Chemistry Commons^™

The Tides They Are A-Changin': A Comprehensive Review Of Past And Future Nonastronomical Changes In Tides, Their Driving Mechanisms, And Future Implications, Ivan D. Haigh, Mark D. Pickering, J. A. Mattias Green, Brian K. Arbic, Arne Arns, Sönke Dangendorf, David F. Hill, Kevin Horsburgh, Tom Howard, Déborah Idier, David A. Jay, Leon Jänicke, Serena B. Lee, Malte Müller, Michael Schindelegger, Stefan A. Talke, Sophie-Berenice Wilmes, Philip L. Woodworth

CCPO Publications

Scientists and engineers have observed for some time that tidal amplitudes at many locations are shifting considerably due to nonastronomical factors. Here we review comprehensively these important changes in tidal properties, many of which remain poorly understood. Over long geological time scales, tectonic processes drive variations in basin size, depth, and shape and hence the resonant properties of ocean basins. On shorter geological time scales, changes in oceanic tidal properties are dominated by variations in water depth. A growing number of studies have identified widespread, sometimes regionally coherent, positive, and negative trends in tidal constituents and levels during the 19th, …

Protein Ligation : Selenocysteine, Komal Shah

Legacy Theses & Dissertations (2009 - 2024)

Selenium is present in human and animal body in the form of selenocysteine and

Carl Bosch And The Haber-Bosch Process, Jacob Larkin

Natural Sciences Student Research Presentations

This poster for the Natural Sciences Poster Session at Parkland College features organic chemist Carl Bosch, winner of the Nobel Prize of Chemistry in 1931 for his contribution to the development of chemical high pressure methods, Bosch built on Fritz Haber's process of fixing nitrogen using high pressure chemistry to industrialize the process on a large scale to mass produce fertilizer, now known as the Haber-Bosch process, which takes nitrogen from the air, bonds it with hydrogen from natural gases and converts it to ammonia.

Theranostics Based On Linear Dendritic Block Copolymers, Jon Williams

Electronic Theses and Dissertations

When combining imaging and therapeutic motifs, known as theranostics, amphiphilic diblock copolymers have a strong precedent of success. These polymers can self-assemble into a variety of morphologies that are known to concentrate in areas of inflammation such as tumors. However, prediction of size and morphology from polymer structure still remains an open challenge. Another system with promise of therapeutic efficacy are tree-like struc- tures known as dendrimers, such as poly(amidoamine) (PAMAM) and bis-(hydroxymethyl) propionic acid (bMPA), which can uptake drugs and dyes into their branches. It is desireable to combine these two motifs, using linear-dendritic block copolymers (LDBCs). These represent …

Toward An Enzyme-Coupled, Bioorthogonal Platform For Methyltransferases: Probing The Specificity Of Methionine Adenosyltransferases, Tyler D. Huber

Theses and Dissertations--Pharmacy

Methyl group transfer from S-adenosyl-l-methionine (AdoMet) to various substrates including DNA, proteins, and natural products (NPs), is accomplished by methyltransferases (MTs). Analogs of AdoMet, bearing an alternative S-alkyl group can be exploited, in the context of an array of wild-type MT-catalyzed reactions, to differentially alkylate DNA, proteins, and NPs. This technology provides a means to elucidate MT targets by the MT-mediated installation of chemoselective handles from AdoMet analogs to biologically relevant molecules and affords researchers a fresh route to diversify NP scaffolds by permitting the differential alkylation of chemical sites vulnerable to NP MTs that are unreactive to …

One-Pot Enol Silane Formation-Mukaiyama Aldol Reactions: Crossed Aldehyde-Aldehyde Coupling, Thioester Substrates, And Reactions In Ester Solvents, C. Wade Downey, Grant J. Dixon, Jared A. Ingersoll, Claire A. Fuller, Kenneth W. Maccormac, Anna Takashima, Rohina Sediqui

Chemistry Faculty Publications

Trimethylsilyl trifluoromethanesulfonate (TMSOTf) and a trialkylamine base promote both in situ enol silane/silyl ketene acetal formation and Mukaiyama aldol addition reactions between a variety of reaction partners in a single reaction flask. Isolation of the required enol silane or silyl ketene acetal is not necessary. For example, crossed aldol reactions between α-disubstituted aldehydes and non-enolizable aldehydes yield b- hydroxy aldehydes in good yield. In a related reaction, the common laboratory solvent ethyl acetate functions as both an enolate precursor and a green reaction solvent. When thioesters are employed as enolate precursors, high yields for additions to non-enolizable aldehydes are routinely …

