Physical Sciences and Mathematics Commons^™

Contributions Of Tunneling In 8Π-6Π Electrocyclic Cascade Reactions Of Bicyclo[4.2.0]Octa-2,4-Diene Moieties, Ishika Jain, Claire Castro, William L. Karney

Featured Student Work

Six-electron electrocyclic reactions usually require relatively high temperatures; however recent research has shown that such reactions can occur at significantly lower temperatures in biosynthetic and biomimetic pathways. Pathways resulting in bicyclo[4.2.0]octa-2,4-diene moieties arise from thermally allowed 8π-6π electrocyclization cascade reactions of 1,3,5,7-octatetraenes, as in the biosynthesis of endiandric acids, elysiapyrones, and numerous other natural products. We report multidimensional tunneling calculations to explore the possible contribution of heavy-atom tunneling (e.g. by carbon) to biosynthetic pathways and biomimetic syntheses, and thus to provide a more complete picture of biochemical kinetics. M06-2X/cc-pVDZ calculations on the 8π-6π cascade cyclizations of methylated octatetraene model systems …

Microscale Chemical Manipulation And Imaging Using Photoactive Molecules And Light, Uroob Haris

Chemistry Theses and Dissertations

Chemical manipulation with light has been an active and growing area of research with important implications in materials science, biotechnology, and environmental science. From early investigations of light sensitive materials for photography in the 19^th century, to printing billions of transistors on a semiconductor chip in present day, scientists have gained a deep understanding of photochemistry and the processes that allow us to harness light for everyday applications. In this work, we explore microscale fabrication and molecular imaging using light and photoactive molecules as foundational tools. We develop a visible-light mediated technique for high resolution microscale chemical lithography comprising …

Reduced Metal Nanocatalysts For Selective Electrochemical Hydrogenation Of Biomass-Derived 5-(Hydroxymethyl)Furfural To 2, 5-Bis(Hydroxymethyl)Furan In Ambient Conditions, Baleeswaraiah Muchharla, Moumita Dikshit, Ujjwal Pokharel, Ravindranath Garimella, Adetayo Adedeji, Kapil Kumar, Wei Cao, Hani Elsayed-Ali, Kishor Kumar Sadasivuni, Naif Abdullah Al-Dhabi, Sandeep Kumar, Bijandra Kumar

Chemistry & Biochemistry Faculty Publications

Selective electrochemical hydrogenation (ECH) of biomass-derived unsaturated organic molecules has enormous potential for sustainable chemical production. However, an efficient catalyst is essential to perform an ECH reaction consisting of superior product selectivity and a higher conversion rate. Here, we examined the ECH performance of reduced metal nanostructures i.e., reduced Ag (rAg) and reduced copper (rCu) prepared via electrochemical or thermal oxidation and electrochemical reduction process, respectively. Surface morphological analysis suggests formation of nanocoral and entangled nanowire structure formation for rAg and rCu catalysts. rCu exhibits slight enhancement in ECH reaction performance in comparison to the pristine Cu. However, the rAg …

The Chemistry And Catalytic Activity Of Dehydrogenative Silylation And Hydroboration Of Complexes Bearing Semirigid Ligands With Group 14 Elements, Niroshani S. Abeynayake

Theses and Dissertations

Incorporation of silicon in the ligand backbone would yield electron-rich metal complexes upon coordination to transition metal complexes. The coordination chemistry of semirigid benzyl phosphines bearing a single or multiple phosphorus atoms and varying number of Si−H moieties has gained interest in recent years. This dissertation focuses on synthesizing silyl and germyl transition metal complexes of groups 9 and 10. Chapter II presents the synthesis of a family of four coordinated 14-electron rhodium complexes. The newly synthesized complexes were characterized in solution by multinuclear NMR spectroscopy and in the solid-state by single-crystal X-ray diffraction. These d⁶ complexes possess sawhorse …

Prediction And Confirmation Of A Switch-Like Region Within The N-Terminal Domain Of Hsirt1, Angelina T. Huynh, Thi-Tina N. Nguyen, Carina A. Villegas, Saira Montemorso, Benjamin Strauss, Richard A. Pearson, Jason G. Graham, Jonathan Oribello, Rohit Suresh, Brooke Lustig, Ningkun Wang

Faculty Research, Scholarly, and Creative Activity

Many proteins display conformational changes resulting from allosteric regulation. Often only a few residues are crucial in conveying these structural and functional allosteric changes. These regions that undergo a significant change in structure upon receiving an input signal, such as molecular recognition, are defined as switch- like regions. Identifying these key residues within switch-like regions can help elucidate the mechanism of allosteric regulation and provide guidance for synthetic regulation. In this study, we combine a novel computational workflow with biochemical methods to identify a switch-like region in the N-terminal domain of human SIRT1 (hSIRT1), a lysine deacetylase that plays important …

