Chemistry Commons^™

End-Capping Strategies For Triggering End-To-End Depolymerization Of Polyglyoxylates, Bo Fan, John Trant, Elizabeth Gillies

Chemistry Publications

Polymers that undergo end-to-end depolymerization in response to the cleavage of a stimuli-responsive end-cap are promising for diverse applications from drug delivery to responsive coatings and plastics. It is critical that the end-cap is designed to respond to an appropriate stimulus for the application. In the current work, end-caps for triggering the depolymerization of poly(ethyl glyoxylate) (PEtG) were explored. First, a phenylboronate, a disulfi de, and an azobenzene were utilized to impart redox-responsive properties to PEtG. Then, methoxy-substituted trityl groups were used to provide sensitivity to mild acid. A multiresponsive platform was also introduced, allowing PEtG to respond to multiple …

Synthesis Of Metal-Containing Phosphines And Their Use In Coordination, Polymer, And Materials Chemistry, Amir Rabiee Kenaree

Electronic Thesis and Dissertation Repository

This thesis describes the investigation of a novel strategy for the synthesis of metal-containing small molecules, polymers, and nanomaterials. In this context, a new family of air-stable, homo- and heterometallic primary, secondary, and tertiary phosphines were prepared via the radical-initiated hydrophosphination reaction of PH₃ with vinylferrocene and/or vinylruthenocene. The full characterization of the phosphines confirmed their targeted structures and proved that the properties of the starting metallocenes are reflected in those of the resulting phosphines.

To study the coordination behavior of this family of phosphines, primary, secondary, and tertiary ethylferrocene phosphines were reacted with Group 6 metal carbonyl adducts …

Creating Functional Materials With Phosphorus, Tyler John Cuthbert

Electronic Thesis and Dissertation Repository

Understanding the relationship between small molecules or polymers and how they affect the properties of materials they compose is the basis of materials science. Using unique and versatile components can impart useful and interesting properties to materials. Here, we aimed to extend this understanding to phosphorus, and the known properties it possesses. This included the production of photopolymerizable coatings containing phosphonium molecules and polymers for antifouling and antibacterial applications. The synthesis and characterization of these phosphonium components was completed and materials were produced utilizing UV curing technology. Addition of these components produced coatings that could resist bacteria attachment and efficiently …

X-Ray Absorption And Emission Studies Of Anodic Titania Nanostructures, Jun Li

Electronic Thesis and Dissertation Repository

One-dimensional (1D) TiO₂ nanomaterials with ordered structure have been extensively applied in various fields, such as photocatalysts, solar cells, supercapacitors and rechargeable batteries, due to the unique structural and functional properties compared to the disordered nanoparticulate forms. Nevertheless, intrinsic disadvantages of TiO₂, such as its large band gap (~3 eV), fast recombination rate of photoexcited electron–hole pairs and insufficient ionic conductivity, severely limit the development of 1D TiO₂ nanomaterials for practical applications. To address the above issues, the scope of this thesis focus on the fundamental understandings of the electronic structure of highly ordered TiO_{2 …}

Synthesis Of Metal-Containing Polymers And Stable Organic Radical-Containing Polymers And Their Use As Advanced Functional Materials, Joseph A. Paquette

Electronic Thesis and Dissertation Repository

The work presented in this thesis details the synthesis and characterization of two different families of multifunctional polymers. The first family involved the incorporation of stable 6-oxoverdazyl radicals into polymer scaffolds. This was originally achieved by the polymerization of the radical precursors, phenyl- and isopropyl-6-oxotetrazanes, followed by post-polymerization oxidation to afford the phenyl- and isopropyl-6-oxoverdazyl polymers. A second methodology involved the direct polymerization of isopropyl-6-oxoverdazyl radicals using ring-opening metathesis polymerization (ROMP) to afford polymers with controlled molecular weights and narrow molecular weight distributions. The polymers were characterized by the close comparison of the physical and spectroscopic properties …

Properties Of High Nitrogen Content Carbon Nitride Thin Films Prepared By A Radio Frequency Magnetron Sputtering Deposition Technique, David Pipher

