Other Chemistry Commons^™

Methanol Decomposition On Ni(111) And O/Ni(111), Henrik Öström, Bingjie Zhang, Tiffany Vallejo, Bryn Merrill, Jeremy Huang, Jerry Larue

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Methanol decomposition on Ni(111) surfaces has been studied in the presence and absence of oxygen using temperature-programmed desorption and temperature-dependent sum frequency generation spectroscopy. Under both conditions the C–H and O–H bonds break, forming carbon monoxide and atomic hydrogen on the surface. No C–O bond scission was observed, limiting the number of reaction pathways. The O–H bonds break first (>150 K), forming surface methoxy, followed by C–H bond breakage (>250 K). All atomic hydrogen desorbs from the surface as H2 through H+H recombinative desorption. H2 desorbs at a higher temperature in the presence of oxygen (>300 K) …

Esipt-Enabled Alkyne Migration Provides Rapid Access To Benzoxazinones, Andrés G. Muñoz

Electronic Theses and Dissertations

Benozoxazinones have long been of interest to agrochemical scientists and medicinal chemists because of their widespread biological activity. These scaffolds are also of interest to synthetic chemists, who recognize the utility of benzoxazinones for accessing functionalized heterocycles. The use of efavirenz, a benzoxazinone-based reverse transcriptase inhibitor used in the treatment of HIV-1, has brought increased attention to this privileged pharmacophore. While there exist numerous strategies for synthesizing benzoxazinones, methods that do not require the use of acutely toxic and environmentally hazardous reagents are lacking. Consequently, there is a need to develop new methods for constructing this valuable scaffold. Herein, we …

Electro-Organic Synthesis Of Schiff-Bases And Azo-Schiff Bases By Electrochemical Reduction Of The Nitro Group Group In Different Media, Siba Naseef, Deep Bakair, Rushdi Mador

Hadhramout University Journal of Natural & Applied Sciences

In this research synthesized amino is derivative of Schiff-bases by using electrolysis cell. Electrochemical reduction of para-nitroaniline and electrocatalysed condensation have been carried out at zinc electrode and anode from coal in the presence of potassium chloride as supporting electrolyte in water/methanol solution, and in the application of 20V voltage, where interaction is in two stages: the first stage involves the electrochemical reduction of nitro group and get the amino and the second phase also, azo Schiff was synthesized between para-nitroaniline and metoxybenzealdehyde by electrolysis method, which was supplied with a zinc electrode as cathode to perform electrochemical reduction in …

Oxidation Alters The Architecture Of The Phenylalanyl-Trna Synthetase Editing Domain To Confer Hyperaccuracy, Pooja Srinivas, Rebecca E. Steiner, Ian J. Pavelich, Ricardo Guerrera-Ferreira, Puneet Juneja, Michael Ibba, Christine M. Dunham

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

High fidelity during protein synthesis is accomplished by aminoacyl-tRNA synthetases (aaRSs). These enzymes ligate an amino acid to a cognate tRNA and have proofreading and editing capabilities that ensure high fidelity. Phenylalanyl-tRNA synthetase (PheRS) preferentially ligates a phenylalanine to a tRNA^Phe over the chemically similar tyrosine, which differs from phenylalanine by a single hydroxyl group. In bacteria that undergo exposure to oxidative stress such as Salmonella enterica serovar Typhimurium, tyrosine isomer levels increase due to phenylalanine oxidation. Several residues are oxidized in PheRS and contribute to hyperactive editing, including against mischarged Tyr-tRNA^Phe, despite these oxidized residues not …

Enhanced Platinum (Ii) Drug Delivery For Anti-Cancer Therapy, Marek T. Wlodarczyk

Dissertations, Theses, and Capstone Projects

Over the years, anti-cancer therapies have improved the overall survival rate of patients. Nevertheless, the traditional free drug therapies still suffer from side effects and systemic toxicity, resulting in low drug dosages in the clinic. This often leads to suboptimal drug concentrations reaching cancer cells, contributing to treatment failure and drug resistance. Among available anti-cancer therapies, metallodrugs are of great interest. Platinum (II)-based agents are highly potent and are used to treat many cancers, including ovarian cancer (OC). Cisplatin (cis-diaminedichloroplatinum (II)) is the first Food and Drug Administration (FDA)-approved metallodrug for treatment of solid tumors, and its mechanism …

