Chemistry Commons^™

Study Of Fast Switching Metastable-State Photoacids And Controlled Drug Release From Polycaprolactone (Pcl) Vascular Scaffold, Rana Salman Abbood Abbood

Theses and Dissertations

Metastable-state photoacid (mPAH) has become a common tool for controlling and driving chemical processes with light. mPAHs with fast reverse reactions are desirable for precise temporal control or generating quick pulses of proton concentration. In this work, different approaches towards fast reversing mPAHs are studied. Experimental and computational results showed that stabilizing the charge–transfer intermediate is an effective way to increase the rate. A novel mPAH with a reverse reaction ≈500 times faster than the most widely used mPAH in methanol has been developed. Another water-soluble mPAH exhibited a reverse reaction with a rate constant of 7.8 s−1, the fastest …

Stimuli-Responsive Proton Transfer: Photoacid Design, Co2 Sorbent Regeneration, And Polymer Applications, Melyse Ava Laud

Theses and Dissertations

Control over proton transfer enables the regulation of many pH-dependent chemical and material processes. Stimuli-responsive functional materials provide a means of achieving this control. Functional materials such as Metastable-state photoacids (mPAHs) reversibly release large amounts of protons when stimulated by light from a weakly acidic site within their structure. However, the dark acidities of previously reported mPAHs limit their use under basic conditions. To address this limitation, a benzimidazole-type mPAH was developed with an improved ground-state pKa of 11.9 and a metastable-state pKa of 9.8, enabling reversible proton transfer under mildly basic conditions. Additional mPAHs were examined to determine how …

A Fundamental Study Of Fatty Acid Ionic Liquids And Their Effects On Biomolecules, Achismita Dutta

Theses and Dissertations

Fatty acid ionic liquids (FAILs) are a class of ionic liquids (ILs) with relatively low toxicity and potential applications in biological systems. This study examined the interactions of tetramethylguanidinium decanoate, tetramethylguanidinium octanoate, choline decanoate, and choline octanoate with lipid membranes, proteins, and nucleic acids. Membrane leakage experiments using model lipid vesicles showed that decanoate-based FAILs produced greater membrane permeabilization than octanoate-based analogues, consistent with their higher membrane permeability. These effects were stronger for the ILs than for decanoate alone and occurred below the critical micelle concentration (CMC), suggesting that micelle formation may not be essential for membrane disruption. The ability …

Tuning Ion Mobility And Molecular Confinement In High-Performance Polymer Electrolytes For Energy Storage, Ezzeldien Yousef Muhammed Yousef

Theses and Dissertations

This research addresses the critical energy density limitations of aqueous supercapacitors, which are traditionally constrained by the narrow electrochemical stability window (ESW) of water 1.23 V. By employing two distinct molecular engineering strategies, this study developed high-performance electrolyte systems that significantly extend voltage stability and thermal resilience.

The first system, CsBr@PAM/HA, utilizes a polyacrylamide and hyaluronic acid hydrogel matrix. This system exploits the chaotropic nature of Cs⁺ ions to disrupt the aqueous hydrogen-bonding network, enhancing ionic conductivity to 104 mS cm^-1. Through systematic salt screening, CsBr was identified as the optimal electrolyte, enabling a stable 2.0 V …

Engineering Nanoelectrocatalytic Systems For Co2 And Nitrate Conversion Into Value-Added Chemicals, Abdelrahman Mohamed Abdelmohsen

Theses and Dissertations

The thesis addresses two major related environmental crises: nitrate pollution of water systems and the ever-increasing levels of atmospheric carbon dioxide. Both challenges are closely linked to anthropogenic disturbance of nitrogen and carbon cycles and require sustainable, energy efficient mitigation techniques. In this study, we investigate electrochemical conversion routes as a unified approach to convert these pollutants into value-added compounds: ammonia (NH3) via nitrate reduction (NO3-RR) and ethylene (C2H4) via carbon dioxide reduction (CO2RR). The first half of this work deals with the design and engineering of Cu-Zn alloy electrocatalysts for efficient NO3-RR. Tuning the alloy composition and surface nanostructure …

Low-Dimensional Metal Halides For Light-Emitting Diodes (Leds): Photophysical Aspects And Device Engineering, Udara Madushanka Kuruppu Kuruppu Achchige Don

Theses and Dissertations

In recent years, low-dimensional metal halides have garnered significant interest due to their exceptional optical properties. This dissertation focuses on the structural, optical, and photophysical properties of both lead-based and lead-free low-dimensional metal halides and investigates their applications in light-emitting diodes. In Chapter II, the nature of Mn2+ doping in two-dimensional (2D) lead halide perovskites is discussed. 2D perovskites show strong excitonic and dielectric confinement due to their quantum well structures. Introducing optically active Mn²⁺ dopant ions into these 2D perovskites further enhances their optical properties and promotes energy transfer from the host to the Mn²⁺ dopants, resulting in dual …

