Chemistry Commons^™

Cf⁺ Excitation In The Interstellar Medium, Benjamin Desrousseaux, François Lique, Javier R. Goicoechea, Ernesto Quintas-Sánchez, Richard Dawes

Chemistry Faculty Research & Creative Works

The detection of CF⁺ in interstellar clouds potentially allows astronomers to infer the elemental fluorine abundance and the ionization fraction in ultraviolet-illuminated molecular gas. Because local thermodynamic equilibrium (LTE) conditions are hardly fulfilled in the interstellar medium (ISM), the accurate determination of the CF⁺ abundance requires one to model its non-LTE excitation via both radiative and collisional processes. Here, we report quantum calculations of rate coefficients for the rotational excitation of CF⁺ in collisions with para- and ortho-H₂ (for temperatures up to 150 K). As an application, we present non-LTE excitation models that reveal population inversion …

Bacteria-Mediated Synthesis Of Cobalt(Ii,Iii) Oxide Nanostructures, Ryan Loughran

Honors Program Theses and Projects

This work describes the synthesis of Co₃O₄ using rod-shaped Gram-positive bacteria Lactobacillus rhamnosus as a template. The motivation behind this project was to find potentially cheaper and environmentally benign protocols in comparison to the current solution-based methods.

The Electronic Properties Of Ni(Pnn) Pincer Complexes Modulate Activity In Catalytic Hydrodehalogenation Reactions, Denan Wang, James R. Gardinier

Chemistry Faculty Research and Publications

Three chloronickel(II) complexes of PNN‐ pincer ligands with pyrazolyl and diphenylphosphino donors appended to different arms of diarylamido anchors were prepared and fully characterized. The three derivatives (1‐OMe, 1‐Me, 1‐CF₃) differ only by the identity of the para‐aryl substituent on the pyrazolyl arm with 1‐OMe being 310 mV easier to oxidize than 1‐CF₃. All three complexes are competent catalysts for hydrodehalogenation reactions of 1‐bromooctane and a variety of aryl halides in dimethylacetamide using NaBH₄ as both base and hydride source. Comparative studies using diverse substrates showed that catalytic activity correlates with electron donor properties; …

Functionalized Materials From Atom Transfer Radical Processes, Sean Fischer

Electronic Theses and Dissertations

This work is focused on the synthesis, characterization, and application of functionalized materials prepared from atom transfer radical processes. Atom transfer radical processes encompass both atom transfer radical addition (ATRA) and polymerization (ATRP) reactions, both of which are catalyzed by ppm amounts of copper complexes. The synthetic efforts of ATRA include increasing adduct selectivity through optimization of reaction conditions to generate small molecules in high to moderate yields. ATRA provides retention of the halogen moiety, which is an attractive functional group that can be further modified with other transformations. Specifically, the copper-catalyzed azide-alkyne [3+2] cycloaddition (CuAAC) allows for the realization …

Accurate Quantitation Of Hexavalent Chromium For Reference Standard Certification And Quality Control Testing Using Speciated Isotope Dilution Mass Spectrometry, James E. Henderson

Electronic Theses and Dissertations

The ability to perform accurate, repeatable, and defensible elemental and molecular speciated analysis is immensely significant for measurements that support human health, environmental science, and industry. This is especially true since trivalent chromium [Cr(III)] is necessary for proper nutrition, while hexavalent chromium [Cr(VI)] is extremely toxic, genotoxic, and carcinogenic. The main challenges associated with speciated analysis are related to reactive species that are continuously transformed or converted to other species during sample processing. Accurate determination of Cr(III) and Cr(VI) species require a method that is capable of monitoring and correcting for interconversion, bias, and instrumental error. Traditional quantitative methods, such …

Atom Transfer Radical Processes: From Catalyst Design To Polymer Synthesis, Characterization, And Application, Michael Novak

Electronic Theses and Dissertations

Due to the toxicity of heavy metals and their prevalence in the environment there exists a need to develop highly active transition metal catalysts ultimately reducing the amount needed for chemical transformations. Additionally, there is interest in the scientific community for creating new materials that can remove these pollutants from industrial wastewater prior to its release into the environment. The work presented here focuses on the reduction and removal of heavy metals from industrial hazardous waste by designing novel highly active catalysts and developing polymeric adsorbents.

