Physical Sciences and Mathematics Commons^™

Greening Of Catalytic Processes Using First-Row Transition Metals For Atom Transfer Radical Addition And Transfer Hydrogenation, Gabrielle Pros

Electronic Theses and Dissertations

This work focused on “greening” catalytic processes, atom transfer radical addition (ATRA), which adds an alkyl halide across and alkene, and transfer hydrogenation/dehydrogenation, which reduces a carbonyl without needing direct H₂ gas. Part of “greening” of these processes is through using abundant first row metals, Cu and Ni for catalysis. One aim was to design new ligands which would be more active in these systems; the second was investigation of additives for catalyst regeneration to reduce the catalyst loading necessary for high yields.

The TPMA^* family was investigated in ATRA. Rate constants followed the expected trend, which increased …

C-Metalated Nitriles: Diastereoselective Alkylations And Arylations, Robert John Mycka

Electronic Theses and Dissertations

Development of an sp³ hybridized halogen-magnesium exchange route to Grignard reagents, chelation-controlled asymmetric induction of γ- and δ-hydroxynitriles as well as a diastereoselective arylation procedure for C-zincated nitriles have been explored. Sequential addition of i-PrMgCl and n-BuLi to 3- and 4-carbon iodoalcohols triggers a facile halogen-metal exchange to generate cyclic magnesium alkoxides capable of intercepting electrophiles to produce a diverse range of substituted alcohols. This work advances progress toward the synthesis of highly desirable chiral Grignard reagents.

Double deprotonation of γ- and δ-acyclic hydroxynitriles with i-PrMgCl effects highly diastereoselective alkylations via a singly-chelated magnesiated nitriles. …

Design And Applications Of Charge-Separated Metal-Organic Frameworks, Sheela Thapa

Chemistry and Chemical Biology ETDs

Ionic tetrapodal ligands with colinear coordinating arms are very effective for designing hybrid porous materials with unusual structure and properties. The novelty of this research work lies in the utilization of a unique borate ligand that leads to charge-separated MOF structure with tailor designed properties. Borate ligands being tetrahedral afford 3D materials and the negative charge of borate anion can compensate the positive charge of metal ion in the framework. The borate ligands designed in this research consists of quaternary ammonium cation and anionic borate with four pyridine arms. These ligands upon coordination with Cu(I), Cu(II), Ag(I) and Co(II) metal …

The Alpha-Activator Complex, Cellular Maturation, And Catalytic Mechanism Of Iron-Type Nitrile Hydratase, Wasantha Lankathilaka Karunagala Pathiranage

Dissertations (1934 -)

In industry, chemicals are typically synthesized through catalytically accelerated chemical processes. The use of biocatalysts is an increasingly important trend in achieving environmentally friendly chemical production processes. Nitrile Hydratases (NHases) are well-known biocatalysts that are used by several manufacturers such as Mitsubishi Rayon Corporation and Lonza for the conversion of acrylonitrile to acrylamide and 3-cyanopyridine to nicotinamide, respectively. Amides, in general, are used in polymer preparation, adhesive manufacturing, and the paper industry. Refrigeration is needed in the enzymatic hydration process on the industrial scale to maintain a low reaction temperature to stabilize the NHase enzyme. The use of whole cells …

Photoelectrochemical Catalysis Of Hydrogen Peroxide With Tellurium Containing Chromophores, James Eliott Lohman

Dissertations and Theses

Growing concerns over climate change and demand for energy worldwide have made development and implementation of alternative energy sources more necessary than ever. Many of the leading energy alternatives suffer from inconsistent energy production due to fluctuations in availability of natural resources, and the current methods of addressing the issue have tremendous ecological and social ramifications of their own. While fuels like hydrogen gas are providing some promise of relief, the scope of infrastructure changes necessary for implementation and the implicit hazards of the use of such fuels complicate their application as an immediate solution. However, hydrogen peroxide carries far …

Interfacial Amino Acids Support Spa47 Oligomerization And Shigella Type Three Secretion System Activation, Hannah J. Demler, Heather B. Case, Yalemi Morales, Abram R. Bernard, Sean J. Johnson, Nicholas E. Dickenson

