Chemistry Commons^™

The Formation Of Monosubstituted Cyclopropenylidene Derivatives In The Interstellar Medium Via Neutral-Neutral Reaction Pathways, Athena R. Flint, Ryan C. Fortenberry

Faculty and Student Publications

Five substituted cyclopropenylidene derivatives (c-C3HX, X = CN, OH, F, NH2), all currently undetected in the interstellar medium (ISM), are found herein to have mechanistically viable, gas-phase formation pathways through neutral-neutral additions of ·X onto c-C3H2. The detection and predicted formation mechanism of c-C3HC2H introduces a need for the chemistry of c-C3H2 and any possible derivatives to be more fully explored. Chemically accurate CCSD(T)-F12/cc-pVTZ-F12 calculations provide exothermicities of additions of various radical species to c-C3H2, alongside energies of submerged intermediates that are crossed to result in product formation. Of the novel reaction mechanisms proposed, the addition of the cyano radical …

Large Variability And Complexity Of Isothermal Solubility For A Series Of Redox-Active Phenothiazines†, Anton S. Perera, Thilini Malsha Suduwella, Nuwan Harsha Attanayake, Rahul Kant Jha, William L. Eubanks, Ilya A. Shkrob, Chad Risko, Aman Preet Kaur, Susan A. Odom

Chemistry Faculty Publications

The development of redox-active organic molecules (ROM) with large solubilities in all states of charge in organic electrolytes is imperative to the continued development of non-aqueous redox flow batteries. The capability to a priori predict ROM solubility would be a game changer, allowing for a move away from time and resource consuming trial-and-error approaches to materials design and deployment. However, it is not presently clear that such predictions are generally possible, even for chemically related ROM, given the large number of physicochemical factors in play. Here we use quantitative structure–property relationships (QSPR) to examine solubility trends for a set of …

Symmetry Breaking Charge Transfer In Dna-Templated Perylene Dimer Aggregates, Katelyn M. Duncan, Donald L. Kellis, Jonathan S. Huff, Matthew S. Barclay, Jeunghoon Lee, Daniel B. Turner, Paul H. Davis, Bernard Yurke, William B. Knowlton, Ryan D. Pensack

Chemistry and Biochemistry Faculty Publications and Presentations

Molecular aggregates are of interest to a broad range of fields including light harvesting, organic optoelectronics, and nanoscale computing. In molecular aggregates, nonradiative decay pathways may emerge that were not present in the constituent molecules. Such nonradiative decay pathways may include singlet fission, excimer relaxation, and symmetry-breaking charge transfer. Singlet fission, sometimes referred to as excitation multiplication, is of great interest to the fields of energy conversion and quantum information. For example, endothermic singlet fission, which avoids energy loss, has been observed in covalently bound, linear perylene trimers and tetramers. In this work, the electronic structure and excited-state dynamics of …

The Coastal Monitor: Vol. 9 No. 5, John Tanacredi Ph.D.

The Coastal Monitor

There are a multitude of lessons learned from the last 3 years of the Covid-19 pandemic. But one truly stands out ...the total lack of understanding of the basic chemistry associated with the nitrogen cycle, which in Suffolk County, NY, continues to be declared as the “evil-nitrogen”. The major source of nitrogen into the water body comes from the atmosphere which is the predominate constituent of the air we breathe79% nitrogen. Nitrogen compounds contribution to eutrophication in freshwater (ponds & lakes) systems is legendary and, the concentration of nitrogen in marine waters has always been known as a limiting agent …

Determination Of Nitrate In Aqueous Media, Ebony Arauz Tellez, John Bohannon, Rebecca Mills, Virginia Tam, Isabelle Villarreal, Melissa C. Rhoten

