Chemistry Commons^™

Current And Future Applications Of 3d Printing Using Custom-Made Materials, Bridger T. Irons

Honors Thesis

The use of 3D printers has increased exponentially from its inception in the 1980s. Recently, the ability to design and create detailed objects has drawn the attention of many who wish to capitalize on this highly customizable process. With much of the focus in this industry being placed on finding new printable materials, many are overlooking the possibility of modifying existing materials. The aim of our research was to modify the materials already being used by 3D printers to alter their properties and explore future possible applications. We examined the addition of graphene powder, carbon microfibers, and other nanoparticles to …

A Hybrid Lipid Membrane Coating “Shape-Locks” Silver Nanoparticles To Prevent Surface Oxidation And Silver Ion Dissolution, Thomas J. Miesen, Arek M. Engstrom, Dane C. Frost, Ramya Ajjarapu, Rohan Ajjarapu, Citlali Nieves Lira, Marilyn R. Mackiewicz

Chemistry Faculty Publications and Presentations

The controlled synthesis of stable silver nanoparticles (AgNPs), that do not undergo surface oxidation and Ag⁺ ion dissolution, continues to be a major challenge. Here the synthesis of robust hybrid lipid-coated AgNPs, comprised of L-α-phosphatidylcholine (PC) membranes anchored by a stoichiometric amount of long-chained hydrophobic thiols and sodium oleate (SOA) as hydrophobic binding partners, that do not undergo surface oxidation and Ag+ ion dissolution, is described. UV-Visible (UV-Vis) spectroscopy, transmission electron microscopy (TEM), and inductively coupled plasma mass spectrometry (ICP-MS) demonstrate that in the presence of strong oxidants, such as potassium cyanide (KCN), the hybrid lipid-coated AgNPs are stable …

Photophysical Properties And Excited State Dynamics Of Porous Organic Materials, Korlan Duisenova

Master's Theses (2009 -)

Charge transfer complexes are charge separated states that are formed at donor - acceptor interfaces and play significant role in charge photogeneration. One of the main criteria for efficient charge transfer is suppression of charge recombination process. Previous experiments show that one of the most effective ways to inhibit recombination is an introduction of bridge molecules between donor and acceptor or increase the number of electron donating and withdrawing groups. These solutions are inspired by photosynthetic reaction centers where charge transfer occurs over long distances. Covalent Organic Frameworks (COFs) are advanced porous crystalline materials that can be constructed of multiple …

Purification Of Dna Origami Nanostructures Using Capillary Electrophoresis, Janan Hui , '20

Senior Theses, Projects, and Awards

DNA origami are nanostructures designed based on Watson-Crick base-pairing that fold a scaffold into non-arbitrary morphologies using an excess of linear single-stranded DNA "staples". As an engineered nanomaterial (ENM) with great customizability, DNA origami also enjoys the benefit of naturally encoded and well-studied structural and functional properties. The flexibility of different folding patterns allows for construction of a wide variety of shapes and sizes of DNA origami, showing potential applications in fields such as medicine, biocomputing, biomedical engineering , and measurement science. Despite the successes as a functional nanomaterial, a major barrier to the applicability of DNA origami rests in …

Hybrid Metal/Covalent Organic Frameworks For Solar Fuel Conversion, Sizhuo Yang

Dissertations (1934 -)

Due to the harsh environment issues such as air pollution and global warming and global energy crisis raised by using fossil fuels, it is urgent to find an alternative sustainable energy source. How to utilize solar energy-the most clean and abundant energy source on earth is challenging. Convert solar energy to clean fuel energy like H2 or hydrocarbons is ideal energy conversion strategy. Thus, design new materials for hydrogen generation or CO2 reduction have attract researcher’s attention.The present study focuses on two types of materials of interest, the first of which is Metal Organic Frameworks (MOFs), including enhancing the …

Theoretical And Experimental Investigation Of Non-Covalent Interactions In S-Nitrosothiols And Thio-Carboxylic Acids, Niloufar Hendinejad

