Physical Sciences and Mathematics Commons^™

Progress Toward Synthesis Of Molecular Beacons Incorporating Dabcyl Analog Quenchers, Christie M. Ettles

Electronic Thesis and Dissertation Repository

Progress toward the synthesis of molecular beacons containing analogs of the universal quencher 4-(4'-dimethylaminophenylazo)benzoic acid (DABCYL) has been made. A synthetic methodology has been developed for the differential labeling of a PNA molecular beacon with quencher and fluorophore moieties. A DABCYL analog diarylazo compound and three small fluorescent molecules have been derivatized with terminal alkyne groups for incorporation into azide-decorated PNA oligomers by on-resin “click” chemistry. An optimized on-resin procedure was used to determine the viability of the fluorophores and quencher for incorporation into PNA.

The synthesis of a pyrrolocytidine phosphoramidite containing a diarylazo DABCYL analog moiety was undertaken with …

Multinuclear Solid-State Nuclear Magnetic Resonance Spectroscopy Of Microporous Materials, Jun Xu

Electronic Thesis and Dissertation Repository

Microporous materials have attracted tremendous attention since 18^th century due to their industrial importance. It is essential to understand the relationships between the properties of microporous materials and their structures. However, the structures of many microporous materials are determined from the more limited powder X-ray diffraction (XRD) data due to the lack of suitable single-crystals for XRD. In such cases, an unambiguous structure solution of microporous materials requires additional information from other techniques such as solid-state NMR (SSNMR) spectroscopy. This thesis is focused on the study of two types of microporous materials, metal–organic frameworks (MOFs) and titanosilicates, by multinuclear …

Electrochemical And Surface Compositional Studies On Uranium Dioxide, Mayuri Razdan

Electronic Thesis and Dissertation Repository

This thesis describes electrochemical and surface compositional studies performed on a number of simulated nuclear fuel (SIMFUEL) materials under conditions relevant to permanent disposal of spent nuclear fuel in a geologic repository. This is important since a number of critical issues have been identified in the event of waste container failure. The research performed was mainly focused in three areas: (i) the influence of low pH on the surface chemistry of UO₂, since acidity could develop within corrosion product deposits and flaws in the fuel; (ii) the combined influence of dissolved H₂ and H₂O_{2 …}

Characterization Of The Corrosion And Oxide Film Properties Of Alloy 600 And Alloy 800, Melissa Faichuk

Electronic Thesis and Dissertation Repository

The passive film properties of Alloy 600 and Alloy 800, both of which are used as steam generator tubing in CANDU reactors, have been studied using techniques such as polarization scans, electrochemical impedance spectroscopy and X-ray photoelectron and Auger spectroscopies. The composition of the oxides formed in a 0.1 M Na₂S₂O₃ solution have been characterized over a wide range of potentials from the pre-passive, through the passive to the transpassive regions. These changes have been correlated to the electrochemical behaviour. A second set of experiments was performed to determine the effectiveness of the surface mechanical …

Crevice Corrosion Behavior Of Ni-Cr-Mo-W Alloys In Aggressive Environment, Ajit K. Mishra

Electronic Thesis and Dissertation Repository

Ni-Cr-Mo (W) alloys, having an optimum concentration of Cr. Mo and W, are highly corrosion resistant alloys which do not fail by uniform corrosion in aggressive environments. However, when creviced at high applied potential and high temperatures, these materials can be susceptible to crevice corrosion. This study focuses on a family of seven commercial Ni-Cr-Mo (W) alloys containing various amounts of Cr, Mo and W.

Different electrochemical techniques were used to determine the characteristic potentials and temperature which indicate susceptibility to crevice corrosion, and to investigate the individual and synergistic roles of major and minor alloying elements. The corroded alloys …

Development Of Biodegradable And Stimuli-Responsive Macromolescules And Their Assemblies, Ali Nazemi

Electronic Thesis and Dissertation Repository

Polymersomes are potentially multifunctional soft materials constructed by the self-assembly of amphiphilic block copolymers in aqueous medium. While much research has focused on controlling the assembly and encapsulation properties of polymersomes, their surface functionalization has been relatively unexplored. This is important because it plays a critical role in determining their properties such as toxicity and biodistribution behavior. The work described in this thesis involves the development of a biocompatible and biodegradable polymersome systems based on poly(ethylene oxide)-b-polycaprolactone (PEO-PCL) block copolymers with azide surface groups as a novel scaffold for various biomedical applications. The surface functionalization of these polymersomes …

Investigating The Effects Of Radiation On Phosphonium-Based Ionic Liquids, Susan Howett