Don't Sell Them Short, There's More To Bacterial Natural Products Than Antibiotics, Alison Clare Domzalski

Dissertations, Theses, and Capstone Projects

Recent genomic studies of microbiomes have revealed an overwhelming number of biosynthetic genes of unknown function. Most of these “cryptic” biosynthetic genes are not expressed in laboratory monocultures of individual microbes. Thus, there remains tremendous untapped potential for natural products discovery. Here we employ mixed microbial culture (MMC) as a simple yet powerful approach to awaken cryptic biosynthetic gene clusters. Our preliminary studies demonstrated that arrays of metabolites could be induced in MMCs upon environmental cues, such as surface adhesion. Using this system, we have screened, identified, and isolated bioactive bacterial metabolites, which were characterized structurally and biologically. Of the …

Assessing Competitive Reaction Rates In The Nitration Of 2-Methylbiphenyl, Biphenyl, And Toluene To Determine Steric Restriction In Resonance-Stabilized Planarization Of The Carbocation Intermediates, Victor A. Hanson, Tristan Wine, Kevin Bartlett, Joshua Padilla, Alessandro Rizzi

Honors Projects

Electrophilic aromatic substitution (EAS) reactions have long been a fundamental addition to sophomore-level organic chemistry classes, allowing students the opportunity to explore the electron donating and withdrawing effects of electrons contained in the substituents of the aromatic reactant. In this paper we present preliminary findings on the nitration of methylated biphenyls using kinetic and regioselective assessments to analyze steric influences on the planarization of 2-methylbiphenyl after EAS nitration. Our preliminary findings show that nitration favors the methylated phenyl ring of 2-methylbiphenyl, indicating that the steric influence of the methyl group restricts planarization of the carbocation intermediate. Furthermore, a competition nitration …

Photoassisted Synthesis Of Complex Polyheterocycles Via Rational Design Of Tailored Photoprecursors, Tina Alanna Holt

Electronic Theses and Dissertations

Natural products remain the most common source for drug leads, although diversity-oriented synthesis of unnatural complex molecules is gaining momentum. Our lab has been developing experimentally simple and straightforward approaches to complex molecular architectures via photochemical reactions involving a minimal number of experimental steps. In order to achieve this, photoprecursors were assembled via high yielding reactions. Next, we deployed photoinduced cycloadditions to create complex 3-dimentional structures. Lastly, with this obtained primary photoproduct, post-photochemical transformations were used to further grow its scaffold complexity.

One method to increase scaffold complexity is the [4+2] intramolecular cycloadditions of azaxylylenes, which are developed through standard …

Identification Of Degradation Products Formed From Glycerol And Terpenes In Aromatherapy Vaporizers, Alisha Ortiz

University Honors Theses

Degradation chemistry has been widely studied to assess the safety of aerosols in many fields. The study herein investigates the degradation products formed from MONQ personal aromatherapy devices- a new non-nicotine aromatherapy vape pen device on the market. These pens are marketed to alleviate symptoms of an unrecognized medical syndrome called “terpene deficiency”. These pens contain a glycerin (GL), or glycerol (VG), base and a blend of terpene-rich essential oils. Previous studies have investigated the degradation of both VG and terpenes and have shown that concerning compounds are released in the gas phase, including benzene, benzaldehyde, methacrolein and methyl vinyl …

I. Non-Degradable Polysiloxane Networks For Controlled Release Applications, And Ii. Additive Free, Degradable Silyl-Ether Furyl-Maleimide Networks, Caleb M. Bunton

Chemistry Theses and Dissertations

I. Two different series of non–degradable polysiloxane networks were prepared for the encapsulation and controlled release of a small molecule agent. For the first series, hydrosilylation was utilized to prepare networks of varying crosslink densities, as determined from swelling studies, from vinyl terminated and silylhydride functional poly(dimethyl)siloxanes. For the second series, the thiol-ene reaction was utilized to prepare networks of varying crosslink densities, as determined from swelling studies, from vinyl terminated and mercaptopropyl functional poly(dimethyl)siloxanes. Nile red dye was used as an encapsulated agent and dye release from each series of networks was measured using UV–vis spectroscopy to determine controllability …

Synthesis Of Unsymmetrical Bidentate Ligands From Secondary Phosphine Oxides, Malachy J. Brink, Ryan Anderson

Student Research, Papers, and Creative Works

Stereochemistry is a key component in the field of asymmetric catalysis. The properties of a molecule can be drastically changed with the change of one stereocenter. Typically, chirality is imparted to a metal by the ligand. "Chiral-at-metal" compounds are unique because the metal complex is chiral, but the ligands are not. Phosphine ligands are notoriously difficult to work with (pyrophoric, toxic, prone to oxidation). The goal of this research was to prepare unsymmetrical bidentate ligands using secondary phosphine oxides, which are air-stable and easy to handle on the benchtop.

