Chemistry Commons^™

Turning Ligands On Their Side: Computational Investigation Into The Binding Of N2o And N2 In Transition Metal Complexes, Cole Donald

Electronic Theses and Dissertations

Common greenhouse gas nitrous oxide (N₂O) is a thermodynamically potent and environmentally benign oxidant, making it a desirable target for metal center activation. Unfortunately, N₂O is a poor ligand for transition metals due to its weak sigma-donating and pi-accepting properties; as a result, few transition metal complexes capable of interacting with N₂O have been found. As the primary source of all nitrogen in organisms, abundant gas dinitrogen (N₂) is a crucially important tiny molecule and an essential part of daily existence. However, due to its inertness, it has limited practical uses in …

Unassisted Photoelectrochemical Solar-To-Hydrogen On Cubi2o4 Photocathodes Using Glycerol As A Sacrificial Oxidant, Caroline Eddy

Chemistry & Biochemistry Undergraduate Honors Theses

The need to decarbonize society has driven the development of alternative energy technologies. Solar panels are capable of generating electricity at large scale and at competitive costs to fossil fuels, such as coal or natural gas. However, they are only capable of generating electricity when the sun is out. It is therefore necessary to understand how to store that energy for on-demand use. It is also desirable that the storage be portable, lightweight, and compatible with transportation infrastructure like fossil fuels are. A very desirable chemical fuel is H₂ which can be produced simply by water electrolysis. Production of …

Designing Single Molecule Diode, Tinsae Alem

Longwood Senior Theses

The field of single molecule electronics is based on using single molecule devices to control current in electronic circuits. One area of interest is to reproduce the functionality of traditional components such as wires, switches, and diodes using single molecule junctions. We used computational chemistry to design diodes to investigate what molecular features affect their performance including using different donors, acceptors, and connectors. A comparison of the diode's performance was made by comparing the rectification ratio. About 50 diodes were designed and tested, with rectification ratios ranging from 1.0 to 5.8. The results indicate that multiple factors have a significant …

Development Of In Situ Second-Order Nonlinear Optical Scatterings For Molecular Behaviors At Aerosol Surfaces, Yuqin Qian

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Aerosol particles are one of the most important components of the atmosphere. During the growth of aerosol particles, they directly or indirectly affect air quality, human health, and environmental chemistry. Therefore, understanding the chemical and physical properties of such particles is an important scientific, engineering, and medical issue. The growth of aerosol particles in the atmosphere is closely related to the chemical structure at its surface, as well as the heterogeneous reactions which take place at and below the particle’s surface. However, there is a lack of suitable surface-specific analytical techniques which directly measure the chemical structure of aerosol particle …

Functional Characterization Of The Newly Discovered Type V Crispr-Cas Protein Cas12a2, Dylan J. Keiser

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Similarly to people, bacteria are under the treat of infection by viruses. To circumvent these threats, bacteria evolve complex immune systems. Our understanding of some of these immune systems has led to many advancements in the field of Biotechnology including tools that made expressing proteins for study in a lab easier, tools that revolutionized the feasibility of gene editing, and tools that could change the way we think about viral diagnostics and cancer therapeutics. A certain type of immune system that bacteria use to fight virus is called a CRISPR system. Presented here is work to understand the function of …

Perfect Polar Alignment Of Parallel Beloamphiphile Monolayers: Synthesis, Characterization, And Crystal Architectures Of Unsymmetrical Phenoxy-Substituted Acetophenone Azines, Harmeet Bhoday, Michael Lewis, Steven P. Kelley, Rainer Glaser

Chemistry Faculty Research & Creative Works

It remains a great challenge to achieve polar order in organic molecular crystals because anti-parallel alignment of side-by-side molecules is intrinsically preferred. We have addressed this problem with a rational design that focuses on the polar stacking of parallel beloamphiphile monolayers (PBAMs) with strong lateral quadrupole-quadrupole attractions. We employ arene-arene interactions as lateral synthons. The first successes were achieved with unsymmetrical donor (X), acceptor (Y) substituted acetophenone azines which form polar PBAMs with double T-contacts between the azines. Near-perfect alignment was achieved with the methoxy series of (MeO, Y)-azines with Y=Cl, Br, I. Here, we report on the synthesis, the …