Dissertations (1934 -)

S-Nitrosothiols (RSNOs) are ubiquitous biomolecules whose chemistry is tightly controlled in unknown. In this work, we demonstrate, using high-level ab initio and DFT calculations, the ability of RSNOs to participate in intermolecular interactions with electron pair donors/Lewis bases (LBs) via a σ-hole, a region of positive electrostatic potential on the molecular surface at the extension of the N–S bond. Analysis of the nature of the intermolecular interactions in σ-hole bound RSNO-LB complexes shows the dominant role of electrostatic and dispersion interactions. Importantly, σ-hole binding is able to modulate the properties of RSNOs by changing the balance between two chemically opposite …

Mechanistic Investigations Of Isothiourea Catalyzed Silylations Of Secondary Alcohols Using Reaction Progress Kinetic Analysis, Brandon Kane Redden

Theses and Dissertations

The primary focus of this research is in expanding the knowledge and scope of the asymmetric silylation of alcohols. Since it was discovered in 2011 that chiral isothioureas can selectively silylate alcohols through kinetic resolution reactions, the Wiskur group has been working to increase the applications of the methodology. Understanding the kinetics behind the mechanism of the reaction is fundamental in the designing both improved kinetic resolutions and other silylation methodology. Chapter 2 focuses on using reaction progress kinetic analysis to monitor silylations of secondary alcohols with thiourea catalysts in real time using in situ IR to determine the rate …

Development Of Natural Product-Derived Cationic Polymers For Biomaterial Applications, Moumita Sharmin Jui

Theses and Dissertations

In this thesis, multicyclic natural products and metallocene-containing polymers were synthesized for biomedical applications.

Chapter 1 describes the overall background, the recent development of natural product-based antimicrobial biomaterial and metallocene containing polymer for biomedical application. Afterward, the primary research objectives of my research are illustrated.

In chapter 2, a multicyclic natural product derived guanidine-based facially amphiphilic homopolymers and copolymers were synthesized. Cholic acid is one of the bile acid derivatives used to prepare facially amphiphilic moieties. A neutral polyethylene glycol (PEG) component was used to prepare copolymers with cholic acid. Reversible-addition fragmentation chain transfer (RAFT) polymerization technique was used to …

Biophysical And Structural Characterization Of Non-Canonical Dna Structures, Linda Yingqi Lin , '20

Senior Theses, Projects, and Awards

Non-canonical DNA structures known as G-quadruplexes (GQs) and i-motifs can form from G-rich and C-rich sequences within the genome, respectively, which are prominent within telomeres and oncogene promoters. These non-canonical quadruplexes likely play roles in regulating gene expression and in DNA replication and repair. However, much remains to be understood about their structural features and diversity. In this work, we investigate the interaction of a GQ-forming sequence with a water-soluble porphyrin, N-methyl mesoporphyrin IX (NMM). Biophysical studies revealed an impressively tight, thermodynamically favorable binding interaction. We then solved the GQ-NMM crystal structure at 2.39 Å, which showed that the DNA …

Quantitative Analysis Of Silver Nanoparticle Dissolution Kinetics In Complex Matrices Using Point-Of-Use And End-Of-Use Models, Daniel J. Boehmler , '20

Senior Theses, Projects, and Awards

Engineered nanomaterials (ENMs) have become increasingly popular for use in both industrial and consumer settings in recent years. Of the myriad of materials used to synthesize ENMs, silver is one of the most common. Silver nanoparticles (AgNPs) undergo dynamic transformations in biological environments, leading to modifications in their reactivity, surface interactions, and speciation. In particular, release of ionic silver (Ag(I)(aq)) through AgNP dissolution can have significant impacts on ecological and human health. Thus, quantifying AgNP dissolution rates in biologically relevant matrices can provide valuable information regarding their potential cytotoxic effects. Linear sweep stripping voltammetry (LSSV) is a technique …

Development Of Electroanalytical Techniques To Quantify Silver Nanoparticle Dissolution, Aggregation, And Release Kinetics, Zachary J. O'Dell , '20

