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Articles 121 - 150 of 2535
Full-Text Articles in Chemistry
The Delocalized Toolbox: Tuning Strain, Energetic And Optoelectronic Properties Of Aryl Heterocyclic Scaffolds For Application-Driven Endeavors, Michael Josef Holzmann
The Delocalized Toolbox: Tuning Strain, Energetic And Optoelectronic Properties Of Aryl Heterocyclic Scaffolds For Application-Driven Endeavors, Michael Josef Holzmann
Chemistry and Chemical Biology ETDs
This is a three-part dissertation. Part 1 is composed of chapters 1-3 which revolves around the optimization of cyclononyne reactivity towards 1,3 dipolar cycloadditions. Specifically, the synthesis and reactivity of sulfate, sulfamate and sulfamide-bearing cyclononynes will be discussed. Chapters 4-5 comprise Part 2 which addresses optimization of ruthenium olefin metathesis towards reversible activation and inhibition. The mechanism of reversible inhibition mediated by a hexaarylbiimidazole photo-inhibitor will be elucidated. Part 3 consists of chapters 6-8 which describes structure-functional relationship studies on carbon dots and harnessing that insight for sensing applications. Data relating to assays performed with explosive analytes will be analyzed …
The Effect Of Nanomorphology As Quantified Via The K‑Index On The Drug Delivery Properties Of Isocyanate-Derived Aerogels, Stephen Y. Owusu, A. B. M. Shaheen Ud Doulah, Vaibhav A. Edlabadkar, Kamden J. George, Chariklia Sotiriou-Leventis
The Effect Of Nanomorphology As Quantified Via The K‑Index On The Drug Delivery Properties Of Isocyanate-Derived Aerogels, Stephen Y. Owusu, A. B. M. Shaheen Ud Doulah, Vaibhav A. Edlabadkar, Kamden J. George, Chariklia Sotiriou-Leventis
Miners Solving for Tomorrow Research Conference
No abstract provided.
Exploring 7-Bbh As An Alternative To 9-Bbn, Katelyn P. Griffin
Exploring 7-Bbh As An Alternative To 9-Bbn, Katelyn P. Griffin
ASPIRE 2025
9-BBN is an important compound in the synthesis of terminal alcohols by providing high regioselectivity for the anti-Markovnikov position. It is also used as a reducing agent for ketones and aldehydes and various alkyl ligation reactions. The processes involved in its synthesis and 9-BBN’s relative low solubility in most solvents renders it expensive and difficult to transport. We have made 2-isopropyl-5-methyl-7-borabicyclo[2.2.1]heptane (7-BBH) from relatively inexpensive precursor γ-terpinene and borane dimethyl sulfide complex. Characterization data and preliminary results from the use of 7-BBH for hydroboration and reduction will be discussed.
Click-Based Synthesis Of Hemibastadin Derivatives And Their Applications As Antimicrobial And Biofilm Inhibiting Agents, James B. Daniel Iii
Click-Based Synthesis Of Hemibastadin Derivatives And Their Applications As Antimicrobial And Biofilm Inhibiting Agents, James B. Daniel Iii
Longwood Senior Thesis Proposal
Antimicrobial agents are one of the most important tools used in the medical industry. With the ever growing numbers of antibiotic resistant bacteria, new strategies have been developed to combat them, one of which being biofilm inhibiting agents. A class of molecules called hemibastadins, first discovered from sea sponges, have been of recent interest in the field. Building from previous work done in this lab on hemibastadins, a hemibastadin derivative containing a triazole in place of the oxime has been identified as a potential antibiofilm agent. This work will target a derivative that will more closely mimic the hemibastadins found …
Synthetic Protein Mimetic Based Therapies For Neurodegeneration, Nicholas H. Stillman
Synthetic Protein Mimetic Based Therapies For Neurodegeneration, Nicholas H. Stillman
Electronic Theses and Dissertations
Protein-protein interactions (PPIs) are crucial for the regulation of a majority of, if not every fundamental cellular process. Despite their role in regular biological processes, dysregulated and/or aberrant protein-protein interactions (aPPIs) are often related to the onset of disease including cancer, viral infection, and amyloid diseases. aPPIs have historically been deemed ‘undruggable’ due to their large surface area and lack of a binding cavity; however, today, more than 40 disease-related aPPIs have been targeted with small molecules and several of those have reached clinical trials.