Veratrum Parviflorum Poisoning: Identification Of Steroidal Alkaloids In Patient Blood And Breast Milk, Jared T. Seale, Xinzhu Pu, Owen M. Mcdougal

Chemistry and Biochemistry Faculty Publications and Presentations

Introduction

The Veratrum genus is composed of plants containing a diverse set of steroidal alkaloids. Veratrum plant material has been utilized for centuries as herbal medicines, however the alkaloids have such a low therapeutic index that they are not used in modern medicine. Here we report an incident of inadvertent ingestion of V. parviflorum by hikers in Georgia that allowed detection, and in several instances identification of alkaloids from the plant, and correlated their presence within patient blood and breast milk specimens.

Case history

Eight patients, three male and five female, presented in the spring of 2020 and 2021 with …

Elucidation Of Active Site And Mechanism Of Metal Catalysts Supported In Nu-1000, Hafeera Shabbir

All Dissertations

Advances in extraction of shale oil and gas has increased the production of geographically stranded natural gas (primarily consisting of methane (C1) and ethane (C2)) that is burned on site. A potential utilization strategy for shale gas is to convert it into fuel range hydrocarbons by catalytic dehydrogenation followed by oligomerization by direct efficient catalysts. This work focuses on understanding metal cation catalysts supported on metal-organic framework (MOF) NU-1000 that will actively and selectively do this transformation under mild reaction conditions, while remaining stable to deactivation (via metal agglomeration or sintering). I built computational models validated by experimental methods to …

Characterization Of An Amine-Thiol Cosolvent System : Ethylenediamine And Mercaptoethanol, Fernanda Giongo Fernandes

Legacy Theses & Dissertations (2009 - 2024)

Since its introduction, the amine-thiol cosolvent system has been successfully utilized for the deposition of various thin-film devices, but its mechanism of action is still uncertain. Herein, we have attempted to dissect some of the chemical characteristics of amine-thiol cosolvents, with a special interest taken towards a mixture of ethylenediamine (en) and mercaptoethanol (ME). Conductivity was measured for multiple amine-thiol combinations at different ratios to determine extent of ionization in solution, with en-ME having one of the highest solution conductivities. Exposing the solution to air for several days was found to decrease the conductivity of en-ME, indicating the formation of …

Organic Gunshot Residue : Detection, Identification, And Characterization For Forensic Purposes, Shelby R. Khandasammy

Legacy Theses & Dissertations (2009 - 2024)

The major focus of this thesis was to explore methods for the detection, identification, and characterization of organic gunshot residues (OGSRs) for forensic purposes using various spectroscopic techniques. There are four major projects detailed in this thesis. The first project details the development of a novel-two step method for the detection and identification of organic gunshot residues using fluorescence spectroscopy for detection and Raman spectroscopy as a confirmatory step. The second chapter builds upon the study conducted in the first chapter by applying the novel-two step method covered in the first chapter to OGSRs directly fired into cloth substrates. This …

Soil From Footwear Is A Newly Rediscovered Type Of Forensic Evidence Due To The Application Of Modern Analytical Techniques : A Review, Rhilynn Haley Ogilvie

Legacy Theses & Dissertations (2009 - 2024)

Traces of soil discovered on a footwear were historically among the first types of evidence used by crime scene investigators. This type of evidence has been rediscovered recently due to the application of powerful analytical techniques providing quantitative characteristics of the soil (bio)chemical composition. Advanced statistical analysis of the quantitative data further improves the probative value of the soil evidence. The article overview main aspects of the emerging techniques for the forensic soil analysis and the factors that challenge data interpretation including mixing, contamination, and composition complexity. Overcoming these issues is crucial for utilizing soil analysis for forensic purposes.

