Physical Sciences and Mathematics Commons^™

From Small Molecules To Infinite Crystals: Probing Noncovalent Interactions Through Vibrational Spectroscopy, Sadisha Nanayakkara

Chemistry Theses and Dissertations

During my four years in the CATCO group supervised by Dr. Kraka, I have been exposed to various topics targeted to address a multitude of chemical problems, broadening our knowledge of modern chemistry research as we know it. In undertaking the age-old problem of understanding the nature of chemical bonding, I could modestly contribute with my work, using in-house tools based on vibrational spectroscopy.

First part of my dissertation is focused on inventing new methods and tools to efficiently investigate chemical bonding, followed by the study of some non-covalent interactions, imperative in catalysis and solid-state chemistry. This includes analysis of …

Quantum Chemical Investigation Of Novel Noncovalent Interactions Utilizing Vibrational Spectroscopy, Seth Francis Yannacone

Chemistry Theses and Dissertations

Theoretical/computational methods have been utilized to investigate a diverse array of questions currently at the forefront of modern chemistry research. The focus of this work is Local Vibrational Mode (LVM) Theory, originally formulated by Konkoli and Cremer, and under continuous development by the CaTcO research group. Derived from LVM theory, local stretching force constants (ka) represent physically meaningful measurements of chem- ical bond strength. Decomposition of normal vibrational modes into LVM contributions, also called characterization of normal modes (CNM), is another powerful manifestation of LVM theory; most notably when applied to the analysis of theoretical/experimental IR/Ra- man spectra. Recent developments …

Identification Of Chemical Structures And Substructures Via Deep Q-Learning And Supervised Learning Of Ftir Spectra, Joshua D. Ellis

MSU Graduate Theses

Fourier-transform infrared (FTIR) spectra of organic compounds can be used to compare and identify compounds. A mid-FTIR spectrum gives absorbance values of a compound over the 400-4000 cm^-1 range. Spectral matching is the process of comparing the spectral signature of two or more compounds and returning a value for the similarity of the compounds based on how closely their spectra match. This process is commonly used to identify an unknown compound by searching for its spectrum’s closes match in a database of known spectra. A major limitation of this process is that it can only be used to identify …

Structure And Reactivity Of The First Row Transition Metals Bearing Redox-Active Ligands And Tunable H-Bonding Interactions, Khashayar Rajabimoghadam

Chemistry Theses and Dissertations

Metalloenzymes, as natural catalysts, can break a reaction with high activation energy to multiple small reactions with lower activation energies; in these small reactions, multiple bonds form and dissociate rapidly, some metalloenzymes use redox-active ligands in their active site to provide the needed electrons for these multiple small reactions. Additionally, in the secondary coordination sphere in the vicinity of the metalloenzymes, the hydrogen bonding interactions facilitate the transfer and interaction of the substrates and the stabilization of the active intermediates. These unique features in metalloenzymes inspired chemists to design molecular models that can partially mimic the structure and reactivity of …

Ahr Expression On Rorc-Expressing Immune Cells Is Essential For I3c-Mediated Protection Against Colitis, Michal C. Williams

Senior Theses

Colitis is an inflammatory bowel disorder (IBD) whose etiology is attributed to modification in the luminal microbiota and dysregulation in the immune response. Indole is a signaling molecule which is naturally produced by gut luminal microbiota. Indole-3- carbinol (I3C) is a compound commonly found in vegetables and a ligand for the aryl hydrocarbon receptor (AhR). Previous studies have detected decreased expression and activation on the AhR receptor in colitis patients, thought to possibly alter gut microbiota metabolism, subsequently promoting colitis. 1 AhR, expressed in a variety of immune and epithelial cells, contributes to gut homeostasis by affecting vital mediators such …

The Coordination Chemistry Of The Rhodizonate Dianion And Its Decomposition Products, Joshua A. Silverman

FIU Electronic Theses and Dissertations

The rhodizonate dianion is of importance for forensic testing, specifically with regard to the sodium rhodizonate test for lead in gunpowder residues. In an effort to understand this test from a chemical perspective, the coordination of rhodizonate and its decomposition products, croconate and oxalate, with several metals has been investigated with a variety of structural and spectroscopic methods.