Electronic Thesis and Dissertation Repository

This thesis presents work on the understanding of the effects of ionizing radiation on phosphonium-based ionic liquids (ILs). The capability of ILs to dissolve a wide range of molecules, and the potential of ILs to be highly resilient in energy-intensive environments makes them particularly promising media for the separation and sequestration of metal ion contaminants from radioactive waste effluents in nuclear fuel cycles. For this application, a water/IL system will be exposed to a continuous stream of ionizing radiation. The radiation environment will strongly influence the chemical state of the water phase in the system and the chemical parameters affecting …

Solid State Nmr Spectroscopic Studies Of Metal-Organic Frameworks, Peng He

Electronic Thesis and Dissertation Repository

Metal−organic frameworks (MOFs) are a class of novel porous materials with a wide range of chemical applications. Structural characterization is important because understanding the relationship between the properties of these industrially relevant materials and their structures allows one to develop new applications and improve current performance. In this thesis ¹⁷O solid state NMR (SSNMR) spectroscopy is used to differentiate chemically and, under favorite circumstances, crystallographically nonequivalent oxygens and to follow the phase transitions in MOF-based materials. Several cost-effective approaches were used to prepare ¹⁷O-labelled MOFs. The metal centers of MOFs, including ^47/49Ti, ⁶⁷Zn, ⁹¹Zr, ^{115 …}

Functionalized Polyisobutylene: From Synthesis To Properties And Applications, Solmaz Karamdoust

Electronic Thesis and Dissertation Repository

Polyisobutylene (PIB) is a polymer well known for its desirable properties such as high chemical stability, impermeability to gases, and biocompatibility in certain applications. However in some applications it is limited by properties such as high hydrophobicity, lack of chemical functionalities, and the adsorption of proteins and organisms to its surface. Butyl rubber (IIR) is a copolymer of isobutylene (IB) with small percentages of isoprene (IP). Typically these IP units serve as sites for the covalent cross-linking of the IIR, in addition can serve as sites for further functionalization of IIR. These modifications can expand the potential applications of IIR. …

Optical Properties, Electronic Structures And High Pressure Study Of Nanostructured One Dimensional Titanium Dioxide By Synchrotron Radiation And Spectroscopy, Ankang Zhao

Electronic Thesis and Dissertation Repository

One dimensional (1D) titanium dioxide (TiO₂) nanomaterials have been extensively studied in recent years due to their superior electrical, optical mechanical and chemical properties compared with their bulk counterparts. Two different kinds of 1D TiO₂ nanomaterials, TiO₂ nanowires (TiO₂ NW) and TiO₂ nanotubes (TiO₂ NT), are studied in this thesis by using various techniques.

In one study, TiO₂ NW synthesized by hydrothermal method and a series of calcinated TiO₂ NW were investigated by using absorption near edge structures (XANES), X-ray diffraction (XRD) and X-ray excited optical luminescence (XEOL). It is found …

In Situ High-Pressure Studies Of Energetic Materials By Vibrational Spectroscopy And X-Ray Diffraction, Liang Zhou

Electronic Thesis and Dissertation Repository

Nitrogen-rich materials have been considered as the most promising replacement of traditional energetic materials due to the large energy gap between the different nitrogen allotropes as well as the generation of environmental friendly nitrogen gas as the end-product. As a result, methods of synthesizing the nitrogen-rich materials have received increasing attention. Apart from the traditional chemical synthesis, high-pressure technique had been proved an effective tool to create such kinds of materials. However, several issues still existed concerning the high-pressure synthesis of energetic materials. Therefore, searching for precursors is of great interest. Here we report studies of four promising precursors, 5-aminotetrazole, …

Studies Of The Charge Storage Properties Of Poly(Bithiophene) And Amorphous Carbon Nitride, Timothy Adam Forristal

Electronic Thesis and Dissertation Repository

The charge storage properties of several potential materials for battery applications have been investigated. Poly(bithiophene) films were prepared by potentiostatic and potentiodynamic electropolymerization methods. These films were then subject to galvanic cycles at varying rates and to various potential limits in order to explore their use as electrodes in a battery. Potentiodynamically deposited films retain their charge better over multiple cycles. By comparing to data collected by atomic force microscopy, we conclude that these films are less crystalline than films deposited potentiostatically and are better suited for the volume changes that occur when being charged and discharged.

Amorphous carbon nitride …

Approximation Of Exchange-Correlation Potentials For Orbital-Dependent Functionals, Alexei Kananenka

Electronic Thesis and Dissertation Repository

Density-functional theory (DFT) is the most widely used method of modern computational chemistry. All practical implementations of DFT rely on approximations to the unknown exchange-correlation functional. These approximations may be devised in terms of energy functionals or effective potentials. In this thesis, several approximations of the latter type are presented.