Electronic Thesis and Dissertation Repository

The properties of carbon nitride (CNx) films deposited onto various substrates using a radiofrequency magnetron sputtering technique were studied as a function of deposition parameters, especially magnetron power, gas pressure and nitrogen content in the plasma. Indium tin oxide (ITO) coated glass and fluorine tin oxide (FTO) coated glass as well as metal substrates (silver and tungsten) were used. Scanning electron microscopy (SEM) was used to study the surface morphology of the prepared CNx films. Energy-dispersive X-ray spectroscopy (EDX) as well as survey X-ray photoelectron spectroscopy (XPS) spectra were used to perform the elemental analysis of the CNx films.

Ultraviolet-visible …

Post-Polymerization Functionalization Of Poly (Ethylene Oxide)–Poly (Β-6-Heptenolactone) Diblock Copolymers To Tune Properties And Self-Assembly, Elizabeth Gillies, Brooke M. Raycraft, Jarret Macdonald

Chemistry Publications

Polyester-based amphiphilic block copolymers and their nanoassemblies are of significant interest for a wide range of applications due to the degradability of the polyester block. However, the commonly used polyesters lack functional groups on their backbones, limiting the possibilities to chemically modify these polymers. Described here are new poly(ethylene oxide) (PEO)–poly(β-6-heptenolactone) (PHEL) block copolymers having pendant alkenes at each repeat unit on the PHEL block. First, the self-assembly of these block copolymers in aqueous solution was studied and it was found that they formed solid nanoparticles and vesicles depending on the relative block lengths. Next the alkene moieties of the …

Solvothermal Preparation And Characterization Of Superstructures Of Nanoscopic Cds And Cdse, Tetyana Levchenko

Electronic Thesis and Dissertation Repository

Micrometer-sized superparticles, self-assembled from metallic or semiconducting nanoclusters, can be used as convenient building blocks for preparing functional materials, utilizing the electronic and photophysical properties resulting from the quantum confinement as well as from the coupling between individual nanoscopic constituents.

This research aimed at developing a novel approach utilizing the conversion of a cadmium phenylchalcogenolate precursor (Me₄N)₂[Cd(EPh)₄] (where E = S or Se) under solvothermal conditions for the preparation of nanoscopic CdE, including both crystalline superlattices of large discrete nanoclusters and superstructures with more complex morphology. In particular, 3D cubic superlattices of molecular CdS …

Synthesis, Self-Assembly, And Immunological Activity Of Α-Galactose-Functionalized Dendron–Lipid Amphiphiles, John Trant, Namrata Jain, D. M. Mazzuca, J Trevor Mcintosh, Bo Fan, S M Mansour Haeryfar, Sebastien Lecommandoux, Elizabeth Gillies

Chemistry Publications

Nanoassemblies presenting multivalent displays of biologically active carbohydrates are of significant interest for a wide array of biomedical applications ranging from drug delivery to immunotherapy. In this study, glycodendron–lipid hybrids were developed as a new and tunable class of dendritic amphiphiles. A modular synthesis was used to prepare dendron–lipid hybrids comprising distearylglycerol and 0 through 4th generation polyester dendrons with peripheral protected amines. Following deprotection of the amines, an isothiocyanate derivative of C-linked α-galactose (α-Gal) was conjugated to the dendron peripheries, affording amphiphiles with 1 to 16 α-Gal moieties. Self-assembly in …

Photocontrolled Degradation Of Stimuli-Responsive Poly(Ethyl Glyoxylate): Differentiating Features And Traceless Ambient Depolymerization, Bo Fan, John Trant, Rebecca Yardley, Andrew Pickering, Francois Lagugne-Labarthet, Elizabeth Gillies

Chemistry Publications

The depolymerization of coatings prepared from a 6-nitroveratryl carbonate end-capped poly(ethyl glyoxylate) (PEtG) self-immolative polymer was studied. This polymer undergoes end-to-end depolymerization following cleavage of the end-cap by UV light. Several important fundamental diff erences between this class of polymers and conventional degradable polymers were revealed. For example, polymer backbone cleavage and depolymerization exhibited different dependencies on pH, emphasizing the decoupling of these processes. Probing of the coating erosion mechanism illustrated an interesting combination of features from surface erosion and bulk degradation mechanisms that arise from the end-to-end depolymerization mechanism and further differentiate these polymers from convention degradable polymers. It …

