Physical Sciences and Mathematics Commons^™

Selective Tripodal Titanium Silsesquioxane Catalysts For The Epoxidation Of Unactivated Olefins, Sarah M. Peak

Theses and Dissertations--Chemistry

Regiomeric mixture of HMe₂Si(CH₂)₃(i-Bu)₆Si₇O₉(OH)₃ (6), containing a Si-H group in one of the ligands of the silsesquioxane, was tethered onto a vinyl terminated hyperbranched poly(siloxysilane) polymer via a hydrosilation reaction to generate extremely active catalysts, P1-8 and c-P1-8. The synthesis of 6, in good yield, was accomplished via hydrosilation of CH₂=CHCH₂(i-Bu)₇Si₈O₁₂ (1) to generate ClMe₂Si(CH₂)₃(i-Bu)₇Si₈O_{12 …}

Spectroscopic Characterization Of Lanthanum-Mediated Hydrocarbon Activation, Dilrukshi C. Hewage

Theses and Dissertations--Chemistry

Lanthanum (La)-promoted hydrocarbon activation reactions were carried out in a laser vaporization metal cluster beam source. Reaction products were identified by time-of-flight mass spectrometry, and the approximate ionization thresholds of La-hydrocarbon complexes were located with photoionization efficiency spectroscopy. The accurate ionization energies and vibrational frequencies of the La complexes were measured using mass analyzed threshold ionization (MATI) spectroscopy. Their molecular structures and electronic states were investigated by combing the MATI spectroscopic measurements with quantum chemical and Franck-Condon factor calculations.

In this dissertation, La-mediated C-H and C-C bond activation reactions were investigated for several small alkynes (acetylene, propyne) and alkenes (propene, …

Fluorescence Imaging Of Analyte Profiles In An Inductively Coupled Plasma With Laser Ablation As A Sample Introduction Source, Lance Moses

Theses and Dissertations

Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has risen to among the top tier techniques for the direct analysis of solid samples. However, significant problems remain that must be solved to achieve the full analytical potential of LA-ICP-MS. Inefficient conversion of aerosol to ions within the ICP or transmission through the MS interface may decrease precision, sensitivity, and/or accuracy. Although fundamental mechanisms that govern ion production and transmission have been studied extensively in solution-nebulization (SN) ICP-MS instruments, significant gaps in our understanding remain. Furthermore, it is unclear to what extent differences between the aerosols generated during SN and LA …

A Simpler Route To Building Photochromic Cinnamaldehyde Semicarbazones, Byron R. Ebbert

Masters Theses

Photochromic semicarbazones are an interesting group of compounds that show potential in a broad range of applications, including as a more environmentally friendly replacement for photochromic metal complex compounds. Previous work has shown the feasibility to synthesize photochromic cinnamaldehyde semicarbazones (CSCs) from a benzaldehyde and a protected acetaldehyde Wittig reagent. A new, quicker, and cheaper approach to constructing these CSCs from crotonaldehyde was explored in this research. A three reaction sequence would convert crotonaldehyde to a CSC; first, an allylic bromination of the semicarbazone with N-bromosuccinimide (NBS); second, an Arbuzov reaction to prepare the semicarbazone phosphonate; and finally a condensation …

Investigation Of Β-Cyclodextrin's Ability In Differentiating Chiral Guest Molecules And Synthesis Of 1,6-Diphenyl-2,4-Hexadiene-1,6-Dione, Guang Yang

Masters Theses

This research work comprised two projects. The first one mainly focused on the synthesis of 12 alanine derivatives and analysis of their interactions with β-cyclodextrin through ¹H NMR titration. And the other project was an investigation of the conjugation effect of alkynones in its addition reactions with tributyltin hydride.

The synthesis of the alanine derivatives involved methyl esterification of alanine and then the substitution of an NH hydrogen with a benzoyl group. A total of 4 different substitution groups, labeled as the "A" groups, were introduced on the para-position of the benzoyl's phenyl group. Since alanine has one chiral …

Novel Bodipy Dyes For Dye-Sensitized Solar Cells, Hafsah Klfout

Masters Theses

Dyes-sensitized solar cells (DSCs) are of importance to efficient conversion of solar energy to electricity. The modern version of a DSC is a titanium dioxide nanoparticles-based electrochemical device, in which solar energy is absorbed by dye molecules and electrons from excited dye molecules are injected into the conduction band of titanium dioxide nanoparticle. The electrons are then transported through a network of interconnected TiO₂ particles to the fluorine- tin -oxide layer to the external circuit. In this process dye molecules are crucial to the device's energy conversion efficiency.