Fast Photochemical Oxidation And Footprinting Of Proteins Via Trifluoromethyl Radical Chemistry, Elaine Morrow

Honors Theses

Fast photochemical oxidation of proteins (FPOP) is a useful tool in proteomics because of the ability for modifications to occur on the scale of microseconds which reduces the modifications to tertiary and quaternary structure allowing for more accurate labeling of the protein. Labels for FPOP are generated from various radicals in our experiments which include hydroxyl radicals and trifluoromethyl radicals. Hydroxyl radicals are easily generated by using an excimer laser (KrF laser, 248 nm) or a UV flash lamp (as a part of the Fox™ System) by the photolysis of hydrogen peroxide. Trifluoromethyl radicals, however, need hydroxyl radicals to be …

Synthesis Of Phosphonate-Based Diimide Ligands, Kenya V. Medina, Adelani Pius

Honors Program Theses and Research Projects

There has been a resurged interest in the synthesis of metal-organic frameworks because of their potential applications in energy production and drug delivery. Although diimides are insoluble in aqueous solutions, the addition of phosphonic acid allows the complex to be water soluble, which greatly increases their application. Therefore, the creation of a hybrid metal-organic complex by the addition of phosphonic groups to diimide ligands can result in a polar porous compound. In this project the ligand design included the use of dianhydrides including pyromellitic dianhydride, naphthalenetetracarboxylic dianhydride, perylenetetracarboxylic dianhydride, and biphenyl-tetracarboxylic acid dianhydride. These dianhydride precursors were refluxed under argon …

Statistical Potentials For Rna-Protein Interactions Optimized By Cma-Es, Takayuki Kimura, Nobuaki Yasuo, Masakazu Sekijima, Brooke Lustig

Faculty Research, Scholarly, and Creative Activity

Characterizing RNA-protein interactions remains an important endeavor, complicated by the difficulty in obtaining the relevant structures. Evaluating model structures via statistical potentials is in principle straight-forward and effective. However, given the relatively small size of the existing learning set of RNA-protein complexes optimization of such potentials continues to be problematic. Notably, interaction-based statistical potentials have problems in addressing large RNA-protein complexes. In this study, we adopted a novel strategy with covariance matrix adaptation (CMA-ES) to calculate statistical potentials, successfully identifying native docking poses.

Identification Of Chemical Structures And Substructures Via Deep Q-Learning And Supervised Learning Of Ftir Spectra, Joshua D. Ellis

MSU Graduate Theses

Fourier-transform infrared (FTIR) spectra of organic compounds can be used to compare and identify compounds. A mid-FTIR spectrum gives absorbance values of a compound over the 400-4000 cm^-1 range. Spectral matching is the process of comparing the spectral signature of two or more compounds and returning a value for the similarity of the compounds based on how closely their spectra match. This process is commonly used to identify an unknown compound by searching for its spectrum’s closes match in a database of known spectra. A major limitation of this process is that it can only be used to identify …

Emergent Photophysics In Diketopyrrolopyrrole Superstructures, Andrew Levine

Dissertations, Theses, and Capstone Projects

Organic semiconductors have received substantial attention as active components in optoelectronic devices because of their processability and customizable electronic properties. Tailoring the organic active layer in these devices to exhibit desirable optoelectronic properties requires understanding the complex and often subtle structure-property relationships governing their photophysical response to light. Both structural organization and frontier molecular orbitals (FMO) play pivotal roles in energy relaxation processes, and complex interplay between organization and orbital energies are difficult to anticipate based upon the molecular structure of the components alone, especially in systems comprised of multiple components. In pursuit of design rules, there is a need …

Cu-Promoted C-H Bond Hydroxylation Inspired By Cu-Dependent Metalloenzymes, Rachel Trammell

Chemistry Theses and Dissertations

From 2003 to 2015, Schӧnecker and Baran proposed a dinuclear Cu/O₂ species in their mechanistic proposal for the hydroxylation of sp³ C-H bonds within their systems (proposed based on yields). Inspired from the site selectivity of this methodology and poor analysis of the mechanism, the first project was inspired to re-examine the sp³ C-H bond hydroxylation by Schrӧnecker and Baran and perform an intensive investigation into understanding how Cu/O₂ interact which led us to propose a new mechanism based on the evidence collected (i.e., LCu^II-hydroperoxide species that undergoes homolytic O-O bond cleavage). From there …

