Chemistry Commons^™

Gold(I)-Hydroarylation In Polymer Modification – Alkynes And Alkenes With Unexpected Reactivity, Samuel B. Hunt

Dissertations

Polymer modification is crucial for developing new properties and materials from recalcitrant waste polymers. Synthetically, polymers possess a chemical inertness that renders their functionalization challenging. Specifically, the omnipresence of C–H bonds in all commercial polymers endows their chemical resistance. Thus, developments in C–H activation chemistry are crucial to polymer diversification processes and allow for fundamental insight into the role of material processing conditions on novel chemical reactions. Au(I)-chemistry has recently come to the fore owing to a unique chemical reactivity nonexistent with other transition metals. The alkynophilicity of Au(I), in tandem with their insensitivity to common polymer processing conditions (air, …

Novel Pathways To Tailor Charge And Spin In Materials And Investigating The Impact On Sensing And Electrochemical Energy Applications, Aruna Narayanan Nair

Open Access Theses & Dissertations

Catalysis is integral to our daily lives, as it streamlines and accelerates numerous chemical reactions essential for producing various materials, fuels, and chemicals. With the rising demand for clean, sustainable energy sources, optimizing catalytic materials and processes becomes increasingly vital. In the realm of renewable energy production, catalysis is crucial for efficiently converting energy from sustainable resources, such as solar, wind, and biomass, into chemical energy stored in fuels or directly into electrical energy.The electronic charge distribution in materials significantly influences their physical and chemical properties, facilitating the development of advanced electronic, optoelectronic, sensing, and energy conversion devices. Since catalysis …

Separation Of Organic Acids Through Direct Catalysis From Sugars, Katelyn Robinson

Chemical Engineering Undergraduate Honors Theses

Society relies on plastic products, whether they are single use or durable. A downside of plastic is that the most common type is a product of oil and oil is not only a limited resource but also a climate-damaging resource. Polylactic acid (PLA) is a bio-based, biodegradable plastic. However, the process of converting biomass to polylactic acid polymer has the largest environmental impact of the PLA production process, so alternative methods of conversion are needed (Moretti et al., 2021). The polylactic acid polymer can be made with lactic acid, which can be converted from glucose.

The Kinetic Control Of Polymer Micelles; Chemical Functionality, Material Interactions, And Equilibration, Taylor Larison

Theses and Dissertations

Polymer micelles have found significant uses in areas such as, energy storage devices, catalysis, opto-electronics, drug-delivery, oil additives, and nanoreactors. In many of these applications the overall micelle size (aggregation number) and chemical functionalization determines performance. To progress towards more advanced materials synthesized from the facile bottom-up approach with polymeric micelles the implementation and study of thermodynamic handles were investigated. Here the kinetic control of micelles was studied across a range of applications; independent control over micelle functionality, the spatial orientation of multiple metal oxide nanoparticles in mesoporous materials via self-assembly, and the use of small-angle neutron scattering (SANS) to …

Traffic Lights For Catalysis: Stimuli-Responsive Molecular And Extended Catalytic Systems, Grace C. Thaggard, Johanna Haimeri, Roland A. Fischer Prof. Dr., Kyoung Chul Park, Natalia B. Shustova Prof. Dr.

Faculty Publications

The advances made in the field of stimuli-responsive catalysis during the last five years with a focus on the novel recently-emerged directions and applications have been surveyed. Metal-free catalysts and organometallic complexes, as well as biomimetic systems and extended structures, which display switchable catalytic activity for a variety of organic transformations, are discussed. Light-activated systems comprised of photochromic molecules capable of modulating reaction rate, yield, or enantioselectivity based on geometric and electronic changes associated with photoisomerization are the focus of the detailed discussion. Alternative stimuli, including pH and temperature, which could be applied either alone or in combination with light, …