Boron-dipyrromethenes, known as BODIPY dyes, show strong absorption in the visible …

Morphological And Surface Chemistry Characteristics Of Silica Nanoparticle Based Cryogels From Specific Processing Parameters, Ben Walusiak

Masters Theses

The goal of this research was to determine the effects of processing conditions on the morphology and surface chemistry of silica nanoparticle based cryogels. All processing conditions resulted in a change in morphology or surface chemistry compared to the starting material, CAB-O-SIL HS5 fumed silica. N₂ adsorption isotherms were used to characterize surface area and pore size distributions of fumed silica and silica cryogels. TGA (thermogravimetric analysis) was performed on all samples in order to characterize the adsorbed water and hydroxyl group content of the silica surface. Solid state ²⁹Si NMR was also used to evaluate surface chemistry …

Synthetic Study Of Karlotoxins And Investigation Of Alpha-Diaminoboryl Carbanion Chemistry, Yusuke Takahashi

Electronic Theses and Dissertations

Karlotoxins (KmTxs), produced by a toxic marine/estuarine phytoplankton, the dinoflagellate Karlodinium veneficum, are known to be ichthyotoxic, thus being associated with numerous fish deaths events worldwide. They have also been reported to show a variety of biological activities such as hemolytic, cytotoxic, and anti-fungal activities. Recently, the Hamann group successfully assigned the absolute configurations of KmTx2, the first complete structure elucidation among the congeners. In a structural sense, karlotoxins are a family of linear polyketides with three distinctive regions; a bis-tetrahydropyran core fragment, a long, highly oxygenated carbon chain, and a lipophilic chlorodiene unit. Such potent biological activities as well …

Derivatization And Separation Of Natural Estrogens (Estrone, 17Β-Estradiol, And Estriol) Using Gas Chromatography With Flame Ionization Detection (Gc-Fid), Dena L. Guptill

Masters Theses

A major cause of concern for estrogens found in the environment is that even at very low concentrations (10-100 ng/L) they can have a negative effect on aquatic ecosystems by disrupting endocrine systems. Due to the increasing importance of monitoring the levels of estrogens in the environment, a detection method was developed to identify and quantify three natural estrogens (estrone, 17β-estradiol and estriol) using gas chromatography with flame ionization detection (GC-FID). In addition, the efficacy of two derivatizing agents, N,O-bis(trimethylsilyl) acetamide (BSTA) and N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), was evaluated. The GC detector (FID) was most responsive with E3, followed by E1 and …

Expression And Characterization Of Mouse Notch1 Abruptex Egf Repeats In E. Coli, Amid Paudyal

LSU Master's Theses

Notch1 is a transmembrane protein involved in cell signaling, which is found to be linked to various genetic and neurodegenerative diseases. The extracellular domain of the Notch1 protein consists of 36 tandem epidermal growth factor-like (EGF) repeats, which are directly involved in ligand binding and are heavily glycosylated. EGF 24-29 repeats lie in the Abruptex region of the Notch1 protein, and regulate the ligand binding activity through structural changes. The role of glycosylation in ligand binding events and the overall structure of the Abruptex region are not known. Also, the role of calcium binding in Notch activation or inhibition is …

A Study Of The Impact Of Ph On The Structure And Stability Of Epithelial Cadherin, Catherine Abadie

Honors Theses

Epithelial (E-) cadherin is a transmembrane protein whose function lies in cell-to-cell adhesion. It is a transmembrane component of adherens junctions of epithelial tissues, thereby connecting the actin cytoskeletons of adhered cells. It has five extracellular domains, a small transmembrane portion, and a cytoplasmic tail. The molecule must bind calcium in order to form an adhesive dimer with a cadherin molecule emanating from an adjacent cell. Cancer of the epithelial tissue, carcinoma, is accompanied by acidification of the tissue and a loss in cell adhesion. The long-term goal of this project is to determine the effect of a decrease in …

An Investigation Into The Synthesis Of A Four-Armed Diamino Swallowtail, Christopher Carter Barnett