A class of synthetic protein mimetics called oligopyridylamides (OPs) has been shown to inhibit disease-related …
Development Of S(Vi) And S(Iv) Chemistry: From Asymmetric Synthesis To Covalent Reactive Groups, Chuan Shan
Development Of S(Vi) And S(Iv) Chemistry: From Asymmetric Synthesis To Covalent Reactive Groups, Chuan Shan
USF Tampa Graduate Theses and Dissertations
This dissertation mainly covers the development of synthetic methodologies related to several heteroatom functional groups, including phosphonates P(V), sulfoximines S(VI), sulfonimidamides S(VI), sulfonimidoyl fluorides S(VI), and sulfinamides S(IV). The interests in these functionalities are not only out of chemistry curiosity but also due to their pharmaceutical importance indicated by the existing drug molecules that contain these functional groups. The first chapter introduced the importance of phosphonates in biochemistry and organic synthesis, also provided some essential background of our synthetic efforts. The second chapter described the phosphonate synthesis from commercially available starting materials, with the purpose to obtain heterocyclic phosphonates in …
Refining Chlorosulfonation Methods For The Synthesis Of A Perfluoroalkyl Arylsulfonimide (Pfsi) Monomer, Ainsley P. Foster, Ben Varney, Hua Mei
Refining Chlorosulfonation Methods For The Synthesis Of A Perfluoroalkyl Arylsulfonimide (Pfsi) Monomer, Ainsley P. Foster, Ben Varney, Hua Mei
SPARK Symposium Presentations
Proton-exchange membrane (PEM) fuel cells are sources of energy that are clean, quiet, and highly responsive to changes in power needs, making them promising for use in automobiles and other portable power devices. The electrolyte of a PEM cell–the layer responsible for conductivity–is a polymer membrane, commonly consisting of perfluoroalkyl sulfonic acid (PFSA) polymers. In place of the PFSA polymers, perfluoroalkyl arylsulfonimide (PFSI) polymers are expected to improve the efficiency of PEM fuel cells with better stability and proton conductivity. The trifluovinylether (TFVE) aryl perfluorosulfonamide monomer is a new PFSI monomer proposed to fulfill these benefits once polymerized. The previous …
Effect Of Pre-Adsorbed Species On High-Pressure Adsorption Of Methane In Zeolite 5a Using Grand Canonical Monte Carlo (Gcmc) Simulations, Kanhamardi Lao, Brooks D. Rabideau
Effect Of Pre-Adsorbed Species On High-Pressure Adsorption Of Methane In Zeolite 5a Using Grand Canonical Monte Carlo (Gcmc) Simulations, Kanhamardi Lao, Brooks D. Rabideau
Shelby Hall Graduate Research Forum Posters
Natural gas upgrading, which removes impurities from methane (CH4), is essential for industrial applications, including liquefied natural gas (LNG) production and power generation, as well as for residential use. Removing non-hydrocarbon impurities such as carbon dioxide (CO2), nitrogen (N2), and water vapor (H2O), among others, along with separating heavier hydrocarbon gases from raw natural gas, is required to achieve high- purity methane and prevent pipeline corrosion. Zeolite 5A is a microporous aluminosilicate material with a pore size of approximately 5 Å, containing sodium and calcium cations that balance the framework’s negative charge. Its structure offers high thermal stability and a …
Electro-Oxidative Deoxyfluorination Of Arenes With Net3·3hf, En Chih Liu, Sabrina M. Reich, Mayank Tanwar, Matthew Neurock, Long Luo, Melanie S. Sanford
Electro-Oxidative Deoxyfluorination Of Arenes With Net3·3hf, En Chih Liu, Sabrina M. Reich, Mayank Tanwar, Matthew Neurock, Long Luo, Melanie S. Sanford
Chemistry Faculty Research & Creative Works
This report describes the design, development, and optimization of an electrochemical deoxyfluorination of arenes using a tetrafluoropyridine-derived leaving group. NEt3·3HF serves as the fluoride source, and the reactions are conducted using either constant potential or constant current electrolysis in an undivided electrochemical cell. Mechanistic studies support a net oxidative pathway, in which initial single-electron oxidation generates a radical cation intermediate that is trapped by fluoride. The resulting radical undergoes a second oxidation reaction, followed by the loss of the leaving group to yield the fluoroarene product.