Nanostructured Air Electrodes And Electrochemical Reaction Mechanism Studies For Sodium-Oxygen Batteries, Hossein Yadegari

Electronic Thesis and Dissertation Repository

Alkali metal-O₂ batteries, i.e. Li- and Na-O₂, are considered as the next generation of energy saving technologies with potential application in electric transportation. The high theoretical energy density in these cells is related to the use of high energy alkali metals as negative and oxygen as the positive electrode materials. The performance of alkali metal-O₂ cells is highly dependent on the positive electrode material, where oxygen reduction and evolution reactions take place. Besides, the primary products of oxygen reduction reaction in these cells are typically metal oxides, which are insoluble in nonaqueous electrolytes, resulting in accumulation …

Model Of The Formation Of Iron Oxide Nanoparticles By Irradiation In Aqueous Media, Thomas I. Sutherland

Electronic Thesis and Dissertation Repository

This thesis aims to develop the mechanistic understanding of the formation of iron oxide nanoparticles by γ-irradiation. Under irradiation water breaks down into a wide array of redox active species (H•, •OH, H₂O₂, •e^-_(aq)) uniformly throughout the solution. These species are capable of rapidly interconverting any soluble Fe^II and insoluble Fe^III species resulting in the formation of nanoparticles with a narrow size distribution. The initial concentration of Fe²⁺ in the solution, the solution pH, the presence of any radical scavengers, the temperature of the reaction, and the dose rate of …

Investigating Mycotoxins And Secondary Metabolites In Canadian Agricultural Commodities Using High-Resolution Mass Spectrometry, Megan J. Kelman

Electronic Thesis and Dissertation Repository

Mycotoxins are secondary metabolites produced by fungi, which are harmful to humans and/or animals. Alternaria is a common fungal plant pathogen that can produce mycotoxins in agricultural commodities, such as processed wheat products, and fruit juices. Liquid chromatography mass spectrometry (LC-MS) is commonly used for the detection, characterization and quantitation of mycotoxins in agricultural products. Canadian Alternaria species were assessed to provide a risk assessment of their secondary metabolites in agricultural products by describing their global metabolome data obtained from the Orbitrap LC-MS instrument. Combination of this high mass accuracy data with post data-acquisition analysis techniques resulted in the discovery …

Novel Reactions Of Donor-Acceptor Cyclopropanes, And Diels-Alder Approach Towards Fargesine And Fumimycin, Polydoros Kyriacou

Electronic Thesis and Dissertation Repository

The first chapter of this thesis consists of two related projects that explore novel reactivity of donor-acceptor cyclopropanes, specifically 2-substituted cyclopropane 1,1-diesters. The first project involves the nucleophilic ring opening of donor-acceptor cyclopropanes with potassium organotrifluoroborates. It was found that during the ring opening of the cyclopropane, the diesters of the cyclopropane formed a malonyl-BF₂ complex. The complex could then be hydrolyzed to afford substituted malonates. The reaction was limited to aryl cyclopropanes and potassium alkynyltrifluoroborates. The second project in this chapter explores modifying the Kerr group’s previous synthesis of tetrahydro-1,2-oxazines, such that geminal allyl, methyl esters are now …

Fabricating And Characterizing Chalcogenide Thin Films As Light Absorbing Layers In Solar Cells, Daniel Vaccarello

Electronic Thesis and Dissertation Repository

Solar cell development has been a focus in energy research, with light-absorbing layers as the key theme. Copper indium disulphide (CuInS₂) and copper zinc tin sulphide (Cu₂ZnSnS₄ or CZTS) have energy band gaps that are optimal for solar energy conversion. New preparation methods have been developed with practicality, safety, and low costs in mind. The one-pot method developed in this thesis group has been utilized to create nanocrystals that can be used to absorb light and generate current. The use of low temperatures and minimalistic reaction conditions has led to the production of CIS and …