Turning Density Functional Theory Calculations Into Molecular Mechanics Simulations : Establishing The Fluctuating Density Model For Rna Nucleobases, Christopher A. Myers

Legacy Theses & Dissertations (2009 - 2024)

Molecular mechanics (MD) simulations and density functional theory (DFT) have been the backbone of computational chemistry for decades. Due to its accuracy and computational feasibility, DFT has become the go-to method for theoretically predicting interaction energies, polarizability, and other electronic properties of small molecules at the quantum mechanical level. Although less fundamental than DFT, molecular mechanics (MM) algorithms have been just as influential in the fields of biology and chemistry, owing their success to the ability to compute measurable, macroscopic quantities for systems with tens of thousands to hundreds of thousands of atoms at a time. Nevertheless, MD simulations would …

Molecular Dynamics Simulations Of The Adenylate Kinase Enzyme And Its Mutant States, Beata Izabella Dulko Smith

Chemistry & Biochemistry Dissertations - Archive

Adenylate kinase (AK) is a small, monomeric enzyme present across all domains of life. It is responsible for maintaining homeostasis of an intracellular adenylate pool and catalyzes a reversible transfer of the phosphoryl group from NTP (nucleoside triphosphate) to NMP producing two NDP molecules. While most known isoforms take ATP as phosphate donor, AK3 present in mitochondrial matrix employs GTP. Crystallographic investigations revealed that the basis for its selectivity for GTP over ATP came from an additional hydrogen bond between guanosine’s O6 and backbone nitrogen of threonine is responsible for recognition of GTP. Molecular dynamics (MD) simulations have demonstrated that …

Development Of Colorimetric And Fluorescent Antibiotic Biosensors And Synthesis Of Drug-Related Biomimetic Molecules For Calcium Carbonate Polymorph Control And Stabilization, Shan Hazoor

Chemistry & Biochemistry Dissertations - Archive

Polydiacetylene (PDA) polymers are conjugated macromolecules with desirable sensing properties. The presence of alternate double and triple bonds (en-yne subunits) generates electron delocalization in the PDA backbone, yielding a characteristic blue color, which changes to red upon environmental perturbations to the conjugated backbone structure. In chapter 1 PDA polymers containing a functional monomer 10,12- pentacosadiynoic acid-vancomycin conjugate (PCDA-Van) were prepared. Syntheses of different monomers containing different polar head groups were carried out to investigate a compatible monomer with PCDA-van stability. Gram-positive bacterial cell wall sequencing oligopeptides (OP) D-Ala-D-Ala and L-Lys-D-Ala-D-Ala were synthesized as a model for bacterial sensing. The PCDA-Van …

Probing Short-Range Structural Distortion Of Stereochemically Active Lone Pairs In Extended Solid-State Materials, Uyen Phuong Dang

Chemistry & Biochemistry Dissertations - Archive

The structural and electronic effects of the lone pairs play an important role in magnetic, photocatalytic, and semiconducting behaviors of materials. Investigating the role of stereochemically active ns2 lone pairs derived from p-block cations in solid-state materials is important to phenomena associated with polarizable bonding, e.g., ferroelectricity. The effect of lone pairs in ferroelectric polarization has been studied on the lead metaniobate in which the covalency between Pb and O stabilizes the in-plane polarization which leads to orthorhombic symmetry. PbTiO3 has been widely studied for ferroelectric polarization associated with the off-centering of Ti in TiO6 due to the characteristic 6s2 …

Intelligent Fluorescence Image Analysis Of Giant Unilamellar Vesicles Using Convolutional Neural Network, Il Hyung Lee, Sam Passaro, Selin Ozturk, Juan Ureña, Weitian Wang