Highly active catalyst complexes consisting of novel hybrid ligands, 2-(dimethylamino)ethyl-bis-[2-(pyridylmethyl)amine] (M1-T2), and bis[2-(dimethylamino)ethyl]-2-(pyridylmethyl)amine (M2-T1), …

Control Of Corrosion On Ss316l Using Surface Initiated Polymers, Alexander Rupprecht

Electronic Theses and Dissertations

Pitting corrosion is arguably one of the most destructive and dangerous forms of corrosion, resulting in damage to structures, the environment, and public health. In addition, damage caused to structures such as bridges, pipelines, and boats, corrosion also has a profound effect on the biomedical community. Implanted metallic devices (i.e., vascular stents and artificial joints) are prone to pitting corrosion caused by aggressive ions present in extracellular fluid. To provide a corrosion-resistant surface on SS316L, films of poly(styrene), poly(methyl acrylate), and poly(methyl methacrylate) were formed using surface-initiated atom transfer radical polymerization (SI-ATRP). The resulting hydrophobic polymer films had a fractional …

Nanomaterial Composites Based On Potassium Hexaniobate, Perovskites, And Iron Triazole Spin Crossover Complexes, Alexis A. Blanco

LSU New Orleans Theses and Dissertations

Development of novel materials with sought after properties has been the forefront in the field of nanomaterials. Hybrid nanomaterial architectures, or nanocomposites, is an important subgroup within the material chemistry umbrella. One such example of nanocomposite systems is peapod-like structures that are composed of 0D nanoparticles (“peas”) and 2D nanosheets (“pods”). Nanopeapods may display unique properties that were not attainable within individual components. BaTiO₃ nanoparticles can be produced using solvothermal methods (20 h) in the presence of Ba(NO₃)₂, titanium (IV) butoxide, and oleic acid as the surfactant. Synthesis parameters were modified to allow for both …

Applied Molecular Dynamics: From Targeting Viral Helicases, To Understanding The Interactions Of Cucurbituril Complexes In Ionic Solutions, Bryan Raubenolt

LSU New Orleans Theses and Dissertations

Molecular Dynamics simulations are a highly useful tool in helping understand the fundamental interactions present in a variety of chemical systems. The work discussed here illustrates it’s use in determining the conformational dynamics of the Zika and SARS-Cov-2 helicase in a physiological environment, largely in an effort to discover inhibitors capable of rendering the protein inert. Additionally, we show how it can be used to understand paradoxical trends in the anion-induced precipitation of Cucurbituril cavitands.

Viral helicases are motor proteins tasked with unwinding the viral dsRNA, a crucial step in preparing the strand to be translatable by host cells. By …

Fluorinated Phthalonitriles And Phthalocyanines: Synthesis And Spectroscopic Properties, Marius Pelmus

Seton Hall University Dissertations and Theses (ETDs)

Since their discovery at the beginning of the 20^th century, phthalocyanines (Pc) have come a long way; today they are replacing the porphyrins (natural products) in most of their applications. The functionalization of the organic macrocycle, the use of different metals, and the change of the axial ligands resulted in Pc applications in a wide range of fields, ranging from photochemistry, paints, catalysis, to fuel cells and cosmetic products.

In Dr. Gorun’s group was developed a series of electron-deficient Pcs that benefit from a Teflon-like chemical shield, meant also to break the π-π interactions, namely the F₆₄PcM …

Thermally Stable Fluorogenic Zn(Ii) Sensor Based On A Bis(Benzimidazole)Pyridine-Linked Phenyl-Silsesquioxane Polymer, Chamika U. Lenora, Nai-Hsuan Hu, Joseph C. Furgal

Chemistry Faculty Publications

A 2,6-bis(2-benzimidazolyl) pyridine-linked silsesquioxane-based semi-branched polymer was synthesized, and its photophysical and metal-sensing properties have been investigated. The polymer is thermally stable up to 285 °C and emits blue in both solid and solution state. The emission of the polymer is sensitive to pH and is gradually decreased and quenched upon protonation of the linkers. The initial emission color is recoverable upon deprotonation with triethylamine. The polymer also shows unique spectroscopic properties in both absorption and emission upon long-term UV irradiation, with red-shifted absorption and emission not present in a simple blended system of phenylsilsesquioxane and linker, suggesting that a …

The Tolerance Of Shewanella Woodyi For Electric Potentials And Heavy Metals As Biofilms, Christopher Thomas Mortensen