Senior Theses, Projects, and Awards

Recently, the manufacture of engineered nanomaterials has seen an increase worldwide. This is due to the desirable properties of materials at the nanoscale rather than the bulk scale, such as improved optical, electronic and magnetic properties. Silver nanoparticles (AgNPs) are one of the fastest growing nanomaterials to be incorporated into consumer products due to silver’s well known antibacterial and antimicrobial properties. AgNP-enhanced products represent the largest proportion of engineered nanomaterial products on the consumer market, despite questions regarding the life cycle of such products. AgNPs can undergo a number of transformations during their life cycle including dissolution, aggregation, and protein …

Scanning Electron Microscopy (Sem) Investigation Of Morphology Changes In The Reduction Of Silica Nanoparticles To Elemental Silicon, Allison M. Cairns

University Honors Theses

The application of silicon nanoparticles varies from energy storage materials, to drug-delivery, and molecular recognition. Various chemical and physical properties of the Si nanoparticles arise from their morphology. This paper aims to reveal the morphology of Si nanoparticles following magnesiothermic reduction of silica (SiO₂) nanoparticles. Two sets of SiO₂ nanoparticles were used, commercially available NanoXact nanoparticles and laboratory-synthesized Stöber nanoparticles. A Zeiss Sigma VP FEG SEM was used to examine the morphology. Following the magnesiothermic reduction, the nanoparticles were etched with HF. Ten sets of images were taken of both Stöber and NanoXact nanoparticles: 1,2: the SiO …

Visible-Light Photooxidation In Water By 1o2-Generating Supramolecular Hydrogels, Sankarsan Biswas, Mohit Kumar, Andrew Levine, Ian Jimenez, Rein V. Ulijn, Adam Braunschweig

Advanced Science Research Center

We report supramolecular photocatalytic hydrogels, produced by the enzymatically driven self-assembly of low molecular weight gelators (LMWGs). These LMWG precursors are composed of the organic chromophore diketopyrrolopyrrole (DPP), which is bi-functionalized with a series of amino acid (Phe, Tyr, Leu) methyl esters. In situ enzymatic hydrolysis of these photoactive precursors results in supramolecular hydrogels that provide a high density of photocatalytic sites. Under visible light irradiation these hydrophobic fibers recruit the reaction substrates and also produce ¹O₂, which is used here for the photooxidation of thioanisole (aromatic substrate) and cyclohexyl methyl sulfide (aliphatic substrate), with yields as …

Versatile Bismuth Salts-Induced Reactions From Our Laboratory: A Perspective, Debasish Bandyopadhyay, Bimal Krishna Banik

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Bismuth salts-mediated reactions are developed for the synthesis of diverse organic molecules of medicinal significance. Reactions conducted with bismuth salts are environmentally friendly and these may proceed due to the release of acids in the media. Bismuth salt may also act as a Lewis acid in these reactions. Versatile organic molecules in chiral and achiral forms are synthesized using bismuth salts-induced reactions at our research laboratory.

Structure–Activity Relationship Of Rgd-Containing Cyclic Octapeptide And Αvβ3 Integrin Allows For Rapid Identification Of A New Peptide Antagonist, Aaron Silva, Wenwu Xiao, Yan Wang, Wei Wang, Heng Wei Chang, James B. Ames, Kit S. Lam, Yonghong Zhang

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

The αvβ3 integrin, a receptor for many extracellular matrix proteins with RGD-sequence motif, is involved in multiple physiological processes and highly expressed in tumor cells, therefore making it a target for cancer therapy and tumor imaging. Several RGD-containing cyclic octapeptide (named LXW analogs) were screened as αvβ3 antagonists with dramatically different binding affinity, and their structure–activity relationship (SAR) remains elusive. We performed systematic SAR studies and optimized LXW analogs to improve antagonistic potency. The NMR structure of LXW64 was determined and docked to the integrin. Structural comparison and docking studies suggested that the hydrophobicity and aromaticity of the X7 amino …