Department of Chemistry and Biochemistry Faculty Scholarship and Creative Works

Background: Fluorescence image analysis in biochemical science often involves the complex tasks of identifying samples for analysis and calculating the desired information from the intensity traces. Analyzing giant unilamellar vesicles (GUVs) is one of these tasks. Researchers need to identify many vesicles to statistically analyze the degree of molecular interaction or state of molecular organization on the membranes. This analysis is complicated, requiring a careful manual examination by researchers, so automating the analysis can significantly aid in improving its efficiency and reliability. Results: We developed a convolutional neural network (CNN) assisted intelligent analysis routine based on the whole 3D z-stack …

Rational Design Of Precisely Tailored Electrocatalysts For Efficient And Durable Electrocatalytic Devices, Mohmed Sanad Noufal

Open Access Theses & Dissertations

Due to their superior conversion efficiency, high power density, and green nature, sustainable energy technologies such as Fuel cells and Zinc-air batteries, once installed to produce green hydrogen fuel as well as energy storage devices, are expected to play an essential role in reducing the environmental effect of human transportation by replacing fossil fuels. However, the current bottleneck for the low-temperature polymer membrane fuel cells that dominate the fuel cell vehicle market is the sluggish kinetics of the oxygen reduction reaction (ORR) at the cathode. The slow ORR kinetics significantly reduce the efficiency of chemical-electrical energy conversion. Similarly, hydrogen production …

Rapid Detection Of Recurrent Non-Muscle Invasive Bladder Cancer In Urine Using Atr-Ftir Technology, Abdullah I. El-Falouji, Dalia M. Sabri, Naira M. Lofti, Doaa M. Medany, Samar A. Mohamed, Mai Alaa-Eldin, Amr Mounir Selim, Asmaa A. El Leithy, Haitham F. Kalil, Ahmed El-Tobgy, Ahmed Mohamed

Chemistry Faculty Publications

Non-muscle Invasive Bladder Cancer (NMIBC) accounts for 80% of all bladder cancers. Although it is mostly low-grade tumors, its high recurrence rate necessitates three-times-monthly follow-ups and cystoscopy examinations to detect and prevent its progression. A rapid liquid biopsy-based assay is needed to improve detection and reduce complications from invasive cystoscopy. Here, we present a rapid spectroscopic method to detect the recurrence of NMIBC in urine. Urine samples from previously-diagnosed NMIBC patients (n = 62) were collected during their follow-up visits before cystoscopy examination. Cystoscopy results were recorded (41 cancer-free and 21 recurrence) and attenuated total refraction Fourier transform infrared (ATR-FTIR) …

Photoproducts And Transformations Of Organic Pollutants In Aquatic Environments, Elizabeth Whisenhant

LSU New Orleans Theses and Dissertations

The degradation of petroleum-derived organic pollutants in aquatic systems occurs through lengthened exposure to UV and visible light. In this thesis, organic pollutants include crude oil, refined fuels, and plastic particles or films. The photo-oxidation of these pollutants are monitored over natural waters. To characterize the molecular signatures of photo-oxidized petroleum, bench-scale spills of refined fuels and crude oil were irradiated over Alaskan waters. A 4-component fluorescence PARAFAC model revealed a unique feature associated with photo-oxidized refined fuel unlike traditional “microbial”- or “terrestrial-like” components. In contrast, crude oil photolytically decomposed into humic-like components and oxidized aliphatics. FT-ICR MS data corroborated …

Synthesis And Electrochemical Characterization Of Alkali Metal Borides As Redox Active Anion Frameworks, Michael R. Shabetai

LSU New Orleans Theses and Dissertations

Redox activity in intercalation cathodes is commonly attributed to changes in oxidation states of transition metal ions. Recently, a growing body of evidence revealed that the redox activity of oxygen contributes to the capacity of some known cathodes. We focused on designing an oxygen free intercalation cathode with redox-active anions. In order to overcome the entropic driving force for the decomposition of a charged redox active anion cathode, we looked for chemistries with solid (no gases) possible decomposition products. Additionally, the involvement of anions in a network of covalent bonds with shared electrons was considered as a possible way for …

