Chemistry Commons^™

Karena Mckinney: Mapping A Clearer Picture Of Air Pollution's Effects, Christina Nunez

Colby Magazine

"If we want to control air quality and address climate change, the solution won't involve fiddling with nature's emissions-it will be about cleaning up man-made ones." -Karena McKinney, associate professor of atmospheric chemistry

I. Non-Degradable Polysiloxane Networks For Controlled Release Applications, And Ii. Additive Free, Degradable Silyl-Ether Furyl-Maleimide Networks, Caleb M. Bunton

Chemistry Theses and Dissertations

I. Two different series of non–degradable polysiloxane networks were prepared for the encapsulation and controlled release of a small molecule agent. For the first series, hydrosilylation was utilized to prepare networks of varying crosslink densities, as determined from swelling studies, from vinyl terminated and silylhydride functional poly(dimethyl)siloxanes. For the second series, the thiol-ene reaction was utilized to prepare networks of varying crosslink densities, as determined from swelling studies, from vinyl terminated and mercaptopropyl functional poly(dimethyl)siloxanes. Nile red dye was used as an encapsulated agent and dye release from each series of networks was measured using UV–vis spectroscopy to determine controllability …

Effect Of Post-Consumer Content And Bioplastic Incorporation On Polymeric Resin In Consumer Applications, Shelby Bicknell

Electronic Theses & Dissertations

Controversy surrounds the use of plastic products, primarily due to their potentially negative impact on the environment at the end of their lifecycle. The most widely used plastics are manufactured from petrochemicals such as petroleum, coal or natural gas. Petrochemical plastics are not able to readily breakdown in the environment, which aggravates the existing pollution problems. Fortunately, there are eco-friendly alternatives to petrochemical-based plastics. Bioplastics may be derived from renewable sources, biodegradable, or both. Bio-based plastics are plastics that may be derived from renewable biomass sources including, but not limited to, vegetable oils, cornstarch, straw, woodchips, and food waste. They …

Elucidation Of Radical Cation Trapping Chemistry: Using Electrochemical And Photochemical Techniques To Qualitatively Assess The Kinetics Behind Anodic Oxidative Cyclizations, Luisalberto Gonzalez

Arts & Sciences Graduate Student Theses and Dissertations

While the field of organic chemistry has grown throughout the decades, its primary concern has always been on the generation, conversion, and study of molecular structures. Within that philosophy, the development of new reactions affords chemists the ability to overcome previous synthetic barriers or develop more elegant and simple synthetic routes to difficult-to-construct molecules. Within that realm, electrochemistry is seeing increased attention due its ability to generate highly reactive intermediates, recycle chemical reagents, and reverse the polarity of known functional groups. One example of such an application is the use of electrochemistry to form radical cations. While radical cations have …

Spectroscopic Investigations Of Excited Charge Carriers In Ii-Vi Nanoparticles, William Matthew Sanderson

Arts & Sciences Graduate Student Theses and Dissertations

The large absorption cross sections and the tunability of the energetic spacings between the states in the conduction (CB) and valence band (VB) within a semiconductor nanoparticle (NP) make them promising media for capturing electromagnetic radiation and converting it into charge carriers, or electricity. In photovoltaic devices that incorporate semiconductor NPs, it would be ideal if every photon could be absorbed by a NP and the carriers could be collected with perfect efficiency and without loss of energy. The relaxation pathways of the carriers within the NPs down to the band edge and their fate at the band edge contribute …

Facile Surface Exchange On 2d Cadmium Selenide Quantum Belts, Yuewei Yao

Arts & Sciences Graduate Student Theses and Dissertations

This dissertation presents various surface-ligand exchange reactions on cadmium selenide quantum belts (QBs), specifically between L-type, Z-type and bound-ion-pair AX salt type ligation. The surface ligation of nanocrystals determines their optical and transport properties, and thus purposeful control of nanocrystal surface chemistry is under active investigation. Colloidal 2D II-VI (specifically CdSe) QBs provide an ideal system for the study of rapid, complete, and reversible surface exchange at room temperature. Interchange of different types of ligands is observed. The surface exchanges are characterized by a variety of means, and the absorption and emission spectra of the QBs are extremely sensitive to …

Influence Of The Spatial Distribution Of Cationic Functional Groups At Nanoparticle Surfaces On Bacterial Viability And Membrane Interactions, Yongqian Zhang, Natalie V. Hudson-Smith, Seth D. Frand, Meghan S. Cahill, Larissa S. Davis, Vivian Feng, Christy L. Haynes, Robert J. Hamers