Given a set of canonical Kohn–Sham orbitals, orbital energies, and an external potential for a many-electron system, one can invert the Kohn–Sham equations in a single step to obtain the corresponding exchange-correlation potential, vXC(r). We show that for orbitals and orbital energies that are solutions of the Kohn–Sham equations with …

Investigations Of The Crystallization Processes Of Molecular Sieves, Lu Zhang

Electronic Thesis and Dissertation Repository

Molecular sieves have been used extensively in industrial fields. A better understanding of their crystallization processes is very useful for controlling the structural properties in order to meet the industrial needs. This thesis focuses on examining the crystallization of several catalytically important molecular sieves by dry gel conversion (DGC) method which includes steam-assisted conversion (SAC) and vapor-phase transport (VPT), or hydrothermal synthesis (HTS) method or a combination of both.

For SAPO-34 templated by DEA, it crystallizes similarly under SAC and VPT conditions. It forms from the transformation of a semi-crystalline layered phase. When morpholine was used as the template, the …

Development Of Novel Contrast Agents For Magnetic Resonance Imaging, Mark Milne

Electronic Thesis and Dissertation Repository

Magnetic resonance (MR) has outstanding potential as a noninvasive imaging modality. Possessing spatial resolution at the millimeter scale, MR imaging of anatomical features is unrivalled by other imaging techniques. Although MR imaging has outstanding spatial resolution it suffers from inherently low signal intensity. With a low sensitivity, the signal to noise ratio is low; thus MRI scans may take upwards of an hour to generate an acceptable image without a contrast agent. This drawback clearly justifies the need for contrast agents and the long held interest in their development.

Our development of novel MRI contrast agents focuses on the synthesis …

Electrochemical Evaluation Of Ionic Liquids For Biphasic Extraction Of Metal Ions Common To Spent Nuclear Fuel, Thomas J. Stockmann

Electronic Thesis and Dissertation Repository

Over the past 30 years electrochemistry at a liquid|liquid interface has been used to observe and quantify simple ion transfer (IT) as well as ligand assisted, or facilitated ion transfer (FIT) reactions. Liquid|liquid electrochemistry has developed to where valuable thermodynamic constants – for example, the metal ion to ligand stoichiometry and overall complexation constant, β, in FIT - can be evaluated using cyclic voltammetry (CV). Recently, ionic liquids (ILs) have shown greater metal ion extraction efficiencies in water-IL biphasic separations relative to conventional molecular organic solvents. In this way, they are of interest to the nuclear industry for applications …

Electrochemiluminescence Of Thienyltriazoles, Iridium Complexes, Au25 Clusters And Pbs Nanoparticles, Kalen N. Swanick

Electronic Thesis and Dissertation Repository

Electrogenerated chemiluminescence or electrochemiluminescence (ECL), produces light in the vicinity of a working electrode by the excited species of a luminophore formed via electron transfer between radical cations and anions, which are electrogenerated. In order for the ECL system to be efficient, the radicals must be stable in solution. This can be enhanced by adding co-reactants such as benzoyl peroxide (BPO) and tri-n-propylamine (TPrA) that produce strong oxidizing or reducing radicals upon redox reactions. ECL pairs electrochemical and spectroscopic methods and is a powerful analytical technique that is highly sensitive and selective.

A comprehensive, mechanistic study of ECL …

The Synthesis, Reactivity And Electrochemical Study Of Metallocene Substituted Α-Diimine Ligands, Eleanor Magdzinski

Electronic Thesis and Dissertation Repository

The synthesis of transition metal complexes containing redox-active ligands or ligands with redox-active substituents have been areas of ongoing interest in chemical research. To date, only a handful of examples involving redox-active ligands containing main group centres have been reported.

This thesis presents work on the development of novel redox-active ligands utilizing an assortment of nitrogen-based frameworks (diiminopyridine (DIMPY), 1,4-diaza-1,3-butadiene (DAB), N-heterocyclic carbene (NHC)) that contain metallocene substituents (ferrocene and an understudied redox-active Co(III) moiety). Initially the syntheses of an N, N’-differocenyl diiminopyridine and its low-valent chalcogen (S²⁺, Se²⁺, Te²⁺) and pnictogen …

Fluorescent Cytidine Analogues, Kirby J. Chicas

Electronic Thesis and Dissertation Repository

Three luminescent cytidine analogues have been synthesized in order to perform SNP analysis by fluorescence spectroscopy. Herein is described the synthesis of 6-pyrenylpyrrolocytidine (PypdC), its photophysical characterization, and its subsequent incorporation into oligodeoxynucleotides (ODNs). The behavior of PypdC in ODNs is described as well as fluorescence intensity changes with respect to the match and mismatch cases. In order to obtain a greater understanding of pyrene’s interaction with pyrrolocytidine, a congener, pyrenyl ethynyl cytidine (PyEtdC) was synthesized. The congener was photophysically studied and prepared for oligo synthesis. Finally, exploration into indole substituted pyrrolocytidines (pdCs) was undertaken to explore new pdC structures.

