Chemistry Commons^™

Synthesis And Surface Modification Of Azide Decorated Silver Nanoclusters, Alexander H. Stöckli

Electronic Thesis and Dissertation Repository

In nanocluster research, easy modification of the cluster surface while maintaining the cluster core remains a key challenge. Herein we report the synthesis, structure, and properties of four targeted Ag₂₀ nanoclusters (NCs) with surface azide moieties, two of which have 8 azide moieties, [CO₃@Ag₂₀(S^tBu)₁₀(m-N₃-C₆H₄COO)₈(DMF)₄] and [CO₃@Ag₂₀(S^tBu)₁₀(p-N₃-C₆H₄COO)₈(DMF)₄], and two of which have 6 azide moieties, [CO₃@Ag₂₀(S …

Near-Ir Laser Ablation Of Simulated Radiologically Contaminated Oxides On Carbon Steel Feeder Pipes, Thao Viet Do

Electronic Thesis and Dissertation Repository

As nuclear power plants age and retire from service, many countries face significant challenges concerning the safe long-term storage and disposal of large volumes of low and intermediate level radioactive wastes (L&ILW). The volumes of metallic waste are of particular concern, as when metal corrodes it produces hydrogen that could lead to pressure build-up in interim storage and disposal. In Canada, a significant fraction of the metallic wastes for Canada Deuterium Uranium (CANDU) nuclear reactors are out-of-core reactor components, such as carbon steel (CS) feeder pipes. The radioactive contamination is expected to be largely confined to the surface oxide layers …

Expanding The Scope Of Clickable Azide-Functionalized Nanoclusters To Include Au144, Johanna A. De Jong

Electronic Thesis and Dissertation Repository

Thiolate-protected Au₁₄₄ nanoclusters (NCs) are an intriguing member of the gold NC family. Their geometric structure, distinct electrochemical features, and susceptibility to structural rearrangement under the duress of ligand exchange have been studied. However, there are currently no established protocols for surface modification or tuning of their ligand shells post synthesis. Here, the direct synthesis of three regioisomers of azide-modified Au₁₄₄ NCs with 60 azide moieties, i.e., Au₁₄₄(SC₂H₄C₆H₄-N₃)₆₀, is reported, in which the azide functionality is located at the ortho-, meta-, or …

The Synthesis, Lewis Acidity And Catalytic Activity Of Bis(Catecholato)Germanes, Andrew T. Henry

Electronic Thesis and Dissertation Repository

Main group Lewis acids have been shown to be viable alternatives to state-of-theart transition metal catalysts. While extensive research into a variety of p-block Lewis acids have been reported, the field of germanium Lewis acid chemistry has been described as “almost non-existent”. A variety of bis(catecholato)germane derivatives have been synthesized. The Lewis acidity of these compounds was analyzed by the Gutmann-Beckett and fluoride ion affinity methods demonstrating the high Lewis acidity of these complexes. The bis(catecholato)germanes were utilized as Lewis acid catalysts for the hydrosilylation of aldehydes, the hydroboration of alkynes, Friedel-Crafts alkylation of alkenes, and the oligomerization of styrene …

Developing Carbon Quantum Dots As A Luminescent Material And Revisiting Ecl And Led Absolute Measurement Methods, Jonathan Ralph Adsetts

Electronic Thesis and Dissertation Repository

Luminescent materials play increasingly important roles in our lives. Improvements in these materials’ quantum efficiencies (QEs), costs and toxicity can greatly reduce the power consumption, price and environmental damage to the planet, respectively. Carbon quantum dots (CQDs) and luminescent materials exhibiting thermally activated delayed fluorescence (TADF) are two interesting materials in these aspects. Furthermore, measurements on electrochemiluminescence (ECL) and electroluminescence of these luminescent materials can quickly evaluate their performance for many applications. In this thesis, controlled CQD syntheses are revealed beneficial to luminescent materials applications. Their film ECL demonstrated relatively stable anionic and cationic radicals leading to high emission at …

