Chemistry Commons^™

Application Of Functionalized Organosilicas In Adsorption Of Nitrates, Stephen Amoako

Electronic Theses and Dissertations

This study addresses the critical environmental issue of elevated nitrate levels in water bodies, primarily due to excessive use of nitrogenous fertilizers and improper waste disposal. It focuses on reducing nitrate concentrations in polluted water to permissible levels through the effectiveness of hybrid materials in nitrate adsorption. We synthesized nine amino-functionalized adsorbents using grafting and sol-gel techniques. Batch adsorption tests confirmed the high nitrate adsorption capacities of these adsorbents, with sol-gel materials showing the highest efficiency due to their abundant amino group contents. Among these, the surfactant-free, sol-gel adsorbent was the most effective, combining ease of synthesis with cost-efficiency. Our …

Use Of Molecular Logic Gates For The Tuning Of Chemosensor Dynamic Range, Orhan Acikgoz

Undergraduate Honors Theses

The first molecular logic gates were created in the 1990s; integrating such logic gates into fluorescent chemosensors allowed for the detection of different types of ions in solution. In this study, we have developed a new use of molecular logic gates by having two of the same type of binding site. The two binding sites on a fluorophore that both detect Na⁺ ions led to an increase in the detection limit compared with the chemosensor with a single binding site. Since the two sodium binding sites create an AND logic gate, two sodium ions are needed to generate a …

Harnessing The Power Of Virtual Reality For Organic Chemistry Education, Jungmin Shin

Undergraduate Honors Theses

Understanding organic chemistry concepts heavily relies on visualization of the geometry of molecules and spatial arrangement of molecules during mechanisms. 2D textbook depictions have their limitations in visualizing the three-dimensionality of organic chemistry. Student learning outcomes could be greatly improved from 3D visualizations of these topics. This project explores the potential of an emerging technology, Virtual Reality (VR), being incorporated as a teaching resource for organic chemistry.

This paper discusses two trials for evaluating the potential of VR as a teaching resource for organic chemistry in select topics of the Diels-Alder reaction and R/S configurations and stereoisomers. The Diels-Alder reaction …

Molybdenum Alkylidyne Complexes With Phenoxide Ligands For Alkyne Metathesis, Marvin L. Stewart Jr

LSU Doctoral Dissertations

Abstract

Alkyne metathesis is a powerful synthetic tool, which provides easy access to complex organic molecules in a single-step. It is a dynamic covalent reaction that scrambles alkynes, carbon-carbon triple bonds (C≡C). Molybdenum- or tungsten-alkylidyne (Mo≡C, W≡C) complexes are typically used as catalyst to cleave and reform alkyne bonds. Our goal has been to gain a deeper understanding of the intrinsic differences between functional ligands by the development of novel phenoxide ligands.

In chapter 2 we explore the detailed synthesis of novel phenoxide podand ligands in an effort to identify their mo-alkylidyne complexes. We were able to synthesize a variety …

Stereospecific Cross-Coupling Reactions Of Vinyl Triflates And An Investigation Of The Synthesis And Reactivity Of Activated Alkyltricyclohexylstannanes, Pejman Ghaemimohammadi

Dissertations, Theses, and Capstone Projects

Organic chemistry exists in all aspects of everyday life from polymers to pharmaceutics. Formation of carbon-carbon bonds is essential for the synthesis of complex organic compounds. This goal can be achieved by using transition metal catalysts. Second-row transition metals such as Pd, Pt, Rh, and Ir have shown remarkable efficacy in these reactions. Metal-catalyzed cross-coupling reactions form carbon-carbon bonds between electrophiles and nucleophiles using transition metal catalysts. Pd is mainly used in this reaction.

Transition metal-catalyzed cross-coupling reactions that form a bond between two C(sp²) carbons have been widely studied over the past decades. C(sp²)-C(sp^{3 …}

Studies Of Oxidopyrylium Ylide Dimers And Their Utility In The Synthesis Of Densely Functionalized Troponoids, Daniel V. Schiavone

Dissertations, Theses, and Capstone Projects

Herein, we describe our efforts to investigate mechanistic considerations of oxidopyrylium ylides and their use in cycloadditions to form complex bicyclic structures and the advancement of these cycloadducts to the synthesis of densely functionalized tropolones. This work also describes applications of tropolones as biologically relevant structures and dynamic fluorophores.