Improving The Value Of The Coconut With Biotechnology, Fabian M. Dayrit, Quang Nguyen

Chemistry Faculty Publications

The fruit of the coconut tree is perhaps the most useful plant resource in the tropics. All parts of the coconut fruit have traditional uses that have been developed commercially in recent times (Foale 2003, Dayrit and Dayrit 2013). Due to its widespread household use, trade and industry statistics on coconut products reflect only part of the actual importance of the coconut. Today, coconut-based products have gone beyond the tropics and are consumed in many temperate countries and global regions such as Australia, China, Europe, North America, and the Middle East (Costello 2018). Coconut milk is the basic ingredient of …

“Treat Me Covalently” – New Tools To Improve Covalent Drug Design For Advancement Of Cancer Treatments, Yuliya Mazo

Student Theses and Dissertations

The goal of this project was to investigate the complex mechanism of covalent bonding among different molecules and their targets in a modeling software ICM-Pro. Specifically, it included the identification of fundamental aspects of a covalent bonding mechanism of the Michael addition reaction. Michael addition reaction of electrophilic α, β-unsaturated carbonyl compounds with a nucleophilic cysteine residue in thymidylate synthase, papain, and EGFR tyrosine kinase were examined. Thymidylate synthase and EGFR were chosen because they are important targets in the treatment of various types of cancer. In order to find the most optimal parameters, identification and assessment of the effect …

It's Elementary: A Review Of Forensic Analysis Techniques Of Inorganic Components Of Explosives, Sadie Schultz

Chemistry & Biochemistry Student Projects

No abstract provided.

Antioxidants And Beta-Carotene: A General Overview, A Research History, And Modern Scholarship, James Joseph Dickman Iv

Chemistry & Biochemistry Student Projects

This paper seeks to provide a cursory overview of oxidative stress and the accompanying biomolecules which are used to combat it. From there, the paper will provide a somewhat comprehensive list of major historical discoveries regarding antioxidant molecules, in particular beta-carotene. After this, an overview of more modern scholarship on the issue of these molecule’s antioxidant properties specific (from the 1970s onward) will be discussed up to modern times. The paper will conclude with an in depth look at the modern scholarship on beta-carotene that was performed here at Taylor University.

Bone Regeneration Via Inorganic/Organic Compatibility In A Newly Synthesized Hydrogel: Nhap-Bmp-2, Hannah Ewing

Chemistry & Biochemistry Student Projects

In this paper, nHAp-BMP-2 hydrogel is carefully synthesized in order to optimize the organic and inorganic compatibility which induces osteogenesis—the formation of new bone. This new method is a novel development within the medical field, giving more hope to those suffering from traumatic bone injuries. A drawback with using hydrogels is the difficulty of controlling peptide release in the affected areas. Too quick of a release alarms the human inflammatory response resulting in more substantial injury and an even prolonged recovery time. On the other hand, if the peptides that promote bioactivity are released too slowly, the bone will not …

Quantum Chemical Methods: Its History And Future, Erica Mitchell

Chemistry & Biochemistry Student Projects

No abstract provided.

Significance And Implications Of Vitamin B-12 Reaction Shema- Eth Zurich Variant: Mechanisms And Insights, David Joshua Ferguson

Chemistry & Biochemistry Student Projects

This is an undergraduate chemistry thesis document. This involves a discussion of the mechanisms and overall reactions involved in the total synthesis of vitamin B-12.