Hydraulic And Electrokinetic Delivery Of Remediants For In-Situ Remediation, Ahmed I. A. Chowdhury

Electronic Thesis and Dissertation Repository

Nano-scale zero valent iron (nZVI) has shown promising mobility and in-situ reactivity with chlorinated volatile organic compounds when injected into saturated porous media. The current study evaluated nZVI mobility and subsequent reactivity with in-situ contaminants in a variably saturated porous media. The nZVI particles, synthesized onsite at subzero temperatures, demonstrated complete trichloroethene (TCE) degradation within the target area. Furthermore, a three dimensional finite difference model (CompSim) was utilized to investigate nZVI mobility in variably saturated zones. Model predicted well head data were in very good agreement with field observations. Simulation results showed that the injected slurry migrated radially outward from …

Development Of Novel Anode Materials For Lithium Ion Batteries, Mike A. Nieradko

Electronic Thesis and Dissertation Repository

This thesis focuses on the development of new anodes for Li ion batteries. Aluminium has been long considered as promising anode material for Li ion batteries because of its low cost, abundance, and low toxicity. Aluminium undergoes alloying with lithium through intermetallic LiAl formation which offers a relatively high theoretical capacity of 993 mAh/g compared to 372 mAh/g for graphite that is currently the principal anode material in commercial Li ion batteries. However, despite intensive research, all aluminium-based anodes tested so far suffered from rapid capacity fading and failure within first few cycles. Furthermore, there is insufficient understanding of the …

Photo-Isomerizable Self-Complementary Hydrogen Bond Arrays, Iamnica Janic Linares Mendez

Electronic Thesis and Dissertation Repository

This thesis exploits the use of a photochromic system in a self-complementary hydrogen bond array; i.e. the azo group, -N=N. The novelty of the approach described in this thesis resides in the double function of the azo group within the array: as a hydrogen bond acceptor site and as an element that promotes a structural change capable of disrupting the complexation equilibrium when irradiated with light.

The photo-isomerizable self-complementary hydrogen bond arrays presented are obtained by a general and practical synthetic method from inexpensive starting materials. Their self-complementary recognition was corroborated by ¹H NMR dilution experiments and single crystal …

Selective Oxygen Atom Insertion Into An Aryl-Palladium Bond, Ava Behnia, Paul D. Boyle, Johanna M. Blacquiere, Richard J. Puddephatt

Chemistry Publications

The chemistry of a palladium(II) complex containing both an alkyl- and an aryl-palladium bond is reported. The reaction of [Pd(CH2CMe2C6H4)(MesN=CHCH=NMes)] with bromine or iodine leads to reductive elimination of 1,1-dimethylcyclobutabenzene with formation of [PdX2(MesN=CHCH=NMes)] (X = Br, I). However, the reaction with hydrogen peroxide gives [Pd(CH2CMe2C6H4O)(MesN=CHCH=NMes)] by overall oxygen atom insertion into the aryl-palladium rather than the alkyl-palladium bond. This complex [Pd(CH2CMe2C6H4O)(MesN=CHCH=NMes)] reacts with bromine, iodine, or hydrogen peroxide to give 3,3-dimethyl-2,3-dihydrobenzofuran and the corresponding complex [PdX2(MesN=CHCH=NMes)]. The mechanisms of reaction and basis for selectivity are discussed. The results support the view that oxygen atom insertion is a mechanistically viable …

Fractional Charge Methods For Correcting Approximate Kohn-Sham Potentials, Darya N. Komsa

Electronic Thesis and Dissertation Repository

The Kohn-Sham density functional theory relies on approximating the exchange-correlation energy functional or the corresponding potential. The behavior of the exchange-correlation potential as a function of position in a system can be used to detect and correct deficiencies of the parent functional. The too-fast decay of the potentials derived from common density functionals is a major problem, because it causes inaccurate Rydberg excitation energies and erroneous fractional charges in dissociating molecules. An efficient method to correct the shape of the exchange-correlation potential was proposed by Gaiduk et al. [A. P. Gaiduk, D. S. Firaha, and V. N. Staroverov, Phys. Rev. …