Honors Theses

Perylenebisimides (PBIs) complex with quadruplex DNA and may influence the formation of telomeres. PBIs with amine groups are ionized at neutral pH and therefore soluble in water [1]. Swallowtails are long alkyl chains usually attached to PBIs to inhibit self-aggregation by pi-stacking [2]. Past attempts to create a PBI with swallowtails containing extra nitrogens were unsuccessful due to purification issues and methylene connectors. The purpose of this research is to investigate the synthesis of a diamino swallowtail with a methine connector. The first step is to create 1,3-bis(dibenzylamino)propan-2-one by way of an SN2 substitution reaction using 1,3-dichloroacetone and dibenzylamine [3]. …

An Investigation Of Protein-Dna Binding Characteristics By Fluorescence Anisotropy, Danna Nobile

Honors Theses

Recent studies have illustrated the presence of several secondary, non-B DNA structures that are associated with the promoter regions of several oncogenes, such as the intensely studied MYC gene. Two such secondary structures, G-quadruplexes and i-Motifs, have become topics of interest due to their prevalence within oncogenic promoters and their potential accessibility for future drug targeting due to their globular natures. Though fairly extensive research has been conducted to understand different factors affecting G-quadruplex formation and stability, similar studies for i-Motifs, particularly related to thermodynamics, are still evolving. One factor known to contribute to the additional energy required for duplex …

The Effects Of Hg2+ On Secondary Structures Formed By T-Rich Dna, Zachary Boynton

Honors Theses

Single stranded DNA that forms secondary structures has been a popular area of research in recent years. Much research has also been done in the field of heavy metals binding to DNA. Recently, it has been discovered that mercury in the presence of thymines will form T-HgII-T bonds. It is our hypothesis that single stranded DNA rich in thymine residues will form into a structure similar to i-motifs, formed from C-rich single strands, in the presence of mercury. Based on spectral changes during a mercuric titration, it is evident that mercury induces a structural change in T-rich DNA. We then …

The Biogeochemistry Of Elemental Sulfur Contaminated Soils: Insights Into Effective Remediation, Michael Ryan Mctee

Graduate Student Theses, Dissertations, & Professional Papers

Soil contamination that results from elemental sulfur (S⁰) deposition is a new occurrence. Elemental sulfur is stockpiled as a byproduct from the oil and gas industry and is deposited by biodegradable trap and skeet targets at shooting ranges. Chemolithotrophs and mixotrophs can oxidize S⁰ to H₂SO₄. Consequently, in areas where excess S⁰ is deposited or stockpiled, soils can acidify to pH values observed with acid mine drainage.

I studied S⁰ contamination at a former sporting clay range. For seven years, the range used biodegradable trap and skeet targets that contained S …

Structural Requirements For Ribosome-Dependent Gtpase Activity And Binding, Markus A. Carlson

WWU Graduate School Collection

The two billion years of evolution since the divergence of prokaryotes and eukaryotes has left earth with very few molecules conserved across these two domains of life. One such molecule, the ribosome, is an enormous ribonucleoprotein responsible for translation, the process of converting the information contained within an organism’s genetic code into functional proteins. Translation is facilitated by a number of other proteins, termed translation factors, required to catalyze the synthesis of these proteins. A large number of antibiotics prescribed today target either the ribosome or translation factors, and with increasing antibiotic resistance being found in infectious bacteria there is …

Structural Studies Of Blood Coagulation Factor Viii In Protein Complexes, Michelle E. Wuerth

WWU Graduate School Collection

A deficiency in blood coagulation factor VIII (fVIII) is responsible for the inherited bleeding disorder hemophilia A, which affects approximately 1 in 5000 males. The development of inhibitory antibodies is a significant issue faced by hemophilia A patients receiving therapeutic infusions of fVIII. The C-terminal C2 domain of fVIII has been shown to be highly immunogenic and the site of binding for numerous antibodies of both the classical and non-classical classifications. A detailed understanding of the structural components involved in C2-antibody binding interactions is vital for the development of improved therapeutics for hemophilia patients. Here we present the structure of …

Probing The Hydrodesulfurization Properties Of Nickel-Rich Bimetallic Phosphides: Supported Catalysts And Encapsulated Nanoparticles, Samuel J. Danforth

WWU Graduate School Collection

The need for improved hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) catalysts is being driven by increasingly demanding requirements for ultralow sulfur fuels and by the fact that sulfur levels in crude oil have been trending upward over recent decades. Current industrial catalysts are based on molybdenum sulfide (MoS₂) and its highly anisotropic structure severely limits the number of exposed active sites. Transition metal phosphides (e.g. Ni₂P/SiO₂) are a new class of materials with promise to have improved properties relative to sulfided Ni-Mo/Al₂O₃ catalysts. The addition of a second metal can have large …