Studies On The Synthesis, Function, And Properties Of Troponoids, John-Charles A. Baucom
Studies On The Synthesis, Function, And Properties Of Troponoids, John-Charles A. Baucom
Dissertations, Theses, and Capstone Projects
Troponoids are a unique class of non-benzenoid aromatic compounds with a wide range of demonstrated applications in pharmaceuticals and molecular sensing. The cycloheptatrienone scaffold possesses a noteworthy degree of tunability as a function of ring oxygenation. This manuscript describes our efforts toward a better understanding of the physical consequences of the scaffold to better utilize the motif. Chapter the first discusses our efforts at elucidating the mechanism of troponoid inhibition of the Hepatitis B virus reverse transcriptase RNAse H enzymatic domain. Using homology modeling in conjunction with traditional in vitro assays we were able to establish the likely mechanism of …
In Memoriam - Nora Sabelli: Master Orchestrator Of Grant Programs And Mentor For Advancing The Interdisciplinary Learning Sciences Field, Eric Hamilton, Jeremy Roschelle, Roy Pea, Barbara Means, Louis Gomez, Kim Gomez, Nancy Butler Songer
In Memoriam - Nora Sabelli: Master Orchestrator Of Grant Programs And Mentor For Advancing The Interdisciplinary Learning Sciences Field, Eric Hamilton, Jeremy Roschelle, Roy Pea, Barbara Means, Louis Gomez, Kim Gomez, Nancy Butler Songer
Education Division Scholarship
On Friday, September 6, 2024, the learning sciences field lost a giant in Dr. Nora Sabelli, 87 years old, a personal mentor to many researchers and an inspiration to so many learning scientists and STEM leaders. Nora’s first professional career was as a computational chemist, and later she became a passionate leader in research for improving STEM education. Nora’s time as a senior program officer at the National Science Foundation’s (NSF) Education and Human Resources (EHR) directorate was legendary; she was a force of nature who reshaped funding priorities for stronger science and a stronger connection of science to education …
Developing Phenanthroimidazole-Based Fluorescent Sensors For Efficient Analyte Detection, Brian Kellogg
Developing Phenanthroimidazole-Based Fluorescent Sensors For Efficient Analyte Detection, Brian Kellogg
Masters Theses & Specialist Projects
The highly efficient design and synthesis of organic fluorophores with an excellent quantum yield have received extensive attention. Compared with instrumental techniques, fluorescent sensors derived from organic small molecules offer many impressive benefits, such as selective detection, lower cost, and higher efficiency. Various detection mechanisms such as colorimetric, ratiometric, and fluorescence turn on/off have been reported for single analyte detection. Developing molecular probes that are capable of detecting two (or more than two) different analytes (cations, anions, and/or biomolecules) had emerged as a new research area and attracted considerable attention in the field of chemo- and biosensors.
