Chemistry Commons^™

Investigation Of Amyloid Β Oligomer Dissociation Mechanisms By Single Molecule Fluorescence Techniques, Hope Cook Abdalla

Theses and Dissertations--Chemistry

Alzheimer’s disease (AD) is currently considered the most prevalent neurodegenerative disease and places a large financial burden on society as healthcare resources are limited and the disease does not have a cure. Alzheimer’s disease is characterized by the presence of amyloid beta (Aβ) plaques and neurofibrillary tangles; however current literature suggests Aβ oligomers are the main aggregating species leading to AD symptoms. Therefore, the underlying cause of Alzheimer’s, accumulation of amyloid beta, is currently being studied in hopes of developing treatment options. Our research aims at determining the mechanism and kinetics of Aβ oligomer dissociation into non-toxic monomers in the …

Development Of Chromatography And Mass Spectrometry Methods For Enzyme Kinetics And Inhibition In Glycolysis And The Methylerythritol Phosphate (Mep) Pathways, Allison Fabino Carr

Graduate Research Theses & Dissertations

This dissertation focuses on method development for enzymatic activity and inhibition assays for use in screening potential antibacterial compounds. Infection by antibiotic-resistant pathogens in on the rise globally and several enzymes, including the those in the methylerythritol phosphate (MEP) pathway and fructose bisphosphate aldolase, as strong targets for novel pharmaceuticals because they are not present in humans. Several assays exist for the MEP pathway and aldolase, but there is always work to be done to improve sensitivity, increase throughput, and lower cost. This dissertation describes the development of several methods – hydrophilic interaction chromatography (HILIC), liquid chromatography-mass spectrometry (LC-MS), and …

New Synthetic Methods Using Superelectrophiles, Sean Kennedy

Graduate Research Theses & Dissertations

The work outlined in this dissertation describes new synthetic methods in the synthesis of heterocyclic compounds mediated by superacid catalysis. Superacids are powerful reagents that enhance the reactivity of electrophiles, thereby opening the door to new reactive pathways with very weak nucleophiles. In this work, trifluoromethanesulfonic acid (triflic acid, CF3SO3H) is employed as a superacid catalyst to effect new transformations. These concepts are summarized in chapter 1. Chapter 2 describes a new acid-catalyzed cascade leading to the indolizidine ring system, which is present in a number of natural products. Experiments support a proposed mechanism involving vinylogous keto-enol tautomerization. The synthesis …

Lewis Base Promoted Annulations Of Allenoates With 1,4-Naphthoquinones, Nicole Marie Shoup

Electronic Theses and Dissertations

Lewis base promoted cyclization of allenoates with electron deficient olefins open up the possibility to generate more complex organic structures. By generating more complex molecules, we are able to produce new compounds for biomedical and material applications. Both phosphine and amine Lewis bases offer interesting annulations with allenoates resulting in Lu or Morita–Baylis–Hillman type reactions. Once the Lewis base engages with the allenoate there can be several modes of nucleophilic reactivity that allows for the allenic ester to act as a two or three carbon synthon. The allenoate can then react with varying electron deficient olefins generating more complex molecules …

Utilization Of Superelectrophiles In Organic Synthesis, Hien Quoc Vuong

Graduate Research Theses & Dissertations

This dissertation describes the use of triflic acid as a catalyst in organic synthesis. The first chapter is an introduction of reaction classes, reactive intermediate, and superacids.