Cobalt Mediated Oxidative Cyclizations: The Diastereoselective Synthesis Of Trans-Tetrahydrofuran Rings, Cory D.N. Palmer

Electronic Thesis and Dissertation Repository

The Mukaiyama oxidative cyclization has been a major area of study within the Pagenkopf group and within the field of THF containing natural products. This document contains a brief discussion of the major divisions of THF synthesis; S_N2, cycloadditions, and transition mediated strategies. The development of the Mukaiyama cyclization is described from the earliest applications of cobalt acac type ligand in Mukaiyama’s work to the initial discovery of the cyclization reactivity. Initial finding from the Mukaiyama group is shown, accompanied by its applications to the synthesis of mucosin, aplysiallene, and bullatacin. Previous attempts at improved catalyst design are …

Mechanism Of Ethanol Partial Oxidation Over Titania Supported Vanadia Catalysts: Geometric And Electronic Structure Consequences On Reaction Kinetics, Dongmin Yun

Electronic Thesis and Dissertation Repository

Supported vanadium oxide catalysts (VO_x) are used for a wide range of industrial processes. A significant amount of research has been carried on this specific system with the aim to identify the critical parameters involved in catalytic activity. The results on this relative large body of research indicate that the catalyst support plays a critical role in determining the catalytic activity of vanadia and the use of titanium dioxide as support renders a catalyst with superior activity. Studies on supported vanadia on titanium oxide (VO_x/TiO₂) have provided an understanding on support interactions that result …

New Chemistry Of Donor-Acceptor Cycloalkanes And Studies Towards The Synthesis Of Streptorubin B, Naresh Vemula

Electronic Thesis and Dissertation Repository

This dissertation presents two separate chapters within the broad area of synthetic organic chemistry. The first chapter describes the annelation chemistry of donor-acceptor (DA) cyclopropanes and cyclobutanes for the synthesis of heterocycles. The Yb(OTf)₃-catalyzed [4+2] cycloaddition between DA cyclobutanes and nitrosoarenes facilitated the synthesis of tetrahydro-1,2-oxazines in good to excellent yields as single diastereomers. Additionally, an unexpected deoxygenation occurred with electron-rich nitrosoarenes under MgI₂-catalysis that afforded pyrrolidine products. The GaCl₃-catalyzed [4+2] cycloaddition of DA cyclobutanes and cis-diazenes provided hexahydropyridazine derivatives in good to excellent yields as single diastereomers. Furthermore, a procedure to make …

Development And Optimization Of Solid Polymer Electrolyte For Lithium Ion Batteries, Ladan Eskandarian

Electronic Thesis and Dissertation Repository

This thesis focuses on the development of new poly(ethylene oxide) (PEO)-based solid polymer electrolytes (SPEs) in order to enhance their ionic conductivity at ambient temperature and fabricate the prototypes of novel Li ion batteries using these SPEs. Different types of SPEs have been developed: (i) blends of high molecular weight PEO and low molecular weight poly(vinyl acetate) (PVAc); (ii) composites of high molecular weight PEO and titanium dioxide (TiO₂)nanoparticles; and (iii) blend-based composite electrolytes consisting of PEO and PVAc with dispersed TiO₂. The SPEs were characterized by scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), and …

Synthesis, Characterization, And Pre-Ceramic Properties Of Π-Conjugated Polymers Based On Ni(Ii) Complexes Of Goedken’S Macrocycle, Joseph A. Paquette, Joe Gilroy

Chemistry Publications

Nickel(II) complexes of Goedken’s macrocycle bearing alkyne substituents were copolymerized with 2,7-dibromo-9,9-dihexylfluorene, 2,5-dibromo-3-hexylthiophene, and 1,4-dibromo-2,5-bis(hexyloxy)benzene via microwave-induced Sonogashira cross-coupling reactions to produce copolymers 6F, 6T, and 6B. The spectroscopic and electrochemical properties of the copolymers were examined and compared to model compounds. Specifically, each polymer exhibited a nickel-based absorption centered at ca. 589 nm and two π → π* transitions between 272 and 387 nm. While the copolymers did not exhibit extended π conjugation, the nature of the organic spacer did affect the high energy transitions. Furthermore, each copolymer underwent two ligand-based one-electron oxidations at potentials …