Applications Of Sodium Azide In The Synthesis Of Tetrazines And Hydrolysis Reactions, My Le

Honors Theses

The inverse electron demand Diels−Alder cycloadditions of heterocyclic azadienes have provided a robust methodology for synthesizing highly substituted and functionalized heterocycles. It is widely used in organic synthesis and the pharmaceutical industry in the divergent construction of screening libraries and bioorthogonal conjugation. Each heterocyclic azadiene was found to possess a unique reactivity toward different classes of dienophiles, display predictable modes of cycloaddition, and exhibit substantial substituent electronic effects impacting their intrinsic reactivity and cycloaddition regioselectivity. Synthesis of 1,2,4,5-tetrazine has been reported in the literature since the late 19th century, showing scientists' tremendous interest in its application.

Herein we attempt to …

Synthesis Of A Dd-Π-Aa Organic Dye For Dye-Sensitized Solar Cells, Hope Lovell

Honors Theses

This project investigates the synthesis of a DD-π-AA (dual donor/dual acceptor) organic dye as a potential sensitizer for dye-sensitized solar cells (DSCs). The design of this dye was based off previous research that found dual donor/dual acceptor dyes exhibited promising results when used in a DSC. The donor groups, acceptor groups, and π-bridge were chosen for their stability, ability to absorb in the near-infrared (NIR) region, and intramolecular charge transfer (ICT) abilities.

While many components of the dye were synthesized, the final stages of the synthetic scheme were not completed due to the loss of time from COVID-19. Had the …

The Synthesis Of Photoswitchable Triptan Derivatives, Chelsea Sainsbury

Honors College

Serotonin has various functions throughout the body and directly effects many neurological diseases/disorders, like depression, that are linked to the dysregulation of serotonin. Triptans are indole containing drugs that bind to a subset of serotonin receptors (5-HT1Band 5-HT1D) and are used to treat migraines. In this project, the synthesis of anindole intermediate is attempted. Ideally, an azobenzene would have been added to the 5th position (replacing the primary amine). Azobenzenes are compounds composed of 2 benzene rings connected by a nitrogen-nitrogen double bond that can switch between cis and trans conformations by absorbing different wavelengths of light. The transformation of …

Synthesis Of A Zinc Dipyrrin Complex For Photocatalytic Reduction Of Co2, Sylvia Meredith

Undergraduate Honors Theses

Zinc dipyrrin complexes have the potential to act as cheap, effective photosensitizers. Synthesizing and studying different types could lead to more efficient solar energy harvesting processes, especially the production of solar fuel. Here, two attempts to synthesize 1,3,7,9-tetraphenyl-5-mesityldipyrromethene are reported and discussed. According to ¹H NMR, the first synthesis attempt was not successful. The second synthesis attempt was not purified effectively, so ¹H NMR produced inconclusive results. Further purification strategies or alternate synthesis methods are required.

Indolizine Donor-Based Dyes For Applications In Fluorescence Biological Imaging, William Meador

Honors Theses

NIR emissive fluorophores are intensely researched due to their potential to replace modern imaging procedures. Many molecular strategies have been employed in the literature to optimize fluorophores for deeper NIR absorption and emission, biocompatibility, and higher fluorescence quantum yields. Amongst the fluorophores studied to date, proaromatic indolizine donors are attractive alternatives to traditional alkyl amine and indoline based donors due to their 1) lower energy absorption and emission facilitated by proaromaticity, 2) large Stokes shifts due to increased dihedral angles about the π-system, 3) ease of functionalization and capacity for bioconjugation at the phenyl ring, and 4) potential for further …

Visualization Without Vision – How Blind And Visually Impaired Students And Researchers Engage With Molecular Structures, Croix J. Laconsay, Henry B. Wedler, Dean J. Tantillo

Journal of Science Education for Students with Disabilities

This article examines the tools and techniques currently available that enable blind and visually impaired (BVI) individuals to visualize three-dimensional objects used in learning chemistry concepts. How BVI individuals engage with and visualize molecular structure is discussed and recent tactile (or haptic) and auditory methods for visualization of various chemistry concepts are summarized. Remaining challenges for chemistry education researchers are described with the aim of highlighting the potential value of educational research in further enabling BVI students to pursue careers in science, technology, engineering, and mathematics (STEM) fields.

