novel, hybrid epoxy-amine networks. The work is split into two primary sections: the first is the synthesis and characterization of multifunctional glassy networks based on aryl-ether-ketone diamine curatives, while the second is based on the synthesis and characterization of hyperbranched epoxy polymers and their resulting networks.

Three aryl-ether-ketone (AEK) diamines of increasing molecular weights were synthesized and used to cure 4,4’-tetraglycidylether of diaminodiphenylmethane (TGDDM); the resulting networks were compared to 4,4’-diaminodiphenyl sulfone cured TGDDM. Architectural differences were created by varying cure …

Development Of Dual-Cure Hybrid Polybenzoxazine Thermosets, Jananee Narayanan Sivakami

Dissertations

Polybenzoxazines are potential high performance thermoset replacements for traditional phenolic resins that can undergo an autocatalytic, thermally initiated ring - opening polymerization, and possess superior processing advantages including excellent shelf-life stability, zero volatile loss and limited volumetric shrinkage. The simplistic monomer synthesis and availability of a wide variety of inexpensive starting materials allows enormous molecular design flexibility for accessing a wide range of tailorable material properties for targeted applications. Despite the fact, once fully cured, benzoxazines are difficult to handle due to their inherent brittleness, leaving a very little scope for any modifications. The motivation of this dissertation is directed …

Asymmetric Synthesis Of Cα-Methyl-Γ- And Δ-Amino Acids From A Common Synthon And Evaluation Of Thionyl Chloride Assisted Peptide Esterifications, Emily Rose Vogel

Dissertations

C^α-methyl-γ- and δ-unnatural amino acids (UAAs) are important class of biomolecules used extensively as structural scaffolds, peptidomimetics, and in the development of pharmaceuticals. Due to steric congestion surrounding the quaternary center, asymmetric preparation of α,α-disubstituted UAAs are synthetically challenging. Herein, two methods for the synthesis of chiral synthons to prepare C^α-methyl-γ- and -δ-UAAs are reported. A crucial step in both strategies includes an enzymatic hydrolysis of prochiral malonic esters with pig liver esterase (PLE). The first method utilizes the Meyer Schuster rearrangement to prepare α,β-unsaturated diesters synthons, but the preparation of the precursor propargyl alcohol decomposes …

Hydrogen Bond-Mediated Structural Order In Hydroxylated Bis-Mpa Dendritic Polymers: Experimental And Molecular Dynamics Simulation Study, Maliha N. Syed

Dissertations

Dendritic architectures are echoed throughout nature. While the significance of these pervasive patterns is not entirely clear, connections between their structures and physical properties are fascinating to contemplate. Particular interest has been paid to a family of synthetically manufactured and commercially available dendritic polymers based on 2,2-bis(hydroxymethyl) propionic acid (bis-MPA) as a monomer. Composed of two hydroxyls and a carboxyl group, bis-MPA based structures hydrogen bond (H-bond) profusely. Given the high concentration and unique spatial orientation of end-groups, as well as the multitude of carbonyl, ester, and ether interior H-bond acceptors, a set of distinct H-bond organizations may be observed …

Development Of The Regenerative Glycosylation Approach For Manual And Automated Oligosaccharide Synthesis, Swati Sudhir Nigudkar

Dissertations

It has been recognized that carbohydrates are involved in all phases of life beginning with the embryonic development and cell growth. However, it is the involvement of carbohydrates in the progression of various deadly diseases that gave these natural compounds significant roles in diagnostics and as pharmaceuticals. Although carbohydrates are highly desirable to the biological and medical communities, these molecules are still very challenging targets for chemists. Functionalization, derivatization, controlling anomeric stereoselectivity, purification, and characterization are all existing experimental hurdles towards producing synthetic carbohydrates in large quantities and high purity. Advances in chemistry and biochemistry have certainly facilitated the synthesis …

Soluble Amyloid-Beta 42 Aggregates Stimulate Cellular Inflammation Independent Of Cd47, Sanjib Karki

Dissertations

Alzheimer’s disease (AD) is a neurodegenerative disease characterized by the accumulation and deposition of aggregated amyloid-β protein (Aβ). Most of the studies indicate that Aβ1-42) and Aβ(1-40) play an important role in the neurodegenerative pathology in AD. A critical component of AD pathology is inflammation, which results from the activation of glial cells around the Aβ deposits. The goal of my dissertation research was to determine the role of Aβ aggregation in microglia-triggered inflammation and identify cellular components that mediate the inflammatory response. CD47 is a cellular receptor found on the microglia surface and it has been proposed to have …

Ultrafast Charge Carrier Dynamics In Bare And Surface-Modified Semiconductor Nanoparticles, Jameel Abdul-Hadi Hasan

Dissertations

Charge-carrier relaxation dynamics in semiconductor nanoparticles has been in the forefront of research for last three decades both for their fundamental nature as well as for applications in light-harvesting, luminescent labels, light-emitting diodes and nonlinear optics. Significant research has focused on II-VI semiconductors with emphasis on CdS and CdSe that are toxic. On the other hand, ZnO and TiO2 semiconductor nanoparticles are less toxic and have enormous applications in photo-catalysis, water splitting, solar cells and optical sensors. However, the investigations of charge-carrier dynamics in these semiconductor nanomaterials compared to II-VI semiconductor quantum dots are quite limited. The knowledge of charge-carrier …

Picolinyl-Assisted Approaches To Stereocontrolled Glycosylation, Jagodige Prithika Yasomanee

Dissertations

Although carbohydrates are the most abundant molecules on Earth, our current knowledge of these fascinating natural compounds is still limited. Some aspects that are already known include the carbohydrate involvement in damaging cellular processes such as bacterial and viral infections, development of tumors, metastasis, septic shock, etc. Consequently the development of effective methods for the synthesis, isolation, analysis, and investigation of complex carbohydrates has become critical in all areas of glycoscience. Among various focus areas, stereocontrolled glycosylation has emerged as a topic of particular importance. Yet, it remains a remarkable challenge to chemists because a new chirality center is formed …