Chapter 2 discusses a series of compounds have been prepared by the Fischer indole synthesis and Friedel–Crafts reactions, using a single acid catalyst in a one-pot conversion. The reactions have worked best with pyridyl-substituted hydrazones/indoles. Chlorination and bromination products are formed in good yields and high regioselectivities. Acylation products have also been prepared by the two-stage reaction. In the case of alkylation, the expected alkyl-substituted indoles are obtained however they are accompanied by …

Design, Synthesis, And Evaluation Of Potential Burkholderia Pseudomallei Ispf Inhibitors, Sydney Marie Watkins

Graduate Research Theses & Dissertations

This body of work focuses on the inhibition of Burkholderia pseudomallei enzyme IspF. Burkholderia pseudomallei is the causative agent of Whitmore’s disease, and IspF is an essential enzyme in the synthesis of isoprenoids, a vital class of compounds. This work has involved the design and synthesis of nearly five dozen compounds, as well as the design, modification, and use of assays to demonstrate potential interactions between the compounds being investigated and the targeted organisms or enzymes. Development of assays was made challenging by the difficulty in observing the consumption of an unstable substrate or production of a product without a …

Coupling Reactions Of Triaryl Carbocations Via Cationic Charge Delocalization, Hongfang Xue

Graduate Research Theses & Dissertations

This thesis describes a coupling reaction involving cationic charge delocalization. This work began as a study of the Piancatelli rearrangement, a reaction involving furan-based triaryl methyl cations. A new synthetic reaction has been discovered using these furan-based triaryl methyl cations as electrophilic intermediates. Zinc chloride has been found to be an effective Lewis acid catalyst for the ionization of the triaryl methanols to the carbocations. It has been found that furan-based triaryl methyl cations react with nucleophiles such as enol silyl ethers and silyl ketene acetals. Similar to the Piancatelli reaction, nucleophilic reactions are found to occur at the 5-position …

Oleic Acid Vesicles: Formation, Mechanisms Of Reactivity, And Uses In Determination Of Terpene Activity, Laura A. Walther

Theses and Dissertations--Chemistry

This dissertation will focus on the volatile compounds released upon the burning of incense which are numerous and varied. The first part of this dissertation is the gas chromatography-mass spectral (GC-MS) analysis of burning incense collected via solid phase microextraction (SPME) with the aim of developing a library of compounds found in incense as used in the Orthodox church.

The second part of this dissertation has the aim of developing a method for forming oleic acid bilayer vesicle membranes and a fluorescence spectroscopy method by which the reactivities of these vesicles can be analyzed. These reactivities include permeability, fluidity, aggregation, …

Modeling The Condensed-Phase Behavior Of Π-Conjugated Polymers, Walker Mask

Theses and Dissertations--Chemistry

It is well established that the morphology and physical properties of an organic semiconducting (OSC) material regulate its electronic properties. However, structure-function relationships remain difficult to describe in polymer-based OSC, which are of particular interest due to their robust mechanical properties. If relationships among the molecular and bulk levels of structure can be found, they can aid in the design of improved materials. To explore and detail important structure-function relationships in polymer-based OSC, this work employs molecular dynamics (MD) simulations to study various π-conjugated polymers in different environments. Two independent investigations are discussed in this work. One investigation examines how …

Development Of Synthetic Methodologies Of Nucleophile-Electrophile Chemistry, Michael R. Stentzel

Graduate Research Theses & Dissertations

The work outlined in this dissertation describes the development of synthetic methodologies utilizing a wide electrophilicity range of substrates towards the synthesis of new compounds. Substitution, addition, and superelectrophilic chemistry are powerful tools to afford potentially important compounds. These concepts are summarized in chapter 1.

Chapter 2 describes the capture of superacid catalyzed fluorenyl cations with nitriles (Ritter reaction) and alcohols. Optimization of reaction conditions and extensive scope studies were performed.