Fall Showcase for Research and Creative Inquiry

Determining the amount of inorganic ions in aqueous media is important in the food industry and environmentally. In the environment high levels of ions like nitrate (NO₃^-), nitrite (NO2^-), and phosphate (PO₄^3-) can lead to unhealthy conditions for aquatic species. Similarly, high levels of nitrate and nitrite can cause health issues in humans. One method for determining nitrate levels in aqueous samples involves reducing the nitrate species to nitrite via a redox reaction with finely divided zinc powder followed by conversion to a diazonium salt and complexation with 1-napthylamine to form a …

Cultivating Teacher Expertise In The Landscape Of Green Chemistry: The Development Of Pedagogical Content Knowledge In Beyond Benign’S Lead Teacher Program, Philip Charles Nahlik

Dissertations

Chemistry Education, Green Chemistry, Pedagogical Content Knowledge, Professional Learning Communities, Sustainability, Teacher Training

Investigation Of Carbon Dioxide Oxidation Reaction Pathways On Rh(111) Via Reflection Absorption Infrared Spectroscopy (Rairs), Elizabeth A. Jamka

Dissertations

CO oxidation, RAIRS, Rh(111), Surface Science, UHV

Using Ftir-Atr And Chemometric Methods To Detect Sucrose Adulteration In Commercial Honey Samples, Dylan T. Roberts, Kevin Kittredge

Virginia Journal of Science

Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR–ATR) was used to analyze pure and adulterated honey samples. The FTIR spectra was analyzed using principal component analysis (PCA) and partial least squares (PLS) regression analysis to determine if these methods could differentiate between pure, commercial, and sucrose-adulterated honey samples. PCA showed a clear distinction between pure and adulterated honey samples. Commercial honey samples showed clustering around the unadulterated samples. PLS regression analysis correctly identified 81.8% of the standards and samples used in the PCA analysis. The five commercial samples were tested and shown to have a concentration of less than 3% adulterant, …

Polarclean & Dimethyl Isosorbide: Green Matches In Formulating Cathode Slurry, Amrita Sarkar, Richard May, Zoren Valmonte, Lauren E. Marbella

Department of Chemistry and Biochemistry Faculty Scholarship and Creative Works

In this study, two green organic solvents are reported in LiNi1/3Co1/3-Mn1/3O2 (NMC111)-based slurry preparation and subsequent cathode fabrication for Li ion batteries. NMC111, conductive carbon and poly(vinylidene fluoride) binder composite slurries prepared with methyl-5-(dimethylamino)-2-methyl-5-oxopentanoate (Polar-Clean) and dimethyl isosorbide (DMI) exhibit mechanically stable, crack-free uniform coating structures. Both slurries showed similar shear-thinning viscosity behavior that suggests similar processibility during electrode casting and coating. When used as the cathode in Li/NMC111 half cells, the electrode slurries prepared with Polar-Clean show promising electrochemical performance metrics with an average specific charge capacity of 155 ±-1mA h g-1 at C/10 over 100 cycles, comparable to …

Is It Useful? Orthophosphate Mapping Of An Excavated Cellar Of A Mid 1700’S Tavern In New London Va, Thomas M. Bender, Randy Lichtenberger

Faculty Publications and Presentations

The partially backfilled cellar of Mead’s Tavern (VDHR # 015-0120) a circa 1760’s building in New London Virginia, was studied by orthophosphate (PO₄³) mapping of the recently exposed, culturally sterile, subsoil floor. Prior studies of the cellar had exposed a hearth along with features that were speculated to be wall partitions for subdivision of the cellar. The full intended purpose for those exposed features is unknown. To further probe that exposed subsoil prior to a major engineering stabilization of the tavern’s foundation, a chemical mapping of surface PO₄^3- levels in the cellar was done. The …

Converting Hydrazone-Based Photoswitches Into Functional Materials, Sirun Yang

Dartmouth College Ph.D Dissertations

The development of new classes of molecular switches with enhanced performance and brand-new functionalities enables practitioners to push the frontiers of adaptive materials. In the realm of photoswitches, the bistability of hydrazones (i.e., molecules that incorporate the C=N-NH functional group) allows for the kinetic trapping of polymer and supramolecular assemblies resulting in multistate actuation and emergent phenomena that are not tractable with other photoswitches. This property has transformed hydrazone photoswitches into powerful tools that can be used in understanding fundamental molecular interactions and how to apply them in modulating the physicochemical properties of materials.

