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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 …
Tethered Axial Coordination As A Control Modality In Rhodium(Ii)-Catalyzed Carbene Transfer Reactions, Anthony Dean Abshire
Tethered Axial Coordination As A Control Modality In Rhodium(Ii)-Catalyzed Carbene Transfer Reactions, Anthony Dean Abshire
Doctoral Dissertations
Rhodium(II) paddlewheels are versatile carbene transfer catalyst that are broadly applied in insertion reactions, cycloadditions, and ylide transformations. The effects of axial coordination in rhodium(II)-catalyzed carbene transfer reactions are still little understood due to compounding factors that are difficult to isolate. Traditionally, researchers study axial coordination by addition of Lewis base additives. To ensure interaction between the Lewis base and catalyst, high molar equivalents are used. This can also have the undesired effect of hampering the activity of the catalyst and suppressing the yield of the reaction. We have developed ligands with a tethered Lewis base to overcome these issues. …
Elucidation Of Active Site And Mechanism Of Metal Catalysts Supported In Nu-1000, Hafeera Shabbir
Elucidation Of Active Site And Mechanism Of Metal Catalysts Supported In Nu-1000, Hafeera Shabbir
All Dissertations
Advances in extraction of shale oil and gas has increased the production of geographically stranded natural gas (primarily consisting of methane (C1) and ethane (C2)) that is burned on site. A potential utilization strategy for shale gas is to convert it into fuel range hydrocarbons by catalytic dehydrogenation followed by oligomerization by direct efficient catalysts. This work focuses on understanding metal cation catalysts supported on metal-organic framework (MOF) NU-1000 that will actively and selectively do this transformation under mild reaction conditions, while remaining stable to deactivation (via metal agglomeration or sintering). I built computational models validated by experimental methods to …
The Synthesis, Lewis Acidity And Catalytic Activity Of Bis(Catecholato)Germanes, Andrew T. Henry
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 …
Intersections Of Environmentalism, Chemistry, And Racism: An Experimental Study Of Halobenzene Hydrogenolysis And Critical Communication Studies Of Equitable Learning Practices Rooted In Black Feminism, Lauren O. Babb
Electronic Theses and Dissertations
Increasing concentrations of fluorinated aromatic compounds in surface water, groundwater, and soil pose threats to the environment. Fundamental studies that elucidate mechanisms of dehalogenation for C-X compounds (where X represents a halide) are required to develop effective remediation strategies. For halogenated benzenes, previously published research has suggested that the strength of the C-X bond is not rate-determining in the overall rate of dehalogenation. Instead, the rate-determining step has been hypothesized to be adsorption of the C-X compound onto the surface of a catalyst. Building on this hypothesis, in this work, we examine the reaction kinetics of fluorobenzene conversion to benzene, …
Synthesis And Evaluation Of Water-Dispersed Aryl-Gold Nanoparticles And Applications In Catalysis, Ahmad Al Ahmad
Synthesis And Evaluation Of Water-Dispersed Aryl-Gold Nanoparticles And Applications In Catalysis, Ahmad Al Ahmad
Electronic Theses and Dissertations
Gold nanoparticles have been used in environmental remediation as catalysts through biological and chemical redox reactions of many types of industrial waste including nitroarenes, organic dyes, carbon monoxide, and others. These reactions occur in harsh environmental conditions (e.g. changing temperature, presence of salts, extreme pH solutions) which require robust nanoparticles that can keep their activity and resist aggregation. This thesis describes the synthesis, characterization, and investigation of the catalytic activity of gold-aryl nanoparticles. Gold–aryl nanoparticles (AuNPs-COOH) fabricated using a mild reduction process of a molecular aryldiazonium gold(III) salt [HOOC-4-C6H4N≡N]AuCl4 showed high stability in the presence of high ionic strength salt, …
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 …
C-H On The Oxo Ferryl Wheel: Comparison Of Pyridine And Imidazole-Substituted Ligands For C-H Activation And Functionalization, Elizabeth Milem
C-H On The Oxo Ferryl Wheel: Comparison Of Pyridine And Imidazole-Substituted Ligands For C-H Activation And Functionalization, Elizabeth Milem
Electronic Theses and Dissertations
The selective and efficient transformation of hydrocarbon feedstocks is of high value for industry and research. While Shilov-type organometallic methods have facilitated this goal, systems designed after nature’s use of cheap and abundant iron-based enzymes are desired for wider-scale applications. This work establishes hydrocarbon oxidation efficiency of synthetic pyridine-based ligands (BPMEN, BPMPN) compared to commercially available TPA with in situ generated catalysts. Literature studies of traditionally synthesized BPMEN systems and initial in situ studies offered evidence for enhanced reactivity (TON) as compared to TPA. Expansion to a propyl backbone to produce BPMPN tested the increased chelate ring size’s impact on …
