Analytical Chemistry Commons^™

Hypervalent Iodine Compounds With Carboxylate And Tetrazolate Ligands, Avichal Vaish

Chemistry Theses and Dissertations

In modern organic chemistry, hypervalent (HV) iodine(III) compounds are frequently used as oxidizing agents but application of λ³-iodanes in polymer and material chemistry is still underexplored. This dissertation describes the preparation of dynamic and self-healing materials by employing ligand exchange reactions involving HV iodine(III) compounds of the type ArIL₂ (Ar = Aryl, L = ligand, e.g., carboxylate or (pseudo)halide). These compounds can undergo ligand exchange reactions in presence of nucleophiles (Nu^-) to form ArINu₂. Diacetoxyiodo benzene was successfully employed as a crosslinker to prepare dynamic and self-healing gels derived from carboxylate-containing polymers. Furthermore, …

Reactivity Of Photogenerated Amine Radical Cations, Qile Wang

Graduate Theses and Dissertations

Recently photoredox catalysis has emerged as a powerful tool in organic synthesis led by Professor McMillan, Stephenson, Yoon. Upon absorption of visible light, photocatalyst can be excited to its singlet state followed by intersystem crossing to form a long lived excited triplet state. While amine serves as electron donor, single electron transfer (SET) can happen between excited triplet photocatalyst and nitrogen atom on amine to give a reduced photocatalyst and amine radical cation.

Cyclopropylamines or cyclobutylamines can be oxidized by excited photocatalyst to generate amine radical cations and due to the ring strain, subsequent C-C bond cleavages can lead to …

Structure Elucidation Of A Pyrrolobenzodiazepine Alkaloid And A Biologically Active Polyketide Produced By Rhodococcus Sp. Mtm3w5.2 Via Two-Dimensional Nmr Spectroscopy, Garrett Johnson

Electronic Theses and Dissertations

As the battle against ever-increasing drug resistence bacteria rages on, novel and sometimes more complex natural products can be used to combat this. In this study, two-dimensional NMR techniques were utilized to collect a complete spectral data set for two natural products. The first structure, a synthesized Pyrrolobenzodiazepine alkaloid natural product was confirmed through these methods. The second, a strain of Rhodococcus, MTM3W5.2, produces a novel antibacterial molecule in broth cultures and the active compound was fractionated using a Sephedex LH-20 column. Chromatographic purification yielded a pure sample at 58.90 minutes, RT.58. HRMS data deduced an exact mass of …

Protein Detection And Structural Characterization By Mass Spectrometry Using Supramolecular Assemblies And Small Molecules, Bo Zhao

Doctoral Dissertations

Mass spectrometry (MS) has played an increasingly prominent role in proteomics and structure biology because it shows superior capabilities in identification, quantification and structural characterization of proteins. To realize its full potential in protein analysis, significant progress has been made in developing innovative techniques and reagents that can couple to MS detection. This dissertation demonstrates the use of polymeric supramolecular assemblies for enhanced protein detection in complex biological mixtures by MS. An amphiphilic random co-polymer scaffold is developed to form functional supramolecular assemblies for protein/ peptide enrichment. The influences of charge density and functional group pK_a on host-guest interactions …

Methodologies For Metal Functionalization Of Phosphorus Based Photopolymer Networks, Vanessa Béland

Electronic Thesis and Dissertation Repository

Photopolymer networks with phosphonium cation, alkyl phosphine and olefin functionality were designed, synthesized and functionalized with metals by metathesis, coordination and hydrometallation reactions, respectively. The materials were strategically designed so that the metal functionalization step could be monitored and quantified. In some cases, this involved characterization by IR, NMR, or X-ray spectroscopic techniques, or by comparison to molecular analogues. It was found that by using a bi-functional photopolymer network, the material could be bi-metallized by orthogonal mechanisms. All metallized polymer networks were tested for their suitability as precursors to metal-containing ceramics. The polymers were pyrolyzed, and on analysis it was …

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.