In Situ High-Pressure Studies Of Ammonia Borane Derivatives By Vibrational Spectroscopy, Zhihao Yu

Electronic Thesis and Dissertation Repository

Hydrogen has been regarded as a promising candidate to replace the conventional fossil fuel, and thus attracted enormous research efforts. However, hydrogen storage remains to be a big challenge to its practical applications. Consequently, the investigation of suitable hydrogen storage materials has become a highly active research field. Here we reported the first high pressure studies of three promising hydrogen storage materials, N(CH₃)₃BH₃, NH(CH₃)₂BH₃ and NaNH₂BH₃ by Raman and IR spectroscopy.

First, N(CH₃)₃BH₃ was studied at room temperature and pressures up …

The Role Of Metallothionein In Zinc Homeostasis, Kelly L. Summers

Electronic Thesis and Dissertation Repository

The structure of the unique metal-binding protein, metallothionein (MT), consists of two metal-thiolate-clustered binding domains; the β-domain binds up to three divalent metals and the α-domain binds four. The mechanisms through which the metals are bound and arranged into domains, as well as the function of MT in metal ion homeostasis, remains largely unknown. By utilizing electrospray ionization mass spectrometry (ESI MS) to identify each species, and by comparing the data with simulations, MT 1a was found to bind Zn²⁺ non-cooperatively. Through a competition experiment between MT and its individual domain peptides, MT was proposed to bind Zn^{2+ …}

Donor-Acceptor Cyclobutanes And Their Application For Heterocycle Synthesis And Progress Towards Biselide A, Benjamin Machin

Electronic Thesis and Dissertation Repository

The chemistry of cyclobutane-1,1-diester has been investigated with aldehydes and alkyne reaction partners independently of each other. Under Yb(OTf)₃ catalysis donor-acceptor cyclobutanes undergo a formal [4+2] cycloaddition with aldehydes to generate tetrahydropyrans exclusively in a cis disposition. Activated aldehydes were generally well tolerated giving tetrahydropyrans in moderate to good yields (51 - 89%) whereas less reactive congeners gave lower yields (51 - 72%).

All carbon reaction partners were used in BF₃·OEt₂ mediated conditions to afford an unexpected 2,3-dihydrooxepine product resulting from alkynyl addition and rearrangement. Aryl acetylenes were compatible with the reaction conditions and moderate yields …

Cycloaddition Chemistry For The Synthesis Of Heterocyclic Compounds And Progress Towards The Total Synthesis Of Grandilodine A, Andrew C. Stevens

Electronic Thesis and Dissertation Repository

This thesis describes three separate research projects within the broad topic of synthetic organic chemistry. The synthesis of alkyl-substituted siloles and their reactivity in Diels-Alder chemistry is reported. Furthermore, the cleavage of the bicyclic adducts by Tamao-Fleming oxidation has been achieved which reveals a highly substituted cyclohexene-1,4-diol structure.

The second chapter describes the cycloaddition chemistry of alkoxy-activated cyclobutane dicarboxylates with aldehydes, nitrones and nitrosoarenes. The cycloaddition occurs, in the case of aldehydes, with uniformly high diastereoselectivity to afford tetrahydropyrans in good to excellent yield. When nitrones were used as the dipolarophile the cycloaddition occurs in a rather unselective manner though …

Degradation Kinetics And Functional Design Of Linear Self-Immolative Polymers, Ryan A. Mcbride

Electronic Thesis and Dissertation Repository

Linear self-immolative polymers display a potential to address many of the limitations in the control over the degradation process in traditional biodegradable polymers. These materials are unique relative to most degradable 
polymers, in that they undergo end-to-end depolymerization in
 response to the cleavage of a stabilizing end-capping agent. Although one of their cited 
attributes is a dependence of their degradation time on chain length, no conclusive study has been conducted to demonstrate and study this 
effect. Using a previously reported linear self-immolative backbone derived from alternating 4-hydroxybenzyl alcohol and N,N’-dimethylethylenediamine spacers, this work offers the first conclusive study demonstrating …

