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Mechanism Of Iron-Catalyzed Oxidative Α-Amination Of Ketones With Sulfonamides, Gloria M. Parrales, Nina C. Hollin, Fubin Song, Yangyang Lyu, Anne-Marie O. Martin, Alexandra E. Strom

Chemistry: Faculty Publications

We report the mechanism of the iron-catalyzed oxidative α-amination of ketones with sulfonamides. Using linear free energy relationships, competition experiments, and identification of reaction intermediates, we have found that the mechanism of this reaction proceeds through rate-limiting electron transfer to 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) from an iron enolate in the process of forming an α-DDQ adduct. The adduct then serves as the electrophile for substitution with sulfonamide nucleophiles, accelerated by iron and additional DDQ. This mechanistic study rules out formation of an α-carbocation intermediate and purely radical mechanistic hypotheses.

Impaired Waters: New Treatments And Improved Methods For Pfas And Algae Toxins, Alexandria Forster

Theses and Dissertations

Per- and polyfluoroalkyl substances (PFAS) are high-profile environmental contaminants, many having long persistence in the environment and widespread presence in humans and wildlife. Following phase-out of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) in North America and restrictions in Europe, PFAS replacements are now widely found in the environment. While liquid chromatography (LC)-mass spectrometry (MS) is typically used for measurement, much of the PFAS is missed. To more comprehensively capture organic fluorine, we developed sensitive and robust methods using activated carbon adsorption, solid phase extraction, and combustion ion chromatography (CIC) to measure total organic fluorine (TOF) in industrial wastewaters, river …

Experimental Determination Of The Unusual Ch Stretch Frequency Of Protonated Fullerenes, Laura Finazzi, Vincent J. Esposito, Julianna Palotás, Jonathan Martens, Els Peeters, Jan Cami, Giel Berden, Jos Oomens

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

We report experimental values for the CH stretch frequencies of the protonated fullerenes C₆₀H⁺ and C₇₀H⁺. Anharmonic frequency calculations at the B3LYP/6-31G level of theory, which are independent of empirical scaling factors, reproduce the experimental values to within approximately 5 cm⁻¹. Scaling theoretical harmonic frequencies by applying factors derived for polycyclic aromatic hydrocarbons deviate significantly from the experimentally measured frequency. We attribute this deviation to the unusual hydrocarbon structure that affects the degree of anharmonicity of the CH stretch. This result allows us to propose an original, specific scaling factor of …

Detection And Analysis Of Solid-Phase Nutrients In Complex Benthic Cyanobacterium Communities, Cassidy Ann Crandell

Theses and Dissertations

Eutrophication is one of the most serious water quality issues affecting aquatic systems in the United States. Densely populated urban areas as well as mining and agriculture are major sources of anthropogenic nutrient loading into lakes and rivers. Excess loading of nutrients like phosphorus (P) into these ecosystems can cause native algal species to be outcompeted by harmful algal bloom (HAB) species. Increases in these HAB events are a growing public health concern as contact with excreted toxins can be harmful for human, aquatic, and land species. Remediation techniques like total maximum daily loads (TMDLs) have been implemented to reduce …

Molecular And Hybrid Catalysts For Selective Hydrodeoxygenation Of Lignin Model Compounds, Jacob G. Tillou

Theses and Dissertations

Lignin is a highly aromatic, branched polymer and could be utilized as a renewable source of liquid fuel. The advent of “lignin-first” depolymerization processes have allowed for the high-yield isolation of oxygenated aromatic monomers from lignin. These oxygenated aromatic compounds are lower in energy and stability than their deoxygenated counterparts. Selective deoxygenation of these compounds would result in stable, higher value liquid fuels. Using molecular catalysts, selective deoxygenation, or hydrodeoxygenation (HDO), of lignin-derived compounds in the presence of hydrogen is possible.