Honors Theses

Shewanella woodyi is a bioluminescent marine organism that is known to be metal tolerant and modulate the intensity of its luminescence with electrochemical potential. The viability of S. woodyi as a bioreporter for the toxic heavy metal zinc, copper, and silver was analyzed. Biofilms of S. woodyi was grown on marine broth agar plates and then exposed to various concentrations of each metal ion to evaluate biofilm response to the metal ions that were generated from an operating short circuited electrode containing either Zn, Cu, or Ag metal. The ability of the bacteria to tolerate the heavy metals and continue …

Synthesis Of Linear Oligo[N]Catenanes Via Orthogonal Metal Templation, Nathan Colley

Arts & Sciences Graduate Student Theses and Dissertations

No abstract provided.

Editorial Board

Karbala International Journal of Modern Science

No abstract provided.

In Silico Apc/C Substrate Discovery Reveals Cell Cycle-Dependent Degradation Of Uhrf1 And Other Chromatin Regulators, Jennifer L. Franks, Raquel C. Martinez-Chacin, Xianxi Wang, Rochelle L. Tiedemann, Thomas Bonacci, Rajarshi Choudhury, Derek L. Bolhuis, Taylor P. Enrico, Ryan D. Mouery, Jeffrey S. Damrauer, Feng Yan, Joseph S. Harrison, M. Ben Major, Katherine A. Hoadley, Aussie Suzuki, Scott B. Rothbart, Nicholas G. Brown, Michael J. Emanuele

College of the Pacific Faculty Articles

The anaphase-promoting complex/cyclosome (APC/C) is an E3 ubiquitin ligase and critical regulator of cell cycle progression. Despite its vital role, it has remained challenging to globally map APC/C substrates. By combining orthogonal features of known substrates, we predicted APC/C substrates in silico. This analysis identified many known substrates and suggested numerous candidates. Unexpectedly, chromatin regulatory proteins are enriched among putative substrates, and we show experimentally that several chromatin proteins bind APC/C, oscillate during the cell cycle, and are degraded following APC/C activation, consistent with being direct APC/C substrates. Additional analysis revealed detailed mechanisms of ubiquitylation for UHRF1, a key chromatin …

Synthesis Of The Oxidative Metabolites Of Di(2-Ethylhexyl) Phthalate And Analysis Of Metabolite Binding With Peroxisome Proliferator-Activated Receptors, Alexis Brooner

Departmental Honors & Graduate Capstone Projects

Di(2-ethylhexyl) phthalate (DEHP) is a persistent organic pollutant that is added to increase the flexibility of soft plastics, such as polyvinyl chloride (PVC). Since DEHP is not bound to the polymer, it leaches into the environment, leading to human exposure. When DEHP is metabolized by the body, it is cleaved into mono-(2-ethylhexyl) phthalate (MEHP). MEHP is then oxidized to produce the secondary-oxidized metabolites mono-(2-ethyl-5-carboxypentyl)phthalate (5cx-MEPP), mono-(2-ethyl-5-oxohexyl)phthalate (5oxo-MEHP), and mono-[2-(carboxymethyl)hexyl]phthalate (2cx-MMHP). DEHP and its metabolites interact with peroxisome proliferator-activated receptors (PPARs), which can alter lipid metabolism. To synthesize 5cx-MEHP, an enolate alkylation was performed with ethyl butyrate to form ethyl 2-ethyl-6-heptenoate. …

The Impact Of Biological Components On A Dog's Personality, Kinsley Batson

Fall Student Research Symposium 2020

We interact with dogs every day, and they are often referred to as "man's best friend." But what makes a dog the happy-go-lucky, cuddly fur ball of happiness that so many love? Similar to humans, there is a nature vs. nurture debate on what shapes a dog's personality. While it is likely a mixture of both, I've researched a variety of biological components that help to make a dog a dog. Some of these include face shape, how their brain responds to audio stimuli, and a specific gene, also found in children with Williams syndrome, that is thought to make …

Why Dogs Are Feared, Hannah Ericson

Fall Student Research Symposium 2020

From German Shepherds to Pit bulls, a specific breed of dog is often singled out as being more dangerous than the others. There are stories and myths behind the behavior of such breeds, as well as simply looking scary. In this presentation, I will discuss why certain traits in dogs promote fear (such as dark coloring) and why certain breeds promote fear - such as a modern day prejudice that is quite similar to racism in the human society.