In Chapter 1, we expand upon previous studies done in the Murelli Lab describing the ability of 3-hydroxy-4-pyrone derived oxidopyrylium dimers to revert back to ylides in situ and as result can be used as a clean oxidopyrylium ylide source in accessing oxabicyclic compounds. Intermolecular cycloadditions of these ylides can be …

Exploring The Reactivity Of Metal-Ligand Cooperative Complexes With Dioxazolones, Terminal Alkynes, And 2-Ethynylbenzyl Alcohol, Megan A. Hoffer Miss

Electronic Thesis and Dissertation Repository

N-Acyl ketenimines were attempted to be synthesized catalytically by [Ru(Cp)(P^Ph₂N^Ph₂)(NCMe)]PF₆ with phenylacetylene and 3-phenethynyl-1,2,4-dioxazol-5-one. Trapping agents were employed to identify the major product of the reaction, as many products were formed. [Ru(Cp)(P^Ph₂N^Ph₂)(NCMe)]PF₆ reacts with 3-phenethynyl-1,2,4-dioxazol-5-one generating an isocyanate via the Curtius rearrangement, confirmed by a forced Curtius rearrangement with 3-phenethynyl-1,2,4-dioxazol-5-one and 1,2,4-triazole. Rates of vinylidene formation using [Ru(Cp)(P^Ph₂N^Ph₂)(NCMe)]PF₆ and various terminal alkynes of different sterics and electronics were evaluated using a Hammett analysis for and simple rate comparisons. …

Chemical Synthesis Of Sensitive Dna, Komal Chillar

Dissertations, Master's Theses and Master's Reports

Over the past decades, researchers have tried various chemical methods to synthesize modified oligodeoxynucleotides (ODNs, i.e. short segments of DNAs). Traditional ODN synthesis methods require strong basic, and nucleophilic conditions for the deprotection and cleavage of the ODN from the solid support. However, the sensitive ODNs containing labile functionalities are vulnerable to such harsh conditions. Sensitive ODNs have a wide range of applications in research and pharmaceuticals. To synthesize sensitive ODNs, researchers devised different strategies but no practical methods have been developed. To overcome these challenges, we developed alkyl Dim alkyl Dmoc technology. This innovative technology uses weakly basic and …

Synthesis Of Chiral Amino Acids Via Direct Amination Of Diazo Ester With A Rhodium-Based Catalyst, Steven J. Boyles

Honors College Theses

Amino acids are critical molecules within living organisms as they are the building blocks of proteins. In organisms, proteins serve as regulators of necessary processes, structural components in tissue, hormones, and neurotransmitters. Amino acid therapy is an emerging treatment in the medical field used to treat symptoms of diseases such as Alzheimer’s disease, Parkinson’s disease, and multiple sclerosis. Amino acid therapies have also shown promising effects when it comes to treating mood disorders and weight management. In order to increase the number of amino acids available and increase the potential treatments for other ailments, there is a drive to increase …

Photoinduced Alpha-Hydroxy C–H Alkylation Of Mono-Alcohols Via Hydrogen Atom Transfer (Hat) Of An Activated Boron-Containing Complex, Courtney Deanna Glenn

Graduate Theses, Dissertations, and Problem Reports

Hydroxy (-OH) groups are one of the most abundant functional groups found in natural products and pharmaceuticals with many of these compounds containing multiple alcohol classes. The ability to selectively functionalize a specific α-OH C–H bond in the presence of other competitive sites would provide straightforward access to new, potentially bioactive compounds. In recent literature, photoredox catalysis has been implemented to perform site and stereoselective α-OH C–H functionalization of cis-diol containing substrates. Incorporating an organoboron cocatalyst into these systems have proven to be crucial in decreasing the bond dissociation energy (BDE) and increasing hydricity of the α-OH C–H bond …