Progressing from disordered to …

Aircraft Engine Particulate Matter Emissions From Sustainable Aviation Fuels: Results From Ground-Based Measurements During The Nasa/Dlr Campaign Eclif2/Nd-Max, Tobias Schripp, Bruce E. Anderson, Uwe Bauder, Bastian Rauch, Joel C. Corbin, Greg J. Smallwood, Prem Lobo, Ewan C. Crosbie, Michael A. Shook, Richard C. Miake-Lye, Zhenhong Yu, Andrew Freedman, Philip D. Whitefield, Claire E. Robinson

Chemistry Faculty Research & Creative Works

The use of alternative jet fuels by commercial aviation has increased substantially in recent years. Beside the reduction of carbon dioxide emission, the use of sustainable aviation fuels (SAF) may have a positive impact on the reduction of particulate emissions. This study summarizes the results from a ground-based measurement activity conducted in January 2018 as part of the ECLIF2/ND-MAX campaign in Ramstein, Germany. Two fossil reference kerosenes and three different blends with the renewable fuel component HEFA-SPK (Hydroprocessed Esters and Fatty Acids Synthetic Paraffinic Kerosene) were burned in an A320 with V2527-A5 engines to investigate the effect of fuel naphthalene/aromatic …

Identification Of Nitrates Within Coldwater Cave, Blake Schany, Joshua Sebree

Fall 2022 - Chemical Analysis Class Projects

Agricultural runoff has the potential to greatly damage the ecosystem of Coldwater Cave. Agricultural runoff includes elements found in herbicides and fertilizers used on crops as well as increased amounts of nitrogen in the water due to runoff from cattle sites. Identification of the presence of water soluble pollutants from cattle feedlot runoff and toxic components found in common herbicides used in maintaining cropland within the cave is needed to address the potential damage that the contaminants can do to the ecosystem of the cave. Identifying contaminants present within the cave systems using UV Vis will allow for more targeted …

An Investigation Of Fluorescent Synthetic Rocks At The Shrine Of The Grotto Of The Redemption, Austin Heidbreder, Joshua Sebree

Fall 2022 - Chemical Analysis Class Projects

The Grotto of the Shrine of Redemption is a religious site in West Bend, Iowa. The large structure is made of a variety of minerals and rocks, some synthetic, that can be studied. Many of these synthetic rocks are a product of smelting crayons together. It was found that several of these synthetic rocks were fluorescent. Those found in the Grotto of the Shrine of Redemption were studied with fluorescence spectroscopy and cross-referenced with knowledge of pastel dyes in use in the 1930s. It was found that some of the fluorescing rocks were likely made using crayons containing various red …

Determination Of The Elemental Composition Of ‘Druzy’ In Crystalline Quartz Using Uv & X Ray Fluorescence, Margaret Ierien

Fall 2022 - Chemical Analysis Class Projects

The purpose of this experiment was to identify and detected the elemental composition of ‘druzy’ in quartz and to differentiate its compositions from other crystalline minerals, including other forms of quartz, calcite, and fluorite. The methods of UV fluorescence and X ray fluorescence were used. The composition of druzy quartz was analyzed and found to exhibit multiple elements absent in clear quartz and other crystalline minerals.