Immobilization of these molecular catalysts on metal oxide surfaces eliminates the possibility of bimolecular decomposition and allows for easier …

The Control And Operation Of Optical Sensors For Environmental Monitoring With Microcontrollers As Data Acquisition And Processing Systems, Zechariah Kitzhaber

Theses and Dissertations

Phytoplankton are microscopic unicellular organisms, and they are ubiquitous in marine and freshwater environments across the globe. They play a critical role in primary production, carbon fixation, and O2 production through photosynthesis. Phytoplankton comprise an abundant variety of genera and species, and the taxonomic makeup of a community can be an important indicator of environmental health. Phytoplankton are spatially and taxonomically diverse; they change in size and cellular content throughout their lifetime, and they can also alter their pigmentation in response to environmental factors, so it is important to understand the variability in size and pigmentation between individuals of the …

Electronic Structure Investigation Of Photoswitch-Embedded Organic Frameworks And External Electric Field Effects On Carbon Dioxide, Austin Hill

Theses and Dissertations

Metal- and Covalent-Organic Frameworks (MOFs and COFs, respectively) are chemically versatile systems that have diverse applications, ranging from drug delivery to energy storage. This versatility is due to the highly tunable nature of organic frameworks, which utilize metal clusters, chemically diverse metals, and organic ligands. Researchers have recently demonstrated how MOFs and COFs can be remotely tuned through the use of photochromic organic linkers and light (Martin, et al., 2022). The implications of these findings are significant and have numerous applications, primarily in optical switching and energy storage. However, the photochromic mechanism within the organic framework must be investigated, which …

Alternate Conformational Trajectories In Ribosome Translocation, Jose L. Alejo, Dylan Girodat, Michael J. Hammerling, Jessica A. Willi, Michael C. Jewett, Aaron E. Engelhardt, Katarzyna P. Adamala

Chemistry & Biochemistry Faculty Publications and Presentations

Abstract

Translocation in protein synthesis entails the efficient and accurate movement of the mRNA-[tRNA]₂ substrate through the ribosome after peptide bond formation. An essential conformational change during this process is the swiveling of the small subunit head domain about two rRNA ‘hinge’ elements. Using iterative selection and molecular dynamics simulations, we derive alternate hinge elements capable of translocation in vitro and in vivo and describe their effects on the conformational trajectory of the EF-G-bound, translocating ribosome. In these alternate conformational pathways, we observe a diversity of swivel kinetics, hinge motions, three-dimensional head domain trajectories and tRNA dynamics. By finding …

Synthesis Of Addressable Libraries: New Lessons And The Need For Proper Characterization For Microelectrode Array-Based Reactions, Albert Huang

Arts & Sciences Graduate Student Theses and Dissertations

The Moeller group has been developing synthetic tools for building molecular libraries on microelectrode arrays since 2004. Such a library is intriguing because one can take advantage of the library for biological signaling studies. Microelectrode arrays can serve as a powerful platform for those experiments since every electrode in the array can be addressed individually. Unique members of the library targeting biological receptors that one is interested in can be restricted only above unique electrodes in an array. Thus, high-affinity ligands for those receptors can be identified with this strategy. To make this method work, one has to make sure …

Northern Fur Ssal Vibrissae Organochlorine Contaminant Concentrations, Dimitri Giarikos, Amy Hirons, Courtney White

SECLER Data

The eastern Pacific stock of northern fur seals (Callorhinus ursinus) on the Pribilof Islands has experienced population declines since 1980. The decline may be due to anthropogenic persistent organic pollutants (POPs) which bioaccumulate, are toxic, and persistent. This study conducted a comparison of 21 organochlorine (OC) and 39 polybrominated diphenyl ether (PBDE) analyte concentrations utilizing archived vibrissae (whiskers) from individual fur seals sampled in 1993 (n=30) and 2013 (n=41). The PBDEs had values five times greater than the legacy status OCs. There were no significant mean concentration differences between 1993 and 2013 for total organochlorines (ΣOCs), or total …

Northern Fur Seal Vibrissae Polybrominateddiphenylether Concentrations, Dimitri Giarikos, Amy Hirons, Courtney White