In chapter 3, the Michael addition of organometallic reagents with N-heterocyclic substituted olefins is explored. The nucleophilic carbanion intermediate species is shown to have reactivity towards strong electrophiles. With …

The Design, Synthesis, And Evaluation Of Inhibitors Of The Ispf Enzyme In The Mep Pathway, Christopher G. Stewart

Graduate Research Theses & Dissertations

Isoprenoids are a class of over 50,000 compounds that serve as key precursors for many compounds in plants and animals. These compounds play critical roles in many biological functions such as cellular growth, respiration, and go on to form critical compounds such as steroids and vitamins. Despite their overall necessity to life their biosynthesis only follows two synthetic pathways. These pathways are the Mevalonic Acid (MVA) Pathway and the 2-C-Methyl-D-Erythritol-4-Phosphate (MEP) Pathway also known as the non-mevalonate pathway. The MVA pathway is found primarily in humans and some higher plants while the MEP pathway is found in bacteria and some …

Investigation Of Thiol-Containing Biomarkers And Their Role In The Exposome, Tracy Gastineau-Stevens

Theses and Dissertations--Chemistry

Exposomics is an emerging area of study that looks at how the environment around a person or persons affects their overall health. Biomarkers have emerged as useful tools to better understand how the exposome affects a person. In this work, we investigate two potential endogenous biomarkers, homocysteine and glutathione that have been previously implicated in a number of diseases that have been linked to environmental causes. We also investigated an environmental exposure, the fungicide Ziram, which epidemiologically has been linked to diseases. In our investigation, we utilized capillary electrophoresis and capillary electrophoresis-mass spectrometry to develop a method for homocysteine and …

Synthesis Toward A Molecular Container Based On P-Tert-Butylcalix[4]Arene With Gate Features, Balasooriya Appuhamilage Dinesh Madushan Balasooriya

Masters Theses

Nowadays molecular and supramolecular chemistry have endless examples for the development of smart devices. Among those applications, nano-baskets of calixarenes play vital roles in host-guest chemistry. One of the main appealing concepts of this field is the development of host molecules with gate features. These hosts are designed and constructed for the delivery of chemical or biochemical species that are volatile, or reactive, or sensitive to normal solution environment and they are mainly functioned by predefined groups that are responsive toward stimuli such as concentration, temperature, pH and so on. In our previous study, we found that benzyl bromides can …

Chemometric Applications In Fire Debris Analysis: Likelihood Ratios From Naive Bayes And Frequency Of Component And Pyrolysis Product Occurrence, Anuradha Akmeemana

Electronic Theses and Dissertations

One of the major challenges in fire investigation is the determination of the cause of fire. The fire can be accidental or intentional. The determination of ignitable liquid residue (ILR) from fire debris helps the process and this process is called fire debris analysis in forensic science. This is one of the most complex areas in the field of forensics because of the evaporation of the ILR from the debris and the interference of the substrate matrix with the ILR if present. In the present, the final decisions in fire debris analysis are based on categorical statements and it only …

Construction Of A Cross-Layer Linked G-Octamer Via Conformational Control: A Stable G-Quadruplex In H-Bond Competitive Solvents, Ying He, Yanbin Zhang, Luksaz Wojtas, Novruz G. Akhmedov, David Thai, Heng Wang, Xiaopeng Li, Hao Guo, Xiaodong Shi

Faculty & Staff Scholarship

Methanol soluble and stable guanosine octamers were successfully achieved via H-bond self-assembly. Through structural conformational design, we developed a new class of guanosine derivatives with modification on guanine (8-aryl) and ribose (20 ,30 -isopropylidene). This unique design led to the formation of the first discrete G8-octamer with its structure characterized by single crystal X-ray diffraction, MS and NMR spectroscopy. The G8-octamer showed unique cation recognition properties, including the formation of a stable Rb+ templated G-quadruplex. Based on this observation, further modification on the 8-aryl moiety was performed to incorporate a cross-layer H-bond or covalent linkage. Similar G-octamers were obtained in …

Solvation Of Isoelectronic Halide And Alkali Metal Ions By Noble Gas Atoms, Carly A. Rock