Cloning Type Iv-B Crispr System Into A Plasmid, Olivia Gornichec, Kailey Welch

Fall Student Research Symposium 2020

Bacterial CRISPR-Cas systems have recently been repurposed as RNA-guided genome editors in research labs across the world. Yet CRISPR-Cas adaptive immune systems are very diverse and many systems remain uncharacterized. Discovering the structure and function of newly discovered and uncharacterized systems may further advance existing genome editing technologies, or lead to new ones. To better understand the function of the little-researched Type IV-B system we cloned the genes of a Type IV-B system from Mycobacterium J623 into a plasmid containing a target sequence of a Type IV-A and Type V system. The Type IV-B system was placed on the target …

Pure Breeding At Its Finest, Justin Hunter

Fall Student Research Symposium 2020

This is a poster of my research on the affects pure breeding has on dogs and their health. There is a focus as well on the focus on neoteny and its affects on dogs.

Synthesizing Octahedral Polyomavirus Capsids For Cryogenic Electron Microscopy, Miles Robertson

Fall Student Research Symposium 2020

Polyomavirus capsids are polymorphic under different chemical conditions. These capsids have been synthesized artificially using purified VP1, the primary building block of the capsid. Five VP1 proteins come together and form a highly stable structure called a pentamer, and these pentamers can form capsids (Figure 1). Depending on chemical conditions, the capsids can form three distinct sizes: T=7, octahedral and icosahedral (Figure 2). Only one form is found in infectious virions, and its structure has been well studied. However, no high-resolution structure of the octahedral capsid currently exists. The goal of this research is to solve the structure of the …

Dogs In The Home Improve The Quality Of Life Of The People Living Inside, Tanner Stevenson

Fall Student Research Symposium 2020

This poster explores how dogs improve the quality of life of the people they interact with. Regardless of underlying issues that the human faces, every dog helps to improve the situation of that human. From service animals helping to improve the quality of life of their owners in other ways than what meets the eye, to dogs improving the chance of allergy immunity for children, dogs impact the lives of humans for good. This project explores the way that studies have proven the worth of the dog in the home.

Enabling Mars Farms Through Microbial Remediation Of Wastewater, Tyler Wallentine

Fall Student Research Symposium 2020

This research evaluates the capacity of photoheterotrophic purple non-sulfur bacteria to utilize wastewater organics to grow and produce nitrogen-rich biomass. Inhibitory components of wastewater are determined. A scaled up production system is designed and utilized to culture bacteria in wastewater. The application of this technology in the production of agriculturally viable amounts of nitrogen-rich biomass is evaluated in the context of a Mars mission and enabling agriculture in a barren environment.

Synthesis Of Structurally Diverse Molecular Scaffolds Enabled By Protected Oxyallyl Cations, Joshua Andrew Malone

LSU Doctoral Dissertations

This dissertation focuses on the synthesis of diverse molecular scaffolds through the use of protected oxyallyl cation intermediates. Chapter One provides background on the generation and applications of oxyallyl and silyloxyallyl cations, while focusing on the direct nucleophilic capture of theses intermediates to generate functionalized ketones and silylenolates. Chapter Two depicts our approach to generate six-membered silyloxyallyl cations through the use of mild Brønsted acid activation. Regioselective nucleophilic capture of these intermediates successfully produced diverse a,a’-substituted silylenol ethers enabled by polar solvent and residual water.

Chapter three details strategies to generate 1,4-dicarbonyl compounds, focusing on the capture of cationic intermediates …

Understanding The Role Of Atom Trapping In The Evolution Of Hydrocarbon Transformation Catalyst Morphology, Griffin Alexander Canning

Chemistry and Chemical Biology ETDs

Converting alkanes to other, more chemically and economically valuable molecules requires catalysts that can survive elevated temperatures and highly reducing environments. These environments can cause many metal-nanoparticle based catalysts to sinter rapidly, causing a loss of activity. They must also tolerate the coke formation, as well, since coke can restrict access to active sites by gas phase molecules, thus lowering catalytic activity. While there are routes to improve both the sinter and coke resistance of catalysts, an alternative strategy is to develop a protocol for regenerating the activity of the catalyst in question when coke formation or sintering becomes problematic. …

Characterizations Of Bimetallic Silver-Copper Nanoparticles, Omar Lezcano

Undergraduate Honors Theses

The goal of this study was to characterize alloy nanoparticles with different bimetallic ratios of silver (Ag) and copper (Cu) by determining the composition and alloy structures. One specific objective was to determine how the composition affects the electrical properties of the nanoparticles in terms of electrical resistance and nanoparticle sintering. The desire for this study stems from the need to make conductive pastes for low-cost solar panel manufacturing. We performed experiments to develop the aqueous synthesis of core-shell bimetallic nanoparticles.

