Chemistry Commons^™

Nickel-Catalyzed Cross-Coupling Reactions Involving Secondary And Tertiary Alkyl Nucleophiles, Amruta Ajit Joshi

Dissertations, Theses, and Capstone Projects

In the first chapter, introduction of transition metal-catalyzed cross-coupling reactions has been given. These transition metal-catalyzed C-C bond forming reactions have been used extensively in organic synthesis. Among them, C(sp2)-C(sp2) bond forming reactions have been widely studied over decades. More recently, some reports have demonstrated the use of C(sp3) nucleophiles and electrophiles in cross-coupling reactions. However, use of secondary and tertiary alkyl nucleophiles has remained a challenge due to competitive β-hydride elimination and slow transmetallation of bulky secondary and tertiary alkyl organometallic nucleophiles.

In the second chapter, the first general nickel-catalyzed Negishi reaction for the cross-coupling of unactivated, acyclic secondary …

Conformational Features Of The Human U2-U6 Snrna Complex, Ravichandra Bachu

Dissertations, Theses, and Capstone Projects

The splicing of precursor messenger (pre-m) RNA, during which noncoding intervening sequences are excised and flanking coding regions ligated, is an integral reaction of gene expression. In eukaryotes, it is carried out by a dynamic RNA-protein complex called the spliceosome, in which five small nuclear (sn) RNA components are actively involved in recognition and chemical aspects of the process. A complex formed between U2 and U6 snRNAs is implicated in the chemistry of pre-mRNA splicing. The catalytic activity of the U2-U6 snRNA complex is dependent on the presence of Mg2+ ions, and the complex has been shown to have several …

Property Enhancements Of Dielectric Nanoparticles Via Surface Functionalization, Andrew Byro

Dissertations, Theses, and Capstone Projects

This thesis describes the surface modification of barium strontium titanate nanoparticles for use in polymer/ceramic composite thin film capacitors with resultant improved dielectric and film-making properties. Phosphonic acid-type ligands proved to be most effective for surface conjugation to the surface of the barium strontium titanate nanoparticles. Amine-terminated ligands proved to be effective at removing surface adsorbed water before being almost entirely removed during the sample washing stage. Carboxylic acid terminated ligands proved to adhere less well to the nanoparticle than the phosphonic acid, but resulted in thin films with a higher dielectric constant, which was more stable in the measured …

Fabrication And Assembly Of Patchy Particles With Uniform Patches, Zhenping He

Dissertations, Theses, and Capstone Projects

Patchy colloidal particles have been widely studied as the self-assembly building blocks to illustrate their potential for forming complex structures. The parameters affecting the final assembly structures include (i) patch size, shape, and number per particle, (ii) their relative positions, and (iii) the surface properties of the patch material. Recent computational studies have highlighted the impact of patch shape on assembly structure; however, there are only a limited number of methods that can provide control over patch shape and size. In this thesis, a template is introduced to the Glancing Angle Vapor Deposition method (GLAD) to create surface anisotropy on …

An Ethnobotanical, Ecological And Lc-Ms-Based Chemometric Investigation Of Phaleria Nisidai, A Traditional Adaptogen Containing Diterpene Esters From Palau, Micronesia, Daniel Kulakowski

Dissertations, Theses, and Capstone Projects

An ethnobotanical, ecological and LC-MS-based chemometric investigation of Phaleria nisidai, a traditional adaptogen containing diterpene esters from Palau, Micronesia

Palau is a country with a rich heritage of traditional medicine still being practiced. One of the most popular and respected remedies in Palau is a tea made from fresh leaves of Phaleria nisidai Kaneh. (Thymelaeaceae). Interviews conducted to determine the use of this plant revealed that it is employed non-specifically to treat a variety of general health concerns. Its use as a prophylactic to keep away sickness, as a 'system cleaner', as well as for strength and energy indicate …

Development Of Mesoporous Silicas, Responsive Polymer Microgels, And Related Nanocomposites, Yingyu Li

Dissertations, Theses, and Capstone Projects

This dissertation covers research on polymer-templated nanoporous materials and functional soft materials, and it consists of four major parts. The first part is on introduction. The next part (Chapters 2-3) describes the research work on the synthesis of silicas with spherical mesopores. Chapter 2 is focused on the synthesis of large-pore FDU-12 silicas at room temperature by using surfactants with large hydrophilic blocks and relatively small hydrophobic blocks (such as Pluronic F108 (EO132PO50EO132)) as the template. Chapter 3 discusses an interesting mesopore structure, which is the hollow silica nanosphere (HSN). The single-micelle-templating strategy provides a general approach for the synthesis …