Asymmetric Cuh-Catalyzed Reductive Coupling Of Allenamides With Carbonyl And Imine Electrophiles, Stephen Collins

Theses and Dissertations

The carbon scaffold of many drugs and natural products contain multiple stereogenic centers bearing heteroatoms. As a result of this, chemists have long sought methods to efficiently install these multi-heteroatom functionalities. Reductive coupling reactions have been extensively studied over the past decades, and the allylation of carbonyls via the reductive coupling approach has been a key method for generating chiral allylic alcohols. This work utilizes inexpensive Cu for the asymmetric reductive coupling of allenamides with carbonyls or imines to simultaneously install two heteroatoms (either oxygen and nitrogen or nitrogen and nitrogen, respectively) onto the product. These molecules have a polarity …

Assessing Interatomic Potentials For Molecular Dynamics Simulation Of Soybean Oil Pyrolysis, Tanner Garrett Rust

MSU Graduate Theses

The world today relies on hydrocarbon combustion for many reasons, including its high energy density that provides ease of transportation. However, hydrocarbons sourced from fossil fuels are not expected to last forever. Biodiesel, a renewable alternative, has many attractive benefits but comes with other downsides. Biodiesel can gel in cold environments and may leave residue in an engine. Pyrolysis of biodiesel has shown promise in addressing these common detriments. Inducing pyrolysis on biodiesel feedstock (commonly soybean oil in the USA) would be an attractive option presuming it continues to produce fossil fuel analogs similar to biodiesel pyrolysis. Herein, Langevin molecular …

C–H Alkylation Of Diol Substrates Using Bifunctional Boronic Acid Catalysts, Matthew Ryan Ross

Graduate Theses, Dissertations, and Problem Reports

Boronic acid catalysts in combination with a Lewis base have been used in previous work to perform site-selective C–H alkylation reactions targeting the α-hydroxy C–H bond of diols through a photoredox activated hydrogen atom transfer. This is done by accessing a tetracoordinate boronic acid – Lewis base complex which then mediates the hydrogen atom transfer. The research hypothesizes that combining the boronic acid and Lewis base into one molecule not only simplifies the reaction but also has the potential to unlock C–H alkylation sites previously inaccessible. This is plausible because the Lewis base portion of the synthesized bifunctional boronic acid …

Investigation Of Deoxyfluorination Of Alkyl Alcohols Using Pentafluoropyridines Through A Covalent Intermediate, Christopher Allen Bias

Graduate Theses, Dissertations, and Problem Reports

Organofluorines are an omnipresent class of organic molecules, especially in pharmaceuticals. Selective fluorination of drug molecules allows for the influence of properties including metabolic activity, solubility, and intrinsic potency. Deoxyfluorinations are typically performed via generation of nucleophilic fluoride from a deoxyfluorination agent. Traditionally, diethylaminosulfur trifluoride (DAST) is the reagent of choice for these reactions, and it remains a popular reagent today. However, it has a propensity to form elimination side products and explode. Several research groups have recently developed new classes of deoxyfluorination agents including imidazole-based reagents (PhenoFluor) and sulfonyl fluorides (PyFluor) that exhibit better functional group tolerance and much …

Covalent Inhibition Of Enzyme Sortase A As A New Pathway Against Bacterial Resistance Of Staphylococcus Aureus, Umyeena Bashir

Master's Theses

The continued rise of antibiotic-resistant bacteria, such as MRSA (methicillin-resistant Staphylococcus aureus), has made the discovery of novel antibiotics critical. While bacteriostatic and bactericidal antibiotics inevitably exert evolutionary pressure on bacteria to develop resistance, small molecules that target mechanisms of bacterial virulence present a promising alternative for treatment. Sortase A (Srt A), a cysteine protease of S. aureus, promotes bacterial virulence by covalently attaching proteins such as pilin to the bacterial surface, enabling bacterial adhesion to mammalian cells. Inhibitory studies of this enzyme have gained prominent interest as a new pathway for drug development since blocking this enzyme's ability to …