Chemistry and Biochemistry Faculty Publications

Like many Gram-negative pathogens, Shigella rely on a type three secretion system (T3SS) for injection of effector proteins directly into eukaryotic host cells to initiate and sustain infection. Protein secretion through the needle-like type three secretion apparatus (T3SA) requires ATP hydrolysis by the T3SS ATPase Spa47, making it a likely target for in vivo regulation of T3SS activity and an attractive target for small molecule therapeutics against shigellosis. Here, we developed a model of an activated Spa47 homo-hexamer, identifying two distinct regions at each protomer interface that we hypothesized to provide intermolecular interactions supportingSpa47 oligomerization and enzymatic activation. Mutational analysis …

Synthesis And Characterization Of A Homogeneous Cobalt Catalyst For The Hydrogenation Of Acetone To Isopropanol, Joselyn G. Molina

Honors Projects

To lessen environmentalstrain and decrease dependency on noble metals for catalysis, first-row metals are continuously being explored as alternative catalysts for reactions of interest, particularly those that close the carbon cycle or promote fuel production. Recently, homogeneous cobalt catalysts have been shown to be viable options for effective hydrogenation of C-O double bonds, with cobalt-triphos being of particular interest. Here, we report the characterization of synthesized a cobalt-triphos complex by nuclear magnetic resonance spectroscopy and optical spectroscopy. Analysis of the electrochemistry of the cobalt-triphos complex suggests promising electrocatalytic capability for the hydrogenation of acetone to produce isopropanol.

Oxidative C–C And C–Heteroatom Reactivity Of High-Valent Nickel Complexes, Sofia Marie Smith

Arts & Sciences Electronic Theses and Dissertations

ABSTRACT OF THE DISSERTATION

Oxidative C–C and C–Heteroatom Reactivity of High-Valent Nickel Complexes

by

Sofia M. Smith

Doctor of Philosophy in Chemistry

Washington University in St. Louis, 2019

Professor Liviu M. Mirica, Chair

Professor Kevin D. Moeller, Co-Chair

Nickel catalysts are commonly used for cross-coupling reactions such as Negishi, Kumada and Suzuki couplings. While Ni(0), Ni(I), and Ni(II) intermediates are most relevant in these transformations, Ni(III) and Ni(IV) species have also been recently proposed to play a role in catalysis. The formation of C–C and C–heteroatom bonds plays a fundamental role in organic transformations, and today cross-coupling reactions are one …

Nontraditional Hydrogen Bonding In Asymmetric Lewis Acid Catalysis, Brandon Vernier

Electronic Theses and Dissertations

In the field of asymmetric induction, there is a shift from the synthesis of reaction

specific chiral auxiliaries towards a broader mechanistic approach. Our approach is to

develop a theory of asymmetric catalyst design from first principles. The Diels-Alder

reaction of 2-methacrolein and 1,3-cyclopentadiene in the presence of 15 mole % lmenthoxy

aluminum dichloride, reported by Koga, achieved the (S)-exo-Diels-Alder

cycloadduct with 72% ee (0% ee Endo for acrolein). The dramatic change from 72% to 0%

ee is a significant fact that has been overlooked in practical organic synthesis.

In the first phase of this work, the conformational landscape of …

Preparation Of Enantioenriched Alkyltin Species And Their Application In Stereospecific Transformations, Glenn O. Ralph

Dissertations, Theses, and Capstone Projects

Organometallic reagents containing the tin-carbon bond are used extensively in modern synthetic chemistry for the formation of new bonds to carbon. Over recent decades, transition metal catalyzed cross coupling reactions between two C(sp²) centers have been widely developed. However, the introduction of a C(sp³) center complicates the catalytic cycle, and opens unproductive chemical pathways which lead to isomerization, elimination, and racemization. Our lab has developed a modified-Stille reaction to combat the deleterious effects of β-hydride elimination. Our protocol enables unactivated 2° alkyl organotin nucleophiles to undergo efficient cross coupling reactions with C(sp²) electrophiles, avoiding …

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 …

Beyond Density Functional Theory: The Multiconfigurational Approach To Model Heterogeneous Catalysis, Samuel J. Stoneburner, Carlo Alberto Gaggioli, Christopher J. Cramer, Laura Gagliardi

Educator Scholarship

Catalytic processes are crucially important for many practical chemical applications. Heterogeneous catalysts are especially appealing because of their high stability and the relative ease with which they may be recovered and reused. Computational modeling can play an important role in the design of more catalytically active materials through the identification of reaction mechanisms and the opportunity to assess hypothetical catalysts in silico prior to experimental verification. Kohn-Sham density functional theory (KS-DFT) is the most used method in computational catalysis because it is affordable and it gives results of reasonable accuracy in many instances. Furthermore, it can be employed in a …