Glutaminyl-Trna Synthetase From Pseudomonas Aeruginosa: Characterization, Structure, And Development As A Screening Platform, Yaritza Escamilla, Casey A. Hughes, Jan Abendroth, David M. Dranow, Samantha Balboa, Frank B. Dean, James M. Bullard

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Pseudomonas aeruginosa has a high potential for developing resistance to multiple antibiotics. The gene (glnS) encoding glutaminyl-tRNA synthetase (GlnRS) from P. aeruginosa was cloned and the resulting protein characterized. GlnRS was kinetically evaluated and the KM and kcatobs , governing interactions with tRNA, were 1.0 μM and 0.15 s-1 , respectively. The crystal structure of the α2 form of P. aeruginosa GlnRS was solved to 1.9 Å resolution. The amino acid sequence and structure of P. aeruginosa GlnRS were analyzed and compared to that of GlnRS from Escherichia coli. Amino acids that interact with ATP, glutamine, and tRNA are well …

Chemistry Of A Biscarborane Dithiol And Its Nickel (Ii) Complex, Tyler Hemingway

Theses and Dissertations

Neutral biscarborane dithiol and its anionic dithiolate form were successfully synthesized and structurally characterized. The C–C intracluster bond lengths were found to be responsive to the electron density on the cluster. Introduction of two thiol groups on biscarborane led to the significant increase of intracluster C–C bond lengths compared to those of unsubstituted biscarborane. Furthermore, the anionic dithiolate form had even longer C–C cluster bonds. This comparison shows electronic effect of substituents attached to carbon atoms of biscarborane on the strength of its C–C bonds. Additionally, a novel Ni complex was obtained using this dithiolate as a ligand. This complex …

Tailored Multifunctional Heterometallic Metal-Organic Frameworks, Otega Anthonia Ejegbavwo

Theses and Dissertations

Metal-organic frameworks (MOFs), which are well-defined and porous extended structures consisting of organic linkers connected to inorganic secondary building units, are a class of materials that have received tremendous attention over the last decade. This geometrically growing interest in MOFs is attributed to their properties of porosity, tunability, modularity, crystallinity, flexibility, and long-term stability, which makes them attractive candidates for various applications. This dissertation focuses on two major studies, the first part encompasses the strategic design, preparation, and extensive studies of actinide containing MOFs (An-MOFs). This work, presented within the first two chapters, demonstrates the effective utilization of MOF modularity …

Structural, Functional And Immunological Studies Of Group 1 And 2 House Dust Mite And Profilin Allergens For The Development Of Allergen Specific Diagnostics And Immunotherapy, Anyway B. Kapingidza

Theses and Dissertations

Group 1 and 2 house dust mites (HDM) allergens elicit IgE response in more than 80% of sensitized individuals. These allergens affect 10-30% of the world’s population. Prolonged inhalation of low doses of allergens (microgram amounts inhaled over months or years) by genetically predisposed individuals leads to the induction of a Th2-type immune response induced by allergen-specific immunoglobulin E (IgE) produced by plasma cells resulting in allergic diseases like asthma, atopic dermatitis, and rhinitis. Group 1 and 2 HDM allergens, in particular, are associated with the development of the aforementioned allergic diseases. The goal of this research was to characterize …

An Examination Between Neighborhood Characteristics And Alzheimer’S Disease And Related Dementias And Caregiver Mental Health In South Carolina, Mohammad Jahirul Islam

Theses and Dissertations

Carboranes are of topical interest due to their unique structures and applications in the fields of catalysis, polymers, material sciences and supramolecular chemistry. Icosahedral closo-dicarbadodecaboranes are remarkably robust three-dimensional boron-carbon clusters with two slightly acidic C-H bonds. Moreover, coordinatively unsaturated transition-metal complexes containing C-functionalized ortho-carborane are considered as potential catalysts for activation of small molecules.