Phenanthroimidazole represents a …
Syntheses And Characterization Of Isomeric 3-Bromopropanol Capped Oligoviologens, Marcus Anthony White
Syntheses And Characterization Of Isomeric 3-Bromopropanol Capped Oligoviologens, Marcus Anthony White
Theses, Dissertations and Capstones
The work described in this thesis has generated new oligoviologen structures designed to facilitate the formation of supermolecules that incorporate photoactive and redox-active groups. These viologens have several potential uses; for example, the 4+ oligoviologen (viologen 5) exhibits solvatochromic properties in various polar protic and polar aprotic solvents, indicating suitability for use as a solvatochromic dye. The syntheses of bis(4,4’-bipyridine)ortho-xylene, bis(4,4’-bipyridine)meta-xylene, and bis(4,4’-bipyridine)para-xylene were demonstrated through 1H NMR characterization and confirmed through literature. Bis(4,4’-bipyridine)ortho-xylene, bis(4,4’-bipyridine)meta-xylene, and bis(4,4’-bipyridine)para-xylene were produced in 68%, 72%, and 54% yields, respectively. 4,4’-Bipyridine-1-[4-(bromomethyl)phenylmethyl]-1’- …
Transition Metal Alkoxide Complexes Synthesis Using Thallium Reagents And Design Of Iron(Ii)-Alkoxide Carbene Complexes And Their Reactivity, Lakshani Wathsala Kulathungage
Transition Metal Alkoxide Complexes Synthesis Using Thallium Reagents And Design Of Iron(Ii)-Alkoxide Carbene Complexes And Their Reactivity, Lakshani Wathsala Kulathungage
Wayne State University Dissertations
ABSTRACTTRANSITION METAL ALKOXIDE COMPLEXES SYNTHESIS USING THALLIUM REAGENTS AND DESIGN OF IRON(II)-ALKOXIDE CARBENE COMPLEXES AND THEIR REACTIVITY by LAKSHANI WATHSALA KULATHUNGAGE May 2025 Advisor: Dr. Stanislav Groysman Major: Chemistry (Inorganic) Degree: Doctor of Philosophy
This dissertation focuses on the synthesis and reactivity of transition metal and main group metal alkoxide complexes. The dissertation began with exploring a novel, efficient synthetic route towards transition metal alkoxides involving thallium reagents. A novel dimeric Tl2(OCtBu2Ph)2 complex was synthesized in the reaction between a lithium alkoxide and thallium precursor TlPF6. Tl2(OCtBu2Ph)2 served as a convenient precursor to the formation of old and new transition …
Identification Of Fentanyl And Fentanyl Analogs Found In Human Urine Using Gas Chromatography-Mass Spectrometry, Adam M. Fisher
Identification Of Fentanyl And Fentanyl Analogs Found In Human Urine Using Gas Chromatography-Mass Spectrometry, Adam M. Fisher
Electronic Theses & Dissertations (2024 - present)
Identification of fentanyl and its analogs in unknown samples is a frequent practice completed in forensic crime labs, as the fentanyl epidemic continues. With the continued increase in illicit drug use, crime labs are not able to keep up with the flooding of new fentanyl analogs being developed, resulting in new analogs slipping past the crime labs’ authority. This research is to start to develop a database of commonly found fentanyl analogs in New York State. Gas Chromatography-Mass Spectrometry (GC-MS) is a widely used method for the detection and identification of illicit drugs in forensic crime labs. A database that …
Functionalized 2d Hexaazatriphenylene As Hydrogen Storage Platform: A Dft-Guided Design Approach, Islam Gomaa
Functionalized 2d Hexaazatriphenylene As Hydrogen Storage Platform: A Dft-Guided Design Approach, Islam Gomaa
Nanotechnology Research Centre
No abstract provided.