Conformational Dynamics And Aggregation Of Thermally Stressed Proteins Studied By Hydrogen/Deuterium Exchange Mass Spectrometry, Nastaran Nosrat Tajoddin

Electronic Thesis and Dissertation Repository

Proteins perform various biological functions, e.g., as enzymes or transporters. In addition to naturally occurring proteins, the use of protein therapeutic drugs for treating cancer and other diseases is a rapidly growing area. A thorough biophysical characterization of proteins and protein therapeutics opens the door to a more comprehensive understanding of their role in health and disease. This dissertation aims to expand the capabilities of an existing technique (Hydrogen Deuterium Exchange Mass Spectrometry, HDX-MS), which is widely used for probing protein structure and dynamics. Conventionally, HDX-MS experiments are performed as a function of labelling time. Here we aim to establish …

The Coordination Chemistry And Reactivity Of Pd Phosphine 1-Azaallyl Complexes, Kyle M. Jackman

Electronic Thesis and Dissertation Repository

Structurally responsive ligands (SRLs) are a class of ligands that change their coordination mode with a metal centre, which permits reactions that are difficult with non-SRLs, allow access to unique mechanisms, and allow isolation of unusual coordination complexes. The 1-azaallyl (1-AzA) family of SRLs are capable of isomerizing between η³-NCC and κ¹-N modes that occupy two and one coordination sites, respectively. This thesis investigates a new class of phosphine 1^AzA (P^AzA) ligands and the reactivity of their coordination complexes with palladium.

The first-generation P^AzA ligand contains a phenyl linkage between the two heteroatoms and affords a …

Characterization Of 1d And 2d Materials With Tip-Enhanced Raman Spectroscopy, María Olivia Avilés

Electronic Thesis and Dissertation Repository

Carbon-based materials, such as 1D single-walled carbon nanotubes (SWCNT) or 2D graphene, are promising materials for a variety of applications in energy storage, biosensors, and medical imaging applications. Similarly, beyond graphene, 2D transition metal dichalcogenides (TDM) that can have either a metallic or semiconducting character have gained interest for potential applications in electronics and photonics. Specifically, metallic TMDs such as vanadium disulfide (VS₂) show potential applications in optoelectronics and lithium-ion batteries. On the other hand, semiconducting TDMs like tungsten disulfide (WS₂) show a direct band gap, making them interesting for photovoltaic applications, transistors, or photodetectors. The …

Investigating The Mechanism Of Protein And Peptide Electrospray Ionization, Elnaz Aliyari

Electronic Thesis and Dissertation Repository

Electrospray ionization (ESI) mass spectrometry (MS) is widely used for the detection and characterization of various analytes. However, many fundamental aspects of the ESI process remain poorly understood. Using molecular dynamics (MD) simulations, MS, and ion mobility spectrometry (IMS), this thesis sheds light on the mechanisms whereby gaseous analyte ions are formed from highly charged ESI nanodroplets. After a general introduction (Chapter 1), Chapter 2 focuses on the ion evaporation mechanism (IEM), i.e., the ejection of analyte ions from the droplet surface. The IEM is well established for low MW compounds, but it has remained contentious whether this pathway is …

Pressure-Induced Modifications To The Structural And Optoelectronic Properties Of 2d Hybrid Organic-Inorganic Perovskites, Jesse Ratte

Electronic Thesis and Dissertation Repository

Recently, 2D hybrid organic-inorganic perovskites (HOIP) have garnered lots of research interest for their applications in optoelectronic devices, especially in solar cells. The optoelectronic properties of 2D HOIPs have yet to be optimized for these applications. High external pressure is well known to induce structural modifications to 2D HOIPs, and thus modify their optoelectronic properties. Herein, we report a study of the effects of high pressure (HP) on the structures and optoelectronic properties of cyclohexane methylamine (CMA) lead iodide (CMA2PbI4) and the structures of N,N-dimethylphenylene-p-diammonium (DPDA) lead iodide (DPDAPbI4).