Recently, we reported the synthesis of a pyridine-backbone pincer complex {(C₅H₃N)(C₂B₁₀H₁₀)₂}Ni(CH₃CN) (1) in which two C-functionalized ortho-carborane clusters act as the arms of the pincer ligand. The complex …

Systematic Development Of Photocatalysts, Mary Victoria Bobo

Theses and Dissertations

Photocatalysis is a rapidly growing field and a powerful synthetic tool that has recently seen many advancements, showing immense promise to replace classic catalysis with a mild and elegant alternative methodology. Visible light driven catalysis relies on redox stable transition metal and organic based photoactive catalysts (photocatalysts) that absorb visible light efficiently and facilitate electron/energy transfer. The desire for greener and more renewable catalytic methods has caused research to shifted away from traditional transition metals (due to scarcity and environmental toxicity) and toward organic based photocatalysts. Due to similar photophysical and electrochemical characteristics of each of these classes of photocatalysts …

Fundamental Studies Of Bimetallic Model Surfaces And Metal Organic Framework Thin Films, Fathima Sharfa Farzandh

Theses and Dissertations

This work is mainly focused on gaining a fundamental understanding of conventional bimetallic catalysts in order to correlate their macroscopic properties with the observed kinetic properties. This is achieved by synthesizing and studying fundamental model surface analogues of conventional catalysts that are difficult to study due to their complex, ill-defined nature. A wide array of surface science techniques that use ultra-high vacuum (UHV) conditions are readily available for detailed studies that can be conducted on model surfaces. This work focuses on the synthesis and investigation of two fundamental bimetallic catalysts formed via the addition of a second metal to an …

A Behavioral And Voltammetric Study Of The Effects Of Pb Exposure In Mice As A Model Of Autism Spectrum Disorder, Brenna Parke

Theses and Dissertations

Despite being a known toxin for several centuries, lead (Pb²⁺) is still utilized in commercial products including leaded gasoline, paint, and modern cosmetics. This presence has caused (Pb²⁺) to pollute the environment, including public drinking water sources. The recent outbreaks of elevated levels of (Pb²⁺) in the drinking water in Flint, Michigan and Washington D.C. have caused large populations to be exposed to the heavy metal for months at a time, raising a public health concern over the implications of widespread, long-term (Pb²⁺) exposure. Young children are most susceptible to the effects …

Fundamental Studies Of Bimetallic Model Surfaces And Metal Organic Framework Thin Films, Fathima Sharfa Farzandh

Theses and Dissertations

This work is mainly focused on gaining a fundamental understanding of conventional bimetallic catalysts in order to correlate their macroscopic properties with the observed kinetic properties. This is achieved by synthesizing and studying fundamental model surface analogues of conventional catalysts that are difficult to study due to their complex, ill-defined nature. A wide array of surface science techniques that use ultra-high vacuum (UHV) conditions are readily available for detailed studies that can be conducted on model surfaces. This work focuses on the synthesis and investigation of two fundamental bimetallic catalysts formed via the addition of a second metal to an …

Synthesis, Characterization, Electronic Structure Of Reduced Graphene Oxide And Nh₂-Mil-125(Ti) Modified Binbo₄ And Their Photocatalytic Activities, Maram Yahya Bakiro

Chemistry Theses

The present thesis focuses on the design and synthesis of novel visible light photocatalysts for CO₂ utilization. In recent years, Bi-based materials have shown remarkable photocatalytic activity in the field of CO₂ reduction. Particularly, BiNbO₄ has many promising applications as a visible light-harvesting material due to its bandgap position and orbital hybridization. In this study, an intensive effort has been made to study the effect of different reaction parameters such as temperature and pH of the different synthetic methodologies applied. The new photocatalytic materials have been characterized using different characterization techniques including PXRD, BET, SEM, EDX, and UV-Vis DRS. Since …

Synthesis, Characterization, Electronic Structure Of Reduced Graphene Oxide Modified Fenbo₄, Nh₂-Mil-125(Ti) Modified Fenbo₄ Composities And Their Photocatalytic Activities, Salwa Abdelrahim Hussein

Chemistry Theses

The production of value-added products through CO₂ utilization using photocatalysis offers an alternative green route for CO₂ fixation. Wide bandgap photocatalysts allow the absorption of light in the UV region, which represents the lowest percentage of the sunlight irradiation. On the other hand, narrow bandgap photocatalysts absorb light in the visible region, though the recombination rate of the generated electron-hole pairs affects their activity. In this thesis, the narrow bandgap FeNbO₄ is synthesized, studied and efforts are made to reduce the recombination rate and enhancing the photocatalytic activity.