Tools For Predicting Emulsification Capacity Of Crude Oil Exposed To Sunlight: Impact Of Photoproduced Carboxylic Acids On Emulsion Stability, Chaka Nacaya Brown

LSU New Orleans Theses and Dissertations

The role of acids in the formation of emulsions from sunlight exposed petroleum is not well understood. To elucidate the impact of sunlight on the formation of emulsions from petroleum, Macondo, its surrogate and NIST 1619b and 2717a were separately exposed to simulated sunlight for up to 48 hours as a film dispersed into a quartz dish, or a film spread on water. Emulsion stability was scored from 0-5. All exposures demonstrated a correlation between emulsion stability and sunlight exposure with no observable emulsification in absence of photoproduction due to sunlight exposure. Aqueous studies of DOC_HC (dissolved organic carbon …

First-Principles Study Of Doping Effects On Ferroelectricity And On Rashba Spin Splitting, Zegnet Yimer Muhammed

Graduate Theses and Dissertations

In this dissertation, we have thoroughly studied the effect of chemical and charge dopingon ferroelectrics (PbTiO3 and BaTiO3) and Rashba type semiconductor (BiTeI). In the first project, We investigate the polar instability and soft modes in electron-doped PbTiO3 using linear-response density functional calculations. Because, metallicity and ferroelectric-like polar distortion are mutually non-compatible, and their coexistence in the same system is an intriguing subject of fundamental interest in the field of structure phase transition. However, it is unclear what mechanism may extend the limit of metallicity that allows polar distortion. We find that ferroelectric instability can remarkably sustain up to an …

Visible Light-Assisted Deconstruction/Refunctionalization Of Strained And Unstrained N-Cycloalkylanilines, Elvis Duah Boateng

Graduate Theses and Dissertations

The exploitation of ring strain as a driving force to facilitate chemical reactions is a well-appreciated principle in organic chemistry. Of the strained carbocycles frequently explored in this respect, cyclopropane ring systems have drawn considerably more interest among synthetic chemists than their homolog, the cyclobutane ring systems, even though the strain energy of cyclobutane (26.7 kcal/mol) is similar to that of cyclopropane (27.5 kcal/mol). We have previously developed a [4+2] annulation reaction for the synthesis of aniline-substituted six-membered carbocycles under photoredox catalysis via the oxidative cleavage of N-cyclobutylanilines. The key reaction involved in this method is a ring-opening process of …

Crystal Structures Of (Z)-(Ethene-1,2-Di­Yl)Bis­­(Di­Phenyl­Phosphine Sulfide) And Its Complex With PtIi Dichloride, Brain Rawls, Jeremy Cunningham, John E. Bender, Richard J. Staples, Shannon Biros

Open Access Publishing Support Funded Articles

The crystal structures of (Z)-(ethene-1,2-di­yl)bis­(di­phenyl­phosphine sulfide), C₂₆H₂₂P₂S₂ (I), along with its complex with Pt^II dichloride, di­chlorido[(Z)-(ethene-1,2-di­yl)bis­(di­phenyl­phosphine sulfide)-κ²S,S′]platinum(II), [PtCl₂(C₂₆H₂₂P₂S₂)] (II), are described here. Compound I features P=S bond lengths of 1.9571 (15) and 1.9529 (15) Å, with a torsion angle of 166.24 (7)° between the two phosphine sulfide groups. The crystal of compound I features both intra­molecular C—H⋯S hydrogen bonds and π–π inter­actions. Mol­ecules of compound I are held together …

Direct Ink Write And Thermomechanical Characterization Of Thermoset Composites, Sergio Dante Favela

Open Access Theses & Dissertations

This research will be divided into two sections. The first section discusses direct ink writing and thermomechanical characterization for thermoset composites. The thermoset ink is prepared with fillers aiding the printing process by modifying the rheology of the ink and geometry retention by allowing for the part to have an initial UV cure step. Three specimen formulations with different weight percentages were printed by material extrusion in the shape of tensile specimens following ASTM standard D638 to characterize the mechanical properties at room temperature, 100â?? and 200â??. Furthermore, the ink resin was characterized through DSC, TGA, and rheology testing. The …