An Abundant Dysfunctional Apolipoprotein A1 In Human Atheroma, Ying Huang, Joseph A. Didonato, Bruce S. Levison, Dave Schmitt, Lin Li, Yuping Wu, Jennifer Buffa, Timothy Kim, Gary S. Gerstenecker, Xiaodong Gu, Chandra S. Kadiyala, Zeneng Wang, Miranda K. Culley, Jennie E. Hazen, Anthony J. Didonato, Xiaoming Fu, Stela Z. Berisha, Daoquan Peng, Truc T. Nguyen, Shaohong Liang, Chia-Chi Chuang, Leslie Cho, Edward F. Plow, Paul L. Fox, Valentin Gogonea, W.H. Wilson Tang, John S. Parks, Edward A. Fisher, Jonathan D. Smith, Stanley L. Hazen

Chemistry Faculty Publications

Recent studies have indicated that high-density lipoproteins (HDLs) and their major structural protein, apolipoprotein A1 (apoA1), recovered from human atheroma are dysfunctional and are extensively oxidized by myeloperoxidase (MPO). In vitro oxidation of either apoA1 or HDL particles by MPO impairs their cholesterol acceptor function. Here, using phage display affinity maturation, we developed a high-affinity monoclonal antibody that specifically recognizes both apoA1 and HDL that have been modified by the MPO-H2O2-Cl− system. An oxindolyl alanine (2-OH-Trp) moiety at Trp72 of apoA1 is the immunogenic epitope. Mutagenesis studies confirmed a critical role for apoA1 Trp72 in MPO-mediated inhibition of the ATP-binding …

Studies In Asymmetric Synthesis: Supramolecular Catalysis, C–H Activation, And D-Cycloserine Synthesis, Nathan C. Thacker

Department of Chemistry: Dissertations, Theses, and Student Research

Rh-catalyzed asymmetric hydrogenation has emerged as a powerful tool for the manufacturing of chiral pharmaceuticals. While the mechanism is well understood, catalyst design a priori is not yet possible. Supramolecular catalysis, the use of non-covalent forces to affect a catalytic process, can afford the catalyst diversity required to uncover efficient catalysts and further our understanding. Using a modular design and self-assembly, a large scale supramolecular catalyst screening in a catalyst scaffold optimization study of rhodium-catalyzed asymmetric hydrogenation was carried out. Analyzing the data yields some new insights into the roles of each module making up the supramolecular catalyst. Perhaps most …

Organic Pi-Stacking Semiconducting Material: Design, Synthesis And The Analysis Of Structure And Properties, Bin Wang

Dissertations, Theses, and Capstone Projects

Organic semiconducting materials have been under intensive investigation in the recent decades for potential applications in various electronic or optoelectronic devices such as light emitting diodes, photovoltaic cells and field effect transistors. Compared to inorganic counterparts, organic charge transport materials are attractive for their abilities of forming thin-films, large area manufacturing, compatibility with flexible substrate, light weight and potential low fabrication cost. The charge transport property of the organic active layer is one of the key factors to the electronic or optoelectronic performance of devices. Research projects presented in this thesis focused on improving charge carrier mobility of organic charge …

Large-Scale Solution Synthesis Of Narrow Graphene Nanoribbons, Timothy H. Vo, Mikhail Shekhirev, Donna A. Kunkel, Martha D. Morton, Eric Berglund, Lingmei Kong, Peter M. Wilson, Peter A. Dowben, Axel Enders, Alexander Sinitskii

Nebraska Center for Materials and Nanoscience: Faculty Publications

According to theoretical studies, narrow graphene nanoribbons with atomically precise armchair edges and widths of(1.1 eV), which makes them potentially promising for logic applications. Different top–down fabrication approaches typically yield ribbons with width >10nm and have limited control over their edge structure. Here we demonstrate a novel bottom–up approach that yields gram quantities of high-aspect-ratio graphene nanoribbons, which are only ~1 nm wide and have atomically smooth armchair edges. These ribbons are shown to have a large electronic bandgap of ~1.3 eV, which is significantly higher than any value reported so far in experimental studies of graphene nanoribbons prepared by …

Chemistry Of 6-Monobrominated Indigo, Mbi, Hiroko Ajiki

Dissertations, Theses, and Capstone Projects

6-monobrominated indigo, MBI, is a component of a historically important and the most expensive colorant, Tyrian Purple.