Faculty Authored Articles

While positively charged nanomaterials induce cytotoxicity in many organisms, much less is known about how the spatial distribution and presentation of molecular surface charge impact nanoparticle–biological interactions. We systematically functionalized diamond nanoparticle surfaces with five different cationic surface molecules having different molecular structures and conformations, including four small ligands and one polymer, and we then probed the molecular-level interaction between these nanoparticles and bacterial cells. Shewanella oneidensis MR-1 was used as a model bacterial cell system to investigate how the molecular length and conformation of cationic surface charges influence their interactions with the Gram-negative bacterial membranes. Nuclear magnetic resonance (NMR) …

Photofading Of Black Dyes In Cotton And Polyester Fibers Resulting From Environmental Exposure To Sunlight, Maggie E. Mahaney

Honors Theses

Color is one of the most important properties analyzed during forensic fiber examinations due to its discriminatory power. Differing colors in fibers are usually sufficient grounds for exclusion, but in cases where a lengthy period has passed between crime commission and evidence recovery, the high probability of environmental degradation having altered the questioned fibers’ properties could lead to false exclusions. Photofading, the loss of color resulting from exposure to light, is a common form of degradation observed in fibers. Although well-known in the dyeing industry, it is not typically factored into forensic fiber examinations. Published photofading research has been limited …

Fabrication Of Polymer Monoliths Within The Confines Of Non-Transparent 3d-Printed Polymer Housings, Noor Abdulhussain, Suhas H. Nawada, Sinéad Currivan, Marta Passamonti, Peter J. Schoenmakers

Articles

In the last decade, 3D-printing has emerged as a promising enabling technology in the field of analytical chemistry. Fused-deposition modelling (FDM) is a popular, low-cost and widely accessible technique. In this study, RPLC separations are achieved by in-situ fabrication of porous polymer monoliths, directly within the 3D-printed channels. Thermal polymerization was employed for the fabrication of monolithic columns in optically non-transparent column housings, 3D-printed using two different polypropylene materials. Both acrylate-based and polystyrene-based monoliths were created. Two approaches were used for monolith fabrication, viz. (i) in standard polypropylene (PP) a two-step process was developed, with a radical initiated wall-modification step …

Optimized Xanthene-Based Probes For Pancreatic Cancer Imaging, Ian Ruramai Munhenzva

Dissertations and Theses

Pancreatic Ductal Adenocarcinoma (PDAC) is one of the deadliest human malignancies with an extremely poor 5-year survival rate of below 5%. Surgical resection is the most effective treatment of choice because chemotherapy and radiation therapy do not improve life expectancy. Residual tumor after PDAC surgery is common due to a lack of PDAC targeted intraoperative contrast agents to confirm clear margins.

Fluorescence imaging has the potential to improve surgery outcome and PDAC patients' survival rate via the use of highly PDAC-specific molecular probes to facilitate tumor identification. This thesis describes the application of a focused library of benzoxanthene fluorophores for …

Massive Peatland Carbon Banks Vulnerable To Rising Temperatures, A. M. Hopple, R. M. Wilson, M. Kolton, Cassandra A. Zalman, J. P. Chanton, J. Kostka, P. J. Hanson, Jason K. Keller, S. D. Bridgham

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Peatlands contain one-third of the world’s soil carbon (C). If destabilized, decomposition of this vast C bank could accelerate climate warming; however, the likelihood of this outcome remains unknown. Here, we examine peatland C stability through five years of whole-ecosystem warming and two years of elevated atmospheric carbon dioxide concentrations (eCO₂). Warming exponentially increased methane (CH₄) emissions and enhanced CH₄ production rates throughout the entire soil profile; although surface CH₄ production rates remain much greater than those at depth. Additionally, older deeper C sources played a larger role in decomposition following prolonged warming. Most …

Preliminary Investigation Of The Effects Of Sex And Electrical Venom Extraction On Venom Composition In The Southern Devil Scorpion, Vaejovis Carolinianus, Chase Czaykowsky

Capstone Research Projects

No abstract provided.