Modular Synthesis And Hydroalkylation Of Vicinally Functionalized Ketopiperazines: A Solution To The Piperazine Problem, Antonio Moreno

All Master's Theses

The stereocontrolled synthesis of functionalized piperazines is of great interest to pharmaceutical companies owing to their multiple biological activities such as antidepressant, antiparasitic, anticancer and antiretroviral. Current methods towards functionalized piperazines include intramolecular cyclization of appropriately tethered on acyclic precursors as well as α-C–H functionalization of intact piperazine rings. Although effective for the most part, these methods suffer from drawbacks such as the use of expensive catalysts, potentially toxic reagents, limited scope and functional group compatibility. Seeking to side-step some of the aforementioned limitations, we herein describe a step-economical-, cost-effective-, transition metal-free-, and mild approach to highly functionalized piperazines, including …

A Study To Regioselectively Access Fluorinated Triazoles And Isoxazoles, Sweta Adhikari

Electronic Theses and Dissertations

The objective of the thesis is to develop regioselective methods for mono-fluorination of disubstituted triazoles, both 1,4- and 1,5-regioisomer, and isoxazoles. These strategies focus on one-pot direct access to final mono-fluorinated triazoles and isoxazoles. Eventually, these fluorinated substrates will be screened against various biological targets. Similarly, the optimization study of a regioselective method to generate 5-fluoro-1,4-disubstituted triazole was conducted. This reaction also utilized 1,3-dipolar cycloaddition to synthesize fluorinated triazole. However, difluoroalkene was used as a synthetic equivalent of fluoroalkyne for this method. This resulted into the inversion of polarity affording a different regioisomer. Here, fluoronitroalkene was identified as a synthetic …

High Voltage Dye-Sensitized Solar Cells And Molecular Photocatalysis For Co2 Reduction, Roberta Ramalho Rodrigues

Electronic Theses and Dissertations

The development of high voltage solar cells is an attractive way to use sunlight to power electrocatalysts for water oxidation, electrocatalysts for CO2 reduction, and consumer electronics. Through careful molecular dye engineering and redox shuttle pairing, our group has reported a single-junction dye-sensitized solar cell (DSC) employing, for the first time, an iron redox mediator (Fe(bpy)33+/2+) in conjunction with a novel wide band gap dye (RR9). This system generates a high photovoltage of 1.42 V. To the best of our knowledge, this system is the highest photovoltage achieved by a single-junction DSC device without metal oxide doping. The RR9/Fe(bpy)33+/2+ redox …

Functionality Of Membrane Proteins Overexpressed And Purified From E. Coli Is Highly Dependent Upon The Strain, Khadija Mathieu, Waqas Javed, Sylvain Vallet, Christian Lesterlin, Marie-Pierre Candusso, Feng Ding, Xiaohong Nancy Xu, Christine Ebel, Jean-Michel Jault, Cédric Orelle

Chemistry & Biochemistry Faculty Publications

Overexpression of correctly folded membrane proteins is a fundamental prerequisite for functional and structural studies. One of the most commonly used expression systems for the production of membrane proteins is Escherichia coli. While misfolded proteins typically aggregate and form inclusions bodies, membrane proteins that are addressed to the membrane and extractable by detergents are generally assumed to be properly folded. Accordingly, GFP fusion strategy is often used as a fluorescent proxy to monitor their expression and folding quality. Here we investigated the functionality of two different multidrug ABC transporters, the homodimer BmrA from Bacillus subtilis and the heterodimer PatA/PatB …

Exomol Line List - Xxxiv. A Rovibrational Line List For Phosphinidene (Ph) In Its X³Σ¯ And A¹Δ Electronic States, Jonathan Langleben, Jonathan Tennyson, Sergei N. Yurchenko, Peter Bernath

Chemistry & Biochemistry Faculty Publications

A rovibronic line list for the ground (X³Σ⁻) and first excited (a¹Δ) states of phosphinidene, ³¹PH, is computed. The line list is designed for studies of exoplanetary and cool stellar atmospheres with temperatures up to 4000 K. A combination of empirical and ab initio data is used to produce the line list: potential energy curves (PECs) are fitted using experimental transition frequencies; these transitions are reproduced with a root mean square error of 0.01 cm⁻¹. The nuclear Schrödinger equation is solved using these PECs plus Born–Oppenheimer and spin splitting correction terms. …