Production Of Singlet Oxygen (1O2) During The Photochemistry Of Aqueous Pyruvic Acid: The Effects Of Ph And Photon Flux Under Steady-State O2(Aq) Concentration, Alexis J. Eugene, Marcelo I. Guzman

Chemistry Faculty Publications

The photochemistry of pyruvic acid (PA) in aqueous atmospheric particles contributes to the production of secondary organic aerosols. This work investigates the fate of ketyl and acetyl radicals produced during the photolysis (λ ≥ 305 nm) of 5-100 mM PA under steady state [O₂(aq)] = 260 μM (1.0 ≤ pH ≤ 4.5) for photon fluxes between 1 and 10 suns. The radicals diffuse quickly into the water/air interface of microbubbles and react with dissolved O₂ to produce singlet oxygen (¹O₂^*). Furfuryl alcohol is used to trap and bracket the steady-state production of …

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.

An Improved Synthesis Of Adefovir And Related Analogues, Timothy P. O'Sullivan, Et Al

Physical Sciences Publications

An improved synthesis of the antiviral drug adefovir is presented. Problems associated with current routes to adefovir include capricious yields and a reliance on problematic reagents and solvents, such as magnesium tert-butoxide and DMF, to achieve high conversions to the target. A systematic study within our laboratory led to the identification of an iodide reagent which affords higher yields than previous approaches and allows for reactions to be conducted up to 10 g in scale under milder conditions. The use of a novel tetrabutylammonium salt of adenine facilitates alkylations in solvents other than DMF. Additionally, we have investigated how …

The Effects Of Reactant Concentration And Air Flow Rate In The Consumption Of Dissolved O2 During The Photochemistry Of Aqueous Pyruvic Acid, Alexis J. Eugene, Marcelo I. Guzman

Chemistry Faculty Publications

The sunlight photochemistry of the organic chromophore pyruvic acid (PA) in water generates ketyl and acetyl radicals that contribute to the production and processing of atmospheric aerosols. The photochemical mechanism is highly sensitive to dissolved oxygen content, [O₂(aq)], among other environmental conditions. Thus, herein we investigate the photolysis (λ ≥ 305 nm) of 10–200 mM PA at pH 1.0 in water covering the relevant range 0 ≤ [O₂(aq)] ≤ 1.3 mM. The rapid consumption of dissolved oxygen by the intermediate photolytic radicals is monitored in real time with a dissolved oxygen electrode. …

Scale Up Isolation Of Aaptamine For In Vivo Evaluation Indicates Its Neurobiological Activity Is Linked To The Delta Opioid Receptor, Nicole L. Mcintosh, Eptisam Lambo, Laura Millan-Lobo, Fei Li, Li He, Phillip Crews, Jennifer L. Whistler, Tyler Johnson

Tyler Johnson

Opioid receptors belong to the large superfamily of seven transmembrane-spanning (7TM) G protein-coupled receptors (GPCRs). As a class, GPCRs are of fundamental physiological importance mediating the actions of the majority of known neurotransmitters and hormones. The Mu, Delta, and Kappa (MOP, DOP, KOP) opioid receptors are particularly intriguing members of this receptor family as they are the targets involved in many neurobiological diseases such as addiction, pain, stress, anxiety, and depression. Recently we discovered that the aaptamine class of marine sponge derived natural products exhibit selective agonist activity in vitro for the DOP versus MOP receptor. Our findings may explain …

Bisthioether Stapled Peptides Targeting Polycomb Repressive Complex 2 Gene Repression, Gan Zhang

Dissertations, Theses, and Capstone Projects

Interactions between proteins play a key role in nearly all cellular process, and therefore, disruption of such interactions may lead to many different types of cellular dysfunctions. Hence, pathologic protein-protein interactions (PPIs) constitute highly attractive drug targets and hold great potential for developing novel therapeutic agents for the treatment of incurable human diseases. Unfortunately, the identification of PPI inhibitors is an extremely challenging task, since traditionally used small molecule ligands are mostly unable to cover and anchor on the extensive flat surfaces that define those binary protein complexes. In contrast, large biomolecules such as proteins or peptides are ideal fits …

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 …

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 …

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 …