Chemistry In Art: The Science Of Dye, Madeleine Gray Burland

Honors Projects

Fabric arts, and the practice of dyeing fabric using various resist techniques, is a tradition that goes back centuries, and is unique among art mediums in its relation to science, as the innovations in dye production have directly affected the art form. The development of synthetic dyes in the 1800’s greatly affected the way fabric is dyed, and subsequently the way clothes were made and consumed. As opposed to dyes made of natural materials, synthetic dyes cam in more colors, were brighter, easier to make in large quantities, and lasted longer since they didn’t fade with repeated washings. The practice …

Synergistic Use Of Remote Sensing And Modeling For Estimating Net Primary Productivity In The Red Sea With Vgpm, Eppley-Vgpm, And Cbpm Models Intercomparison, Wenzhao Li, Surya Prakash Tiwari, Hesham El-Askary, Mohamed Ali Qurban, Vassilis Amiridis, K. P. Manikandan, Michael J. Garay, Olga V. Kalashnikova, Thomas C. Piechota, Daniele C. Struppa

Mathematics, Physics, and Computer Science Faculty Articles and Research

Primary productivity (PP) has been recently investigated using remote sensing-based models over quite limited geographical areas of the Red Sea. This work sheds light on how phytoplankton and primary production would react to the effects of global warming in the extreme environment of the Red Sea and, hence, illuminates how similar regions may behave in the context of climate variability. study focuses on using satellite observations to conduct an intercomparison of three net primary production (NPP) models--the vertically generalized production model (VGPM), the Eppley-VGPM, and the carbon-based production model (CbPM)--produced over the Red Sea domain for the 1998-2018 time period. …

Uptake Of Co(Ii) Ions From Aqueous Solutions By Low-Cost Biopolymers And Their Hybrid, Mohamdia Nassar, Abel E. Navarro

Publications and Research

Alginate hydrogel beads (AB), spent peppermint leaf (PM), and a hybrid adsorbent of these two materials (ABPM), were studied as potential adsorbents of Cobalt (II) ions from aqueous solutions in batch system at room temperature. Equilibrium parameters such as solution pH, mass of adsorbent and the presence of a crowding agent on the adsorption of Co(II) ions were investigated. The results indicate that Co(II) uptake is maximized at pH values higher than 5, with adsorbent doses in the range 120-200 mg. Co(II) adsorption followed the trend AB > ABPM > PM with adsorption percentages of 77%, 71% and 64%, respectively.

Charge Transfer And Plasmon-Pumped Molecular Excitation Mechanisms In Surface Enhanced Photochemistry, Tefera Entele Tesema

Chemistry and Chemical Biology ETDs

Photochemistry that can be driven at low incident photon flux on optically excited plasmonic nanoparticles is attracting increasing research interest because plasmon-driven reactions offer new pathways for efficient conversion of the abundant solar energy into fuel. The confinement of the electromagnetic field by plasmonic metal nanoparticle and consequent field enhancement gives a dual advantage of ultrasensitive in situ and operando spectroscopic methods to monitor enhanced field-driven photochemical transformation. Charge carrier driven either via direct or indirect excitation mechanism are well-established pathways in plasmon-driven reactions to date. However, the excitation mechanism via plasmon-pumped electron transition from an occupied molecular orbital (HOMO) …

Mechanistic Study Of Cooperative Ligand-Centered Reactivity In Triaminoborane-Bridged Diphosphine Complexes, Clara Kirkvold

Honors Thesis

Reactive ligand platforms containing trisubstituted boranes have been effective in promoting new types of small molecule reactivity and catalysis with transition metals. Our project is aimed at developing triaminoborane-bridged diphosphines that participate in cooperative ligand-centered reactivity while bound to transitions metals. Here we present a density functional theory (DFT) mechanistic study on a series of ligand centered reactions at a boron center on a metal complex, ^PhTBDPhosMCl₂ (M = Ni or Pd and TBDPhos = 1,8,10,9-triazaboradecalin). Our work focuses specifically on the nickel complexes. ^PhTBDPhosNiCl₂ can react with several molecules to produce trans H-X addition (X=OH …

Flavonoid And Cannabidiol Neural Glyoxalase Pathway Enhancement Against Aging And Alzheimer’S Disease, Joel R. Frandsen

Theses & Dissertations

Alzheimer’s Disease is a neurodegenerative condition featuring neural cell death and a decline in cognitive capacity caused by elevated inflammation and production of reactive oxygen species. The glyoxalase pathway is an endogenous antioxidant system that neutralizes reactive methylglyoxal through sequential reactions. Dysfunction of the glyoxalase pathway contributes to oxidative stress and the accumulation of inflammatory metabolic byproducts. Plant-produced compounds with antioxidant activity can enhance endogenous antioxidant pathways and protect cells from elevated ROS production. We hypothesize that flavonoids and limited Cannabis Sativa-produced cannabidiol can enhance glyoxalase pathway function through regulation of antioxidant and pro-apoptotic signaling pathways to prevent methylglyoxal-mediated …