Water Quality Mapping Throughout Coldwater Cave, Jade Nuehring, Joshua Sebree, Raquel Wilhelm, Blake Schany

Fall 2022 - Chemical Analysis Class Projects

Coldwater Cave, located in Decorah, Iowa is surveyed to contain 17.2 miles of passageways. This study is a mapping of how dissolved oxygen levels and water conductivity compare throughout water samples taken at 9 different locations within the cave. In this study we want to know how what is on the surface is impacting the cave water quality as Coldwater Cave sits between two above ground rivers and is covered with land used for agricultural purposes. Water quality studies done on other major rivers have shown that typical conductivity levels are within the 200-1000 micro-Siemen/cm range, and it is important …

Raman Analysis Of Fluorescent Minerals And Rocks At The Shrine Of The Grotto Of The Redemption, Samrin Shahnaz, Joshua Sebree

Fall 2022 - Chemical Analysis Class Projects

The Shrine of the Grotto of the Redemption is a religious tourist attraction in West Bend, IA, which also happens to be the world’s largest grotto. A Catholic priest, Fr. Dobberstein , constructed the grotto using precious stones from all over the US about a hundred years ago, and the caretakers have questions about the chemical compositions of the rocks and minerals, both natural and synthetic. Raman Spectroscopy is a non destructive method for qualitative and quantitative analysis of chemical compounds. In this project, Raman analysis was performed on various fluorescent rocks found at the grotto. This included both natural …

Extraction And Analysis Of Rare Earth Elements From Coal Fly Ash Using Atomic Emission, Owen Lerg, Colleen Lehrer, Joshua Sebree

Fall 2022 - Chemical Analysis Class Projects

• Coal fly ash is a waste product from burning coal
• Recent research has been focusing on if coal fly ash could be a source of rare earth elements (REE)
• REE are a critical raw material needed for many technologies
• Growing importance for finding alternative sources of REE as demand increases every year
• Most of REE export from China
• Goal of this research is to determine what REE are present in the coal fly ash
• Atomic Emission (AE) is the technique that will be used to determine if REE are present
• AE was chosen due to its low limits of detection …

Composition Of Particle-Size Separated Iowa Fly Ash, Colleen P. Lehrer, Joshua Sebree, Owen Lerg

Fall 2022 - Chemical Analysis Class Projects

• Fly ash is a complex mixture of metallic oxides, unburnt carbon compounds, and other particulate which are a byproduct of the industrial burning of coal or biofuels for power production.
• Environmental contaminants including arsenic, lead, cadmium, chromium, and mercury are known to be found in fly ash, prompting EPA regulation and government action in the event of spills.
• Ash composition and morphology are closely related to the composition and processing of its parent fuel. [1,2] Subsequently, the extent to which environmental contaminants are concentrated in fly ash is know to vary.
• Sieving processes are used in many industries as an …

Chemical Interactions And Cytotoxicity Of Terpene And Diluent Vaping Ingredients, Yanira Baldovinos, Alexandra Archer, James C. Salamanca, Robert M. Strongin, Christie Sayes

Chemistry Faculty Publications and Presentations

Vaping devices have risen in popularity since their inception in 2007. The practice involves using a variety of commercially available devices. Internal heating systems in devices aerosolize e-liquid formulations of complex mixtures including an active ingredient (e.g., THC, CBD, and nicotine), diluents (or cutting agents), solvents, and flavoring agents (e.g., terpenes and aldehydes). The vaping toxicology literature consists of cytotoxicity studies of individual chemicals and commercial formulas. Because of the variation of e-liquid composition, there is a limited understanding of the toxicity of ingredient combinations. This study analyzed the cytotoxic effects after exposure to individual and binary mixtures of a …

Taking Action: Two Years After The Asp Diversity, Equity And Inclusion Committee’S Call To Action, Lesley Ann Giddings, Christine Salomon, Asp Dei Committee

Chemistry: Faculty Publications

TASP Newsletterhe three main goals of the ASP Diversity, Equity and Inclusion Committee are to (1) build a pipeline that overcomes structural barriers of entry for underrepresented groups of scientists who wish to engage in natural products research, (2) work with members of the ASP to create a more equitable, inclusive, and supportive community, and (3) recognize and highlight the contributions that members from underrepresented communities make to the ASP. In the summer of 2020, we published an article for the ASP Newsletter that described a series of actions to support these three goals. Here we provide an update on …