SECLER Data

The eastern Pacific stock of northern fur seals (Callorhinus ursinus) on the Pribilof Islands has experienced population declines since 1980. The decline may be due to anthropogenic persistent organic pollutants (POPs) which bioaccumulate, are toxic, and persistent. This study conducted a comparison of 21 organochlorine (OC) and 39 polybrominated diphenyl ether (PBDE) analyte concentrations utilizing archived vibrissae (whiskers) from individual fur seals sampled in 1993 (n=30) and 2013 (n=41). The PBDEs had values five times greater than the legacy status OCs. There were no significant mean concentration differences between 1993 and 2013 for total organochlorines (ΣOCs), or total …

Making And Breaking Bonds: Studying Intrinsic Chemistry In The Gas-Phase, Luke Metzler

Electronic Theses and Dissertations

The nature of chemical interactions can be difficult to ascertain in the condensed phase; chemistry can be observed, but with the plethora of variables such as solvation, mixes of counter-ions, and complex equilibria, the true intrinsic chemical properties of a given chemical species may be obfuscated. By conducting research in the gas-phase, many of these variables can be reduced, if not eliminated entirely, which can allow for the careful observation of the true physical phenomena driving chemical reactivity.

The research presented herein focuses on the use of ion-trapping (specifically in a linear ion trap) as a method for unveiling the …

Assimilating Satellite-Derived Snow Cover And Albedo Data To Improve 3-D Weather And Photochemical Models, Colleen Jones, Huy Tran, Trang Tran, Seth Lyman

Chemistry and Biochemistry Faculty Publications

During wintertime temperature inversion episodes, ozone in the Uinta Basin sometimes exceeds the standard of 70 ppb set by the US Environmental Protection Agency. Since ozone formation depends on sunlight, and less sunlight is available during winter, wintertime ozone can only form if snow cover and albedo are high. Researchers have encountered difficulties replicating high albedo values in 3-D weather and photochemical transport model simulations for winter episodes. In this study, a process to assimilate MODIS satellite data into WRF and CAMx models was developed, streamlined, and tested to demonstrate the impacts of data assimilation on the models’ performance. Improvements …

Rna Secondary Structures: Structure-Function Studies In Viral And Neurodegenerative Diseases, Caylee Cunningham

Electronic Theses and Dissertations

The studies within this dissertation highlight the importance of RNA structure and function, highlighting potential mechanisms in the pathogenesis of the SARS-CoV-2 virus and hallmarks of ALS. Specifically, the s2m, a 41-nt structure found within the hyper variable region of the 3’ UTR of the SARS-CoV-2 virus, was investigated as this element has no definitive role in viruses but its high conservation in several viral families warrants investigation. We used various biophysical techniques to determine if a palindromic sequence in the terminal loop could participate in dimerization activities, which may have implications in recombination and the longevity of the virus. …

Flora And Fauna Lexical Indicators Of Prehistoric Movement Of Yuman Peoples, Adam Ingwerson

Master's Theses

Amyloid fibrils are locally ordered protein aggregates characterized by a filamentous morphology held together by a hydrogen bonding motif known as cross-β structure whereby hydrogen bonds form between backbone amide bond moieties across separate protein segments. The most notable medical significance of amyloid fibrils is their central role in the etiology of Alzheimer’s disease, type 2 diabetes, and other human diseases. Although amyloid fibrils have been studied extensively, the mechanism of their formation is still not fully understood. X-ray crystallography is a leading experimental technique for resolving amyloid fibril structures from crystallized proteins; however, inherent limitations leave open the possibility …

Agnotology Of The E-Cigarette Industry: How The E-Cigarette Industry Continues The Tobacco Industry's Legacy Of Creating Controversy And Confusion Within The Scientific Community And The General Population, Calvin Lewis

University Honors Theses

The purpose of this paper is to determine the extent to which the e-cigarette industry follows in the footsteps of the tobacco industry's attempts to disrupt science and cause controversy. Four tactics are described that the tobacco industry uses to disrupt science: funding research that is designed to show results that support their position, criticizing and suppressing research that goes against their position, changing risk assessment and scientific research standards to fit their aims, and spreading data created by their interest groups to politicians and the nonacademic press. Evidence is found to show that both the tobacco industry and e-cigarette …