The colorant is remarkably stable under the sun, in the air and after extensive washing with water. The color is still vivid after thousands of years. Even though it has such a high stability, MBI and Tyrian Purple have color changes from purple to blue upon temperature changes. This color change has been known for long to certain people, but the mechanism of the color change was unknown.

Tyrian Purple also has recently attracted interests for applications towards semiconducting material due to its …

Intelligent Nano/Microgels For Cell Scaffold And Drug Delivery System, Jing Shen

Dissertations, Theses, and Capstone Projects

Stimulus-responsive polymer microgels swell and shrink reversibly upon exposure to various environmental stimuli such as change in pH, temperature, ionic strength or magnetic fields. Therefore, they become ideal candidates for biomaterial applications. For this work, we focus on the several intelligent microgels and their application on two areas: the cell scaffold and the drug delivery system.

As for the cell scaffold, it can be realized by colloidal supra-structure microgels, which constructed by the thermo-driven gelation of the colloidal dispersion of poly(N-isopropylacrylamide-co-acrylamide) poly(NIPAM-co-AAm) microgels (Chapter 3). Such microgels exhibit a reversible and continuous volume transition in water with volume phase transition …

Acrylamide Production Using Encapsulated Nitrile Hydratase From Pseudonocardia Thermophila In A Sol–Gel Matrix, Salette Martinez, Misty L. Kuhn, James T. Russell, Richard C. Holz, Timothy E. Elgren

Chemistry Faculty Research and Publications

The cobalt-type nitrile hydratase from Pseudonocardia thermophila JCM 3095 (PtNHase) was successfully encapsulated in tetramethyl orthosilicate sol–gel matrices to produce a PtNHase:sol–gel biomaterial. The PtNHase:sol–gel biomaterial catalyzed the conversion of 600 mM acrylonitrile to acrylamide in 60 min at 35 °C with a yields of >90%. Treatment of the biomaterial with proteases confirmed that the catalytic activity is due to the encapsulated enzyme and not surface bound NHase. The biomaterial retained 50% of its activity after being used for a total of 13 consecutive reactions for the conversion of acrylonitrile to acrylamide. The thermostability and long-term …

Nanocarbons As Charge Carriers In Organic Solar Cells, Xinbo C. Lau

Dissertations

Organic photovoltaics (OPV) are an alternate to conventional silicon and thin film solar cells. They have several advantages such as simple fabrication, low material cost, light weight, and the ability to cover large areas. Typical OPV are based on bulk heterojunction structure consisting of a blend of an electron-donating semiconductor polymer and an electron-accepting molecule. Various approaches have been pursued to improve the performance of OPV: low bandgap polymers, new electron acceptors, processing additives, and tandem cell architecture.

Nanocarbons possess unique physical and chemical properties that can contribute to the enhancement of OPV performance, such as charge carrier mobility, thermal …

Paper-Based Standard Addition Assays, Cory A. Chaplan, Haydn T. Mitchell, Andres W. Martinez

Chemistry and Biochemistry

Standard addition assays conducted on paper-based microfluidic devices are introduced as an alternative to external standards for calibrating quantitative tests. To demonstrate this technique, a colorimetric, paper-based, standard addition assay was optimized for the determination of glucose concentrations in the range of 0 to 5 mM. Comparable results were obtained from the assay via digital image colorimetry under three different lighting conditions.

Preparation Of Green Fluorescent Protein Constructs For The Determination Of The Mechanism Of The Excision Of A Novel Intron, John Daniel Clinger, Dr. Daniel L. Simmons

Journal of Undergraduate Research

Recent advances have greatly increased the utility of bioluminescence as a qualitative and quantitative tool in scientific research. The genes encoding fluorescent proteins in several organisms have been identified, cloned, modified, and inserted into several different vectors; thus allowing them to be used in a variety of diagnostic techniques. One such protein, isolated from aequorea victoria, is green fluorescent protein (GFP). Since GFP is encoded by a small gene, 720 base pairs, and fluoresces brightly when irradiated by ultraviolet light; it was seen as good candidate for the study of a novel pre-mRNA splicing mechanism.

