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Articles 1 - 12 of 12
Full-Text Articles in Physical Sciences and Mathematics
Development Of Bifunctional Peptides As Scaffolds For Bifunctional Catalysis And A Novel Method Of Peptide Stapling Using Squaric Esters, Adam X. Wayment
Development Of Bifunctional Peptides As Scaffolds For Bifunctional Catalysis And A Novel Method Of Peptide Stapling Using Squaric Esters, Adam X. Wayment
Theses and Dissertations
Enzymes are some of nature's most powerful tools in chemical processes. However, their molecular complexity makes them difficult to synthesize and complicates their application in traditional organic synthesis. Peptides, a building block of enzymes, can be rapidly synthesized and have been used as a possible alternative in achieving enzyme-like catalysis. However, most peptide-based catalysts are limited in reaction-scope and are unable to incorporate traditional organic catalysts. We have designed a helical peptide scaffold capable of being functionalized with a wide variety of organocatalysts as well as transition-metal based catalysts. In order to understand how the peptide structure effects reactivity and …
Computational Studies Of Dinuclear Catalytic Reaction Mechanisms, James Curtis Coombs Iii
Computational Studies Of Dinuclear Catalytic Reaction Mechanisms, James Curtis Coombs Iii
Theses and Dissertations
Heterodinuclear and homodinuclear metal complexes with a direct metal-metal interaction offer the potential for unique catalysis due to cooperativity effects that impact reaction mechanisms, reactivity, and selectivity. Quantum-chemical density functional theory (DFT) calculations can directly examine the origin of dinuclear reactivity and selectivity effects. Chapter 1 provides a short overview of heterodinuclear and homodinuclear catalysts that have been experimentally and computationally examined. Chapter 2 reports our study using DFT methods to understand the mechanism and reactivity of a heterodinuclear Co-Zr catalyst with phosphinoamide ligands that catalyzes a Kumada coupling between alkyl halides and alkyl Grignards. Chapter 3 reports DFT calculations …
Development Of Cooperative Catalytic Systems And Bimetallic Catalysts For Organic Synthesis, Kelton Guy Forson
Development Of Cooperative Catalytic Systems And Bimetallic Catalysts For Organic Synthesis, Kelton Guy Forson
Theses and Dissertations
The development of new catalysts for organic synthesis is an important pursuit that enables the discovery of new and more efficient reactions and the identification of new reaction mechanisms. Cooperative catalytic systems and bimetallic catalysts represent unique approaches to catalyst development that achieve reactivity that cannot be obtained with a single catalyst or metal. These types of catalysts can activate substrates in unique ways, facilitate reactions under mild conditions, increase substrate scope, and provide access to completely new transformations. The first part of this work describes the development of a cooperative nickel-titanium-catalyzed amination of allylic alcohols. The cooperative effects of …
Developing The Next Generation Of Heterogeneous Catalysts: Metal-Organic Framework Thin Films And Their Derivatives, Hans Christian Anderson
Developing The Next Generation Of Heterogeneous Catalysts: Metal-Organic Framework Thin Films And Their Derivatives, Hans Christian Anderson
Theses and Dissertations
Metal-Organic Frameworks (MOFs) are an important class of materials that are gaining increasing relevance for many fields including energy storage, CO2 capture, photovoltaics, and catalysis. MOF mediated synthesis (MOFMS) is the decomposition of a MOF to form an amorphous carbon material decorated with metal nanoparticles. MOF thin films are an area where MOFMS has not been thoroughly explored, yet they are likely to be industrially relevant due to their potential application as highly dispersed, sinter resistant supported catalysts. In this work, we have developed a method for the growth of copper- and zinc-based MOF thin films on silicon- and aluminum- …
Immobilization Of Copper Nanoparticles Onto Various Supports Applications In Catalysis, Anh Hoang Tu Nguyen Sorenson
Immobilization Of Copper Nanoparticles Onto Various Supports Applications In Catalysis, Anh Hoang Tu Nguyen Sorenson
Theses and Dissertations
Copper-based materials are one of the most promising catalysts for performing transformations of important organic compounds in both academic and industrial operations. However, it is challenging to consistently synthesize highly active and stable copper species as heterogeneous catalysts due to their relatively high surface energy. As a result, agglomeration usually occurs, which limits the catalytic activities of the copper species. The work presented in this dissertation shows different synthetic strategies for obtaining active and stable copper-based materials by modifying chemical/physical properties of copper nanoparticles (NPs). Emphasis is placed on discussing specific catalytic systems, including carbon-supported catalysts (monometallic and bimetallic copper-based …
The Investigation Of Functionalized Carbon Nanotubes For The Carbon Dioxide Capture And Ethane Oxidative Dehyrogenation Catalysts, Zheng Zhou
Theses and Dissertations
Carbon nanotubes (CNT) have gained interest for wide use as both support and catalyst due to the ease of uniquely tunable surface chemistry. Increasingly severe greenhouse effects have attracted attention to novel materials and technologies capable of capturing carbon dioxide (CO2). In this context, we develop a CNT based solid state amine for the CO2 capture. CNT are functionalized under various methods as a support for polymeric amines. Polyethyleneimine are physically adsorbed on CNT and are further characterized and studied for reversible CO2 capture. We obtain a high CO2 capture capacity (6.78 mmol∙g-1) for linear polyethyleneimine (LPEI) and 6.18 mmol∙g-1 …