Butyl Rubber-Aliphatic Polyester Graft Copolymers For Biomedical Applications: Synthesis And Analysis Of Chemical, Physical And Biological Properties, Bethany A. Turowec

Electronic Thesis and Dissertation Repository

Biomaterials can be used in a wide variety of medical applications owing to their breadth of characteristics that can be imparted by varying their chemical structures. Butyl rubber (IIR), which is a copolymer of isobutylene (IB) and small percentages of isoprene (IP), is particularly attractive as a biomaterial because of its elastomeric mechanical properties, biocompatibility, impermeability and high damping characteristics. IIR is typically vulcanized through chemical-based crosslinking mechanisms. However, these methods are not acceptable for biological applications. This thesis focuses on the synthesis of IIR-polyester graft copolymers by grafting biodegradable and biocompatible polyesters including poly(caprolactone) (PCL) and poly(d,l-lactide) (PDLLA) to …

Novel Thiophene Supported N,N'-Chelating Ligands And Their Main Group Compounds, Jacquelyn T. Price

Electronic Thesis and Dissertation Repository

Main group chemistry has advanced from studying fundamental curiosities, including low oxidation state, low-valent, p-block elements to tailoring these unique, reactive species for specific functional applications. This thesis examines the structure, bonding and reactivity of select group 13, 14 and 15 elements supported by N,N'-chelating ligands decorated with either thiophene, benzo[1,2-b:5,6-b']dithiophene or bis(2,5-dimethylthienyl)ethene substituents and allowing for subsequent reactivity and photophysical properties to be determined.

The synthesis of a new diamino ligand containing a thiophene ring in the backbone was used to support a 7-membered phosphenium cation. The 1:1 stoichiometric reaction between the amine:chlorophosphine was dependant on the substitution …

Carbon Nitride And Conjugated Polymer Composite Materials, Josh Byers

Electronic Thesis and Dissertation Repository

The semiconductor and photovoltaic properties of carbon nitride (CNx) thin films prepared using a reactive magnetron sputtering technique were investigated both individually and as composites with the organic conjugated polymers polybithiophene (PBT) and poly(3-hextlthiophene) (P3HT). At low nitrogen content, the film structure was dominated by graphitic sp² percolation networks, whereas at higher nitrogen contents CNx films started to demonstrate semiconductor properties, as evidenced by the occurrence of photoconductivity and the development of a space charge region. When CNx was deposited onto a PBT substrate, it was found to function as an acceptor material improving the photocurrent generation both in …

Carboxylic Acid Functionalized Butyl Rubber: From Synthesis To Applications, Matthew John Mceachran

Electronic Thesis and Dissertation Repository

Butyl Rubber (RB) is a copolymer of isobutylene (IB) with small percentages of isoprene (IP). Typically these IP units serve as sites for the covalent cross-linking of the rubber, but they can also serve as sites to further functionalize RB. These modifications can expand the potential applications of RB. This thesis describes the synthesis of carboxylic acid functionalized RB and some properties and applications of these materials.

Ph Responsive Hydrogen Bonding Motif To Improve The Sensitivity Of Tumor Imaging, Fatimah Mohammed Algarni

Electronic Thesis and Dissertation Repository

Magnetic resonance imaging (MRI) is a powerful non-invasive medical diagnostic technique. Superparamagnetic iron oxide nanoparticles (SPIO) are effective contrast agents and provide high sensitivity contrast in MRI. Recent research has demonstrated that nanoparticle clusters exhibit significantly higher relaxivity than individual nanoparticles.

In order to increase the sensitivity of tumor imaging, supramolecular chemistry was introduced to this field and a novel conjugation method was developed using click chemistry between azide functionalized nanoparticles and pH-sensitive hydrogen bonding building blocks. This pH-sensitive hydrogen bonded complex was synthesized to cluster nanoparticles under mildly acidic biological conditions.

Due to the unexpected X-ray crystal structure of …

Protein Structure And Interactions Studied By Electrospray Mass Spectrometry, Jiangjiang Liu

Electronic Thesis and Dissertation Repository

Since the emergence of electrospray ionization (ESI) mass spectrometry (MS) as a tool for protein structural studies, this area has experienced tremendous growth. ESI-MS is highly sensitive, and it allows the analysis of biological systems ranging in size from a few atoms to large multi-protein complexes. This work aims to solve questions in protein structural biology by using ESI-MS in conjunction with other techniques.

We initially apply ESI-MS for studying the monomeric protein cytochrome c (Chapter 2). The physical reasons underlying the irreversible thermal denaturation of this protein remain controversial. By utilizing deconvoluted charge state distributions, oxidative modifications were found …