Molecular Machine Components Observed In The Gas Phase: Self- Assembling Pseudorotaxanes Of Cucurbit[N]Urils (N=6, 7, And 8) And Doubly-Protonated 1,4-Diaminobutane, Kevin Alan Walker, Dr. David Dearden

Journal of Undergraduate Research

Nanotechnology offers the potential of creating machines the size of molecules. Such machines have limitless possibilities in numerous fields: chemistry, computer science, technology, and medicine, to name a few. Molecular machines could be instrumental in creating computers millions of times faster than our present computers. These machines could catalyze or inhibit a variety of chemical reactions. Such machines could be instrumental in altering and fixing an individual’s genetic makeup to successfully combat disease and illness. However, because nanotechnology is a relatively new field of study, science has yet to scratch the surface of the implications molecular machines may have in …

Calorimetric Investigation Of The Complexation Of Didodecylcalix[4]Arene-Crown-6 With Alkali Metal Cations In Acetonitrile, Dusten M. Macdonald, Dr. John D. Lamb

Journal of Undergraduate Research

Processing and storage of medium and high level activity liquid nuclear wastes (MLW/HLW) present a major challenge for governments around the world. Gamma radiation from 137Cs, as well as radiation from 90Sr and other radionuclides present in the waste, complicates the already troublesome disposal process (1, 2). Removal of such long-life radionuclides from MLW and HLW mixtures would allow for more affordable disposal of the partially decontaminated solutions, would lower the volume of high activity waste to be stored in geological formations, and/or possibly allow for transmutation of these radionuclides into non-radioactive elements (2). Much effort has been expended in …

Electronic Control Of The Photocycloaddition Of Silyl Tethered Alkenes, Kari Cowdell, Dr. Steven A. Fleming

Journal of Undergraduate Research

Solar energy is a major reason for the study of photochemistry. Photochemistry is the investigation of the interaction of organic compounds with light. The ability of plants and bacteria to harness the sun’s energy is an example of photochemistry. One area of photochemical research is the synthesis of cyclobutane rings which are found in plant essential oils and animal pheromones. Anticancer drugs such as taxol also have four member rings in their structures. Biological systems are unique in their ability to produce cyclobutane systems with specific stereochemistry that current methods of synthesis require great effort to acquire. It has been …

Isolation, Purification, And Characterization Of Biologically Active Compounds From Endophytic Fungi, Trisha L. Anderson, Dr. Noel L. Owen

Journal of Undergraduate Research

This project focused on endophytic fungi, fungi that live inside of plants without causing disease, as a source of compounds that may be useful in treating human disease. Endophytic fungi were chosen both because their relationship with the plants in which they live indicates that they provide some benefit to the plant and because they have a more specific relationship with a plant host, making acquisition of future samples of the same fungus more feasible. In addition, these fungal species have been less studied than many other aspects of natural products research. This research centered on the isolation of novel …

Effects Of Sirna-Mediated Silencing Of Phosducin-Like Protein Expression On Protein Folding By The Cytoplasmic Chaperonin Complex, Sarah Warburton, Dr. Barry Willardson

Journal of Undergraduate Research

Our lab has recently described an interaction of Phosducin-like protein (PhLP) with the cytoplasmic chaperonin complex (CCT), a sixteen polypeptide complex required for the native folding of actin and tubulin and many other cellular proteins. We found that the binding of PhLP blocked CCT-dependent folding of firefly luciferase in vitro and that over expression of PhLP in Chinese hamster ovary (CHO) cells inhibited actin folding by 80%. Thus, it appears that PhLP is the first known regulator of CCT-dependent protein folding.

Thermodynamics Of L-Valine And L-2-Aminobutyric Acid, Joshua L. Price, Dr. Earl M. Woolley

Journal of Undergraduate Research

Understanding the thermodynamics of protein hydration is critical to elucidating protein structure and function in aqueous solution. Because they are derivative properties, apparent molar volume Vφ and apparent molar heat capacity Cp,φ are particularly useful in describing solution thermodynamics. It is difficult, however, to resolve the apparent molar volume or apparent molar heat capacity of a large protein into individual contributions from specific amino acid residues and functional groups. Small model compounds like the amino acids can provide useful estimates of these individual contributions. While the apparent molar properties of many amino acids have been studied recently, there is a …

Buruli Ulcer In The Ga District Of Ghana, Jonathan Osorio, Dr. Steven W. Graves

Journal of Undergraduate Research

During this past summer, I had the wonderful opportunity to travel to southern Ghana with the Humanitarian Aid Relief Team to study the effects of Buruli ulcer in rural endemic villages. From May 12 to June 21, I was part of a small research group studying the effects of Buruli ulcer on villagers in the Ga District. Part of my research included investigating their cultural beliefs that related in any way to possible contraction of the disease.