FT-IR data of the three sequential steps of the sodium rhodizonate test show coordination between Pb(II) atoms, tartrate anions, and rhodizonate dianions, with the tartrate being substituted for Cl^- once a 5% HCl solution is added to produce the confirmatory blue-purple …

Lanthanide Interactions With Ligands And Biomolecules: Spectroscopic And Extraction Studies, Setareh Sakhdari

FIU Electronic Theses and Dissertations

Lanthanides (Ln), also known as rare earth metals, have been utilized for industrial and biological purposes and are commonly encountered in the 3+ oxidation state as Ln³⁺. The presence of Ln in spent nuclear fuel introduces problems during the transmutation and partitioning of actinides (An) due to the Ln high neutron cross-sections. Therefore, designing ligands for Ln³⁺ complexation, can be helpful for their separation from An³⁺ in nuclear technology. Also, the biomimetic roles of Ln³⁺ could be suitable for studying the biological macromolecules, such as the Ca²⁺-binding EF-hand proteins that are otherwise inaccessible …

Emergent Photophysics In Diketopyrrolopyrrole Superstructures, Andrew Levine

Dissertations, Theses, and Capstone Projects

Organic semiconductors have received substantial attention as active components in optoelectronic devices because of their processability and customizable electronic properties. Tailoring the organic active layer in these devices to exhibit desirable optoelectronic properties requires understanding the complex and often subtle structure-property relationships governing their photophysical response to light. Both structural organization and frontier molecular orbitals (FMO) play pivotal roles in energy relaxation processes, and complex interplay between organization and orbital energies are difficult to anticipate based upon the molecular structure of the components alone, especially in systems comprised of multiple components. In pursuit of design rules, there is a need …

Cu-Promoted C-H Bond Hydroxylation Inspired By Cu-Dependent Metalloenzymes, Rachel Trammell

Chemistry Theses and Dissertations

From 2003 to 2015, Schӧnecker and Baran proposed a dinuclear Cu/O₂ species in their mechanistic proposal for the hydroxylation of sp³ C-H bonds within their systems (proposed based on yields). Inspired from the site selectivity of this methodology and poor analysis of the mechanism, the first project was inspired to re-examine the sp³ C-H bond hydroxylation by Schrӧnecker and Baran and perform an intensive investigation into understanding how Cu/O₂ interact which led us to propose a new mechanism based on the evidence collected (i.e., LCu^II-hydroperoxide species that undergoes homolytic O-O bond cleavage). From there …

Investigations Involving Mononuclear And Dinuclear Transition Metal Catalysts For Photochemical Carbon Dioxide Reduction, Ansu Edwards

Honors Theses

There is currently a global energy crisis, which is in desperate need of solutions. New energy sources are required that will not pollute as much as our longstanding reliance on nonrenewable fossil fuels as an energy source. This pollution involves large amounts of greenhouse gas emissions, predominantly carbon dioxide (CO₂), that contribute to environmental problems such as climate change. In this context, a fairly recent research direction to address this problem is the development of transition metal catalysts that can convert CO₂ into reduced carbon products that can serve as chemical fuels. This work focuses on the …

Applications Of Sodium Azide In The Synthesis Of Tetrazines And Hydrolysis Reactions, My Le

Honors Theses

The inverse electron demand Diels−Alder cycloadditions of heterocyclic azadienes have provided a robust methodology for synthesizing highly substituted and functionalized heterocycles. It is widely used in organic synthesis and the pharmaceutical industry in the divergent construction of screening libraries and bioorthogonal conjugation. Each heterocyclic azadiene was found to possess a unique reactivity toward different classes of dienophiles, display predictable modes of cycloaddition, and exhibit substantial substituent electronic effects impacting their intrinsic reactivity and cycloaddition regioselectivity. Synthesis of 1,2,4,5-tetrazine has been reported in the literature since the late 19th century, showing scientists' tremendous interest in its application.

Herein we attempt to …

Small Molecule Activation By Transition Metal Complexes: Studies With Quantum Mechanical And Machine Learning Methodologies, Justin Kyle Kirkland

Doctoral Dissertations

One of the largest areas of study in the fields of chemistry and engineering is that of activation of small molecules such as nitrogen, oxygen and methane. Herein we study the activation of such molecules by transition metal compounds using quantum mechanical methods in order to understand the complex chemistry behind these processes. By understanding these processes, we can design and propose novel catalytic species, and through the use of data-driven machine learning methods, we are able to accelerate materials discovery.