Syntheses, Characterizations And Reactions Of Acene-2,3-Dicarbaldehydes, Glen Miller, Qian Liu

Faculty Publications

Here, we report improved syntheses, detailed characterizations and reactions of a series of acene-2,3- dicarbaldehydes including tetracene-2,3-dicarbaldehyde. DFT calculations corroborate and complement the experimental results. Tetracene-2,3-dicarbaldehyde and the benchmark organic semiconductor pentacene have isoelectronic p-systems and similar HOMO–LUMO gaps. Tetracene-2,3-dicarbaldehyde is soluble in a host of organic solvents (e.g., DMF, toluene, THF, chloroform, dichloromethane) and shows excellent photooxidative resistance in solution phases exposed to light and air. Further, it is readily sublimed from the solid-state without decomposition, and can be functionalized using different chemistries. We have demonstrated the utility of acene-2,3-dicarbaldehydes as reactants in the syntheses of novel diaryl-2,3-acenedimethanols and …

63rd Annual Rocky Mountain Conference On Magnetic Resonance

Rocky Mountain Conference on Magnetic Resonance

Final program, abstracts, and information about the 63rd annual meeting of the Rocky Mountain Conference on Magnetic Resonance, co-endorsed by the Colorado Section of the American Chemical Society and the Society for Applied Spectroscopy. Held in the Copper Conference Center, Copper Mountain, Colorado, August 4-8, 2024.

Green Synthesis Of Carbonized Chitosan-Fe3o4-Sio2 Nano-Composite For Adsorption Of Heavy Metals From Aqueous Solutions, Dalia A. Ali Eng, Rinad Galal Ali Eng.

Chemical Engineering

Water pollution with heavy metals owing to industrial and agricultural activities have become a critical dilemma to humans, plants as well as the marine environment. Therefore, it is of great importance that the carcinogenic heavy metals present in wastewater to be eliminated through designing treatment technologies that can remove multiple pollutants. A novel green magnetic nano-composite called (Carbonized Chitosan-Fe3O4-SiO2) was synthesized using Co-precipitation method to adsorb a mixture of heavy metal ions included; cobalt (Co2+), nickel (Ni2+) and copper (Cu2+) ions from aqueous solutions. The novelty of this study was the synthesis of a new

nano-composite which was green with …

Feasibility Study Of Using Energy Extracted From The Process Of Electrochemically Consumed Of Al 2024 For Powering Daily Used Electric Car, Yanuar Mohamad Marda, Rini Riastuti, Muhammad Hamka Ibrahim

Journal of Materials Exploration and Findings

Usage of green energy for transportation has become important due to the contribution of transportation activity to climate change. Electrochemical energy has been used as a source of green energy. The objective of this work is to evaluate sufficiency of energy provided by electrochemically consumed Al 2024 for supplying energy to daily used PHEV electric car. Study of previous articles, observation of typical amount of energy required, electrochemical galvanic cell experiments, and simple calculations have been conducted to determine produced energy feasibility. Electrical energy produced by consuming 340 gr of Al 2024 in galvanic cells has the total lifetime of …

De Novo Synthetic Studies On Tetracyclic Triterpenoid Systems: Stereoselective Preparation, Biological Evaluation And Total Syntheses Of Euphol And Tirucallol, Joshua Nicholson

Dartmouth College Ph.D Dissertations

Tetracyclic triterpenoids have a rich history in biology, medicine, and chemistry. In terms of pharmaceutical relevance, compounds with this scaffold are one of the most successful classes with over 100 FDA approved examples. Despite this success, the vast majority of compounds within this class are prepared through semisynthesis. While this approach is undeniably successful, judged by the sheer number of medications generated, it also has limitations. Namely, semisynthesis requires the use of complex starting materials that have fixed absolute stereochemistry and often sparse functionality. One approach to address the inherent limitations with semisynthesis is through de novo synthesis. Recently, our …