Transient Transmembrane-Electrostatically Localized Protons And Transmembrane Potential In A Laser Flashed Bacteriorhodopsin Purple Membrane Open Flat Sheet - Summary, James Weifu Lee
Chemistry & Biochemistry Faculty Publications
The transmembrane-electrostatically localized protons/cations charges (TELCs, also known as TELPs) model may serve as a unified framework to explain a wide range of bioenergetic phenomena. Transient transmembrane-electrostatically localized protons (TELPs) and transmembrane potential in a laser flash-energized bacteriorhodopsin (bR) purple membrane (PM) open flat sheet are now better analyzed. Under the Heberle et al. (1994) experimental conditions, the number of bR molecules is now calculated to be 8200 per PM open flat sheet with a diameter of 600 nm. With a single-turnover laser flash intensity of 3 mJ/cm² to photoexcite 10% of the bR molecules, the laser flash-induced peak TELCs …
Synthesis Of Bio-Orthogonal Hydrogels For 3d Cell Culture Via Penicillamine Β-Thiolactone-Mediated Native Chemical Ligation, Kaelin E. Marshall, Matthew E. Currier, Nathan J. Oldenhuis
Synthesis Of Bio-Orthogonal Hydrogels For 3d Cell Culture Via Penicillamine Β-Thiolactone-Mediated Native Chemical Ligation, Kaelin E. Marshall, Matthew E. Currier, Nathan J. Oldenhuis
Honors Theses and Capstones
Many hydrogel systems designed to mimic the extracellular matrix (ECM) employ thiol-based chemistries with undesirable functional groups, including vinyl sulfones and methacrylates. In downstream applications, any unreacted functional groups are problematic and render hydrogels non-viable for human use. Here, we introduce modifications to the Native Chemical Ligation (NCL) mechanism, exploring the elimination of cytotoxic byproducts and increased reaction rate by using a β-thiolactone. The inclusion of the β-thiolactone results in retention of the thiol within the gel, as well as enhanced kinetics due to the thermodynamic favorability of the ring opening and amide formation. We achieved this by functionalizing 4-arm …
Instantaneous Hydrolysis Of Methyl Paraoxon Nerve Agent Simulant Is Catalyzed By Nontoxic Aminoguanidine Imines, Emmanuel Kingsley Darkwah, Puspa Aryal, Chi Zhang, Charles B. Musgrave, William A. Goddard, V. Prakash Reddy
Instantaneous Hydrolysis Of Methyl Paraoxon Nerve Agent Simulant Is Catalyzed By Nontoxic Aminoguanidine Imines, Emmanuel Kingsley Darkwah, Puspa Aryal, Chi Zhang, Charles B. Musgrave, William A. Goddard, V. Prakash Reddy
Chemistry Faculty Research & Creative Works
Exposure to organophosphate-based nerve agents and pesticides poses health and security threats to civilians, soldiers, and first responders. Thus, there is a need to develop effective decontamination agents that are nonhazardous to human health. To address this, we demonstrate that instantaneous hydrolysis of methyl paraoxon (Me-POX), a nerve agent simulant, can be achieved in the presence of aminoguanidine imines at pH 10: ● the pyridine-4-aldehyde aminoguanidine-imine (1) and ● the 2,3-butanedione aminoguanidine-imine (2). The hydrolysis of Me-POX under these conditions is substantially faster than that of the state-of-the-art decontaminating agent, Dekon-139 (2,3-butanedione oxime, potassium salt). Furthermore, Dekon-139 shows adverse effects …
Metal-Free Photoredox Catalysis For The S-Trifluoromethylation Of Thiols, Raheemat Rafiu, Puspa Aryal, V. Prakash Reddy
Metal-Free Photoredox Catalysis For The S-Trifluoromethylation Of Thiols, Raheemat Rafiu, Puspa Aryal, V. Prakash Reddy
Chemistry Faculty Research & Creative Works