Influence Of Tethered, Axially Coordinated Ligands On Rh(Ii,Ii)-Catalyzed Carbene Transfer Reactions, Cristian E. Zavala
Influence Of Tethered, Axially Coordinated Ligands On Rh(Ii,Ii)-Catalyzed Carbene Transfer Reactions, Cristian E. Zavala
Doctoral Dissertations
Dirhodium (II,II) paddlewheel complexes have become ubiquitous in diazo-mediated carbene transfer reactions. The Rh(II,II)-carbene intermediate is capable of a large variety of transformations such as cyclopropanation, C-H and X-H (O, N, S, Si, B) insertion reactions, cyclopropenations, and ylide transformations. Cyclopropanation reactions resulting in the formation of functionalized cyclopropane structures has always been a major focus in Rh(II,II)-carbene chemistry. Improvements on catalytic performance in cyclopropanations has largely focused on the modification of the bridging ligands and has resulted in Rh(II,II) catalysts that exhibit high reactivity and selectivity in cyclopropanation reactions. However, high enantio- and diastereoselectivity is not easily achieved with …
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- …
A Comparative Study Of Two Nickel-Based Suzuki-Miyaura Hybrid Molecular Catalysts, Mollie Morrow
A Comparative Study Of Two Nickel-Based Suzuki-Miyaura Hybrid Molecular Catalysts, Mollie Morrow
Senior Theses
Two molecular nickel-based catalysts, (2,2’bipyridine-4,4’-carboxylic acid)nickel(II) chloride and (2,2'-bipyridine-4,4'-diamidopropylsilatrane)nickel(II) chloride, were synthesized and subsequently attached to a solid support in the form of amorphous silicon dioxide to create two hybrid molecular/heterogeneous catalysts. Characterization using ICP-MS and ATR-FTIR confirms that both catalysts are bonded to the SiO2 support. The catalysts were both able to catalyze a Suzuki-Miyarua cross-coupling which their molecular counterparts were unable to; the carboxylate catalyst was able to achieve yields of 10% and the silatrane catalyst achieved yields of up to 50%. Post-reaction analysis indicated that while some catalyst desorption occurred in both complexes, active catalytic species …
Synthesis And Characterization Of Enantioenriched Deuterated And Fluorinated Small Molecules, Mitchell D. Mills
Synthesis And Characterization Of Enantioenriched Deuterated And Fluorinated Small Molecules, Mitchell D. Mills
Master's Theses (2009 -)
The development of novel deuterated and fluorinated bioisosteres has significantly impacted the pharmaceutical and agricultural industry and created a growing demand for new synthetic methodology. Both deuterated and fluorinated small molecules exist at the forefront of drug discovery due to their unique ability to attenuate the pharmacokinetic properties of new and currently existing drugs. Selective, high-throughput methods for deuteration and fluorination are scarce in the literature, especially methods that introduce D or F atoms asymmetrically. Benzylic CH bonds are oftentimes key sites for enzymatic manipulation in metabolic processes, alteration of CH bonds to CD or CF bonds at the benzylic …
Computational Study Of The Reactions Of Heteroatomic Compounds On Ceo2, Suman Bhasker Ranganath
Computational Study Of The Reactions Of Heteroatomic Compounds On Ceo2, Suman Bhasker Ranganath
LSU Doctoral Dissertations
The mechanisms of ambient-temperature reactions of heteroatomic compounds catalyzed by ceria (CeO2), an archetypical reducible oxide, for enzyme mimetics, environmental protection, and chemical synthesis are investigated in this dissertation using theoretical methods. CeO2 is modeled with thermodynamically stable low-index surfaces exposed by commonly studied ceria thin films and nano particles. To understand phosphatase-like dephosphorylation activity, stable adsorption states and surface reactions of model phosphates are examined. Binding of the central P-atom to surface lattice oxygen (Olatt) supplemented by phosphoryl O-Ce interaction is the only stable adsorption state for the un-dissociated molecule. Deprotonation of phosphate monoesters, …
Heterogenous Reduction Of Co2 Over Boron-Rich Alb2, Jose C. Berger
Heterogenous Reduction Of Co2 Over Boron-Rich Alb2, Jose C. Berger
Honors Undergraduate Theses
Evidence suggests that the recent drastic changes in the global climate have been caused by greenhouse gases, especially CO2. As a result, scientists are aiming to develop processes that either minimize the production of these gases or convert them into products of higher value. To that end, the catalytic properties of a two-dimensional boron-rich material were investigated. Herein is reported that such a material can reduce CO2 into benzene, C3 species, and C4 species at relatively low temperatures (225-450 ℃) and pressures (0.38 MPa). Current data suggest that a low-temperature induction period (e.g., 225 ℃) …