Optimization Of Transition-Metal Inclusive Carbon Aerogels For Electrochemical Energy Applications, Allen Dalton Davis

Electronic Theses & Dissertations

The ever-growing need for energy alongside rising concerns for climate change demands the development of renewable energy technologies. Hydrogen fuel cells are a promising technology that can serve to either supplement energy generation or act as a lone power source. Yet for these devices to be truly green, the hydrogen that serves as fuel must be procured from a renewable resource. Electrolytic water splitting is a process that allows for the dissociation of water into H₂ and O₂. For this process to be practical, the electrolyzer needs to demonstrate high efficiency and stability, as well as a …

Enhanced Mechanical Strength Of Soybean Oil-Based Non-Isocyanate Polyurethane Adhesive For Wood Application By Introducing Nanofillers, Vatsal Chaudhari

Electronic Theses & Dissertations

Polyurethane (PU) is a versatile material that finds extensive use in various industries including bedding, construction, automotive, and packaging. Historically, this particular polymer relied significantly on petrochemical resources, a practice that was considered to have negative environmental impacts. The conventional method for preparing PU involves the use of isocyanate, which is a disadvantage due to its negative impact on the environment and human health. The resolution of this problem entails identifying an appropriate substitute for petroleum-derived products that minimize their impact on both the environment and human health. The researchers earlier utilized soybean oil, for the formulation of PUs in …

Exploring Soybean Oil-Based Polyol And Effect Of Non-Halogenated Flame Retardants In Rigid Polyurethane Foam, Sahithi Kondaveeti

Electronic Theses & Dissertations

To address the increasing demand for sustainable biomaterials due to the depletion of fossil fuel resources and growing environmental concerns, a new type of biodegradable and environmentally friendly rigid polyurethane foam (RPUF) has been synthesized. These foams are derived from chemically modified soybean oil-based polyol obtained from soybean oil by epoxidation followed by a ring-opening reaction. Polyurethane foam is generally used in construction, furniture, and automobile industries but is highly flammable and releases toxic gases and smoke during combustion. In this study, a highly efficient synergistic effect halogen-free flame-retardant (FR) melamine salt, 2-carboxyethyl(phenyl)phosphinic acid melamine salt (CMA) was synthesized from …

Thermocatalytic Plasma-Assisted Dry Reforming Of Methane Over Ni/Al2o3 Catalyst, Tyler Wong

Seton Hall University Dissertations and Theses (ETDs)

Plasma catalysis is an advantageous approach that combines the effects of plasma with the enhancements of a catalyst. By utilizing a nickel catalyst in the plasma discharge zone of a dielectric barrier discharge (DBD), it can give an enhancement to the electrical field, boost microdischarges, and increase conversion and selectivity rates of CH₄ and CO₂ in the dry reforming of methane (DRM) reaction.

Industrial application of nickel catalysts in DBD Plasma DRM process are limited by poor stability, which is caused by the sintering of active metal particles and coke deposition on the catalyst surface. In this work, …

Hydrogen Bond Activation Of Donor Acceptor Cyclopropanes, Matthew H.J. Pamenter

Electronic Thesis and Dissertation Repository

Donor acceptor cyclopropanes (DACs) are versatile organic building blocks used in the synthesis of many pharmaceutically relevant heterocycles. The combination of a high ring strain cyclopropane core and vicinal donor and acceptor substituents cause DACs to behave like 1,3-zwitterions. Recently, DACs have been activated by a hydrogen bond donor solvent in place of a Lewis acid catalyst, allowing the elimination of heavy metals commonly used in these transformations. Hexafluoroisopropanol (HFIP) as a hydrogen bond donor cosolvent was found to cause a downfield shift of the DACs electrophilic carbon in the 13C NMR spectrum. This indicates increased electrophilicity at this position …

Chemical Investigation Of Dichloromethane Extract Of Aloe Vera Peels: An Agricultural Waste, Nazmul Huda

