Chemistry Commons^™

Biosynthetic Gene Clusters, Microbiomes, And Secondary Metabolites In Cold Water Marine Organisms, Nicole Elizabeth Avalon

USF Tampa Graduate Theses and Dissertations

Microorganisms and invertebrate animals from cold water marine environments, such as in Antarctica and in Ireland’s deep sea, are a rich source of secondary metabolites. In this dissertation, research was centered around secondary metabolism and natural product biosynthesis. The projects include the delineation of biosynthetic gene clusters hypothesized to be responsible for the biosynthesis of the palmerolides, stratification of the microbiome of the Antarctic ascidian Synoicum adareanum, genomic and peptidomic analysis of a host-associated Antarctic Pseudovibrio sp., and isolation and characterization of secondary metabolites from the Irish deep-sea coral Drifa sp.

Palmerolide A, the principle secondary metabolite associated with S. …

Development Of Next-Generation, Fast, Accurate, Transferable, And Polarizable Force-Fields For Heterogenous Material Simulations, Adam E. Hogan

USF Tampa Graduate Theses and Dissertations

Theoretical modeling is extremely useful in guiding to experiment; however quantitatively accurate modeling of energy-relevant small molecule sorption at the heterogeneous interfaces present in metal-organic materials (MOMs) is currently challenging. MOMs are an emerging class of materials consisting of inorganic clusters and organic linkers that offer great potential in the areas of gas storage, gas separation, and catalysis due to the possibility of large surface areas, complex heterogeneous surfaces, and rational designability. Efficient chemical separations involving these materials could reduce the US’s total energy consumption by approximately 10 to 15%. In this dissertation, the parameterization of small molecules and metal …

Conversion From Metal Oxide To Mof Thin Films As A Platform Of Chemical Sensing, Meng Chen

USF Tampa Graduate Theses and Dissertations

Chemical sensor is working as a widely used device which can be applied to the detection of specific chemicals that are existing in the environment especially in gas phase. The detection of combustible and toxic chemicals can be extremely important in the field of both industrial and civil activities. The chemical sensor is commonly operating by utilizing a chemical or physical interaction between the specific chemical compound and the sensing functional unit, to obtain an electronic signal caused by the property change and realize the chemical detection. Traditional chemical gas sensors such as catalytic gas sensor, thermal conductivity gas sensor, …

The Development Of Aapeptides, Lulu Wei

USF Tampa Graduate Theses and Dissertations

Non-natural peptide mimics are referred to as peptidomimetics, which contains unnatural backbones that mimic the primary peptide structure. There are a large number of peptidomimetics that have been developed including α-peptides, β-peptides, peptoids, arylamide oligomers, cationic polymers, and other peptidomimetics in the last decades. Compared to conventional peptides, these peptidomimetics have many advantages such as resistance to proteolysis, improved bioavailability, and reduced immunogenicity. However, the development of peptidomimetics is still far below the expectation due to the limitation of the availability of backbones. It is an urgent need to generate a new diverse library for novel drug discovery, design antimicrobial …

Multifunctional Metal-Organic Frameworks (Mofs) For Applications In Sustainability, Gaurav Verma

USF Tampa Graduate Theses and Dissertations

Climate change, affordable and clean energy, and responsible consumption and production are some of the important goals to be achieved for sustainable development. The current technologies used to address these challenges are energy and resource intensive. Furthermore, there are various limitations related to cost, storage, scalability and safety.Adsorbent materials are seen as a promising alternative remediation system due to their low energy consumption and minimal chemical waste production. However, most of the traditional adsorbents, such as activated carbon and zeolites lack the structural tunability to have long-term effectiveness and their use is limited. As discussed in Chapter 1, metal organic-frameworks …

Sustainable Non-Noble Metal Based Catalysts For High Performance Oxygen Electrocatalysis, Swetha Ramani

USF Tampa Graduate Theses and Dissertations

Current energy crisis has dramatically shifted the focus of technological advancements towards clean and renewable forms of energy. Continued dependence and utilization of fossil fuels has created global awareness on harmful greenhouse gas emissions and climate change. A need for sustainable technology has gained a lot of significance in the recent years. This has led to the development of devices and technologies that rely on environmentally friendly electrochemical conversion and storage of energy. One such advancement that generates electrical energy from chemical reactions is known as fuel cell technology. While fuel cells have demonstrated potential in replacing the conventional technologies …

Design, Synthesis Of Axial Chiral Triazole, Jing Wang

USF Tampa Graduate Theses and Dissertations

This thesis contains three parts: 1) The briefly review of chiral P, N-ligands. 2) The summary of triazole as ligands. 3) The attempt of designing, synthesizing the chiral triazole ligands.

In the first part, we have reviewed all the major P, N-ligands in the history, including how they were synthesized and resolved into single enantiomer. We also used some examples to show their utility potential in different reactions.