Bimetallic Compound Catalysts With Multiple Active Centers For Accelerated Polysulfide Conversion In Li-S Batteries, Wu-Xing Hua, Jing-Yi Xia, Zhong-Hao Hu, Huan Li, Wei Lv, Quan-Hong Yang

Journal of Electrochemistry

Practical applications of lithium-sulfur (Li-S) batteries are hindered mainly by the low sulfur utilization and severe capacity fading derived from the polysulfide shuttling. Catalysis is an effective remedy to those problems by promoting the conversion of polysulfides to reduce their accumulation in the electrolyte, which needs the catalyst to have efficient adsorption ability to soluble polysulfides and high activity for their conversion. In this work, we have proposed a bimetallic compound of NiCo₂S₄ anchored onto sulfur-doped graphene (NCS@SG) to fabricate a catalytic interlayer for Li-S batteries. Compared to CoS, the NiCo₂S₄ demonstrated much higher …

Synthesis Of A Series Of Trimeric Branched Glycoconjugates And Their Applications For Supramolecular Gels And Catalysis, Jonathan Bietsch, Anji Chen, Dan Wang, Guijun Wang

Chemistry & Biochemistry Faculty Publications

Carbohydrate-derived molecular gelators have found many practical applications as soft materials. To better understand the structure and molecular gelation relationship and further explore the applications of sugar-based gelators, we designed and synthesized eight trimeric branched sugar triazole derivatives and studied their self-assembling properties. These included glucose, glucosamine, galactose, and maltose derivatives. Interestingly, the gelation properties of these compounds exhibited correlations with the peripheral sugar structures. The maltose derivative did not form gels in the tested solvents, but all other compounds exhibited gelation properties in at least one of the solvents. Glucose derivatives showed superior performance, followed by glucosamine derivatives. They …

Ambient Ammonia Synthesis Via Microwave-Catalytic Materials And Plasma Chemistry, Siobhan Brown

Graduate Theses, Dissertations, and Problem Reports (ETD)

Ammonia is critical to supporting human life on earth because of its use as fertilizer. The Haber-Bosch process to produce ammonia has been practiced for over 100 years. This process operates at high pressure and temperature to overcome the thermodynamic and kinetic limitations of the ammonia synthesis reaction thus researchers have tried to overcome it for decades. At present this process represents 1% of global energy usage and 2.5% of global CO₂ emissions. The proposed chemical looping ammonia synthesis approach seeks to reduce the environmental impact of this critical process and to elucidate microwave-catalytic principles.

This research aims to …

Copper-Catalyzed Dehydrogenative Decarboxylation Reactions Of Carboxylic Acids To Alkenes, Michael P. Stanton

Graduate Theses, Dissertations, and Problem Reports (ETD)

Linear alpha olefins (LAOs) are important building blocks in the production of linear low-density polyethylene, a plastic used in products such as shrink wraps, plastic bags, tubing, plasticizers, among others. Commercial methods for generating LAOs utilize ethylene oligomerization, but this method is reliant on fossil fuels and leads to unselective product formation. Synthesis of LAOs from renewable resources, namely carboxylic acids, by decarbonylative dehydration strategies has been well studied, however, this method has inherent drawbacks rooted in the formation of internal olefin side-products through isomerization pathways. With the goal of avoiding internal isomerization, this thesis explores a dehydrogenative decarboxylation strategy …

First Principles Calculations To Investigate Surface And Catalytic Properties Of Materials For Green Energy Generation, Keerthan Raghavendra Rao

Theses and Dissertations--Chemistry

Climate change due to greenhouse gas build up in the earth’s atmosphere is an existential threat to humanity. To mitigate climate change, a significant shift from fossil fuels is necessary. Over the years, several renewable energy sources like solar, wind, geothermal etc. have been explored with the aim providing carbon-free energy. In this work, we focus on using density functional theory (DFT) methods to investigate key functional properties of materials of interest for applications in solar cells and catalytic conversion for energy generation. We show geometric effects of carboxylic acid binding on a transition metal surface to impact the deoxygenation …