Honors Theses

Alkali metal cations (M+ = Li+, Na+, K+, and Rb+), as well as their corresponding isoelectronic atomic anions (X− = H−, F−, Cl−, and Br−) were solvated with argon atoms (i.e., M+Arn and X−Arn where n=1−6). Full geometry optimizations were performed using the MP2 electronic structure method with a series of correlation consistent basis sets augmented with diffuse functions on argon and the anions (aug-cc-pVXZ) and weighted core valence basis sets were used for the cations (cc-pwCVXZ) that include the appropriate pseudopotentials for K+ and Rb+ (cc-pwCVXZ-PP). The basis sets for a particular cluster are, hereafter, simply denoted as XZ …

Unexpected Outcomes During The Attempted Iodination Of Biphenol, Henry Nguyen

Honors Theses

The goal of this research was to create a new procedure to iodinate 4,4- biphenol using a ball miller. Iodination of 4,4-biphenol was first attempted in solution using electrophilic aromatic substitution. Several attempts were made to iodinate 4,4-biphenol, but the general insolubility of crude products inhibited progress. Interestingly, NMR analysis of the aqueous ammonia product suggested that 4,4-biphenol dimerized or polymerized with itself to make an ether. The exact mechanism by which the ether dimer was created is unknown, but the reaction may have occurred using a radical mechanism. Though the original goal of the project is left unmet, a …

Microwave Synthesis And Characterisation Of Zinc Sulfide Nanomaterials For Photocatalytic And Anti-Bacterial Applications, Damian W. Synnott

Doctoral

This thesis is focused on the development of a novel ambient pressure microwave synthesis of ZnS based materials for photocatalytic and anti-bacterial technologies. Chapter 1 introduces the problems with anti-biotic resistant bacteria and the impact that these species are causing within healthcare systems. One of the approaches to tackling these problems is the development of self-cleaning materials to replace the harsh cleaning agents currently in use to sterilize the surfaces of buildings and materials used in healthcare environments. Chapter 1 also introduces semiconductors, semiconductor photocatalysis and the mechanism of action, improving photocatalytic action and how to semiconductor photocatalysts have been …

Synthesis, Characterization And Antibacterial Properties Of Silver(I) N-(4-Pyridyl) Benzamide Complexes With Varying Conterions, Mauro J. Ruiz

Open Access Theses & Dissertations

Organic semiconductor materials composed of - stacking aromatic compounds have been under intense investigation for their potential uses in flexible electronics and other advanced technologies. Herein we report a new family of seven - stacking compounds of Silver(I) N-(4-pyridyl) Benzamide with varying counterions, namely [Ag(NPBA)2]X, where NPBA is N-(4-pyridyl) Benzamine, X = NO3- (1), ClO4- (2), CF3SO3- (3), PF6- (4), BF4- (5), CH3PhSO3- (6), and PhSO3- (7), which form extended - stacking networks in one-dimensional (1D), 2D and 3D directions in the crystalline solid-state via the phenyl moiety, with average inter-ring distances of 3.823 Å. Interestingly, the counterions that contain …

Study Of Multielectron Redox Chemistry In Bimetallic Complexes And Metal-Free Macrocycles, Nancy Rodriguez Lopez

Open Access Theses & Dissertations

Multielectron redox chemistry is fundamental for the activation of small molecules (e.g. H2O, CO2, CO, N2). Although these processes are of great importance, they are not well understood. Unravelling the mechanisms of electron transfer and its principles is essential for the design and development of efficient catalysts. Our approach towards the understanding of multielectron redox chemistry includes theoretical study of mechanistic pathways in the hydrogen evolution reaction (HER) by metal-free porphyrinoids, the study of electronic communication in non-symmetric multimetallic two-state models (D–B–A) and the tuning of the electronic properties of bimetallic systems (Mo, and Au) by ligand control.