Shelf Inputs And Lateral Transport Of Mn, Co, And Ce In The Western North Pacific Ocean, Peter L. Morton, William M. Landing, Alan M. Shiller, Amy Moody, Thomas D. Kelly, Michael Bizimis, John R. Donat, Eric H. De Carlo, Joseph Shacat

Chemistry & Biochemistry Faculty Publications

The margin of the western North Pacific Ocean releases redox-active elements like Mn, Co, and Ce into the water column to undergo further transformation through oxide formation, scavenging, and reductive dissolution. Near the margin, the upper ocean waters enriched in these elements are characterized by high dissolved oxygen, low salinity, and low temperature, and are a source of the North Pacific Intermediate Water. High dissolved concentrations are observed across the Western Subarctic Gyre, with a rapid decrease in concentrations away from the margin and across the subarctic-subtropical front. The particulate concentrations of Mn, Co, and Ce are also high in …

Condensation And Polymerization Explain The Humification Of Lignin Into Aliphatic And Aromatic Structures In Soil, Patrick G. Hatcher, Hongmei Chen, Seyyedhadi Khatami, Derek C. Waggoner

Chemistry & Biochemistry Faculty Publications

Soil organic matter (SOM) constitutes a global reservoir of carbon that is more than twice that of either atmospheric carbon or aquatic carbon; however, the manner in which it forms from degraded plant biomass is poorly understood. Some have recently questioned whether plant biomass is involved directly in SOM formation and suggest that it is microbial carbon that constitutes the main source of stable SOM. Such a view implies that above and below ground plant biomass is rapidly decomposed and mineralized. This view contrasts significantly with traditional ones that involve the transformation of plant biomass to recalcitrant humic materials fueled …

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 …

Effects Of Halogen Bonding And Nir Tuning Of Dyes For Dye-Sensitized Solar Cells, Alexandra Baumann

Electronic Theses and Dissertations

With current energy demands being met through the utilization of energy sources such as petroleum, natural gas, and coal, the non-renewable nature of these sources will eventually approach depletion as world wide energy consumption increases yearly. As a result the need for a renewable energy alternative has become imminent. One appealing alternative that has gained considerable attention since its development due to a low cost and a high solar to electric conversion efficiency are dye-sensitized solar cells (DSCs). This dissertation describes efforts to design and synthesize improved organic dyes utilizing three analogous methods: first, through decreasing non-productive pathways such as …

Targeted Nanocarriers For Small Molecule Drug Delivery To Mycobacteria, Alex Suszcynaski, Anna Mcalpin, Kavini Rathnayake, Unnati Patel

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Self-Assembled Pegylated Poly(Amino Acid)S - A Vehicle For Nanoparticles, Benjamin Tran

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Multidimensional Mass Spectrometry Of Chemonic™ Ccg-6 Nonionic Surfactant With Separation By Polarity And Shape, Charles Johnson

Williams Honors College, Honors Research Projects

Chemonic™ CCG-6 surfactant is a water-soluble poly(ethylene glycol) (PEG) conjugated alkyl glyceride emollient. This surfactant exists as a complex mixture of a glycerol cores conjugated with poly(ethylene glycol) branches (PEGylation) that were partially esterified with caprylic (C8) and capric (C10) acids. These may be esterified on one, two, or all three arms of the glyceride. The architecture of the structures in this mixture was studied using multidimensional mass spectrometry (MS). Mass spectrometry was interfaced with ultra-performance liquid chromatography (UPLC) and ion mobility (IM) separation. The mixture was separated by reversed-phase LC, oligomers of the star-branched polymer were separated according to …

Method Considerations For Compound Identification In Complex Mixtures Using Electrospray Ionization Ultrahigh Resolution Mass Spectrometry, Tyler Leverton

Dissertations, Master's Theses and Master's Reports

Biomass burning aerosols are highly complex organic mixtures of thousands of components with consequences for global climate. Complex mixture component identification requires accurate mass measurement capability to separate components on a milli-Dalton scale, frequently using ultrahigh resolution mass spectrometry with electrospray ionization. Certain sample preparations and the ionization process may introduce artifacts that obscure the composition of the sample. Two method considerations were explored using isotopically labeled ¹⁵NH₄OH and MeOH-d₃ to track artifact formation in biomass burning samples. Informatics techniques and a custom molecular formula assignment software were used to identify the isotopic atoms in artifact …