Moreover, three FeNbO₄/NH₂-MIL-125(Ti) composites with different mole ratios are prepared, characterized and …

Synthesis And Characterization Of Novel Derivatives Of 1, 3, 4- 0xadiazole And Isoniazid, Ranem Mohammad Kaddoura

Chemistry Theses

This thesis describes the synthesis of novel derivatives of isoniazid and 1, 3, 4- oxadiazole piperazines and biological activities evaluation. The synthesis of the isoniazid derivatives (36a-Ɩ) was achieved by nucleophilic substitution of chloroacetylated isoniazid 34 with substituted piperazines (35a-Ɩ) produced isoniazidpiperazines (36a-Ɩ). On the other hand, cyclodehydration of chloroacetylated isoniazid 34 with POCl₃ give the corresponding 1, 3, 4-oxadiazole 37 which upon treatment with substituted piperazines (35a-m) gave 1, 3, 4-oxadiazole-piperazines (38a-m). All newly synthesized compounds were purified and characterized using spectroscopic techniques including ¹H-NMR, ¹³C-NMR, IR spectrometry and mass spectrometry.

The biological activity of the …

Catalytic Carbon–Carbon Bond Activation Of Saturated And Unsaturated Carbonyl Compounds Via Chelate-Assisted Coupling Reaction With Indoles, Nuwan Asanka Pannilawithana, Chae S. Yi

Chemistry Faculty Research and Publications

The chelate assistance strategy was devised to promote a highly regioselective catalytic C–C bond activation reaction of saturated and unsaturated carbonyl compounds. The cationic Ru–H complex 1 was found to be an effective catalyst for mediating the coupling reaction of 1,2-disubstituted indoles with α,β-unsaturated aldehydes and ketones, in which the regioselective C_α–C_β activation of the carbonyl substrates has been achieved in forming the 3-alkylindole products. The analogous coupling reaction of indoles with saturated aldehydes and ketones directly led to the C_α–C_β cleavage of the carbonyl substrates in forming the 3-alkylindole products. The coupling reaction …

Characterization Of Influenza A Virus Full Length Matrix Protein 1 (M1) In Order To Probe M1-M2 Interaction, Elizabeth A. Erler , '20

Senior Theses, Projects, and Awards

Influenza remains a serious global health threat and further characterization of key viral proteins is necessary in order to develop novel drugs and vaccines. Matrix protein 1 (M1) and matrix protein 2 (M2) of Influenza A Virus play key roles in the assembly and release of new infectious viral particles. The cytoplasmic tail of M2 has been shown to be critical for inducing membrane curvature in order to facilitate budding. M1 has multiple roles, including packaging viral RNA and recruiting it to the budozone through interactions with M2 and other viral membrane proteins. In this role as an adaptor protein, …

Lignin: A Likely Precursor Of A Significant Fraction Of Humic Substances Via Oxidative Transformations, Seyyedhadi Khatami

Chemistry & Biochemistry Theses & Dissertations

Lignin is a major component of decaying terrestrial vegetation in soils and has been arguably reported to contribute substantially to the formation of soil carbon humus, and natural dissolved organic matter (DOM). To better understand the process by which this humification occurs, lignin and lignin-derived monomers were subjected to both biotic and abiotic oxidation processes. Two well-known oxidative transformation strategies were employed. The first involved the fungal degradation of brown-rot degraded wood subjected to a white-rot fungus (Phanerochaete chrysosporium) whose enzymes are particularly effective in lignin degradation via enzymatic oxidation. This enzymatic attack was monitored by ultrahigh resolution …