Insights Into Androgen Receptor Allosteric Modulation By P,P'-Dichlorodiphenyldichloroethylene Binding At The Binding Function-3 Site And Site-Specific Binding Function-3 Mutations, Emanuel Aggeo Flores

Theses and Dissertations

One of DDT’s metabolites, p,p’-dichlorodiphenyldichloroethylene (DDE), has been classified as an endocrine disrupting chemical (EDC) due to its ability to interfere with hormone signaling by binding to nuclear receptors (NR) such as the androgen receptor (AR).

Structurally, the AR contains a ligand-binding domain (LBD) where endogenous steroids bind. Furthermore, the LBD contains a surface binding site known as binding function-3 (BF-3), which studies suggest exerts an allosteric effect on bound DHT when small, hydrophobic molecules bind.

Here, we present a study that examines how specific BF-3 site mutations and DDE binding affect steroid stability within the LBP utilizing computational methods. …

General Chemistry Students' Perceptions Of How Various Course Resources Affect Their Learning And Exam Preparation, Jennifer Scoggin Cortez

Theses and Dissertations

The tertiary-level first-semester general chemistry course has a large range of material with different complexities that can be difficult for students to master within one semester. In the general chemistry I course under study here, students were provided with a variety of resources to help with their learning and understanding, with various components of the course, including the lecture, online textbook, Peer-Led-Team-Learning (PLTL) study sessions, and exams, having associated resources. This study aims to analyze students’ experiences with these various resources. Students were given semi-structured interviews where they talked about their experiences with the resources and provided insight into more …

Probing The Dynamic Behavior Of The Androgen Receptor In The Presence Of Heptyl And Methyl Parabens, Edgardo De Leon

Theses and Dissertations

The androgen receptor (AR) mediates physiological signaling from endogenous androgens, a function that can be disrupted by endocrine disruptors with serious reproductive and developmental consequences. Parabens, widely used preservatives, inhibit AR signaling in cell-based assays, with inhibitory potency correlating with alkyl chain length: heptylparaben exhibits stronger antagonism than methylparaben, which shows no effect. We hypothesize this differential potency arises from allosteric modulation at the AR Binding Function 3 (BF-3) site, altering dihydrotestosterone (DHT) binding dynamics. Docking calculations using antagonist-bound AR crystal structures, followed by molecular dynamics simulations, show that methylparaben fails to remain bound at BF-3, whereas heptylparaben maintains stable …

Structure–Property Engineering Of Sn-Based Hybrid Perovskites Via Bulky Organic Cation Incorporation: From 3d To 2d Architectures, Kevin Alejandro

Theses and Dissertations

This thesis investigates tin-based hybrid organic/inorganic perovskites (HOIPs) as a lead-free alternative to silicon solar cells. To manipulate optoelectronic and efficiency of the semiconductors, methylammonium was substituted with bulky propylammonium and tetrabutylammonium cations to induce quasi-2D/3D Ruddlesden-Popper phases. X-Ray Diffraction confirmed 2D layered phases in propylammonium hybrids (5-15%), while tetrabutylammonium hybrids faced steric limits, triggering vacancy ordered perovskite phases at 1% concentration. Optical analysis showed a bandgap narrowing from 1.30 eV to 1.26 eV with increased substitution. Although photovoltaic performance generally declined, the 10% propylammonium hybrid achieved the highest fill factor of ~0.79, indicating superior internal charge transport. This work …

Degradation And Metabolic Analysis Of Synthesized Quorum-Sensing Signals By The Model Eukaryote Chlamydomonas Reinhardtii, Adam Josef Bach

Theses and Dissertations

Bacterial organisms can “talk” with one another on a colony-wide scale using a communication system known as quorum-sensing (QS) via chemical signals. These signals are produced at a basal rate throughout the life of the bacteria and are classified as autoinducers, which diffuse across the cell membrane. Once the critical concentration is reached, they begin to diffuse back into the cell and initiate a phenotypic change. As these signals exist outside the membrane of their producer, they are also accessible to other organisms. It has already been noted that some plant species uptake these compounds through their roots and break …

An Efficient Approximation To The Vibrational Coupled Cluster Method For Large Molecules, Nivedhitha P Ms