Synthesis Of A Zinc Dipyrrin Complex For Photocatalytic Reduction Of Co2, Sylvia Meredith

Undergraduate Honors Theses

Zinc dipyrrin complexes have the potential to act as cheap, effective photosensitizers. Synthesizing and studying different types could lead to more efficient solar energy harvesting processes, especially the production of solar fuel. Here, two attempts to synthesize 1,3,7,9-tetraphenyl-5-mesityldipyrromethene are reported and discussed. According to ¹H NMR, the first synthesis attempt was not successful. The second synthesis attempt was not purified effectively, so ¹H NMR produced inconclusive results. Further purification strategies or alternate synthesis methods are required.

A Project To Dye For : Differentiation Of Dyed And Non-Dyed Human Hairs Using Atr Ft-Ir Spectroscopy, Joseph John Greco

Legacy Theses & Dissertations (2009 - 2024)

IR spectroscopy is widely utilized for forensic purposes due to the chemical fingerprint the method provides. ATR FT-IR spectroscopy is particularly advantageous because it allows for spectra to be collected quickly, accurately, and perhaps most importantly for forensics, non-destructively. Human hair is commonly collected at a crime scene, and further analyzed using DNA analysis and microscopy. However, these techniques have limitations. In the past ATR FT-IR spectroscopy has shown promise in the analysis of human hair for forensic purposes. In this study, the differentiation of undyed hair versus dyed hair classes of varying colors based on their IR spectra were …

The Synthesis Of Photoswitchable Triptan Derivatives, Chelsea Sainsbury

Honors College

Serotonin has various functions throughout the body and directly effects many neurological diseases/disorders, like depression, that are linked to the dysregulation of serotonin. Triptans are indole containing drugs that bind to a subset of serotonin receptors (5-HT1Band 5-HT1D) and are used to treat migraines. In this project, the synthesis of anindole intermediate is attempted. Ideally, an azobenzene would have been added to the 5th position (replacing the primary amine). Azobenzenes are compounds composed of 2 benzene rings connected by a nitrogen-nitrogen double bond that can switch between cis and trans conformations by absorbing different wavelengths of light. The transformation of …

Synthesis Of A Dd-Π-Aa Organic Dye For Dye-Sensitized Solar Cells, Hope Lovell

Honors Theses

This project investigates the synthesis of a DD-π-AA (dual donor/dual acceptor) organic dye as a potential sensitizer for dye-sensitized solar cells (DSCs). The design of this dye was based off previous research that found dual donor/dual acceptor dyes exhibited promising results when used in a DSC. The donor groups, acceptor groups, and π-bridge were chosen for their stability, ability to absorb in the near-infrared (NIR) region, and intramolecular charge transfer (ICT) abilities.

While many components of the dye were synthesized, the final stages of the synthetic scheme were not completed due to the loss of time from COVID-19. Had the …

Synthesis And Conductivity Analysis Of A Methyl (Polyethylene Glycol) Comb Polymer, Olivia Fox

Honors Theses

The overall goal of work in this field is to improve materials for use in a variety of applications in fuel cell and battery production. This thesis specifically investigates the synthesis of two variations of a methyl (polyethylene glycol) comb polymer electrolyte (MePEG_nwhere n=7) to understand how the molecular structure of an ion-conducting polymer affects its electrochemical properties. The MePEG used in this synthesis contains seven ethylene glycol groups and was added to a poly (methylhydrosiloxane) comb polymer backbone. In the first sample, the polymer contained only the MePEG sidechain, and in the second sample, the polymer contained …

Progress Towards Synthesis And Characterization Of Bay-Annulated Indigo Chromophores, Katherine Weiss, Denise Femia

HON499 projects

Through acetylation, N,N’-diacetylindigo was synthesized from indigo. N,N’-diacetylindigo and 2-thiopheneacetyl chloride were combined in an attempt to synthesize 7-thiophenyl bayannulated indigo (BAI). After 1H NMR characterization, it was found that the product was not 7-thiophenyl BAI. A previously synthesized sample of 7-phenyl BAI was purified. UV-VIS absorbance, fluorescence, IR, and 1H NMR were used to characterize the compounds.