Synthetic Methodologies Using Nucleophile-Electrophile Chemistry, Jacob C. Hood

Graduate Research Theses & Dissertations

Synthetic organic chemistry is a vital part of the modern world – making up 15-20% of the U.S. economy. New synthetic reactions can lower manufacturing costs and create more environmentally friendly processes. Substitution, addition, and superelectrophilic chemistry are potent tools to afford potentially essential compounds. The work outlined in this dissertation recounts the expansion of synthetic methodologies employing substrates with a wide range of electrophilicities toward synthesizing heterocyclic molecules. These concepts are summarized in chapter 1. Chapter 2: N-Heterocyclic alcohols are excellent substrates for superacid-promoted Friedel-Crafts reactions. The N-heterocyclic alcohol ionizes to produce reactive, dicationic intermediates, providing good to excellent …

Advancements In Engineered Nanomaterial Synthesis For Selective Oxygen Reduction Reaction Catalysts And Fundamental Electrochemical Studies Of Lead Acid Batteries, Jacob Kaelin

Graduate Research Theses & Dissertations

It has long been known that the catalysis of water and its constituent elements could provide an effective means of storing and producing electricity. The deceptively simple process of producing electricity from Hydrogen and Oxygen is composed of two primary reactions, namely the Hydrogen Oxidation Reaction (HOR) and the Oxygen Reduction Reaction (ORR). While the HOR has largely been optimized on a variety of catalytic materials, the ORR has been plagued by sluggish kinetics and high overpotentials to the point where it is the bottleneck in implementing water catalysis-based technologies in practical scenarios. To help meet these challenges a bevy …

Asymmetric Cuh-Catalyzed Reductive Coupling Of Allenamides With Carbonyl Electrophiles & Development Of Nanocatalysts For Heterogeneously Catalyzed Buchwald-Hartwig Amination, Raphael K. Klake

Theses and Dissertations

Many drugs and natural products contain multiple stereogenic carbons bearing heteroatoms throughout their carbon framework. Therefore, methods that can efficiently install multiple heteroatoms on a molecule are valuable. Reductive coupling reactions have been extensively studied, and the allylation of carbonyls via the reductive coupling approach has been a key method for generating chiral tertiary and secondary allylic alcohols. This work utilizes inexpensive Cu for the asymmetric reductive coupling of allenamides with carbonyls to simultaneously install two heteroatoms (oxygen and nitrogen) on the product. These molecules have a polarity profile that make them difficult to make using traditional methods. Herein, we …

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 …

Surface Structure Engineering Of Feni-Based Pre-Catalyst For Oxygen Evolution Reaction: A Mini Review, Jia-Xin Li, Li-Gang Feng

Journal of Electrochemistry

Nitrite, a widespread raw material, is harmful to human health for long-term consumption. At present, the detection methods of nitrite mainly include chemical analysis, fluorescence, ultraviolet spectrophotometry and chromatography. These methods have ideal sensitivity and selectivity, but also have some characteristics: cumbersome operation, expensive equipment and professional personnel. Therefore, the development of a simple and sensitive nitrite assay is of great significance. In this paper, the Au/rGO/FeOOH composite materials, which revealed good synergistic catalytic performance among the three elements in the composite, were prepared by simple hydrothermal method and reduction method for the first time with large specific surface area …

Synthesis And Catalytic Behaviors Of Sub-10nm Platinum Group Metal Nanocatalysts, Zixin Wang

Theses and Dissertations

Nanoparticles of platinum group elements(Pd, Pt, Rh, Ir, Ru and Os) exhibit intriguing catalytic behaviors that are sensitively dependent upon their particle dimensions, chemical compositions, and surface structures. Platinum group elementbased nanomaterials have been widely utilized for catalyzing a series of important chemical reactions, producing over 90% of chemicals and fuels and accounting for 35% of the world's GDP globally. Reducing the overall particle sizes of the catalysts to the sub-10 nm size regime not only effectively mitigates the cost issues associated with the noble metal-based materials, but also remarkably modifies the surface atomic coordinations and the electronic band energies, …