In Chapter …

Ibuprofen As A Probe Of Lipid Metabolism, Jose Antonio Rosales

Open Access Theses & Dissertations

The hypothesis that deracemization of racemic ibuprofen (IBU) occurs via the enolization of a Candida rugosa lipase (CRL)-ibuprofen ester (Scheme 1.6.2) was disproven by reacting racemic IBU under the conditions that were used to deracemize ibuprofen methyl ester (IME), namely pH 7.6. At pH 7.6, IME through IBU butyl esters were not formed in-situ and racemic IBU was not deracemized by reacting the corresponding primary alcohol with racemic IBU in the presence of CRL.

At pH 7.6, hexyl through dodecyl IBU esters were formed in-situ by reacting the corresponding primary alcohol with racemic IBU in the presence of CRL. The …

New Porous Semiconductor Nanocomposites As Dye-Sensitized Photocatalysts, Tahmina Akter

Open Access Theses & Dissertations

The wide band gap layered semiconductors potassium titanium niobium oxide (KTiNbO5) and potassium hexaniobate (K4Nb6O17) along with a metal co-catalyst can be been used to generate hydrogen fuel from water. However, ultraviolet light is required, which limits their utility in solar energy conversion. Modification of these types of semiconductors can sensitize them to visible light, providing a promising way to produce clean, renewable hydrogen (H2) fuel. Many photocatalysts suffer from poor H2 production efficiencies under visible light, due to inadequate and unstable sensitizers, resulting in photocatalysts that fail quickly.

In this research, several new high surface area dye sensitized nanocomposites …

Application Of Urinary Metabolites For Cancer Detection, Qin Gao

Open Access Theses & Dissertations

Prostate cancer (PCa) is the 3rd most common cause of male cancer mortality in the US. Early diagnosis and treatment of PCa will improve the quality of care and reduce mortality. The prostate specific antigen (PSA) is commonly used in the current PCa screening, but its limitation has resulted in an intense search for more reliable biomarkers. Studies showed that dogs could differentiate PCa patients from negative control by sniffing their urine. As the odor profiles are generated by volatile organic compounds (VOCs), the finding suggests that particular VOCs could be linked to PCa, PCa risk levels and other cancers. …

Synthesis Of Advanced Functional Nanomaterials For Sustainable Water Treatment Technologies, Md Tariqul Islam

Open Access Theses & Dissertations

Water is the most essential resource for the sustenance of life. Water is also necessary for agriculture, industry, household, and environmental conservation. However, due to large population growth and industrial expansion, access to clean water is becoming increasingly difficult around the world. Current water treatment technologies have not changed in over one hundred years and require a large infrastructure due to their low efficiencies and large-scale needs. In this context, the utilization of advanced functional nanomaterials and the adaptation of nanotechnology could potentially allow for miniaturizing water treatment and develop de-centralized solutions for rural areas. This Dissertation presents the design, …

Analysis Of Bodily Fluids Using Vibrational Spectroscopy: A Direct Comparison Of Raman Scattering And Infrared Absorption Techniques For The Case Of Glucose In Blood Serum, Drishya Prachalil, Clément Bruno, Franck Bonnier, Helen Blasco, Igor Chourpa, Matthew Baker, Jennifer Mcintyre, Hugh Byrne

Articles

Analysis of biomarkers present in the blood stream can potentially deliver crucial information on patient health and indicate the presence of numerous pathologies. The potential of vibrational spectroscopic analysis of human serum for diagnostic purposes has been widely investigated and, in recent times, infrared absorption spectroscopy, coupled with ultra-filtration and multivariate analysis techniques, has attracted increasing attention, both clinical and commercial. However, such methods commonly employ a drying step, which may hinder the clinical work flow and thus hamper their clinical deployment. As an alternative, this study explores the use of Raman spectroscopy, similarly coupled with ultra-filtration and multivariate analysis …

Cross Faculty Collaboration In The Development Of An Integrated Mathematics And Science Initial Teacher Education Program, Sharon P. Fraser, Kim Beswick, Margaret Penson, Andrew Seen, Robert Whannell