The Analysis Of Heavy Metals In Samples Of Honey Using X-Ray Fluorescence And Anodic Stripping Voltammetry, Mia Arrieta, Kaleigh Beale

Spring Showcase for Research and Creative Inquiry

A daunting reality is haunting scientists as Colony Collapse Disorder (CCD) is declining bee population in the United States (1). A concrete conclusion as to why CCD is happening remains unclear but extensive research and studies are leaning towards a toxic component in honey to bees called hydroxymethylfurfural (HMF) (1). HMF has been a culprit in question for a while but researchers are still on the fence as to whether it should be concluded as such. It is theorized that HMF is formed in very warm temperatures and catalyzed by a metal in honey; manganese (1). Manganese is one of …

Chemistry Meets Art: Instrumental Analysis At The Lcva, James Rakes, Mia Arrieta, Kaleigh Beale, Adonel Grubb

Spring Showcase for Research and Creative Inquiry

This project is an ongoing collaboration between the Longwood chemistry program and the Longwood Center for the Visual Arts. The demonstration shows the capabilities of the X-ray fluorescence spectrophotometer as a non-destructive elemental analysis technique. Our class visited the LCVA to analyze several pieces in their art collections. We were able to utilize the XRF instrument to analyze the elemental composition of glass and metal, painted pottery and porcelain, oil paintings, and metals. This project lays the groundwork for further research using X-ray fluorescence for non-destructive chemical analysis.

Chemical Analysis Of An Herbal Opioid, Lauren Johnson

Spring Showcase for Research and Creative Inquiry

Different chromatography techniques were used to analyze the concentration of an active component, mitragynine, in kratom samples. The analysis also compared three different extraction methods, one using ultrasonification, the other two using a commercial at home espresso maker. Using gas chromatography mass spectrometry, and high performance liquid chromatography, comparisons between key compounds in the substances were determined and concentrations of mitragynine within the samples were calculated.

Water Quality Assessment Of Farmville, Va, Meghan Hall

Spring Showcase for Research and Creative Inquiry

In Farmville, some people drink tap water, but others choose only to drink filtered or bottled water. Some blame this on taste, and others say the mineral content affects their skin from sinks and showers. I propose to conduct an analysis of water hardness and chloride, nitrate, and lead levels of water from various sources in Farmville, Virginia. To measure each parameter, an EDTA titration was carried out to test for water hardness, anodic stripping voltammetry was conducted to detect lead, ion-selective electrode was used to measure chloride, and a modified Griess reaction was carried out to measure nitrate levels. …

Cis-Trans Isomerism In Single Molecule Electronic Devices, Tinsae Alem

Spring Showcase for Research and Creative Inquiry

We investigated the switching properties of cis-trans isomers of azobenzene for single molecule electronics. Although the cis-trans isomerization leads to structural changes within the molecule, the current flow is found to depend mainly on the relative position of the electrodes. The on/off ratio was determined to measure the performance of these isomers as switches. Different cis-trans isomers were studied to compare results.

A Non-Destructive Analytical Technique Used For Analyzing A Variety Of Glassware Samples In Hopes To Determine Their Elemental Composition Based Off Their Qualitative And Quantitative Data Results., Angela Scarpa

Spring Showcase for Research and Creative Inquiry

In this study, XRF analysis was used to examine and identify specific glassware samples, exported from remote locations, in hopes to determine any correlation between the glass samples being tested. During experimentation, there were 41 glass samples and 3 glass standards that were examined and quantitatively analyzed to determine the elemental compositions of all samples. To ensure optimal sensitivity of these different materials, four methods were utilized to confirm accurate data is collected and to improve all quantitative data results. These four methods contain distinct experimental factors and were purposely selected due to their specific current, voltage, filter, time, and …

Alternative View Of Oxygen Reduction On Porous Carbon Electrocatalysts: The Substance Of Complex Oxygen-Surface Interactions, Giacomo De Falco, Marc Florent, Jacek Jagiello, Yongqiang Cheng, Luke L. Daemen, Anibal J. Ramirez-Cuesta, Teresa J. Bandosz

Publications and Research

Electrochemical oxygen reduction reaction (ORR) is an important energy-related process requiring alternative catalysts to expensive platinum-based ones. Although recently some advancements in carbon catalysts have been reported, there is still a lack of understanding which surface features might enhance their efficiency for ORR. Through a detailed study of oxygen adsorption on carbon molecular sieves and using inelastic neutron scattering, we demonstrated here that the extent of oxygen adsorption/interactions with surface is an important parameter affecting ORR. It was found that both the strength of O2 physical adsorption in small pores and its specific interactions with surface ether functionalities in the …