The History And Development Of Identification: Rediscovery And Application Of Egyptian Blue, Bailee Allen

Chemistry & Biochemistry Student Projects

The use of fingerprints as a form of identification in criminal cases has become a common method of conviction within the criminal justice system. However, with the recent rise in the number of people wrongly convicted, the typical sources of evidence have come into question about their reliability. Multiple common drawbacks found when using fingerprints dusting to obtain prints from crime scenes has led to researchers looking for more efficient ways to collect them that maintain high sensitivity and contrast. These are the two aspects that create the largest problem, especially on highly reflective and highly patterned surfaces. The discovery …

The Chemistry Of Jellybeans, Andrew Carter

Chemistry & Biochemistry Student Projects

Jellybeans are an amazing work of chemistry. In my paper, I outline the history and science behind this little candy. My paper describes taste receptors, molecular structure, and the analytical chemistry that help to make flavor science an interesting field of work.

Metallodrugs And Their Various Impacts On Disorders And Diseases, Paige Wagner

Chemistry & Biochemistry Student Projects

No abstract provided.

The Roundtable Of Scientific Communication: From Classroom To Course Creation, Back To Classroom And Beyond, Sean P. Hickey

LSU New Orleans Theses and Dissertations

This research encompasses many aspects of chemical education research including curriculum and pedagogical changes to the freshman and sophomore courses. Curriculum changes included the addition of recitations to the general chemistry and organic chemistry lectures and the creation of four new classes, CHEM 1001, 1002, 3091, and 3092. The addition of recitations was not limited to but was focused on improving DFW rates for these courses.

CHEM 3091 and 3092 are chemistry internship and undergraduate teaching assistant classes. These courses were necessary to offer outside internship opportunities and training for undergraduate teaching assistants, respectively. CHEM 1001 and 1002 are chemistry …

Preparation Of Enantioenriched Alkyltin Species And Their Application In Stereospecific Transformations, Glenn O. Ralph

Dissertations, Theses, and Capstone Projects

Organometallic reagents containing the tin-carbon bond are used extensively in modern synthetic chemistry for the formation of new bonds to carbon. Over recent decades, transition metal catalyzed cross coupling reactions between two C(sp²) centers have been widely developed. However, the introduction of a C(sp³) center complicates the catalytic cycle, and opens unproductive chemical pathways which lead to isomerization, elimination, and racemization. Our lab has developed a modified-Stille reaction to combat the deleterious effects of β-hydride elimination. Our protocol enables unactivated 2° alkyl organotin nucleophiles to undergo efficient cross coupling reactions with C(sp²) electrophiles, avoiding …

Drug Improvement And Design Involving G-Protein Coupled Receptors, Gabriel Saliba

Chemistry & Biochemistry Student Projects

No abstract provided.

A Chemical Overview Of Opioid Receptors And Their Agonists, Noah Kuszak

Chemistry & Biochemistry Student Projects

This work is a brief overview of the three main opioid receptors and some current research of the ways we can change the agonists and how they affect the opioid receptor pathway.

Dentin Biomodification Potency Of Proanthocyanidins, David J. Ryker

Chemistry & Biochemistry Student Projects

No abstract provided.

Seasonal Origins Of Soil Water Used By Trees, Scott T. Allen, James W. Kirchner, Sabine Braun, Rolf T. W. Siegwolf, Gregory R. Goldsmith

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Rain recharges soil water storages and either percolates downward into aquifers and streams or is returned to the atmosphere through evapotranspiration. Although it is commonly assumed that summer rainfall recharges plant-available water during the growing season, the seasonal origins of water used by plants have not been systematically explored. We characterize the seasonal origins of waters in soils and trees by comparing their midsummer isotopic signatures (δ2H) to seasonal isotopic cycles in precipitation, using a new seasonal origin index. Across 182 Swiss forest sites, xylem water isotopic signatures show that summer rain was not the predominant water source …

Near-Infrared Fluorescent Probes For Sensitive Determination Of Lysosomal & Mitochondrial Ph In Live Cells, Wafa Mazi

Dissertations, Master's Theses and Master's Reports

Varied intracellular pH levels are critical for various physiological processes such as enzymatic activity, cell proliferation and apoptosis, ion transport, and muscle contraction. Cellular compartments, like lysosomes, must retain an acidic environment (pH ~ 4.5) to activate hydrolytic enzymes necessary for the breakdown of large biomolecules. Another cellular organelle, the mitochondria, provides the cell with energy and must retain an alkalis environment (pH ~ 8.0) for proper function. Substantial lysosomal and mitochondrial pH deviation is associated with cellular dysfunction and disease. Therefore, the precise detection of lysosomal and mitochondrial pH is essential to provide a better understanding of cellular physiological …

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 …

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 …