Calcium Bistriflimide-Mediated Sulfur (Vi)–Fluoride Exchange (Sufex): Mechanistic Insights Toward Instigating Catalysis, Nicholas Ball, Brian Han, Samuel R. Khasnavis, Matthew Nwerem, Michael Bertagna, O Maduka Ogba

Pomona Faculty Publications and Research

We report a mechanistic investigation of calcium bistriflimide-mediated sulfur(VI)–fluoride exchange (SuFEx) between sulfonyl fluorides and amines. We determine the likely pre-activation resting state─a calcium bistriflimide complex with ligated amines─thus allowing for corroborated calculation of the SuFEx activation barrier at ∼21 kcal/mol, compared to 21.5 ± 0.14 kcal/mol derived via kinetics experiments. Transition state analysis revealed: (1) a two-point calcium-substrate contact that activates the sulfur(VI) center and stabilizes the leaving fluoride and (2) a 1,4-diazabicyclo[2.2.2]octane additive that provides Brønsted-base activation of the nucleophilic amine. Stable Ca–F complexes upon sulfonamide formation are likely contributors to inhibited catalytic turnover, and a proof-of-principle redesign …

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 …

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 CH bonds are oftentimes key sites for enzymatic manipulation in metabolic processes, alteration of CH bonds to CD or CF bonds at the benzylic …

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 …

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 (O_latt) supplemented by phosphoryl O-Ce interaction is the only stable adsorption state for the un-dissociated molecule. Deprotonation of phosphate monoesters, …

Intramolecular Friedel-Crafts Addition Of Indoles To Tertiary Allylic Alcohols, Bryan H. Wakefield, Romie Barnes, Traeannah Brown, Ashley M. Jones, Victoria A. Knotts, Christina Martinetti

Journal of the South Carolina Academy of Science

An intermolecular Friedel-Crafts alkylation of indole and tertiary allylic alcohols has been developed. The allylic alcohols were synthesized using a two-step procedure, then exposure of these alcohols to diphenyl phosphate facilitated the desired annulation reaction. This reaction tolerated a variety of indole substitutions to yield 1H,2H,3H,4H-pyrido[1,2-a]indoles.

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 ℃) …

Solar Light Degradation Of Organic Dye Pollutants And Preparation Of Bis(Indolyl)Methanes Using Core-Shell Fe3o4@Sio2@Cuo Nanocomposite, Kaveh Parvanak Boroujen, Zeinab Tohidiyan, Mina Mirzaei

Turkish Journal of Chemistry

In this research, a new ferromagnetic-recoverable core-shell Fe3O4@SiO2@CuO nanocomposite of a certain size (20-25 nm) has been synthesized based on Cu(II) complex coated on Fe3O4@SiO2@CuO nanoparticles by facile and fast solid state microwave irradiation method. The photocatalytic activity of the nanocomposite was investigated for degradation of methylene blue (MB) and methyl orange (MO) dye pollutants in aqueous media under solar light irradiation. The nanocomposite could destroy these dyes with high efficiency in short time. With comparison of degradation percentages can be concluded that the nanocomposite shows better photocatalytic activity for MB dye (97% in 180 s). Kinetic study revealed higher …

Selective Oxidation Of Alkenes In Air Catalyzed By Mn3o4 Nanoparticles, Brojo Kishor Shachib Dhali