Application Of Nanodisc Technology To A Membrane-Bound P450: Functional Studies And Resonance Raman Studies On Cyp51a1, Yuanqi Jing

Dissertations (1934 -)

Membrane-bound cytochrome P450s are highly insoluble and tend to form aggregations in aqueous solution due to its hydrophobic N-terminal transmembrane anchor. The traditional methodology of studying membrane-bound proteins depends on the use of detergent; however, detergent solubilization of membrane P450s does not satisfy many criteria of biochemical and biophysical studies on membrane proteins. A well-developed Nanodisc technology has been proven to be an extraordinarily efficient method of studying membrane-bound P450s. The human sterol 14-demethylases (CYP51A1) are membrane-bound P450 enzymes that catalyze oxidative removal of the C32 methyl group of lanosterol by first forming an alcohol, then an aldehyde, and finally …

Evaluating The Impact Of Submarine Groundwater Discharge On Nutrients And Trace Elements In Coastal Systems: The Examples Of The Tuckean Swamp (Australia) And The Mississippi Sound (Usa), Amy Moody

Dissertations

Submarine groundwater discharge (SGD) is the advective flow of both fresh terrestrial groundwater and recirculating seawater through aquifer sediments, which is released into the coastal ocean. In this dissertation, I evaluated the impact of SGD on the distributions and input of trace metals and nutrients. In the Tuckean Swamp, an estuary in Australia dominated by coastal acid sulfate soils, I determined the impact of groundwater on Ba and U during the flood season, when the local aquifer is flushed out after a rapid increase in water table elevation. For Ba and U, groundwater contributed up to 18 and 66 % …

Self-Assembling Porous Supramolecular Networks Capable Of Post-Synthetic Modification With A New Approach To Reticular Design With Semiconductor Potential, Steven A. Sloope

Theses and Dissertations

In past decades, research in self-assembling supramolecular frameworks have been produced with vast surface area, inherent from their porous nature. Predesigning monomers in a reticular manner allows a framework’s structure to be known before self-assembly occurs. This is very helpful since high porosity is sought after for many purposes such as hosting guests within the framework, post-synthetic modifications, sensing and detection, selective catalysis, semiconduction, etc. Methods of design usually focus on forming intrinsic porosity and unfortunately, sometimes the network formed is not as expected and porosity is lost.

In Chapter 1, we discuss novel ways of network formation, their potential …

Computational Investigation Into Heteroleptic Photoredox Catalysts Based On Nickel(Ii) Tris-Pyridinethiolate For Water Splitting Reactions, Avik Bhattacharjee, Dayalis S.V. Brown, Trent E. Ethridge, Kristine M. Halvorsen, Alejandra C. Acevedo Montano, Theresa M. Mccormick

Chemistry Faculty Publications and Presentations

This work demonstrates a strategy to fine-tune the efficiency of a photoredox water splitting Ni(II) tris-pyridinethiolate catalyst through heteroleptic ligand design using computational investigation of the catalytic mechanism. Density functional theory (DFT) calculations, supported by topology analyses using quantum theory of atoms in molecules (QTAIM), show that the introduction of electron donating (ED) −CH3 and electron withdrawing (EW) −CF₃ groups on the thiopyridyl (PyS–) ligands of the same complex can tune the pK_a and E0, simultaneously. Computational modeling of two heteroleptic nickel(II) tris-pyridinethiolate complexes with 2:1 and 1:2 ED and EW −CH₃ and −CF_{3 …}

Reversible Dioxygen Binding To Co(Ii) Complexes With Noninnocent Ligands, Praveen Kumar, Laxmi Devkota, Maximilian C. Casey, Anne A. Fischer, Sergey V. Lindeman, Adam T. Fiedler