Nucleophilic Phosphine Addition: Exploration Of Novel Alkyne Transformations, Brett Pierce

Murray State Theses and Dissertations

Nucleophilic phosphine catalysis has demonstrated its value in synthetic chemistry by allowing for mild carbon-carbon bond formation. Many phosphine-catalyzed reactions with electron-deficient alkynes have been reported in recent years, leading to an array of valuable products. Stemming from this field of study, phosphines can also be utilized as mild chemoselective reductants for alkynes, resulting in the corresponding alkenes. Herein, a mild, stereoselective, phosphine-mediated partial reduction of alkynes to (E)- and (Z)-alkenes is described. Specifically, a general method for the partial reduction of ynoates to the corresponding (E)- and (Z)-enoate, …

New Synthetic Methods Using Superelectrophiles, Sean Kennedy

Graduate Research Theses & Dissertations

The work outlined in this dissertation describes new synthetic methods in the synthesis of heterocyclic compounds mediated by superacid catalysis. Superacids are powerful reagents that enhance the reactivity of electrophiles, thereby opening the door to new reactive pathways with very weak nucleophiles. In this work, trifluoromethanesulfonic acid (triflic acid, CF3SO3H) is employed as a superacid catalyst to effect new transformations. These concepts are summarized in chapter 1. Chapter 2 describes a new acid-catalyzed cascade leading to the indolizidine ring system, which is present in a number of natural products. Experiments support a proposed mechanism involving vinylogous keto-enol tautomerization. The synthesis …

Mechanochemically Synthesized Cobalt Oxide-Based Particles For The Reduction Of Nitrophenols And Impacting Factors To Its Mechanism, Lorianne R. Shultz

Honors Undergraduate Theses

Mechanochemically synthesized cobalt oxide-based particles are employed for the catalytic reduction of 4-nitrophenol (4NP), a toxic water contaminant. This reduction produces 4‑aminophenol (4AP), a less toxic, pharmaceutical precursor for drugs such as paracetamol. The indicated reduction has been completed previously using noble metals and/or catalysts requiring extensive solvent use, and time as part of their preparation. The cost and synthesis of these noble metal catalysts hinders the sustainable broad scale application as an environmental remediation solution. The catalyst synthesis explored in this study utilizes the green chemistry technique of vibratory ball-milling and annealing cobalt oxide-based particles at different temperatures, producing …

Peripherally 1,2-Dinaphthyl Ethanediol Substituted Phthalocyanine Complexes: Synthesis, Characterization, Aggregation, And Application In Benzyl Alcohol Oxidation At Room Temperature, Hali̇l Zeki̇ Gök, Mustafa Kemal Yilmaz

Turkish Journal of Chemistry

In this study, the synthesis of a novel 1,2-dinaphthyl ethanediol substituted phthalonitrile (2) together with tetra-substituted zinc(II) phthalocyanine (Pc) (3) and cobalt(II) Pc (4) bearing 1,2-dinaphthyl ethanediol at peripheral positions was described. The aggregation behaviors of metallophthalocyanines 3and 4 in solution were investigated by carrying out Beer-Lambert experiments at different concentrations. In addition, the catalytic activity of new cobalt(II) Pc 4 was investigated for benzyl alcohol oxidation. Benzyl alcohol was converted to benzaldehyde using cobalt(II) Pc 4 as a catalyst by a conversion of 99% with selectivity of 100% at room temperature in 1 h. Several spectroscopic techniques such as …

Amino-Functionalized Mesostructured Cellular Foam Silica: A Highly Efficient And Recyclable Catalyst In The Knoevenagel Condensation Reaction, Dong Hao, Hongyuan Yang, Tengfei Zhang, Qing Liu

Turkish Journal of Chemistry

Mesostructured cellular foam silica was functionalized by an amino group (MCF-NH$_{2})$ using the postsynthesis grafting method and utilized as a recyclable catalyst for the Knoevenagel reaction to afford $\alpha $, $\beta $-unsaturated compounds. The catalyst was systematically characterized by various analyses such as nitrogen adsorption, X-ray diffraction, Fourier transform infrared spectrophotometry, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and Hammett indicator method. The results showed that MCF-NH$_{2}$ catalyst was successfully prepared with a high surface area of 215 m$^{2}$ g$^{-1}$ and a large pore volume of 1.37 cm$^{3}$ g$^{-1}$. Compared with the nonfunctionalized MCF sample, the window and cell …