Theses and Dissertations

The Watson Hamiltonian is a widely used model for describing anharmonic vibrational motion in polyatomic molecules. It expresses the kinetic energy in separable dimensionless normal coordinates and represents the potential energy as a Taylor series expansion around the equilibrium geometry, usually up to the quartic approximation. Several computational methods have been developed to solve the corresponding vibrational Schrödinger equation for predicting infrared (IR), Raman, and vibrational circular dichroism (VCD) spectra. These include the Vibrational Self-Consistent Field (VSCF) method, Vibrational Configuration Interaction (VCI) and its approximations, and Vibrational Second-Order Perturbation Theory (VPT2), each providing different balances between computational cost and accuracy. …

Factorized Electron-Nuclear Dynamics: Theory Development And Implementation, Julian Stetzler

Theses and Dissertations

In the Born-Oppenheimer (BO) approximation, nuclei are treated as classical particles. The theoretical and computational approaches that go beyond it are impractical for all but the smallest chemical systems. However, such methods are necessary to simulate many photochemical and biological processes. This thesis discusses two important topics of research in this feld: frst, improving electronic structure theory to efciently describe quantum nuclei; second, developing a scalable quantum dynamics method, the factorized electron-nuclear dynamics (FENDy).

Following the BO approximation, the electronic structure of molecules is routinely examined for static arrangements of point nuclei, which is a highly useful premise but not …

Evidence Of Metal-Microcystin Complexation And Its Potential Role In Environmental Fate, Ashley Marie Womer

Theses and Dissertations

Microcystins that enter freshwater systems pose a threat to human health therefore their fate and transport throughout the water column have been intensively studied. While sediment has been regarded as an environmental fate for microcystin (MC), less is known about the molecular mechanisms by which microcystin interacts with the sediment and/or the thermodynamic stability of these interactions. While microcystin has a half-life in lake water on the order of weeks, microcystin adsorbed to sediment can be detected hundreds of years later1-2. Microcystin has been desorbed from these sediments with various EDTA solutions, therefore, work is presented to support the hypothesis …

The Use Of Machine-Learning Interatomic Potentials To Study Bulk Properties Of Aqueous Zn Ion Batteries, Ria Vasdev

Theses and Dissertations

Aqueous Zn-ion batteries (AZIBs) have emerged as a promising energy storage tech- nology owing to their high Coulombic efciency and low environmental impact. However, their practical development is impeded by limited cycling stability, pri- marily caused by parasitic side reactions occurring at the anode surface. These side reactions are strongly infuenced by the bulk solvation structure of Zn-based elec- trolytes, which remains challenging to characterize using conventional experimental techniques. Machine-learning interatomic potentials (MLIPs) provide a powerful computational approach to investigate these systems and can be employed to eluci- date the bulk structural properties of Zn electrolytes.

Raman Spectroscopy Of Biological Molecules And Inorganic Compounds, Jasmine Ervin Gardner

Theses and Dissertations

This dissertation describes the use of multiple Raman spectroscopic techniques for the detection and characterization of non-hazardous organic and inorganic compounds. The first two applications involve the use of Raman and surface enhanced Raman spectroscopy to thoroughly analyze autoinducers (AI) produced by gram negative bacteria. The second set of applications involves the use of anti-stokes Raman and resonance Raman spectroscopy to remotely detect inorganic compounds at distances of up to 12 meters away.

This work describes the use of Raman spectroscopy for the characterization and discrimination of signaling molecules used in bacterial communication. Our initial work shows the potential of …

Stimuli-Responsive Hybrid Materials: From Fundamental Photophysics To Tunable Properties, Grace C. Thaggard

Theses and Dissertations

Photochromic materials exhibit properties that can be dynamically tailored as a function of light exposure and represent a rapidly expanding field driven by applications ranging from molecular computing, nanotechnology, or photopharmacology to programable heterogeneous catalysis. For example, the possibility to tune a material’s catalytic activity “on demand” through exposure to a noninvasive stimulus is a transformative concept that could shift the paradigm in chemical industry by allowing for in-situ suppression of byproduct formation, isolation of reactive intermediates, and even control over product yield and selectivity. Development of the mentioned photochromic materials is based on stimuli-responsive molecular building blocks which undergo …

Synthesis And Characterization Of Transition Metal Carbide (Max) And Mxene Nanoflakes For Energy Storage And [email protected], Srikanth Ragunath B Mr

Theses and Dissertations

Rapid growth in population and industrialization created a huge demand for superior energy storage devices. Thus, the researchers are in constant search of developing exotic materials towards energy harvesting and storage devices. Batteries, supercapacitors, and fuel cells received a great attention to meet the global demand for energy storage. Among them, supercapacitors are widely preferred as energy storage devices due to higher power density, longer cycle life, and fast charging. The performance of the supercapacitors highly depends on the choice of electrode materials and electrolyte.