Chemistry Faculty Research and Publications

A series of mononuclear Co(II) complexes with noninnocent (redox-active) ligands are prepared that exhibit metal–ligand cooperativity during the reversible binding of O₂. The complexes have the general formula, [Co^II(L^S,N)(Tp^R2)] (R = Me, Ph), where L^S,N is a bidentate o-aminothiophenolate and Tp^R2 is a hydrotris(pyrazol-1-yl)borate scorpionate with R-substituents at the 3- and 5-positions. Exposure to O₂ at room temperature results in one-electron oxidation and deprotonation of L^S,N. The oxidized derivatives possess substantial “singlet diradical” character arising from antiferromagnetic coupling between an iminothiosemiquinonate (ITSQ^•–) …

Redefining The Catalytic Hect Domain Boundaries For The Hect E3 Ubiquitin Ligase Family, Emma I. Kane, Steven A. Beasley, Johanna M. Schafer, Justine E. Bohl, Young Sun Lee, Kayla J. Rich, Elizabeth F. Bosia, Donald E. Spratt

Chemistry

There are 28 unique human members of the homologous to E6AP C-terminus (HECT) E3 ubiquitin ligase family. Each member of the HECT E3 ubiquitin ligases contains a conserved bilobal HECT domain of approximately 350 residues found near their C-termini that is responsible for their respective ubiquitylation activities. Recent studies have begun to elucidate specific roles that each HECT E3 ubiquitin ligase has in various cancers, age-induced neurodegeneration, and neurological disorders. New structural models have been recently released for some of the HECT E3 ubiquitin ligases, but many HECT domain structures have yet to be examined due to chronic insolubility and/or …

Deciphering The Molecular Circuitry That Controls Iron Regulation In Non-Pathogenic Yeast, Debolina Hati

Theses and Dissertations

The trace metal iron is essential for the survival of almost all living organisms. It is a co-factor for many proteins involved in a variety of vital functions such as respiration, nitrogen fixation, and DNA biosynthesis, to name a few. Iron homeostasis in non-pathogenic fungi such as Schizosaccharomyces pombe has been extensively studied over the past few decades to better understand how intracellular iron is regulated under different environmental conditions. Iron regulation in S. pombe is controlled by two Fe-responsive transcriptional repressors known as Php4 and Fep1. Both rely on iron-sulfur (Fe-S) clusters as signals to balance iron acquisition, storage, …

Characterization Of The Interaction Between Grx4-Bol2 And The Iron-Responsive Transcription Factor Aft1 In Candida Glabrata, Evan A. Talib

Theses and Dissertations

Iron is an indispensable protein cofactor that plays a critical role in biological functions such as cellular respiration. However, excess iron causes cellular damage via the generation of reactive oxygen species. To obtain optimal intracellular iron levels, eukaryotic cells have developed mechanisms to tightly regulate iron levels. The molecular mechanism for iron regulation in the pathogenic yeast Candida glabrata has not yet been explored, although this yeast bears iron regulation pathways that are very similar to the model yeast Saccharomyces cerevisiae. Understanding how C. glabrata regulates iron levels is critical for the treatment of infections caused by this opportunistic …

Mechanistic Insights Into An Iron-Responsive Repressor, Fep1, From Schizosaccharomyces Pombe, Allison Nicole Kimsey

Theses and Dissertations

Iron is an essential metal cofactor required for a variety of biochemical pathways in most living organisms. In recent years, the nonpathogenic fungi Schizosaccharomyces pombe has been used to study iron regulation and uncover the molecular mechanisms for controlling intracellular iron levels. Some of these regulation pathways are conserved with those of pathogenic fungi, making these studies applicable for the future development of antifungals that target iron homeostasis. In S. pombe, the GATA-type transcriptional repressor Fep1 is responsible for repressing iron uptake genes during times of iron abundance. Previous reports have proposed that the binding of an iron-sulfur (Fe-S) …