High pressure measurements of CMA2PbI4 were performed using Raman spectroscopy, Fourier-transform …

Natural Product Discovery And Mycotoxin Analysis Of Agricultural Endophytes And Pathogens, Jacob P. Walsh

Electronic Thesis and Dissertation Repository

This thesis focuses on the application of fungal natural product chemistry for the use of agriculture fungal pathogenesis research. The research in this work uses many analytical chemistry techniques and instruments such as HPLC, LC-MS/MS and NMR. In Chapter 2, a diagnostic fragmentation module was developed for the identification of compound classes in crude fungal extracts. This module identified the classes cytochalasins and chaetoglobosins from extracts of Penicillium, Chaetomium, and Xylaria. From these extracts a new chaetoglobosin was discovered and the module was implemented into the open-source software package MZmine 2.0. Chapter 3 discusses analytical chemistry techniques with the …

Analyzing Enhanced Electrochemiluminescence Of Novel Materials, Liuqing Yang

Electronic Thesis and Dissertation Repository

As a powerful analytical technique, electrochemiluminescence (ECL) has found wide applications in the fields of bioanalysis and light-emitting devices. However, many ECL materials sustain the shortcomings of low ECL efficiencies. To better design novel materials with ECL enhancement, it is essential to investigate and the enhanced ECL mechanisms. In this thesis, ECL enhancements of various novel materials were analyzed utilizing ECL-voltage curves, potential pulsing experiments, ECL and photoluminescence spectroscopies, and other characterization methods. Specifically, two graphene quantum dots (GQDs) with different heteroatom doping were designed and synthesized. Structural characterizations and spectroscopies demonstrated that the heteroatom doping could change the surface …

Design And Surface Modification Of Noble Metal-Based Nanocatalysts, Xuchun Wang

Electronic Thesis and Dissertation Repository

This thesis investigates approaches to modifying the surface structure of noble metal-based nanocatalysts. Noble metal-based nanocatalysts, such as Pt and Pd, play a significant role in heterogeneous catalysis due to their capabilities in activating the cleavage or formation of chemical bonds, but still suffer from the high-cost issue and unsatisfied catalytic performance due to too strong or too weak adsorption of intermediates. Considering the surface specificity of heterogeneous catalysis, Bi, a cheap metal, was used to modify the surface of Pt- and Pd-based nanocatalysts. This thesis aims to unveil the role of Bi in improving their catalytic performance from both …

Oxygen Speciation In Potassium Silicate And Potassium Aluminosilicate Glasses: Insights From X-Ray Photoelectron Spectroscopy, Ryan Sawyer

Electronic Thesis and Dissertation Repository

In a geological context, glasses are useful analogues for silicate melts as they are more readily studied in the laboratory using a wide range of techniques that are impractical for molten liquids. Understanding the structure of binary silicate glasses can help us understand more about the magmatic processes that affect terrestrial planetary bodies.

Potassium silicate glasses ranging in composition from 10 mol% to 35 mol% K₂O were studied using X-ray Photoelectron Spectroscopy (XPS). From high resolution O 1s XPS spectra, Bridging Oxygen (BO) mole fractions were calculated and compared with those of previous ²⁹Si MAS NMR studies. …

Investigating The Influence Of Synthetic Environments On The Electronic Structure And Luminescence Of Cr-Doped Zinc Gallate, Xincheng Li

Electronic Thesis and Dissertation Repository

Cr doped ZnGa₂O₄ (Cr-ZGO) has shown potential in the field of bioimaging. To achieve the nano-size suiting for bioimaging, Cr-ZGO is normally synthesized using a hydrothermal method. There are few studies on how the hydrothermal conditions influence the structure and optical properties of the Cr-ZGO. The first two parts of this thesis study how different hydrothermal temperatures and pH environments will affect the optical properties of Cr-ZGO by photoluminescence spectroscopy. By combining the electronic structure information extracted from X-ray absorption near-edge structures (XANES) and extended X-ray absorption fine structure (EXAFS), a relationship among hydrothermal conditions, optical properties …

Computational Modelling Of Interfacial Properties Of Droplets, Victor Kwan

Electronic Thesis and Dissertation Repository

Aqueous nanodroplets containing reactive species play an important role in atmospheric chemistry and technology. The presence of atmospheric aerosol particles and the chemical reactions that they host plays a critical role in climate, visibility in the atmosphere, quality of air, and health. Man-made aerosols find applications in ink-jet printing, electrospinning, electrospraying, and ionization methods used in mass spectrometry.