Theses and Dissertations

Aloe barbadensis Miller, commonly called Aloe Vera, is a widely popular succulent plant species cultivated across subtropical regions worldwide from India to the Tex-Mex border. Besides its historical uses, Aloe juice has garnered attention as a potential remedy for various ailments, particularly in treating various skin conditions and facilitating wound recovery, including obesity, diabetes, hepatitis, Crohn's disease, and ulcerative colitis. Regrettably, the agricultural practice following sap extraction involves discarding Aloe vera peels, constituting agricultural waste. As part of our continuous research on extraction, isolation, separation, and spectral characterization of value-added chemicals present in waste botanicals herein, …

Synthesis And Characterization Of Colorimetric And Flurometric Chemosensor For Trivalent Metal Ions, Fazila Haque

Honors Program Theses and Research Projects

There are many biological and environmental uses for trivalent metals (like Fe3+, Al3+, and Cr3+) within our daily lives. Whether these trivalent metals are found in deficiency or excess can cause issues within our environment (global warming) or our bodies (can cause problems with our digestive, cardiovascular, and immune systems). Being able to detect them and understanding their importance becomes crucial in our understanding of the world that surrounds us.
One of the ways we can detect these trivalent metals is through the use of chemosensors. Chemosensors are used to sense analyte (trivalent metal) to produce a signal (fluorescence or …

Synthesis Of Bacterial Glycerophospholipids For Biomembrane Model Studies: A Means To Advanced Biofuels, Felix Adulley

Electronic Theses and Dissertations

To reduce reliance on fossil fuels, sustainable biofuels are being pursued, especially advanced biofuels like 1-butanol that have higher energy content and greater compatibility with existing infrastructure than ethanol. A persistent challenge is the yield-limiting toxicity of biofuels and process solvents, such as tetrahydrofuran, to the microbes that ferment biomass into biofuel. The cell membrane is a focal point of toxicity, and understanding how it interacts with fuels and solvents is key to improving yield. Phospholipid bilayers are the core of biomembranes, and model biomembranes of defined composition provide the ideal platform for biophysical studies. To this end, glycerophospholipids characteristic …

Synthesis Of Block Copolymer Additives For Examining Phase Morphology And Improving Mechanical Properties Of Thermoplastics Elastomers., Bishal Upadhyay

Masters Theses

Polystyrene-block-poly(1,4-butaidene)-block-polystyrene (PS-PB-PS) triblock copolymers are one of the most widely studied thermoplastic elastomers (TPEs) due to their ease of synthesis, non-polar nature, and commercial applicability. Like many block copolymers, incompatibility between PS and PB causes these TPEs to undergo microphase segregation. Many studies have examined the mechanical properties of blends of TPEs and PS homopolymer additives. However, there have been few studies focused on understanding the morphology and mechanical properties of blends of TPEs and copolymer additives with different architectures. Herein, I describe the synthesis of linear and graft copolymer additives based on the random copolymers poly(methyl methacrylate-random-cyclohexyl methacrylate) (PrC). …

Reactive Chemistries For Protein Labeling, Degradation, And Stimuli Responsive Delivery, Myrat Kurbanov

Doctoral Dissertations

Reactive chemistries for protein chemical modification play an instrumental role in chemical biology, proteomics, and therapeutics. Depending on the application, the selectivity of these modifications can range from precise modification of an amino acid sequence by genetic manipulation of protein expression machinery to a stochastic modification of lysine residues on the protein surface. Ligand-Directed (LD) chemistry is one of the few methods for targeted modification of endogenous proteins without genetic engineering. However, current LD strategies are limited by stringent amino acid selectivity. To bridge this gap, this thesis focuses on the development of highly reactive LD Triggerable Michael Acceptors (LD-TMAcs) …