Synthesis Of Fluorinated Pyrazoles Via Intra- And Intermolecular Cyclization Reactions, Matthew Saucier

Honors Theses

Pyrazole-based pharmaceuticals treat a wide array of diseases and conditions including obesity, diabetes, cancer, microbial and viral infections, pain and inflammation, and many neurological disorders. Syntheses for this biologically significant substrate have been well developed, but current methods to afford fluorinated pyrazoles are limited by variability and selectivity. By 2013, over 25% of all drugs available on the market contained the element fluorine due to its unique characteristics leading to improved target protein binding, bioavailability, and metabolic stability. In order to harness these pharmaceutical benefits of fluorine and overcome its difficulty in handling and stability, we set out to develop …

Approaches Towards The Synthesis Of Ketamine Metabolites, Ann K. Patrick

Honors Theses

Major Depressive disorder (MDD) plagues society and stands at the forefront of research as MDD affects approximately 16% of the population. Pharmaceutical drugs, including the selective serotonin reuptake inhibitors (SSRIs), have been used for MDD treatment and remain a popular option today. However, current antidepressant treatments have proven to be ineffective in just less than half of the patients. Research continues with the goal to better understand the mechanisms of the pathology of depression and to search for other treatment options. For example, the stress-neurogenesis hypothesis investigates the role of stress and decreased neuroplasticity within MDD.

Supporting the stress-neurogenesis hypothesis, …

13c Nmr Substituent Effects On Para-Substituted Tolans: Using Deuteration To Assign 13c Signals In Methyltolan, Reece Crumpler

Honors Theses

Substituents are capable of affecting their molecules via induction, resonance, and field effects. Using the Hammett equation, the effect a range of substituents has on different properties of a molecule can be quantified.¹ Hammett’s parameters have been correlated with the substituent effects on ¹H NMR chemical shifts in different molecules, including experiments on substituted chalcones (1,3-diarylpropenones).² The effect a substituent has on a molecule can also be observed using ¹³C NMR. The chemical shifts of carbons throughout the molecule may be affected by the substituent. This was shown to be true by Wilson and Zehr in …

Synthesis Of Polyethylene Glycol - Trifluoromethyl Sulfonamide And Analysis Of Its Ion-Transport Properties, Andrew Groneck

Honors Theses

This project investigates the synthetic pathway to develop a polyethylene glycol – trifluoromethyl sulfonamide compound to be used as an electrolyte in a proton exchange membrane fuel cell. The inspiration to develop a trifluoromethyl sulfonamide compound tethered to a polyethylene glycol polymer was inspired by the work of David P. Siska and D. F. Shriver in their studies of polysiloxane – trifluoromethyl sulfonamide electrolytes.

In this thesis, I have developed the synthesis of MePEG7-Trifluoromethyl sulfonamide (MePEG7-NHSO2CF3) from monomethylpolyethylene glycol (MePEG7OH). Unfortunately, due to the COVID-19 pandemic, I was unable to complete the depronation and ion-exchange to the Li+ and H+ …

Investigation Of The History Of Fingerprinting, Advancements In The Field, And Development Of Potential Methods That Could Improve The Detection Of Endogenous And Exogenous Drugs In Latent Prints, Kristen Malloy

Honors Theses

When someone thinks of fingerprinting, they are most likely going to picture how a latent print is matched to the fingerprint of a suspect based on ridge pattern analysis. However, there is much more information that can be obtained from a latent print. The work performed in this thesis focuses the detection of exogenous and endogenous drugs in latent prints. The experiments performed analyzed fingerprints from volunteers that were contaminated with one of three common painkillers: acetaminophen, acetylsalicylic acid (ASA), and ibuprofen. Three different instruments were tested for this purpose: MALDI-MS, ATR-FTIR, and LC-MS. Based on the results gathered, it …

Silver-Catalyzed Synthesis Of Disubstituted Fluorinated Isoxazoles, Micah Stewart

Honors Theses

The presence of fluorine can provide organic compounds with useful biological properties, such as increased metabolic stability and drug uptake. Because of these advantages, fluorinated compounds make up about 30% of the drug industry. However, fluorination of complex molecules is difficult due to fluorine’s high electronegativity.