Synthesis Of Oligodeoxynucleotides Containing Sensitive Electrophiles, Shahien Shahsavari

Dissertations, Master's Theses and Master's Reports

Oligodeoxynucleotides (ODNs) containing electrophilic groups are useful in many studies including antisense drug development and DNA/protein interaction. Due to the use of strong nucleophiles for cleavage and deprotection, traditional ODN synthesis methods are not suitable for their preparation. To solve this problem, a new ODN synthesis technology using the 1,3- dithiane-2-yl-methoxycarbonyl (Dmoc) function as protecting groups and linker has been developed. Furthermore, Dmoc-derivatives were developed to demonstrate the feasibility of the technology. The Dmoc and Dmoc derivative functions are stable under all ODN synthesis conditions using the phosphoramidite chemistry. Upon oxidation of the sulfides in them, because of the drastically …

Synthesis Of N-Heterocyclic Molecules And Their Applicability Towards Ion Sensing: Polymeric Chemosensors, Aikohi M. Ugboya

College of Graduate Studies: Theses & Dissertations

Critical to biological and environmental processes are anions because often times their relative concentration in our body can be an indicator of one’s well-being. Therefore, highly sensitive and cost-efficient methods for ions recognition is necessary for human health. In recent times, polymeric chemosensors have become a vital tool for sensing ions because of its higher sensitivity and good mechanical properties compared to their monomeric counterparts. These sensors are designed to produce a measurable response in the presence of a targeted ion such as an electrochemical or optical signal. The unique structure and the photophysical properties of the 1,2,3-triazole core coupled …

Copper-Mediated N1-Arylation Of Benzotriazoles, Magdalena R. Andrzejewska

Dissertations and Theses

Benzotriazoles are group of bicyclic heterocyclic compounds that contain three nitrogen atoms fused to a benzene ring. Along with their derivatives, they possess a wide range of properties. They are used in medical field, as they exhibit such properties as antibacterial,antiplasmoidal,antiprotozoal, antifungal and anti-inflammatory activities, among others. They are also used in various industries as herbicides, UV absorbers, deicing and antiicing agents and corrosion inhibitors, to list a few. Because of their wide range of applications, we designed a new two-step synthesis for the formation of N-1-aryl benzotriazoles. 1-Hydroxy-1H-benzotriazole N-oxides were synthesized using phenylboronic acid (PhB(OH) …

In Situ Infrared Spectroscopic Study Of Iron-Catalyzed Hydromagnesiation Of Vinyl Arenes, Jessica Ann Rogers

Graduate Theses, Dissertations, and Problem Reports (ETD)

Iron catalysis, especially homogeneous catalysis, has been a resurging topic of organometallic chemistry research. Discussions of past and present mechanistic analyses for homogeneous iron catalysis will be discussed in Chapter 1. As an expansion of homogeneous iron catalysis, in situ infrared spectroscopy will be used to develop a full mechanistic study of iron-catalyzed hydromagnesiation of vinyl arenes. The kinetic analyses by both initial and observed rate measurements indicate complex concentration dependencies on the (PDI)iron catalyst as well as sacrificial Grignard reagent and styrene. These complexities are not limited to non-linear catalyst and Grignard initial rate and inhibition by styrene/Grignard at …

Avoiding Adverse Effects: New Ideas In Drug Discovery For Targeting Pparγ, Trey M. Patton

Graduate Student Theses, Dissertations, & Professional Papers

Peroxisome proliferator-activated receptor gamma (PPARγ) has been a drug target to treat type 2 diabetes for the last 20 years when rosiglitazone and pioglitazone were approved by the FDA in 1999. While effective at increasing insulin sensitivity, these drugs cause serious adverse effects due to their full agonist characteristics. For that reason, drug discovery efforts have attempted to reduce or prevent the amount of agonist character of new PPARγ targeting ligands. Unfortunately, there have been no new FDA approved drugs for the receptor. There is a need for new ideas to produce better quality pharmaceuticals that lessen the impact of …

Photoluminescent Zirconium Complexes For Visible Light Photoredox Catalysis, Yu Zhang

Graduate Theses, Dissertations, and Problem Reports (ETD)

Early transition metals like zirconium are attractive candidates for the design of luminescent molecules based on earth-abundant elements. Here, a series of zirconium complexes carrying two pyrrolyl-based ligands have been synthesized and characterized. These complexes are photoluminescent upon excitation with visible light and exhibit remarkably long emission lifetimes of hundreds of μs in solution at room temperature. Computational studies using time-dependent density functional theory (TD-DFT) were conducted to identify the nature of the luminescent excited states as mixed intra-ligand/ligand-to-metal charge-transfer (ILCT/LMCT) states. The electrochemistry studies revealed multiple reversible redox events for each zirconium complex. Furthermore, the excited state of the …