Thermodynamics Of Aqueous Nucleic Acid Bases And Nucleosides, Bryan R. Mcrae, Dr. Earl M. Woolley

Journal of Undergraduate Research

Despite the astounding advances in modern genetics research, surprisingly little is known about the thermodynamic behavior and physical properties of DNA’s molecular subunits. Our study investigated several thermodynamic properties of common nucleic acid constituents. Specifically, we calculated the apparent molar volumes (Vφ) and apparent molar heat capacities (Cp,φ) of the nucleosides adenosine, guanosine, cytidine, thymidine, and uridine, and of their corresponding bases adenine, cytosine, thymine, and uracil, in dilute aqueous solutions.

Identification Of The Regulatory Elements Responsible For The Control Of Premrna Splicing Of Intron-1 In Chicken Cox-2, Daniel L. Simmons, Dr. Orlan Kenneth Macdonald

Journal of Undergraduate Research

In order to create a unique clone of chicken COX-2 it was necessary to insert a synthetic DNA tag into the full-length version of the COX-2 cDNA. First, a 21-nucleotide oligo and its complement were produced using a DNA synthesizer. The oligos were purified, phosphorylated and then annealed.

A Search For An Internal Ribosomal Entry Site In The Human Angiotensin 2, Type 1 Receptor, Joseph A. Garcia, Dr. Terry S. Elton

Journal of Undergraduate Research

The study of human genetics has recently exploded into numerous fields and, as a result, our knowledge of genetics and gene related illnesses is growing exponentially. Human DNA undergoes three main levels of control. The first is replication where the genome is reproduced in an exact copy. The second level is transcription, where an RNA polymerase transcribes DNA into mRNA. Finally translation where mRNA, the code for making a protein is recognized by ribosomes. Ribosomes recognize the 5′ region of the mRNA and scan along until they find the start codon to initiate the translation of the mRNA into a …

Distribution Of Isoforms Of The Sodium Pump In Pregnancy-Related Tissues: Changes For Women In Labor, David S. Faux, Dr. Steven W. Graves

Journal of Undergraduate Research

The birth of a baby has always been regarded as a miracle. Even today the carefully orchestrated events that result in birth elude the outreaches of scientific research. Among the most important of these events are the contractions of the uterus termed labor. Several factors are known to be important in the initiation and maintenance of labor, including hormones secreted by the placenta and the aminochorionic membranes. The mechanisms or factors that increase secretion and/or production of these activating agents are less well understood.

Elements Regulating Excision Of Chicken Cyclooxygenase-2 Intron 1, Nathan Evanson, Dr. Daniel L. Simmons

Journal of Undergraduate Research

Cyclooxygenases (COXs) are enzymes that are responsible for the production of a potent class of biological signaling molecules called prostaglandins. Prostaglandins are involved in responses such as inflammation, contraction of smooth muscle, and regulation of water balance in the kidney. They are also found in greatly elevated amounts in some types of cancer. This elevation in prostaglandins is the result of increased production of the form of COX known as COX-2. Because COX-2 may play a role in the development of cancer, an understanding of how COX-2 is regulated is important in the understanding of cancer and may give insights …

Thermochemical Properties Of C3 To C5 Unsaturated Carbonyl Alkenes: Enthalpies Of Formation, Entropy, Heat Capacity, Bond Enthalpy, Ruiqi Jian

Theses

α,β and α-γ unsaturated carbonyl compounds are important classes of carbonyl compounds with the general structure R-(O=C)-Cα=Cβ-R’ and R-(O=Cγ)-Cβ-Cα=Cβ-R’. These compounds are utilized in industry and are also produced as intermediates of hydrocarbon oxidation in chemistry of the atmosphere and in combustion. These unsaturated carbonyls are common environmental pollutants, are frequently associated with adverse effects, and are considered to play an important role in human cancer. Their stability, thermochemical properties are important to understanding their reaction paths in atmospheric, combustion and bio related environments. Enthalpy, entropy, and heat capacity of unsaturated alkene molecules, and radicals corresponding to hydrogen atom …

Evaluation Of The Abilities Of Cationic Steroid Antibiotics To Inhibit Microbial Growth In Food, Timothy W. Winter, Dr. Paul B. Savage

Journal of Undergraduate Research

Food-borne illnesses are a continuing problem in the US. According to figures from the Center for Disease Control, an estimated one million food-borne infections and 500 deaths occur each year associated with Salmonella. Also reported are the cases involving Escherichia coli O157:H7; the death toll is between 50 and 100 people every year. Currently, the only antibiotic approved for use in food in the US is nisin, a cationic peptide antibiotic (CPA) that is active against Gram-positive bacteria but not Gram-negative (including E. Coli and Salmonella).