The S-trifluoromethylation of thiols is accomplished using a simple and cost-effective organic catalyst (diacetyl) along with a bench-stable and environmentally friendly trifluoro methylating reagent (Langloi's reagent). Under optimized conditions (2.5 equivalents of Langlois reagent, Blue LED irradiation, 48-h reaction time at room temperature), the reaction yielded up to 81% S-trifluoro methylated product. This method's high yields, compatibility with a broad substrate scope (aliphatic, heteroaromatic, and aromatic thiols), and environmentally friendly conditions demonstrate its potential for broader synthetic applications. In contrast to traditional methods that rely on organometallic catalysts and environmentally hazardous reagents, this novel photoredox catalysis method offers a more …
Asymmetric Synthesis Of The Hiv Protease Inhibitor Tmc-126 And An Anti-Malarial Agent Via A Titanium Tetrachloride Mediated Asymmetric Glycolate Aldol Addition Reaction. Redefining The Curtius Rearrangement Reaction Via Dehomologation Of Carboxylic Acids Bearing Alpha-Leaving Groups, Kweku Amaning Affram
Theses and Dissertations
Acquired Immune Deficiency Syndrome (AIDS) and malaria are two devastating infectious diseases caused by HIV and Plasmodium parasites. AIDS is caused by HIV-1 and HIV-2, transmitted through sexual contact, blood transfusions, needle sharing, and perinatal routes. Malaria, caused by plasmodium parasites through mosquito bites. Today, millions of people around the world have been infected with HIV and malaria and much research has been done to treat it. However, despite advancements in therapeutic options, these diseases remain a significant global health threat, particularly in developing countries due to the emergence of drug-resistant strains for both HIV and malaria complicating eradication efforts. …
The Development Of A One Pot, Two Reaction Synthetic Preparation Of 1,2,4-Oxadiazole, And Synthesis Of Ataluren, A Novel Drug In The Fight Against Duchenne Muscular Dystrophy. Efforts Towards The Synthesis Of A Potential Protease Inhibitor Against The Main Protease (3clpro) Of Covid-19, Austin J. Carter
Theses and Dissertations
1,2,4-Oxadiazoles are five-membered heterocyclic structures first synthesized by Tiemann and Krüger in 1884. Recent discoveries suggest an array of useful biological properties.In preparation of 1,2,4-oxadiazoles, the most prevalent precursors are amidoximes, which can be created via the reaction of nitriles with hydroxylamine hydrochloride and a base. The amidoximes are reacted with an activated carboxylic acid to yield an acylated intermediate. This intermediate can be exposed to a base to cyclize into the 1,2,4-oxadiazole. This thesis describes the efforts in combining these three steps into a unified one-pot synthesis.
Currently, there are a significant number of commercially available FDA approved and …
Organic Geochemical Evidence For Life In Archean Rocks Identified By Pyrolysis-Gc-Ms And Supervised Machine Learning, Michael L. Wong, Anirudh Prabhu, Conel O'D. Alexander, H. James Cleaves Ii, George D. Cody, Grethe Hystad, Marko Bermanec, Wouter Bleeker, C. Kevin Boyce, Andrea Corpolongo, Andrew D. Czaja, Souvik Das, Robert R. Gaines, Daniel D. Gregory, John A. Jaszczak, Emmanuelle J. Javaux, Jaganmoy Jodder, Andrew H. Knoll, Martin Van Kranendonk, Katie M. Maloney, Nora Noffke, Robert Rainbird, Emersyn Slaughter, Eva E. Stüeken, Roger E. Summons, Frances Westall, Jasmina Wiemann, Shuhai Xiao, Robert M. Hazen
Organic Geochemical Evidence For Life In Archean Rocks Identified By Pyrolysis-Gc-Ms And Supervised Machine Learning, Michael L. Wong, Anirudh Prabhu, Conel O'D. Alexander, H. James Cleaves Ii, George D. Cody, Grethe Hystad, Marko Bermanec, Wouter Bleeker, C. Kevin Boyce, Andrea Corpolongo, Andrew D. Czaja, Souvik Das, Robert R. Gaines, Daniel D. Gregory, John A. Jaszczak, Emmanuelle J. Javaux, Jaganmoy Jodder, Andrew H. Knoll, Martin Van Kranendonk, Katie M. Maloney, Nora Noffke, Robert Rainbird, Emersyn Slaughter, Eva E. Stüeken, Roger E. Summons, Frances Westall, Jasmina Wiemann, Shuhai Xiao, Robert M. Hazen
OES Faculty Publications