Copper-Catalyzed Regioselective Boracarboxylation Of Vinyl Arenes: Catalytic Efficiency And Synthetic Utility, Trina M. Perrone

Graduate Theses, Dissertations, and Problem Reports (ETD)

Hetero(element) carboxylation is an appealing transformation that involves the installation of CO2 and another hetero(element) in one step. This transition metal-catalyzed one-pot synthesis provides a route to achieve highly functionalized carboxylic acid products with an abundant and cheap C1 feedstock. This difunctionalization also avoids the use of reactive metal hydride species, which is a prominent limitation of hydrocarboxylation chemistry. A copper-catalyzed regioselective boracarboxylation of vinyl arenes has been developed to access pharmaceutically relevant β-boryl-α-aryl propionic acid products. One drawback of this reaction is the necessity for high catalyst loading to achieve catalytic turnover. To circumvent this issue, the reduction of …

The Chemical Analysis And Biological Activities Of The Secondary Metabolites From Dalea Mollis And Dalea Albiflora, Nicholas Peter Hansen

All Master's Theses

Multidrug resistance has increased since the introduction of drugs used to prevent growth and kill microorganisms in a host. This has caused a worldwide search to discover new drugs effective against microorganisms. Mechanisms of drug resistance include, but are not limited to, the production of biofilms and efflux pumps. Efflux pumps prevent antimicrobial drugs from reaching their biological target, so the coordinated use of efflux pump inhibitors and antimicrobial drugs has been identified as a potential treatment for multidrug-resistant microorganisms. The secondary metabolites of Dalea mollis and Dalea albiflora were tested against multidrug-resistant (MDR) and engineered strains of the fungi …

Synthesis Of 4-Methylbenzoate(2ʹ,4ʹ,6ʹ-Trimethoxyphenyl) Iodonium Tosylate, Thomas Ludwig Seidl, Aaron Moment, Charles Orella, Thomas Vickery, David R. Stuart

Chemistry Faculty Publications and Presentations

Hypervalent iodine continues to intrigue organic chemists with its diverse breadth of reactivity. The use of diaryliodonium salts as aryltransfer reagents has increased dramatically in the past decade as they have become more available by the development of efficient “one-pot” synthesis methods. Unsymmetrical diaryliodonium salts that selectively, and predictably, transfer one aryl group over the other are particularly desirable reagents, especially for the transfer of elaborate aryl groups to nucleophilic moieties. While the mesityl (Mes; 2,4,6-trimethylphenyl) group effectively serves as a general auxiliary in metal-catalyzed reactions of diaryliodonium salts, a broadly applicable auxiliary has not been adopted in metal-free reactions. …

Oxidative Degradation Of Lignin And Investigation Of Utilization Of Lignin-Derived Materials As Building Blocks For Epoxy Resins, Zhen Fang

Theses and Dissertations--Chemistry

Lignin, the second most abundant biopolymer on earth, is potentially a replaceable source for bulky fuels and chemical feedstocks. There have been numerous reports on methods for the oxidative cleavage of β-O-4 linkages but relatively few reports of how those methods affect other linkages that are present in lignin. We investigated how the β-1 and β-5 linkages respond under oxidative conditions proposed for lignin deconstruction based on their effect on β-O-4 linkages. Mechanochemical treatment of lignin can greatly improve the yield of monomer products and we applied a mechanochemical approach, using powerful ring-and-puck milling to promote lignin degradation. Along with …

Oxidative Depolymerization Of Lignin To Low Molecular Weight Aromatics, Yang Song

Theses and Dissertations--Chemistry

To date, most lignocellulosic biorefinery strategies have focused on optimizing conversion of cellulose to ethanol, leaving lignin as an underutilized biomass constituent. Lignin is engineered by nature with the intent to protect plants from chemical and biological attack; this leaves lignin with high structural irregularity and recalcitrance, rendering conversion of the lignin macromolecule to valuable products particularly challenging. Nevertheless, given that the economics of cellulosic ethanol production are strongly dependent on the value that can be obtained for the lignin co-product, the successful valorization of lignin is a crucial step in the transition towards a bio-based economy.

This thesis focuses …