Aggregation-Induced Emission Enhancement In Boron Difluoride Complexes Of 3-Cyanoformazanates, Ryan R. Maar, Joe Gilroy

Chemistry Publications

Boron difluoride (BF₂) complexes of 3-cyanoformazanates exhibit aggregation-induced emission enhancement in THF-water mixtures due to their severely twisted N-aryl substituents which restrict intramolecular motion and π stacking upon aggregation.

Synthesis, Properties, And Antibacterial Activity Of Polyphosphonium Semi-Interpenetrating Networks, Tyler John Cuthbert, Tristan Harrison, Paul J. Ragogna, Elizabeth Gillies

Chemistry Publications

The development of new approaches to antibacterial surfaces is of growing interest to combat the spread of harmful bacterial infections. Relative to polyammoniums, polyphosphoniums can exhibit enhanced chemical and thermal stability, but have not yet been widely explored for the preparation of antibacterial surfaces. In this work, polyphosphoniums of varying chain lengths were synthesized by reversible addition-fragmentation chain-transfer polymerization of 4-vinylbenzyl derivatives of triethyl, tributyl, and trioctylphosphonium. These polyphosphoniums were then incorporated into semi-interpenetrating networks (SIPNs) based on tetra(ethylene glycol) diacrylate (TEGDA) via a UV light-initiated curing process. Measurements of cure percentage, gel content, water contact angle, and surface charge …

The Corrosion Of Carbon Steel Under Deep Geologic Nuclear Waste Disposal Conditions, Shannon L.W. Hill

Electronic Thesis and Dissertation Repository

The proposed disposal scenario for high-level nuclear waste (spent fuel) in Canada is emplacement within a sealed, deep geological repository (DGR) located in either granitic rock or sedimentary clay. Disposal is based on a multi-barrier approach, with the primary barrier being a sealed container which could be either dual-walled with a copper shell over an inner carbon steel vessel for granitic rock or a single thick-walled steel container for sedimentary clay. This study focuses on the corrosion behaviour of A516 Gr70 carbon steel as well as the corrosion products formed in a variety of groundwater compositions and concentrations expected within …

Boron Difluoride Formazanate Copolymers With 9,9-Di-N-Hexylfluorene Prepared By Copper-Catalyzed Alkyne-Azide Cycloaddition Chemistry, Stephanie M. Barbon, Joe Gilroy

Chemistry Publications

The synthesis and characterization of copolymers based on boron difluoride formazanate (BF₂L) and 9,9-di-n-hexylfluorene (hex₂Fl) units are described. A series of model compounds [(BF₂L)-(hex₂Fl), (hex₂Fl)-(BF₂L)-(hex₂Fl), and (BF₂L)-(hex₂Fl)-(BF₂L)] were also studied in order to fully understand the spectroscopic properties of the title copolymer [(BF₂L)-(hex₂Fl)]_n. The model compounds and copolymers, which were synthesized by copper catalyzed alkyne-azide cycloaddition chemistry, exhibited high molar absorptivities (25,700-54,900 …

Total Synthesis Of (+)-Nemorensic Acid: En Route To (-)-Callosine, Matthew R. Vriesen

Electronic Thesis and Dissertation Repository

An intramolecular oxime ether cyclopropane annulation developed in 2008 by Kerr has been shown to form 2,5-trans and 2,5-cis pyrrolidines in a stereodivergent fashion. When the oxime ether is functionalized with an enantioenhanced α-hydroxy substitutent and a leaving group, the pyrrolizidine core of (-)-callosine can be accessed in short order. Callosine is a structurally unique pyrrolizidine alkaloid isolated from Mexican flowering plant Senecio callosus. In an effort to complete the total synthesis, the total synthesis of (+)-nemorensic acid, the necic acid component of the callosine, has been established. Attempts at appending the ansa bridge via esterification and macrolactonization are discussed.