Recently, “MXenes”  a new class of layered a new class of layered a new …

A Computational Study Of The Chemomechanics Of Paracetamol Polymorphs: Towards Improving Drug Tabletability, Karim Nader Samra

Theses and Dissertations

The mechanical properties of pharmaceutical crystals are of great importance in tablet manufacturing. Also, knowing the mechanical properties of different polymorphs of the same crystal can reduce the overall production cost. In this study, computational work was done via performing density functional theory calculations on 3 paracetamol crystal polymorphs Form I, II, and III. Understanding the chemical bonding helps in predicting the key elastic properties for different crystallographic directions. In Form II, lattice vector C is dominated with the intermolecular hydrogen bond OH…O giving it the stiffest Young Modulus and the least Poisson’s ratio. Then comes the A-Axis which contains …

Development Of Salinomycin Analogs As Potential Anti-Cancer Agents, Pavan Goud Juluri

Theses and Dissertations

Salinomycin, a poly-ionophore antibiotic originally isolated from Streptomyces albus, exhibits antimicrobial activity against Gram-positive bacteria. Over the years Salinomycin has been studied in the effects it has on cancer, specifically cancer stem cells. Poly(ADP-ribose) polymerase (PARP) is an enzyme involved in DNA repair. Inhibiting PARP has been explored as a strategy in cancer treatment, particularly in cancers with defective DNA repair mechanisms, such as those with BRCA mutations. The benzo-thiazoles, and -imidazoles are identified as inhibitor scaffolds, which compete with nicotinamide in the binding pocket of human poly- and mono-ADP-ribosylating enzymes. Benzothiazole, and benzimidazole based compounds particularly with modification at …

Structural Characterization Of Peptide Nanoaggregates At Varying Concentrations And Their Impact On Cellular Responses, Malika Rozmetova

Theses and Dissertations

Peptide nano-assemblies can regulate cellular pathways in a structure-dependent manner. Here, we show that the enzyme-responsive peptide NapFFK(NBD)Yp forms distinct nanoscale assemblies at different concentrations, triggering differential ER stress and extracellular vesicle release in MDA-MB231 cells. These results highlight the importance of supramolecular organization in peptide–cell interactions.

De Novo Protein Binding To Zinc Oxide Through Biomineralization Pathways, Jean-Mark A. Francis

Theses and Dissertations

De novo proteins are structurally distinct from proteins found in nature and thus capable of having their amino acid sequence modified to accomplish tasks such as increasing protein-nanoparticle binding without unfolding or decomposing. Zinc Oxide nanoparticles are functionally distinct from their bulk counterparts and are widely used as semiconductors in a variety of fields such as medicine and agriculture. With demand for these nanoparticles increasing, environmentally sustainable methods of Zinc Oxide nanoparticle synthesis are being investigated as an eco-friendly alternative to currently utilized but environmentally hazardous chemical and physical techniques. This research investigates the binding characteristics between Zinc Oxide nanoparticles …

Schiff Bases As Versatile Platforms: From Multinuclear Dysprosium Complexes To Halogen-Mediated Quasiracemic Crystal Engineering, Macy M. Michorczyk

Theses and Dissertations

Understanding the factors that govern molecular assembly is fundamental in both coordination chemistry and crystal engineering. This thesis investigates these processes through two studies that employ single-crystal X-ray diffraction to elucidate the structural principles underlying the formation of multinuclear metal complexes and the crystal packing of quasiracemates.

The first study examines the unexpected formation of multinuclear metal complexes. Structural characterization of a series of dysprosium complexes was used to compare molecular architectures and identify structural relationships that support a proposed pathway of formation. These findings shed insight into the assembly process that may have lead to their formation.

The second …

Absolute Quantification And Identification Of Rna From Rna-Lipid Nanoparticles Using High Resolution Mass Spectrometry, Jason C. Funderburk

Theses and Dissertations

RNA therapeutics are a rising drug category with potential use for a range of conditions encompassing infectious diseases to therapies for cancer, diseases, and genetic disorders. RNA-lipid nanoparticles (RNA-LNPs) are the prominent delivery method for these therapeutics approved products include mRNA vaccines and polyneuropathy treatments. The emergency use authorizations and orphan drug status of current RNA-LNP drugs has allowed approval without finalization of the regulatory analytical procedures for quality monitoring. The objective of the study was to develop an LC-MS assay to simultaneously measure identity and concentration of two therapeutically relevant intact RNA constructs extracted from RNA-LNPs to enhance quality …