We investigated the room temperature sintering properties with the nanoparticles of varying compositions. The nanoparticles were characterized with several …

An Overview Of The Effect Of Bioaerosol Size In Coronavirus Disease 2019 Transmission, Marcelo I. Guzman

Chemistry Faculty Publications

The fast spread of coronavirus disease 2019 (COVID-19) constitutes a worldwide challenge to the public health, educational and trade systems, affecting the overall well-being of human societies. The high transmission and mortality rates of this virus, and the unavailability of a vaccine or treatment, resulted in the decision of multiple governments to enact measures of social distancing. Such measures can reduce the exposure to bioaerosols, which can result in pathogen deposition in the respiratory tract of the host causing disease and an immunological response. Thus, it is important to consider the validity of the proposal for keeping a distance of …

Iron(Iii)-Bipyridine Incorporated Metal–Organic Frameworks For Photocatalytic Reduction Of Co2 With Improved Performance, Yuan-Ping Wei, Sizhuo Yang, Peng Wang, Jin-Han Guo, Jier Huang, Wei-Yin Sun

Chemistry Faculty Research and Publications

Metal–organic frameworks (MOFs) represent an emerging class of platforms to assemble single site photocatalysts for artificial photosynthesis. In this work, we report a new CO₂ reduction photocatalyst (UiO-68-Fe-bpy) based on a robust Zr(IV)-MOF platform with incorporated Fe(bpy)Cl₃ (bpy refers to the 4′-methyl-[2,2′-bipyridine] moiety) via amine–aldehyde condensation. We show that this hybrid catalyst can reduce CO₂ to form CO under visible light illumination with excellent selectivity and enhanced activity with respect to its parent MOF and corresponding homogeneous counterpart. Using steady state and transient absorption (TA) spectroscopy, we show that the enhanced photocatalytic activity of UiO-68-Fe-bpy is attributed …

Structural Determinants Of Flavin Dynamics In A Class B Monooxygenase, Ashley C. Campbell, Reeder Robinson, Didier Mena-Aguilar, Pablo Sobrado, John J. Tanner

Chemistry Faculty Research & Creative Works

The ornithine hydroxylase known as SidA is a class B flavin monooxygenase that catalyzes the first step in the biosynthesis of hydroxamate-containing siderophores in Aspergillus fumigatus. Crystallographic studies of SidA revealed that the FAD undergoes dramatic conformational changes between out and in states during the catalytic cycle. We sought insight into the origins and purpose of flavin motion in class B monooxygenases by probing the function of Met101, a residue that contacts the pyrimidine ring of the in FAD. Steady-state kinetic measurements showed that the mutant variant M101A has a 25-fold lower turnover number. Pre-steady-state kinetic measurements, pH profiles, and …

Dark Iron-Catalyzed Reactions In Acidic And Viscous Aerosol Systems Efficiently Form Secondary Brown Carbon, Hind A. Al-Abadleh, Md Sohel Rana, Wisam Mohammed, Marcelo I. Guzman

Chemistry Faculty Publications

Iron-driven secondary brown carbon formation reactions from water-soluble organics in cloud droplets and aerosols create insoluble and soluble products of emerging atmospheric importance. This work shows, for the first time, results on dark iron-catalyzed polymerization of catechol forming insoluble black polycatechol particles and colored water-soluble oligomers under conditions characteristic of viscous multicomponent aerosol systems with relatively high ionic strength (I = 1–12 m) and acidic pH (∼2). These systems contain ammonium sulfate (AS)/nitrate (AN) and C3–C5 dicarboxylic acids, namely, malonic, malic, succinic, and glutaric acids. Using dynamic light scattering (DLS) and ultra high pressure liquid chromatography-mass spectrometry (UHPLC-MS), …