I. Non-Degradable Polysiloxane Networks For Controlled Release Applications, And Ii. Additive Free, Degradable Silyl-Ether Furyl-Maleimide Networks, Caleb M. Bunton

Chemistry Theses and Dissertations

I. Two different series of non–degradable polysiloxane networks were prepared for the encapsulation and controlled release of a small molecule agent. For the first series, hydrosilylation was utilized to prepare networks of varying crosslink densities, as determined from swelling studies, from vinyl terminated and silylhydride functional poly(dimethyl)siloxanes. For the second series, the thiol-ene reaction was utilized to prepare networks of varying crosslink densities, as determined from swelling studies, from vinyl terminated and mercaptopropyl functional poly(dimethyl)siloxanes. Nile red dye was used as an encapsulated agent and dye release from each series of networks was measured using UV–vis spectroscopy to determine controllability …

Green Chemistry: The Oxidation Of Benzaldehyde Using Atmospheric Oxygen And N-Heterocyclic Carbenes As Catalysts, Alex Brody, John Morgan

Student Research Poster Presentations 2020

Oxidation is a vital process in organic and biochemical reactions. In particular, the oxidation of aromatic aldehydes to carboxylic acids and esters is a vital process used in many different environments. Benzaldehyde is one common subject of this type of reaction, used in the synthesis of benzoic acid and benzoate derivatives. Unfortunately, the industrial synthesis of these compounds uses harmful heavy metal oxidants such as Chromium(VI) and Manganese(VII), which are very harmful to the environment. We proposed to eliminate these pollutants by using atmospheric oxygen and an organic catalyst in a solvent free reaction. This reaction would then be microwaved …

Chemistry In Medicine, Olivia Visaggio, Alyssa Bondi, Matthew Gillingham, Hailey Loughlin

Student Research Poster Presentations 2020

The chemistry behind medicine is important and necessary to study many different drugs and their effects. In this project, we focused on the chemical composition and mechanisms of various drugs. The drugs we focused on include Opioids, NSAIDs, and other medications, such as Benzodiazepines and antibiotics. For each drug, we provided its structure as well as the functional groups, which include a part of a molecule that is recognized based on its arrangement of atoms. Organic Chemistry provides individuals with an understanding of various organic compounds, and this field of study is important as it explains the ways in which …

Synthesis Of Bio-Based Polymer Products, Joshua Sukie

Williams Honors College, Honors Research Projects

The project covers the synthesis of two bio-based polymers. One aspect of the research investigates the synthesis of materials for use in vegetable oil-based UV-curable coating, and the subsequent polymerization of the materials into a coating film. The second aspect of the research follows the synthesis of a functionalized cellulose material for use as a reinforcer in a vegetable oil-based composite. Both products are subsequently analyzed by various methods.

Electrolytic Oxidative Coupling Of Alcohols With Aldehydes To Form Esters, Katherine L. Verboom

Honors College Theses

There are copious amounts of naturally occurring and synthetic esters known that have a wide range of applications in industry to produce fine chemicals. Traditional methods of ester synthesis involve a reaction between a carboxylic acid and an alcohol in the presence of a Bronsted acid catalyst. The primary objective of this research project was to carry out the ester synthesis using the electrochemical coupling of aldehydes with alcohols instead of with a Bronsted acid catalyst because the electrochemical coupling would be an all-around better alternative of ester synthesis than the traditional method of using the catalyst. Electrochemistry has long …

Hypervalent Iodine Compounds With Carboxylate And Tetrazolate Ligands, Avichal Vaish

Chemistry Theses and Dissertations

In modern organic chemistry, hypervalent (HV) iodine(III) compounds are frequently used as oxidizing agents but application of λ³-iodanes in polymer and material chemistry is still underexplored. This dissertation describes the preparation of dynamic and self-healing materials by employing ligand exchange reactions involving HV iodine(III) compounds of the type ArIL₂ (Ar = Aryl, L = ligand, e.g., carboxylate or (pseudo)halide). These compounds can undergo ligand exchange reactions in presence of nucleophiles (Nu^-) to form ArINu₂. Diacetoxyiodo benzene was successfully employed as a crosslinker to prepare dynamic and self-healing gels derived from carboxylate-containing polymers. Furthermore, …

Cell-Trappable Chemiluminescent Probes For Monitoring Hydrogen Sulfide In Living Cells, Briley Bezner

Chemistry Theses and Dissertations

Hydrogen sulfide (H2S) is an important biological signaling molecule that has been recognized alongside nitric oxide and carbon monoxide as being a small gasotransmitter that is enzymatically produced and impacts multiple physiological functions. To detect hydrogen sulfide, there has been a focus on developing fluorescent probes to target particular analytes; however, fluorescent probes lack sensitivity and depth penetration due to background autofluorescence and light scattering. Chemiluminescence does not require light excitation, which greatly reduces the amount of autofluorescence and photoactivation.