Dissertations and Theses

Catalytic oxidation is a process where compounds are oxidized using catalysts. Solid catalysts exhibit several advantages over homogeneous systems, such as catalyst recovery and excellent stability. Various supported transition-metal oxides (for example: CuO, ZnO, CeO2, Fe2O3 and WO3), metal nanoparticles (for example: Pd and Ru) and polyoxometalate clusters (for example: [W10O32]4-, [Mn2ZnW(ZnW9O34)2]10- and [XW12O40]n- (X = P, Si)) have been applied to selective oxidation of organic compounds, but high associated product conversion still remains a challenge. Recently, a number of materials containing Mn3O4 have been used successfully in different catalytic applications, such as degradation of phenols, reduction of nitrobenzenes, and …

Development Of Visible-Light-Mediated Photoredox Catalysis, Sarbjeet Kaur

Legacy Theses & Dissertations (2009 - 2024)

ABSTRACT

Multinuclear Copper(I) And Silver(I) Pyrazolates: Synthesis, Luminescence, And Catalysis, Monika R. Patterson

Chemistry & Biochemistry Dissertations - Archive

Copper and silver pyrazolate complexes have numerous fascinating properties such as luminescence, catalytic ability, and complexation with small molecules. Using both more widely studied non-fluorinated pyrazolates and less common highly fluorinated pyrazolates as supporting ligands, we successfully synthesized and investigated several new coinage metal complexes. Synthetic details, structures, and properties i.e., luminescence and catalytic ability, have been studied. Chapter 2 of this research describes the synthesis of a new pyrazole with highly fluorinated aryl groups and corresponding trinuclear copper(I), silver(I), and gold(I) complexes. All three metal complexes exhibit bright blue luminescence under exposure to UV light. Additionally, the copper(I) complex …

Catalytic Activity Of Molybdenum-Dioxo Complexes, Randy Tran

Graduate Theses and Dissertations

This dissertation details the development of rationally designed dioxomolybdenum catalyst active for deoxydehydration (DODH), the net reduction of diols and polyols into alkenes and dienes. Catalyst design involved variations on dioxomolybdenum(VI) supported by a dianionic meridional pincer ligand. Rational substrate scope was explored using aliphatic diols, aromatic diols, and biomass derived diols. Various reductants were tested for ability to catalyze the reaction. The substrate specific mechanism of DODH was explored utilizing NMR and in-situ infrared spectroscopy and important rate constants and rate determining steps were found to aid in the optimization of ideal reaction conditions. Catalytic activity was observed to …

Cu-Catalyzed Phenol O-Methylation With Methylboronic Acid, Mairead E. Bartlett, Yingchuan Zhu, Uma Bhagwat Gaffney, Joyce Lee, Miranda Wu, Betemariam Sharew, Angela K. Chavez, David J. Gorin

Chemistry: Faculty Publications

A Cu-catalyzed oxidative cross-coupling of phenols with methylboronic acid to form aryl methyl ethers has been developed, expanding the scope of Chan-Evans-Lam alkylation. Electron-deficient phenol derivatives with a broad array of functional groups are methylated in high yields. Increased reaction temperature and catalyst loading enables the methylation of substrates incorporating pyridine and dihydroquinolone motifs. Electron-rich phenol derivatives are poor substrates for the methylation; the characterization of C−H homodimerization products formed from these substrates illuminates a competing mechanistic pathway.

Electrochemical Characterization Of Surface-Immobilized Metal Nanostructures: Stability, Atomic Level Doping, Catalysis, And Sensing Applications., Badri Prasad Mainali

Electronic Theses and Dissertations

This dissertation has two main themes. The first theme involves voltammetric analysis of the stability of Au nanoparticles (NPs) under electrochemical and thermal treatment as a function of size, ligand stabilizer, and atomic composition. The second theme involves the use of Au NPs, electrophoretic deposition (EPD), and anodic stripping voltammetry (ASV) for electrochemical detection of analytes. The electrochemical size stability of 4.1, 15.1, and 50.3 nm average diameter Au NPs upon treatment with multiple electrochemical oxidation-reduction cycling in acidic electrolyte is monitored by observing changes in the peak oxidation potential (E_p) in ASV and the electrochemically measured surface …