Rapid Kinetic Fluorogenic Quantification Of Malondialdehyde In Ground Beef, Keshav Raj Bhandari

Theses and Dissertations

Presented herein is rapid kinetic fluorogenic method to quantify malondialdehyde (MDA) in ground beef, utilizing 2-thiobarbituric acid (TBA) as the fluorogenic probe. This assay significantly shortens the total analysis time, from sample preparation to data acquisition, to just six minutes presenting a major advancement over traditional methods that typically require two hours and multiple instruments. The assay’s robustness against matrix interferences was validated using sample volume variation and standard addition calibration methods. Additionally, the effects of ambient exposure to air, washing, and cooking on MDA content in raw ground beef were quantified. While both ambient exposure to air and cooking …

Inductively Heated Platinum Electrodes, Jayamini Madumali Mudugamuwa Hewage

Theses and Dissertations

This dissertation presents the fabrication and application of a 150 micrometer platinum microelectrode for induction heating, with a copper coil generating the electromagnetic field and the heating process controlled using pulse width modulation technique (PWM) to regulate the duty cycle of a high-frequency signal. Electrochemical characterization, including resonance frequency determination, peak-to-peak potential optimization, and scan rate variation, is conducted using a 5 mM [Ru(NH3)6]2+/3+ solution in 0.1 M KNO3 to calibrate current variations with changing duty cycles, while the temperature increase (delta T) is estimated using the Seebeck coefficient of [Ru(NH3)6]2+/3+. The study further explores the application of induction heating …

Development Of Natural Product Analogs As Therapeutic Agents, Jacob Mara

Theses and Dissertations

Cancer stem cells (CSC) are cancer cells in a tumor mass that may self-renew and develop into various cell types, resulting in a heterogeneous tumor. CSCs have been shown to have a role in many facets of cancer formation, including tumor genesis, proliferation, and metastatic activity. They are also implicated in chemotherapeutic treatment resistance and the recurrence of some malignancies. Based on these capacities, CSCs have been identified as the next target for cancer therapy and control. Salinomycin's potential for therapeutic use based on ongoing research, as well as the synthesis of its derivatives and their biological activity, will also …

Improved Extraction And Detection Of Disinfection Byproducts, Impacts Of Wildland-Urban Interface Wildfires On Drinking Water, And Change In Disinfection Byproducts Over Time In Chlorinated Vs. Chloraminated Distribution Systems, Patrick Thomas Justen

Theses and Dissertations

Drinking water disinfection is critical to prevent the occurrence of waterborne pathogens in drinking water. However, disinfection causes the unintended formation of disinfection byproducts (DBPs) through the reaction of disinfectants (e.g., chlorine, chloramine) with natural organic matter (NOM), algal matter, or anthropogenic pollutants present in source waters. Exposure to DBPs is associated with increased bladder cancer, colorectal cancer, miscarriage, and birth defects. The U.S. EPA currently regulates eleven DBPs in drinking water—four trihalomethanes, five haloacetic acids, bromate, and chlorite. However, research shows that DBP related toxicity in drinking water is driven mainly by other, non-regulated DBPs, particularly iodinated DBPs and …

Synthesis And Characterization Of Lanthanide Extended Structures And Their Novel Transuranic Analogues, Hunter Bernard Tisdale

Theses and Dissertations

The United States owns a substantial amount of radioactive waste as a result of decades of research, weapons manufacturing, and nuclear energy production. As nuclear energy and research continue to add to our stockpiles of waste, the issue of remediating this waste becomes more pressing. Many of the radioactive constituents of this waste, such as the transuranic (Z > 92) elements, will give off radioactivity at harmful levels for millennia. Thus, a robust method of storing this waste is paramount to ensuring public safety. Currently, nuclear waste is being processed by vitrifying it in borosilicate glass. However, this method has shortcomings …

Molecular Architecture And Mechanical Response In Polymeric Materials: Thin Films, Linear-Ring Elastomers, And Lignin, Siteng Zhang

Theses and Dissertations

Understanding the mechanical behavior of polymeric materials is critical to advancing modern technologies, from flexible electronics to sustainable adhesives. This dissertation investigates the micromechanics of polymer thin films, dual-network elastomers, and bio-based lignin materials, with an emphasis on deformation mechanisms, network topology, and mechanical properties. The work combines principles of polymer physics with materials science to uncover structure–property relationships that inform polymer design. This dissertation primarily uses coarse-grained and atomistic molecular dynamics simulations to investigate molecular-scale behavior beyond experimental reach. Through these methods, critical insights are gained into how entanglement, topology, and chain architecture govern bulk material performance. The first …