Throughout Earth’s history, organic molecules from both abiogenic and biogenic sources have been buried in sedimentary rocks. Most of these organic molecules have been significantly altered by geologic processes through deep time. Nonetheless, the nature and distribution of those ancient fragmentary organic remains have the potential to reveal diagnostic biomolecular information after billions of years of burial. Here, we analyzed 406 fossil, modern biological, meteoritic, and synthetic samples using pyrolysis gas chromatography and mass spectrometry. We explored these analytical data via supervised machine-learning methods to discriminate samples of biogenic vs. abiogenic origin, plant vs. animal phylogenetic affinity, and photosynthetic vs. …
Approaches To The Synthesis Of Highly Substituted Arenes, Kh Tanvir Ahmed
Approaches To The Synthesis Of Highly Substituted Arenes, Kh Tanvir Ahmed
Graduate Theses, Dissertations, and Problem Reports (ETD)
While benzene rings and their derivatives are among the most frequently encountered ring systems in natural products, pharmaceuticals, agrochemicals, dyes, and functional materials, polysubstituted arenes are relatively scarce. The analysis of FDA-approved small molecules provides valuable insights into the characteristics of successful drugs while also highlighting gaps in the availability of synthetic methods capable of efficiently accessing diverse substitution patterns on aromatic rings. Highly substituted arenes are typically synthesized through sequential modification of a pre-existing benzene core; however, this stepwise approach becomes increasingly challenging with each additional substitution. An alternative strategy involves the direct construction of benzene rings via annulation …
Evaluating The Chemical Reactivity Of Wildfire-Derived Dissolved Organic Molecules: Glutathione Binding Through Kendrick Mass Defect Analysis, Hannah M. Hamontree, Patrick G. Hatcher
Evaluating The Chemical Reactivity Of Wildfire-Derived Dissolved Organic Molecules: Glutathione Binding Through Kendrick Mass Defect Analysis, Hannah M. Hamontree, Patrick G. Hatcher
Chemistry & Biochemistry Faculty Publications
The emerging risks to organisms of pyrogenic-derived dissolved organic matter (PyDOM) from forest fires are of concern due to its toxic and mutagenic potential (e.g., pro-oxidative responses in fauna through the depletion of glutathione, a nitrogen- and sulfur-containing tripeptide found in cells). This study simulates this phenomenon in a laboratory setting by identifying bonding between reduced l-glutathione and organic molecules in leachates from environmentally weathered biomass samples (charred and uncharred) using Kendrick Mass Defect (KMD) analysis from formula lists obtained from negative-mode electrospray ionization-Fourier transform-ion cyclotron resonance-mass spectrometry ((-)ESI-FT-ICR-MS). These formula lists reveal a 10-fold increase in nitrogen- and sulfur-containing …
The Importance Of Atomic Charges For Predicting Site-Selective Ir-, Ru-, And Rh-Catalyzed C-H Borylations, Shannon M. Stephens, Kyle M. Lambert
The Importance Of Atomic Charges For Predicting Site-Selective Ir-, Ru-, And Rh-Catalyzed C-H Borylations, Shannon M. Stephens, Kyle M. Lambert
Chemistry & Biochemistry Faculty Publications
A supervised machine learning model has been developed that allows for the prediction of site selectivity in late-stage C-H borylations. Model development was accomplished using literature data for the site-selective (≥95%) C-H borylation of 189 unique arene, heteroarene, and aliphatic substrates that feature a total of 971 possible sp² or sp³ C-H borylation sites. The reported experimental data was supplemented with additional chemoinformatic descriptors, computed atomic charges at the C-H borylation sites, and data from parameterization of catalytically active tris-boryl complexes resulting from the combination of seven different Ir-, Ru-, and Rh-based precatalysts with eight different ligands. Of the over …