In the second part, we summarized the triazole ligands which mainly developed by our group including their structures, their potential and utility in different types of chemical reactions.

In the last part, …

Covalent Organic Frameworks As An Organic Scaffold For Heterogeneous Catalysis Including C-H Activation, Harsh Vardhan

USF Tampa Graduate Theses and Dissertations

Linking small organic molecules into an extended solid usually afford disordered amorphous polymers. The instigation of order into such a material is of profound interest to induce inherent fine control of the overall structure. Covalent organic frameworks (COFs) are new class of porous crystalline material prepared by connecting organic building blocks via strong covalent bonds. The judicious choice of organic monomers can give rise to highly ordered and predictable frameworks with high crystallinity, surface area, and thermal/chemical stability. The role of connecting linkages such as B─O, C─C, C─N extends the principle of fundamental molecular covalent chemistry to the formation of …

Development Of Ultrasonic-Based Ambient Desorption Ionization Mass Spectrometry, Linxia Song

USF Tampa Graduate Theses and Dissertations

Ambient desorption/ionization techniques (ADI) have drawn significant attention in mass spectrometric instrumentation development. The analyte classes that are successfully studied by any ADI mass spectrometry (MS) method strongly depends on how gas-phase ions are generated. Spray-based techniques may ionize molecules across a wide range of mass-to-charge ratios, but are commonly used for polar analyte, however, suffers from severe matrix effect. Contrastingly, methods employing electric (or laser) plasmas are capable of ionization of polar and nonpolar analytes suffering from less matrix effect, but primarily targeting those with low molecular masses. Thus far, developments of universal ionization methods, which do not depend …

Chemical Investigation Of Floridian Mangrove Endophytes And Antarctic Marine Organisms, Bingjie Yang

USF Tampa Graduate Theses and Dissertations

Nature creates diseases and illnesses for mankind, however, nature also provides therapeutics by making biological systems produce secondary metabolites. Although the secondary metabolites originally play roles in chemical defense or evolution, researchers have been working on them for drug discovery. Plants, fungi and marine organisms have been mostly explored by natural products chemists over the century and contributed most drugs to the market. With the increasing need of new drugs resulting from drug resistance and pathogen evolution, the natural products area has been focused on developing innovative methodologies to achieve higher efficiency of isolating new bioactive compounds.

This dissertation herein …

A Chemical Investigation Of Three Antarctic Tunicates Of The Genus Synoicum, Sofia Kokkaliari

USF Tampa Graduate Theses and Dissertations

Marine invertebrates, mainly sponges, tunicates and corals, have in the past few decades attracted the interest of the scientific community in regard to their secondary metabolites and their potential as leads in drug discovery. The genus Synoicum is comprised of multiple organisms found in both deep and shallow waters, tropical and cold environments around the world. The majority of the members of this genus that have been investigated can be found in shallow tropical waters due to the ease of accessing and collecting them. Of the cold environments, Antarctica is a representative of the environments where members of the Synoicum …

Construction Of Giant 2d And 3d Metallo-Supramolecules Based On Pyrylium Salts Chemistry, Yiming Li

USF Tampa Graduate Theses and Dissertations

Pyrylium salts are a type of six-membered cationic heterocycles with one positively charged oxygen atom. Since the discovery of pyrylium salts in 1911, such salts have been underappreciated for a long time. Until 1960s, the importance of pyrylium salts has been realized as versatile precursors in a variety of organic syntheses. Due to their high reactivity towards various nucleophiles, pyrylium salts were widely used for the convenient synthesis of diverse heterocyclic compounds. Starting from 1980s, the high reactive feature of pyrylium salts were further utilized to synthesize viologen polymers with pyridinium salts in the backbones. During the past two decades, …

Breakthroughs In Obtaining Qm/Mm Free Energies, Phillip S. Hudson

USF Tampa Graduate Theses and Dissertations

The computation of free energy is pivotal to understanding the fundamental nature of chemical phenomena. That is, whether a specific molecular outcome occurs spontaneously or is inherently unfavorable. The need to do this with consistent accuracy begs for the use of quantum mechanical (QM) methods. However, techniques for directly computing free energy differences with QM or mixed QM/MM methods are untenable, as the computational expense is quite exorbitant. At present, the most feasible approach for obtaining QM/MM free energies is employing the so-called indirect cycle, which relies on accurately computing free energy differences between low (e.g., molecular mechanical, MM) and …

New Synthetic Methodology Using Base-Assisted Diazonium Salts Activation And Gold Redox Catalysis, Abiola Azeez Jimoh

USF Tampa Graduate Theses and Dissertations

Over the past two decades, homogeneous Au(I) catalysis has been a valuable synthetic tool for activating a series of unsaturated carbon-carbon bonds towards nucleophilic attack. Despite this progress, Au(I/III) redox chemistry has not been well explored. This is largely due to the challenges associated with the high oxidation potential of gold. Hence, the need for an efficient and safe method for Au oxidation.