Fluorinated isoxazoles are of particular interest in the pharmaceutical industry. Isoxazoles are five-membered heterocycles with oxygen and nitrogen in the 1, 2 positions that are able to engage in interactions unavailable to other ring structures, conferring advantageous biological properties upon compounds containing them. However, there are limited synthetic routes for fluorinated isoxazoles, and those …

Intrinsic Buffer Hydroxyl Radical Dosimetry For Hydroxyl Radical Protein Footprinting, Addison Roush

Honors Theses

Hydroxyl radical protein footprinting (HRPF) coupled to mass spectrometry is a powerful technique for the analysis of protein topography as it generates covalent mass labels that can survive downstream sample handling, and it is sensitive to the solvent accessibility of amino acid sidechains. Of the multiple platforms for HRPF, fast photochemical oxidation of proteins (FPOP) utilizes a pulsed 248 nm KrF excimer laser to label proteins by photolyzing hydrogen peroxide. FPOP is the most widely used HRPF platform because it labels proteins faster than unfolding can occur. Variations in FPOP sample conditions make it difficult to compare results between experiments …

Isolation, Identification, And Investigation Of A Novel Bioactive Furanocoumarin From Leaves Of Amyris Elemifera, Amy K. Bracken

Honors Theses

Plants produce biologically active compounds that humans have utilized for many agricultural applications. Amyris elemifera was investigated due to the known bioactivity of its family, Rutaceae, and its use in medicines in tribes of the Bahamas. Biotage® and TLC guided fractionation of the EtOAc, hexane, and MeOH extracts of the leaves of Amyris elemifera yielded bioactive compounds. Most significantly, a novel furanocoumarin, 8-(3-methylbut-2-enyloxy)-marmesin acetate (1), and its analog 8-(3-methylbut-2-enyloxy)-marmesin (2), were isolated. The structures were identified via NMR and X-ray crystallography techniques; the X-ray crystal structure for 1 was reported for the first time, and the …

The Synthesis Of A Mepeg-Based Hydroxide Conducting Electrolyte And The Optimization Of The Mepeg-Tosylation Reaction, Andrew Ladner

Honors Theses

As society is becoming increasingly aware of the effects of climate change and the ever-looming threat of a fuel shortage, exploring green and renewable alternative energy production, such as fuel cells, is paramount. This project investigates the synthesis of a polyethylene glycol monomethyl ether (MePEG_n) based polymer as well as the optimization of the MePEG Tosylation reaction. The MePEG explored contains seven polymerized ethoxy groups (MePEG₇). The MePEG₇ polymer was modified by substituting a positively-charged trimethylamine group in the place of the alcohol functional group at the end of the PEG chain. The reason for …

The Histone Deacetylase Inhibitor Largazole: A Potential Chemotherapeutic Agent, Hannah Lynn Carson

Honors Theses

Histone deacetylase enzymes are known for their inherent activity as epigenetic modifiers. Although, they have become recognized for their role in cancer progression and other diseases. But also, histone deacetylases have other non-histone targets, for example, microtubules, which play important roles in cancer metastasis, apoptosis, and replication. With histone deacetylase inhibitors (HDACi), our research explored HDACi effects on breast cancer cell lines. The overall goal was to understand the potential of largazole, a class one histone deacetylase inhibitor on breast cancer cell lines. The research consisted of two parts: sulforhodamine B (SRB) viability assays under hypoxic and normoxic conditions. The …

Study Of Pharmaceutical Tablets Using Raman Mapping, Kyle Joseph Pauly

Honors Theses

Covalent bonds are the strongest type of bonds holding molecules together. Based on the pattern of bonding of the molecule, the atoms associated with the bond will vibrate at a specific frequency. Utilizing vibrational spectroscopy, such as Raman spectroscopy, these unique vibrational frequencies can be used to detect the presence of analytes over a selected area. Furthermore, the intensities of the vibrational modes can be tracked to comparatively quantify the concentration of analytes at various locations. This is a method of great importance due to its ability to compare pharmaceutical tablets synthesized with different techniques. Here, the presence and concentration …

Detection And Characterization Of Delta-9-Tetrahydrocannabinol And Novel Synthetic Cannabinoid Metabolites Using Human Liver Microsomes, Seema Murugan

Honors Theses

Marijuana and synthetic cannabinoids are the most commonly used and trafficked illicit drug. ∆⁹-tetrahydrocannabinol (THC) is the primary active compound in marijuana. Synthetic cannabinoids were created as a method to study the effects of cannabinoids on the endocannabinoid system, which consists of endogenous cannabinoids, cannabinoid receptors, and the synthetic and degrading enzymes responsible for the synthesis and degradation of endocannabinoids. Cannabinoids activate the same receptors as endocannabinoids. Synthetic cannabinoids gained popularity as recreational drugs due to their ability to avoid detection. Synthetic cannabinoids have been found to have a greater binding affinity to the cannabinoid CB₁ receptor …