Modified N-Heterocyclic Carbene Catalysts For Polyurethane Synthesis, Charise D. Young
Modified N-Heterocyclic Carbene Catalysts For Polyurethane Synthesis, Charise D. Young
Pomona Senior Theses
Polyurethanes are widely used polymers synthesized from diisocyanate and diol molecules. They are ubiquitous polymeric materials with important industrial applications. Their increasing market value prompts the need for selective and efficient production which can be achieved through N-Heterocyclic carbene (NHC) catalysis. N-heterocyclic carbenes are heterocyclic molecules containing a carbene atom and at least one nitrogen adjacent to the carbene center. The nitrogen substituents on the adjacent nitrogen play an important role in influencing their steric and electronic properties and resultant reactivity.1,2 There is a lack of a comprehensive understanding of the steric and electronic properties of NHCs and how …
Optimizing And Scaling Up Tcfh–Nmi Pyrrole Acylation For Organic Syntheses, Grant H. Miller
Optimizing And Scaling Up Tcfh–Nmi Pyrrole Acylation For Organic Syntheses, Grant H. Miller
Pomona Senior Theses
Traditional ketone synthesis often depends on toxic reagents and hazardous solvents, which limits its scalability and environmental compatibility. The TCFH–NMI method has shown strong potential for amide, ester, and thioester formation, but its use in ketone synthesis has only been recently described, and only on small scales. This thesis addresses that gap by optimizing a scalable synthesis of 2-(monomethyl succinyl)-3,5-dimethylpyrrole using monomethyl succinate and 2,4-dimethylpyrrole as model substrates. Key reaction parameters were systematically refined to improve yield, reproducibility, and sustainability. The final protocol avoids chromatography, operates at room temperature, and consistently delivers high yields. These features position it as a …
Stack Bonding In Pentacene And Its Derivatives, Craig A. Bayse
Stack Bonding In Pentacene And Its Derivatives, Craig A. Bayse
Chemistry & Biochemistry Faculty Publications
Understanding the nature of π-stacking interactions is important to molecular recognition, self-assembly, and organic semiconductors. The stack bonding order (SBO) model of π-stacking has shown that the conformations of dimers occur when the combinations of monomer MOs are overall stack bonding in character. DFT calculations show that minima found on the potential energy surface for the π-stacked dimers of pentacene and perfluoropentacene occur when the dimer MOs are constructed from combinations of monomer MOs with an allowed SBO. An ex-amination of the MOs of π-stacked dimers extracted from X-ray structures of alkynyl derivatives like TIPS-pentacene pack at one or more …
Experimental Demonstration And Study Of Transmembrane-Electrostatically Localized Protons Prevail, James Weifu Lee
Experimental Demonstration And Study Of Transmembrane-Electrostatically Localized Protons Prevail, James Weifu Lee
Chemistry & Biochemistry Faculty Publications
In this review in relation to some interesting arguments from Silverstein, it is now reaffirmed that the experimental demonstration of transmembrane-electrostatically localized protons (TELPs) was successfully accomplished through 1) using an aluminum film as a TELPs sensor in a biomimetic anode water-membrane-water cathode system, 2) analyzing the water-electrolysis current curve, and 3) measuring bulk liquid phase pH. Formation of induced TELPs was subsequently discovered in an anode water-membrane-water-membrane-water cathode system. The discovery of induced TELPs enabled clean experimental tests on the cation-TELPs exchange process by using sodium bicarbonate or potassium bicarbonate solution in the central liquid chamber. The sodium/TELPs exchange …