Knowledge Management Of Historical Data: Ontology Development For Chemical Reactions, Quynh D. Tran, Alexander Harding Bradley, Balashanmuga Priyan Rajamohan, Jonathan E. Gordon, Van D. Tran, Kiefer Lin, Erika I. Barcelos, Laura S. Bruckman, Roger H. French

Researchers, Instructors, & Staff Scholarship

Knowledge management of the literature and historical data is critical to accelerated drug and materials discovery. Currently, literature knowledge is scattered in journal articles in various formats: diagrams, texts, plots, etc. Historical data from past experiments are saved in a number of local computers under confusing folder structures with ambiguous file names. To manage and organize historical data and knowledge, our group (SDLE) at CWRU follows FAIR (Findable, Accessible, Interoperable, Reusable) principles, which outline the best practices for data stewardship and data provenance, and ontology, a formal representation of terms and concepts and their relationships, as a tool to improve …

I. Degradable Polymers And Networks Based On Furan-Maleimide Diels-Alder Reactions Of Silyl Ether Derivatives And Maleimides, And Ii. The Michael Addition Of Amines To 1,3,5-Triacryloylhexahydro-1,3,5-Triazine (Tat) As A Synthetic Route To Novel Chelating Agents, Reyad Alkhazalah

Chemistry Theses and Dissertations

Degradable Polymers and Networks Based on Furan-Maleimide Diels-Alder Reactions of Silyl Ether Derivatives and Maleimides. I.

I. Part 1. Two groups of silyl ether monomers, A and B, were synthesized, each containing four different monomers. The monomers of group A were obtained by reacting furfuryl alcohol with four dichlorosilanes with varying siloxane spacers. The monomers of group B were obtained by reacting n-(2-hydroxyethyl)maleimide (HEMI-1c) with the same four dichlorosilanes. Each monomer from group A was individually reacted with each monomer from group B via a Diels-Alder reaction to produce a series of sixteen degradable linear polymers with a variety …

Investigation Of The Prevalence Of Fentanyl Analogs In A Drug Testing Population Using Liquid Chromatography Tandem Mass Spectrometry (Lc-Ms-Ms), Ivan Cordova

Student Theses

This study serves to determine the prevalence of novel fentanyl analogs that are present within a drug testing population in New York State. Samples were analyzed using liquid chromatography tandem mass spectrometry (LC-MS/MS) to qualitatively determine the presence of various possible fentanyl analogs. The sample preparation of this assay consisted of a simple dilute and shoot. This method of sample preparation can be quicker, eliminating sample preparation times as well as being less financially strenuous to clinical laboratories as it eliminates the need for various solvents and solid/liquid phase cartridges. The assay was aimed to see if analytes can be …

Fourier Transform Ion Cyclotron Resonance Mass Spectrometry Applications For Metabolomics, Darcy Cochran, Robert Powers

Robert Powers Publications

Metabolomics is an interdisciplinary field that aims to study all metabolites < 1500 Da that are ubiquitously found within all organisms. Metabolomics is experiencing exponential growth and commonly relies on high-resolution mass spectrometry (HRMS). Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) is a form of HRMS that is particularly well suited for metabolomics research due to its exceptionally high resolution (10⁵–10⁶) and sensitivity with a mass accuracy in parts per billion (ppb). In this regard, FT-ICR-MS can provide valuable insights into the metabolomics analysis of complex biological systems due to unique capabilities such as the easy separation of isobaric and isomeric species, isotopic fine structure analysis, spatial resolution of metabolites in cells and tissues, and a high confidence (error) in metabolite identification. Alternatively, the large and complex data sets, long acquisition times, high cost, and limited access mainly through national mass spectrometry facilities may impede the …

Optimizing The Protein Yield Of The Collagen Mimetic Peptide: Col108, Fahmida Akter

Theses and Dissertations

Abstract

The fibril-forming collagen mimetic peptide Col108, produced in E. Coli, has shown potential for innovative biomaterial applications. However, further research is constrained by its limited yield. My study aims to enhance the experimental parameters and has successfully pinpointed rifampicin as an efficient method to boost the production of Col108.