Development Of New Algorithms For Exploring The Potential Energy Landscape Of Chemical Reactions, Adam Benjamin Birkholz

Wayne State University Dissertations

The research presented in this dissertation is divided into 5 chapters. In Chapter 2, a method for reducing the number of coordinates required to accurately reproduce a known chemical reaction pathway by applying principal component analysis to a number of geometries along the pathway (expressed in either Cartesian coordinates or redundant internal coordinates) is described and applied to 9 example reactions. Chapter 3 introduces new methods for estimating the structure of and optimizing transition states by utilizing information about the atomic bonding in the reactants and products. These methods are then benchmarked against a standard transition state optimization approach utilizing …

Synthesis And Biological Evaluation Of Nitrile-Based Inhibitors Of Cysteine Proteases Caged With Ruthenium Complexes, Rajgopal Sharma

Wayne State University Dissertations

Light activated compounds can be used as tools for understanding and solving numerous biological problems. This dissertation focuses on developing ruthenium-based photocages for caging nitrile-based cysteine protease inhibitors. Four research areas pertaining to this dissertation, i) metals in medicine, ii) photocages in biological applications, iii) photodynamic therapy and iv) cysteine cathepsin proteases were briefly surveyed in the introductory chapter. Next, RuII(bpy)2 group was utilized for synthesizing nitrile-based caged CTSK and CTSB inhibitors. Light activated release of inhibitors, followed by toxicity and stability data were studied. Cathepsin enzyme activity inhibition in 2D and 3D assays were established. This work showcased the …

Isomer Detection Of Radicals Produced By The Flash Pyrolysis Of Heptane And Its Structural Isomers, Steven Lingenfelter

Wayne State University Theses

Radicals can play an important role in combustion chemistry as key intermediates. As such studying them is vital in the study of combustion chemistry. Our study focused on the production of the 1 and 2-propyl radical from heptane isomers. Radicals were produced by flash pyrolysis which was achieved by restively heating a silicon carbide tube through which a molecular beam passed. Strong field ionization was utilized to discriminate between the two propyl isomers. Results indicated the expected trend however the signal intensity was quite low with significant noise. Further improvements are needed to improve the quality as well as the …

Classical And Ab Initio Qm/Mm Simulations Of Bacterial Enzymes, Sajeewa Walimuni Dewage

Wayne State University Dissertations

This thesis describes analyses performed on three enzyme systems. Chapter 2, 3, and 4 involve studies carried out on the GatCAB enzyme of H. pylori and S. aureus. Since information at the electronic level was not required for these studies, sampling of the configuration space carried out at the molecular mechanics level was adequate. In Chapter 2, the snapshots sampled using MD were used as input for average correlation difference calculations and average RMSD difference calculations to ascertain the existence of a communication pathway between two subunits of GatCAB. Experimental and computational results obtained, suggest the existence of a communication …

Assessing The Magnitude And Impact Of Seawater/Pore Water Exchange In Salt Marsh Systems, Carrie Lee Milliken

Theses and Dissertations

Submarine groundwater discharge is a hydrological process that is important to study and understand as it impacts biogeochemical processes and hydrological cycles. Particularly in coastal salt marsh systems, it is an important process to analyze as these systems serve as crucial interfaces between terrestrial and marine waters and particulates. There is evidence that these systems, typically thought to have little exchange across the interface due to impermeable sediments, could actually allow for significant flow of water and particulates at shallow depths. In order to measure and quantify this flow, a method using 224Ra as a tracer has been tested. The …

Modification Of Nanoparticles For Designed Interfaces, Tony Lee Neely, Jr.

Theses and Dissertations

The work contained herein, is focused on the design, synthesis, and characterization of polymer nanocomposite interfaces and the property enhancement afforded from said interface design. Through the use of reversible addition fragmentation chain transfer (RAFT) polymerization for the grafting of polymer chains to silica nanoparticles, the surface of silica nanoparticles can be manipulated to tune the properties of the nanocomposite as a whole.

In the first part of this work, heterogeneity is introduced onto the surface of silica nanoparticles via a sequential RAFT polymerization to afford a bimodal brush system. A densely grafted, short brush population is polymerized from the …