Australian Journal of Teacher Education

This paper describes a collaborative project involving mathematicians, scientists and educators at an Australian university where an innovative initial teacher education (ITE) degree in mathematics/science was developed. The theoretical frameworks of identity theory and academic brokerage and their use in understanding the challenges associated with the early stages of collaborative projects is described. Data from reflections and interviews of the participants after involvement in the project from one to three years are presented to illustrate these challenges. The paper concludes with a description of the importance of the academic broker in overcoming identity challenges and facilitating cultural change for academics …

A Comparison Of The Efficacy Of Newly-Synthesized Antimicrobial Polymers And A Preview Into Their Interaction With The Bacterial Cell Membrane., Kailey Christman

Williams Honors College, Honors Research Projects

Antibiotic-resistant bacteria present an obstacle for physicians and researchers. Over 35,000 people die annually in the U.S. from antibiotic-resistant infections each year. New antibiotics are being developed and studied, and natural products are screened to find potential new antibiotics. In this study, four polymer antibiotics with polyester backbones and peptide functional groups were studied with Escherichia coli and Staphylococcus aureus to determine the polymers’ efficacies on the different bacteria and compare the polymers to each other. Timed fluorescence microscopy experiments were performed to determine how long it takes the antibiotics to compromise the membrane integrity of fluorescently-labelled E. coli. …

Facial Rhenium Tricarbonyl Complexes With Modified Dii Ligands, Dominick Vitale

Williams Honors College, Honors Research Projects

Over the course of this semester, promising preliminary research into a novel area of inorganic chemistry has been underway. Multiple different bis(arylimino)isoindolines (BAI), a compound made from the disubstitution of diiminoisoindoline with aryl amines to form planar tridentate ligands, were tested to determine if the structure could be forcefully bent to fit a facial binding mode. It was theorized that the bending of the usually planar chelate would cause an electronic change, destabilizing the orbitals. Different synthetic techniques were explored allowing the formation a new BAI, 1,3-bis(3-pyrazolylimino)isoindoline which was characterized via X-ray crystallography, as well as a few previously characterized …

Design And Evaluation Of Heterobivalent Par1–Par2 Ligands As Antagonists Of Calcium Mobilization, Mark W. Majewski, Disha M. Gandhi, Ricardo Rosas Jr., Revathi Kodall, Leggy A. Arnold, Chris Dockendorff

Chemistry Faculty Research and Publications

A novel class of bivalent ligands targeting putative protease-activated receptor (PAR) heteromers has been prepared based upon reported antagonists for the subtypes PAR1 and PAR2. Modified versions of the PAR1 antagonist RWJ-58259 containing alkyne adapters were connected via cycloaddition reactions to azide-capped polyethylene glycol (PEG) spacers attached to imidazopyridazine-based PAR2 antagonists. Initial studies of the PAR1–PAR2 antagonists indicated that they inhibited G alpha q-mediated calcium mobilization in endothelial and cancer cells driven by both PAR1 and PAR2 agonists. Compounds of this novel class hold promise for the prevention of restenosis, cancer cell metastasis, and other proliferative disorders.

Non-Covalent And Covalent Interactions Between Phenylacetylene And Quinoline Radical Cations With Polar And Non-Polar Molecules In The Gas Phase, Adam C. Pearcy

Theses and Dissertations

Gas phase molecular clusters present an ideal medium for observing factors that drive chemical reactions without outside interferences from excessive solvent molecules. Introducing an ion into the cluster promotes ion-molecule interactions that may manifest in a variety of non-covalent or even covalent binding motifs and are of significant importance in many fields including atmospheric and astronomical sciences. For instance, in outer space, molecules are subject to ionizing radiation where ion-molecule reactions become increasingly competitive to molecule-molecule interactions. To elucidate individual ion-molecule interaction information, mass spectrometry was used in conjunction with appropriate theoretical calculations.

Three main categories of experiment were conducted …