Herein, a base-assisted diazonium salt activation has been used to facilitate Au redox reactions under mild reaction conditions. This oxidative coupling method afforded functional isoxazolines with good to excellent yields, while the alternative photoactivation method provided trace …

Laser-Induced Breakdown Spectroscopy For Elemental Analysis In Bioarchaeology And Forensic Anthropology, Kelsi N. Kuehn

USF Tampa Graduate Theses and Dissertations

Within bioarchaeology and forensic anthropology, the current processes of differentiating between individual human skeletal remains are imprecise, costly, and inefficient. A novel analytical technique within anthropology, laser-induced breakdown spectroscopy (LIBS) can aid in the identification of human remains using rapid laser ablation occurring at the micro-scale, making the technique virtually non-destructive to the sample. Considering this, LIBS could offer a superior method for materials discrimination and human identification. This research sought to examine whether LIBS can be used to obtain elemental signatures within bones to distinguish individuals from one another in a rapid, non-destructive manner. Seven human skeletal donors and …

Analyzing The Retention Of Knowledge Among General Chemistry Students, James T. Kingsepp

USF Tampa Graduate Theses and Dissertations

General chemistry is a survey course meant to form a foundation for students’ to build upon as they progress into chemistry sub-disciplines. The effectiveness of this foundation rests heavily on students’ abilities to retain or relearn concepts from the course. This study seeks to investigate the utility of a measure of general chemistry students’ knowledge retention across the time period of one semester. This approach was enacted in five different courses of either first or second semester general chemistry. The results showed that one-quarter to one-half of students exhibited a high rate of retention across the semester. A smaller group, …

Optimization Of A Digital Ion Trap To Perform Isotope Ratio Analysis Of Xenon For Planetary Studies, Timothy Vazquez

USF Tampa Graduate Theses and Dissertations

Ion trap mass spectrometers present a powerful analytical tool which not only enables mass spectrometric determination of analyte species but also has the added feature of being able to act as an ion storage device. As a mass spectrometer, ion traps can achieve a reasonable mass range with flexible mass resolution while boasting a considerably smaller footprint when compared to conventional time-of-flight or magnetic sector instruments. Due to their smaller geometries, high-pressure tolerance, and ability to perform tandem mass spectrometry, ion trap mass spectrometers are ideal candidates for portable applications such as deployment to another planetary body. While ideal candidates …

Asking Why: Analyzing Students' Explanations Of Organic Chemistry Reaction Mechanisms Using Lexical Analysis And Predictive Logistic Regression Models, Amber J. Dood

USF Tampa Graduate Theses and Dissertations

In order to evaluate student understanding of chemical reactions and reaction mechanisms, it is necessary to ask students to construct written or oral explanations of mechanistic representations. Studies have shown that students can reproduce pictorial representations of organic chemistry mechanisms without understanding the meaning of the representations. Grading written assessments is time-consuming, which limits their use in large-lecture courses. To address this limitation, lexical analysis and logistic regression techniques can be used to develop models that predict human scoring for constructed-response items. In this dissertation, students’ responses to constructed-response items about what is happening and why in organic chemistry reaction …

Advancing Equity Amongst General Chemistry Students With Variable Preparations In Mathematics, Vanessa R. Ralph

USF Tampa Graduate Theses and Dissertations

Reducing the inequities propagating the lack of representation in Science, Technology, Engineering, and Mathematics (STEM) careers has become a national imperative made increasingly complex given the inequitable preparations in science and mathematics students experience before college. A common institutional-level approach to promoting equity is the use of math and science prerequisites to prepare students who seek to enroll in lower-level STEM coursework. However, the literature does not support the efficacy of this approach, finding no substantive improvement to student performance despite considerable financial and time costs to students, instructors, and universities alike. Set in first-semester General Chemistry courses taken early …

Differential Mobility Spectrometry-Mass Spectrometry (Dms-Ms) For Forensic And Nuclear-Forensic Applications, Ifeoluwa Ayodeji

USF Tampa Graduate Theses and Dissertations

In forensics and nuclear-forensics, the current lab-based analytical technique employed can be laborious, time consuming, and less suitable for in-situ and real time screening. However, it is important to develop fast and fieldable instrumental technique, without a tradeoff for its high throughput, for drug screening and radionuclear analysis. The underlying factors to be considered in the instrument development ranges from: high potency of samples, even at very low concentration; complex nature of samples in the surrounding environment; real-time chemical composition variation; and instrument size, weight and power (SWAP) consideration. Differential mobility spectrometry (DMS), also known as field asymmetric waveform ion …