Developing New Strategy Toward Ruthenium And Gold Redox Catalysis, Chenhuan Wang

USF Tampa Graduate Theses and Dissertations

This dissertation mainly contains three parts: 1) The discovery of triazole-modified Ru carbene catalysts for alkene metathesis and dynamic covalent chemistry; 2) The study of ligand assisted gold oxidative addition toward aryl iodide to achieve the alkene difunctionalization; 3) Gold redox catalysis via chiral P,N-chelating ligands. In the first part, the 1,2,3-triazole coordinated ruthenium carbene complexes (TA-Ru) were reported for the first time as a new class of modified Grubbs catalyst to achieve challenging olefin metathesis at higher temperatures without catalyst decomposition. With this new TA-Ru catalyst, cross-metathesis (CM), ring-closing metathesis (RCM) and dynamic covalent chemistry (DCvC) were achieved. The …

Chemical Analysis Of Metabolites From Mangrove Endophytic Fungus, Sefat E Munjerin

USF Tampa Graduate Theses and Dissertations

Natural products hold a significant place in drug discovery for their abundant and unique secondary metabolites. These secondary metabolites which encompass a range of organic compounds such as alkaloids, phenols, peptides, flavonoids, polyketides, and terpenoids, can easily be exploited for drug development. Endophytic fungi, residing harmoniously with its host, have emerged as generous producers of bioactive secondary metabolites, displaying efficacy against a wide array of human pathogens, including the challenging ESKAPE pathogens.

The research explores endophytic fungi and their prospective for drug discovery and development through the synthesis of distinctive secondary metabolites. Endophytic fungus, HM13-26C-2B, collected from Honeymoon Island, Florida …

A Work Towards A Single-Bridge Hydrazine Sensor, Brenden Jay Schmeltz

Theses and Dissertations

Hydrazine can currently be detected by irreversible methods, Carbazolopyridinophane (2,18-Dithia[3][1,8]carbazolo[3][2,6]pyridinophane) CP was synthesized by Brown et al. to detect hydrazine in real-time while also being reversible. The threshold for detection was 100 ppb, regulatory use requires 10 ppb as this is when permanent damage to humans can be caused. A more sensitive sensor will allow for safer workplaces for many people. A single, 3-atom bridge sensor will further examine the photophysical capabilities of carbazole-pyridine as an emitter/quencher pair. 1-Carbazole-1-methylpyridyl-2methyl sulfide SBCP will allow freedom of rotation as well as the bending of the bridge. These benefits will introduce conformers which …

Synthesis And Evaluation Of Novel Nucleotide Prodrugs Against Sars-Cov-2, Mohammed Attaelmanan

Electronic Thesis and Dissertation Repository

Positive sense RNA (ribonucleic acid) viruses (+ssRNA) are the known causative agents of diseases throughout history. These includes Hepatitis C Virus (HCV), SARS-CoV, and recently SARS-CoV-2. RNA dependent RNA polymerase (RdRp), a critical enzyme in the life cycle of the virus, can be targeted by using nucleotide antivirals thus causing inhibition. Novel ribonucleotides antiviral agents that possess nucleobase modifications and a 5′-phosphoramidate prodrug moiety, referred to as a ProTide, have been synthesized. The ribonucleoside analogues were constructed by CuI catalyzed azide-alkyne cycloaddition chemistry (CuAAC), also referred to as ‘click’ chemistry. The synthetic route utilized 5-ethynylpyrimidines and azidoribofuranoses as CuI ‘click’ …

Synthesis Of Biologically Active Tropolones And Stereochemically Rich Compounds Via Cross-Coupling Reactions, Nana B. Agyemang

Dissertations, Theses, and Capstone Projects

Over the past years the Murelli lab has established research based on the synthesis and biological evaluations of alpha-hydroxytropolones (alpha-HTs). These seven-membered aromatic rings have three contiguous oxygen atoms that chelates to metals, thus, biologically having the ability to bind dinuclear metalloenzymes and promoting inhibition. Synthetic routes to alpha-HT’s are scarce and therefore has been the main driving force in developing efficient and general synthetic methods to obtain variations in alpha-HTs, enabling SAR studies. The Murelli lab have therefore developed an oxidopyrylium cycloaddition/ring-opening strategy that is able to generate polysubstituted alpha-HTs starting from kojic acid, a cheap and readily available …