Despite their small size, these systems show complex chemical and physical behaviour because a significant portion of the system is occupied by a liquid-vapour interface. Interfaces are distinct regions that are characterized by large mass density gradients, shape fluctuations, the particular orientation …

3,4-Annulated Indoles Via Tandem Cyclopropane Ring-Opening/Conia-Ene And Michael Addition/Conia-Ene Reactions, Shane R. Cochrane

Electronic Thesis and Dissertation Repository

The indole moiety is ubiquitous in natural products, and as such their reactions and syntheses are a high priority for organic chemists. The use of tandem reactions is an excellent strategy to optimize the efficiency of chemical processes. This thesis details the process of designing and implementing of strategies for the syntheses of 3,4-annulated indoles from 4-ethynylindoles via tandem cyclopropane ring-opening/Conia-ene and Michael addition/Conia-ene reactions. It was discovered through optimization experiments that the reactions are highest yielding using superstoichiometric amounts of Lewis acidic zinc halides. The cyclopropane variant of the reaction was applied to successfully synthesize 23 new 3,4-cycloheptannoindoles products. …

Humid Air Corrosion Of Carbon Steel And Stainless Steels Under Gamma Radiation: The Role Of Solution Volume And Radiolysis Products, Masoud Zakeri

Electronic Thesis and Dissertation Repository

As nuclear power plants age and their lifetimes are extended, it is critical to be able to accurately assess the long-term integrity of the reactor structural materials. A current investigation into a leak in the End Shield Cooling (ESC) System in Ontario Power Generation’s Pickering Unit 6 reactor has raised a potential issue. The corrosion of the supporting structural materials (carbon steel (CS) and stainless steel (SS)) in the presence of ionizing radiation in small stagnant solutions and humid air conditions therefore needs careful evaluation.

This project investigates the effect of water radiolysis and humid air radiolysis products (H_{2 …}

Plasmonically-Active Nanomaterials For Enhanced Second-Harmonic Generation And Chemical Reactions, Denis Ab Therien

Electronic Thesis and Dissertation Repository

Upon excitation by an electromagnetic field, metallic nanomaterials will produce highly localized areas of electromagnetic enhancement, a phenomenon known as localized surface plasmon resonance (LSPR), which can be applied to a variety of techniques including second-harmonic generation (SHG) and surface chemistry. These tunable LSPRs can be modelled prior to fabrication by finite-difference time-domain (FDTD) calculations and observed experimentally by SHG microscopy (SHGM). In this thesis, two types of nanomaterials were characterized using SHGM: plasmon-active dendritic fractals (dendrimers) and transition-metal dichalcogenides (TMDs). Dendrimers with specific geometries and LSPRs were used to demonstrate how nanomaterial symmetry affects SHG as well as how …

Solid State Nmr Spectroscopic Characterization Of Metal Organic Frameworks, Vinicius Martins

Electronic Thesis and Dissertation Repository

Metal-organic frameworks are porous organic-inorganic materials that have attracted enormous attention due to their promising capabilities for several technologies, including carbon dioxide capture and storage, gas separation, and heterogeneous catalysis. The performance of MOFs for these applications is directly linked to their properties and, by extension, structures. Therefore, it is essential to understand the structure – property relationship. Solid-state NMR (SSNMR) spectroscopy is a technique that provides complementary information to X-ray diffraction-based techniques. SSNMR can provide short-range information around the NMR-active nucleus of interest. Furthermore, SSNMR can provide additional information regarding host-guest interactions and dynamics of adsorbed molecules, which play …