In order to detect hydrogen sulfide in living systems with high sensitivity, a series of sterically stabilized 1,2-dioxetane chemiluminescent reduction-reaction …

Hierarchical Conjugated Polymer Systems Prepared By Controlled Chain-Growth Polymerization, Chunwa Peter Kei

LSU Doctoral Dissertations

π-Conjugated polymer materials may have a significant economic impact on society by providing means for designing affordable, flexible, and portable organic electronic devices. Their successful commercialization will depend on major scientific advancements, which will challenge human society to seek out ever more detailed and fundamental processes to command. Controlled polymerization affords such a power; allowing for the design of meticulous and precisely defined systems granting detailed insight into structure-property relationships in the polymer materials and bettering understanding of novel physical phenomena.

This dissertation primarily focuses on development and preparation of well-defined hierarchically organized macromolecular systems. The novel chain-growth polymerization methodologies …

The Roundtable Of Scientific Communication: From Classroom To Course Creation, Back To Classroom And Beyond, Sean P. Hickey

University of New Orleans Theses and Dissertations

This research encompasses many aspects of chemical education research including curriculum and pedagogical changes to the freshman and sophomore courses. Curriculum changes included the addition of recitations to the general chemistry and organic chemistry lectures and the creation of four new classes, CHEM 1001, 1002, 3091, and 3092. The addition of recitations was not limited to but was focused on improving DFW rates for these courses.

CHEM 3091 and 3092 are chemistry internship and undergraduate teaching assistant classes. These courses were necessary to offer outside internship opportunities and training for undergraduate teaching assistants, respectively. CHEM 1001 and 1002 are chemistry …

Molecular Machines: Synthesis, Modeling, And Applications, Syd Kotar

Student Scholar Symposium Abstracts and Posters

While some of the smallest, most useful machines known to science are the biological molecules that keep living organisms alive, there is a growing advancement of the creation of artificial molecules that have the same function and are more efficient. Molecular machines were invented in 1983 when scientists in France created a machine formed of two interlinked molecular rings. In 2016, the Nobel prize in chemistry was awarded to Feringa, Stoddart, and Sauvage who finally documented molecular machines and put them into energy‐filled states in which their movements could be controlled. From this, molecular machines became known as a group …

A Stereospecific Pd-Catalyzed Suzuki Cross-Coupling Reaction And A Statistical Study Of The Ligand's Role In Stereoselection, Shibin Zhao

Dissertations, Theses, and Capstone Projects

The development of palladium-catalyzed carbon-carbon cross-coupling reactions has profoundly influenced the manner through which we approach the synthesis of complex organic molecules. Among established cross-coupling reactions, which include Kumada, Negishi, and Stille reactions, the Suzuki cross-coupling reaction exhibits particularly wide functional group compatibility, while employing non-toxic, air-stable organoboron nucleophiles. Conventional studies of Pd-catalyzed Suzuki cross-coupling reactions have focused on C(sp²)-C(sp²) cross-coupling reactions, which result in the formation of planar products. Conceptually, the use of C(sp³) (secondary) nucleophiles would enable the reliable manipulation of organic molecules in three dimensions. However, this process has not been …

Design And Synthesis Of Circadian Clock Modulators And The Study Of Lov Domain Protein Lkp2 In Arabidosis Thaliana And Brassica Rapa, Aditi Nagar

Chemistry Theses and Dissertations

Circadian rhythms are self-autonomous endogenous clocks synchronized with the rotation of the Earth. With the Earth’s rotation and revolution on its axis, the internal clock undergoes oscillation in the period of ~24 hour and governs day to day activities in most organisms. In humans, it regulates the day to day physiological activities. Today’s modern lifestyle has an impact on health: shift work, jet lag, and irregular eating habits contribute to the misalignment of the endogenous circadian oscillator, thereby, increasing the risk of many metabolic disorders including diabetes, irregular blood pressure, sleep disorders, obesity, depression, and cancer. The primary goal of …

Rearrangements Of Fluorinated Cyclopropylamines As A Novel Approach Toward Fluoroalkene-Based Peptidomimetics, Igor Mezentsev, Vera Zaborova

The International Student Science Fair 2018

Organofluorine molecules have been widely applied in various research fields because of the unique properties of fluorine atoms. One type of fluorinated compounds is fluoroalkene-based peptidomimetics which are structurally similar to amide-containing compounds. They have been prepared to improve the pharmaceutical properties such as bioactivity, target specificity, and metabolic stability of the bioactive amides.

We suggested a new way of synthesizing fluoroalkene-based peptidomimetics through 2-fluoro-2-halocyclopropylamines, which provides an effective way toward fluoroalkene-based peptidomimetics with increased functional group tolerance and possibility of convergent synthesis.