Radiation-Tolerant Thin-Film Reference Electrodes And Potentiometric Sensors, Bingyuan Zhao, Alexander Wei

Department of Chemistry Faculty Publications

The integration of electronic sensors into single-use systems for bioprocessing is challenged by their sensitivity to sterilizing γ-irradiation. This challenge also applies to reference electrodes (REs), whose potentials may be destabilized upon ionization and drift over time. Here we evaluate the performance of thin-film Ag/AgCl REs over a two-month window following γ-ray sterilization using a 60Co source. γ-REs display a characteristic voltage decay function ascribed to the dissipation of radiation-induced charge defects, and exhibit long-term potentiometric stability when stored in phosphate-buffered saline (PBS) with a 95% confidence interval of 4 mV over 60 days. γ-REs have a mean insensitivity (inertness) …

Settingsorder Article Reprints Open Accessarticle A Model To Account For The Effects Of Load Ratio And Hydrogen Pressure On The Fatigue Crack Growth Behavior Of Pressure Vessel Steels, Ashok Saxena, Kip O. Findley

Mechanical Engineering Faculty Publications and Presentations

A phenomenological model for estimating the effects of load ratio R and hydrogen pressure P_H2 on the hydrogen-assisted fatigue crack growth rate (HA-FCGR) behavior in the transient and steady-state regimes of pressure vessel steels is described. The "transient regime" is identified with crack growth within a severely embrittled zone of intense plasticity at the crack tip. The "steady-state" behavior is associated with the crack growing into a region of comparatively lower hydrogen concentration located further away from the crack tip. The model treats the effects of R and P_H2 as being functionally separable. In the transient …

Stimuli-Responsive Phosphate Hydrogel: A Study On Swelling Behavior, Mechanical Properties, And Application In Expansion Microscopy, Yokly Leng, Collin N. Britten, Fatema Tarannum, Kayla Foley, Christopher Billings, Yingtao Liu, Keisha B. Walters

Chemical Engineering Faculty Publications and Presentations

Phosphorus-based stimuli-responsive hydrogels have potential in a wide range of applications due to their ionizable phosphorus groups, biocompatibility, and tunable swelling capacity utilizing hydrogel design parameters and external stimuli. In this study, poly(2-methacryloyloxyethyl phosphate) (PMOEP) hydrogels were synthesized via aqueous activators regenerated by electron transfer atomic transfer radical polymerization using ascorbic acid as the reducing agent. Swelling and deswelling behaviors of PMOEP hydrogels were examined in different salt solutions, pH conditions, and temperatures. The degree of swelling in salt solutions followed CaCl₂ < MgCl₂ < KCl < NaCl with a decrease in swelling rate at higher concentrations until reaching a saturation point. In water, the degree of swelling increased significantly around neutral pH and remained constant at basic pH values. The effects of polymerization conditions, including pH, temperature (30, 40, 50 °C), and MOEP concentration (40, 50, 60% v/v MOEP/H₂O), on the hydrogel swelling behavior in various salt solutions were also investigated. PMOEP hydrogels …

Elevating Commodity Polymers To Advanced Applications In Polymer Photonics And Polymer-Derived Porous Materials, Mark Robertson

Dissertations

Since the inception of synthetic polymers, polymer-derived materials have permeated into essentially all aspects of our daily lives. The most commonly thought of examples of polymer materials involve single-use, disposable products to increase shelf lives of perishable items, act as personal protective equipment, or provide some degree of convenience for the consumer. However, as we have furthered our understanding of polymer chemistry and polymer physics to develop increasingly sophisticated polymer systems, polymer materials have been employed in incredibly advanced applications. These include solid electrolytes for energy storage, matrices for aerospace grade carbon fiber-reinforced composites, membranes for liquid and gas separations, …