Indolizine Donor-Based Dyes For Applications In Fluorescence Biological Imaging, William Meador

Honors Theses

NIR emissive fluorophores are intensely researched due to their potential to replace modern imaging procedures. Many molecular strategies have been employed in the literature to optimize fluorophores for deeper NIR absorption and emission, biocompatibility, and higher fluorescence quantum yields. Amongst the fluorophores studied to date, proaromatic indolizine donors are attractive alternatives to traditional alkyl amine and indoline based donors due to their 1) lower energy absorption and emission facilitated by proaromaticity, 2) large Stokes shifts due to increased dihedral angles about the π-system, 3) ease of functionalization and capacity for bioconjugation at the phenyl ring, and 4) potential for further …

Substituent Effects On The Solubility And Electronic Properties Of The Cyanine Dye Cy5: Density Functional And Time-Dependent Density Functional Theory Calculations, Austin Biaggne, William B. Knowlton, Bernard Yurke, Jeunghoon Lee, Lan Li

Materials Science and Engineering Faculty Publications and Presentations

The aggregation ability and exciton dynamics of dyes are largely affected by properties of the dye monomers. To facilitate aggregation and improve excitonic function, dyes can be engineered with substituents to exhibit optimal key properties, such as hydrophobicity, static dipole moment differences, and transition dipole moments. To determine how electron donating (D) and electron withdrawing (W) substituents impact the solvation, static dipole moments, and transition dipole moments of the pentamethine indocyanine dye Cy5, density functional theory (DFT) and time-dependent (TD-) DFT calculations were performed. The inclusion of substituents had large effects on the solvation energy of Cy5, with pairs of …

Improving Conceptual Understanding Of Gas Behavior Through The Use Of Screencasts And Simulations, Brianna L. Martinez, Ryan D. Sweeder, Jessica Vandenplas, Deborah Herrington

Peer Reviewed Articles

Engagement with particle-level simulations can help students visualize the motion and interactions of gas particles, thus helping them develop a more scientifically accurate mental model. Such engagement outside of class prior to formal instruction can help meet the needs of students from diverse backgrounds and provide instructors with a common experience upon which to build with further instruction. Yet, even with well-designed scaffolds, students may not attend to the most salient aspects of the simulation. In this case, a screencast where an instructor provides narrated use of the simulation and points students towards the important observations may provide additional benefits. …

Optimization Of Simple And Inexpensive Paper-Based Assay For Lead, Kyla Dewittie, Sagar S. Patel

Summer Scholarship, Creative Arts and Research Projects (SCARP)

The Environmental Protection Agency (EPA) guidelines state that lead is a toxic metal that humans should not be exposed to in any amount. Due to corrosion of water pipes, lead can enter drinking water and be consumed by millions of people. As a group, we decided to reduce this issue by creating a simple and inexpensive paper-based test to detect lead(II) in water. The signal for this test results from encapsulating a phenanthroline-based probe in synthesized polymer nanoparticles. This test will display a colorimetric change, turning from yellow to bright orange if lead(II) is present in the water system. In …

Synthesis And Characterization Of Oxovanadium Compounds As Potential Insulin Mimetic Molecules, Kaitlyn Mercando, Jeffrey A. Rood

Summer Scholarship, Creative Arts and Research Projects (SCARP)

Oxovanadium(IV) complexes have numerous applications in diverse areas such as catalysts for organic transformations and as anti-fungal agents. Complexes that this research focused on have shown potential in acting as insulin mimetics. The goal of this research was to synthesis and fully characterize a new series of oxovanadium complexes and then investigate the insulin mimetic properties of the complexes with adipose cell culture work. Vanadyl complexes involving a series of salicylaldiminato ligands [C6H5N=CHC6H4OH (L1), 2,6-iPrC6H3N=CHC6H4OH (L2), C6H5N=CH-3,5-tBu2C6H2OH (L3) and 2,6-iPrC6H3N=CH-3,5-tBu2C6H2OH (L4)] were synthesized and structurally characterized. The ligand set was investigated due to the ease of sterically tuning the substituents …