Achieving Safe Use Of Advanced Materials In Drinking Water Through Novel Nano Analytics And Enabling Electrification Using Green Catalyst, Kenneth Ray Flores

Open Access Theses & Dissertations

The accumulation of engineered nanomaterials (ENMs) in environmental sectors will continue to increase as more applications are discovered for their unique properties and characteristics. Additionally, the presence of nanomaterials in the environment becomes exacerbated as more consumer products containing nanoparticles are approved for use. It is debated whether the toxic effects of nanoparticles stem from the particles themselves, ionic species, or formation of secondary particles. Therefore, understanding the behavior of nanoparticles in the environment becomes key to discerning the toxicological effects of nanoparticles. Many advancements have been made with ICP-MS to understand the behavior of nanoparticles in the environmental systems, …

Nano-Engineered Soft Magnets: Potential Application In Water Treatment, Hyperthermia And Molecular (Organic) Magnets, Yohannes Weldemariam Getahun

Open Access Theses & Dissertations

Scrutinizing the remarkable and tunable properties of magnetic materials at a nanoscale size "There's Plenty of Room at the Bottom..." Richard Feynman, this study attempts to find sustainable solutions to some of the deteriorating environmental, health, and energy problems the world is encountering. Due to their simple preparation, surface adaptability, and tunable magnetic and optical properties, magnetic nanoparticles have been extensively investigated in water treatment, cancer therapy, data storage, and more. However, relying on non-reusable and chemical-based treatment agents in water, complex and costly cancer treatment procedures and molecular magnets that operate far below room temperature limited those attempts from …

Molecularly Inspired Organic Macrocycles Catalyzed Water Splitting Reaction For Sustainable Fuel Production, Yulu Ge

Open Access Theses & Dissertations

Hydrogen fuel generation through electrochemical water splitting is considered as an advanced energy conversion technology driven by sustainable energy. High activity and cost effective electrocatalysts that are able to drive down the energy cost needed for both two half reactions, namely, hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are required to fulfill the energy transfer process. Exploring new electrocatalysts with enhanced OER and HER activity and stability is crucial for renewable energy applications. Porphyrin and macrocycle derivatives are versatile and can electrochemically catalyze water splitting efficiently. In our work, we use porphyrin as platform for both HER and …

Green Synthesis Of Spiro Compounds And The Phytochemical Investigation Of Diethyl Ether Fraction Of Camu-Camu (Myrciaria Dubia) Leaves, Judith Anane

Theses and Dissertations

There are a lot of lucrative plant species found in the Amazon and camu-camu (Myrciaria dubia (H.B.K.) Mc Vaugh) is distinct among them. This is due to its exceptional Vitamin C content which varies from 1600 to 6112 mg/100g of pulp. Besides the fruits which is popularly used, different parts of camu-camu plants including the stems, leaves, seeds, barks, and roots are also traditionally used in folklore practices for treating various ailments and diseases and research has showed the presence of antioxidant, antimicrobial, anticancer, anti-inflammatory agents present in these parts. In this study, the characterization of a bioactive compound, …

Dft Investigation Of Lewis Acid Assisted C-Cn Bond Activation Of Benzonitrile With [Ni(Dmpe)] Fragment, Lubna Kader

Theses and Dissertations

There has been recent interest in the field of organometallics with C—C bond activation of organic substrates that are mediated by transition metal complexes. The bond activation of C—C bonds is important, not only in organic synthesis but also in industrial processes. However, the activation of these bonds remains difficult since they are thermodynamically more stable and sterically less available to activate than the activation of the C—H bond. Most of the successful C—C cleavage uses the relief of ring strain, achievement of aromaticity, or proximity, as the driving force for the reaction.3 Another strategy is the use of a …