The Investigation Of Nickel-Based Catalysts For The Oxidative Dehydrogenation Of Ethane, Justin Lane Park
The Investigation Of Nickel-Based Catalysts For The Oxidative Dehydrogenation Of Ethane, Justin Lane Park
Theses and Dissertations
The Investigation of Nickel-Based Catalysts for the Oxidative Dehydrogenation of Ethane Justin Lane ParkDepartment of Chemistry & Biochemistry, BYU Doctor of Philosophy Chemistry The advancement of creating ethylene from ethane via oxidative dehydrogenation (ODH) rather than the traditional direct dehydrogenation is right on the cusp of commercialization. The oxidative pathway provides a novel route that reduces the operating temperature of this reaction by 400-500°C. A variety of metals including Mo, V, and Ni that have redox properties suitable for the partial oxidation of small chain alkanes have been investigated. Currently, a MoVNbTe oxide is the most promising catalyst but it …
Electrophilic Catalysis Using Heterobimetallic Complexes, Whitney Kaye Walker
Electrophilic Catalysis Using Heterobimetallic Complexes, Whitney Kaye Walker
Theses and Dissertations
Conventional ligand design in transition metal catalysis capitalizes on the ability of phosphorous, nitrogen, carbon, oxygen, and sulfur-based donors to modify the steric and electronic properties of a reactive metal center. Heterobimetallic transition metal complexes that contain a dative metal-metal bond provide a unique approach to ligand design where the reactivity of the metal center can be modified by metal-metal electronic communication. Our laboratory is interested in using the unique properties of heterobimetallic complexes to address significant limitations in current transition metal catalysis. My PhD work has focused on the ability of early/late transition metal heterobimetallic complexes to facilitate catalysis …
A Study Of Allylic Aminations As Catalyzed By Heterobimetallic Pd-Ti Complexes, Diana Lauren Ellis
A Study Of Allylic Aminations As Catalyzed By Heterobimetallic Pd-Ti Complexes, Diana Lauren Ellis
Theses and Dissertations
Heterobimetallic complexes present a unique approach to catalyzing challenging reactions. By having two metals in close proximity to each other, the metals are able to interact and alter their electronics in a way that simple organic ligands (carbon, nitrogen, sulfur etc.) cannot. Our studies of heterobimetallic complexes focus on a Pd–Ti complex. The complex features a dative interaction between the palladium and the titanium held together by a phosphonamide scaffold. This interaction increases the electrophilicity of the palladium and makes it a very suitable catalyst for allylic amination reactions. We have conducted extensive studies of this catalyst in allylic aminations, …
Rhenium Trioxide, Rhenium Heptoxide And Rehnium Trichloride As Hydrogenation Catalysts, William J. Bartley
Rhenium Trioxide, Rhenium Heptoxide And Rehnium Trichloride As Hydrogenation Catalysts, William J. Bartley
Theses and Dissertations
The purpose of this study was to characterize the catalytic activity of rhenium trioxide and rhenium trichloride as hydrogenation catalysts. Work was also undertaken to further study the catalytic properties of rhenium heptoxide. The activity of this latter compound had received some study in a previous project. A complete review of the literature has been made on the organic and inorganic chemistry of rhenium trioxide and rhenium trichloride. A survey of the literature on catalytic hydrogenation and the chemistry of rhenium heptoxide has also been included. Rhenium trioxide was prepared by three similar methods. The first two involved the formation …
Rhenium Catalysis I. Hydrogenation And Hydroformylation Using Rhenium Carbonyl Compounds ; Ii. Hydrogenation Using Catalysts Obtained From The Reduction Of Perrhenates With Metals In Aqueous Solution, Terry G. Selin
Theses and Dissertations
The purpose of this work was to investigate the catalytic activity in both hydrogenation and hydroformylation reactions of rhenium preparations which have not been previously characterized. Rhenium pentacarbonyl was prepared in good yield from rhenium heptoxide and carbon monoxide. The optimum conditions for preparation were 25 hours per gram of dry rhenium heptoxide at 250° under 3000 psig. (initial) of carbon monoxide. Rhenium chloropentacarbonyl was prepared in 62% yield from potassium chlororhenite and carbon monoxide at high temperatures and pressures. The iodopentacarbonyl was prepared in 29% yield from potassium perrhenate, methyl iodide, and carbon monoxide. The preparation of rhenium hydrocarbonyl …
Iron And Cobalt Salts As Catalysts In The Oxidation Of Sodium Sulfite By Free Oxygen, Loren C. Bryner
Iron And Cobalt Salts As Catalysts In The Oxidation Of Sodium Sulfite By Free Oxygen, Loren C. Bryner
Theses and Dissertations
The present investigation was carried out to show the catalytic effect of some iron and cobalt salts on the oxidation of sodium sulfite solutions by free oxygen. The rate of reaction was determined by measuring the volume of water required to replace the absorbed oxygen. A photograph and diagrammatical arrangement of the apparatus is given, (Page 14). From the preliminary experiments it was found that the rate of oxidation of sodium sulfite solutions is dependent upon concentration, and speed of the shaker.