Organic Chemistry Commons^™

Carbon "Quantum" Dots: Structures, Properties, And Issues, Weixiong Liang

All Dissertations

Carbon dots (CDots) are small carbon nanoparticles (CNPs) with effective surface passivation. The effective passivation has been achieved by the surface functionalization of pre-existing CNPs with organic molecules, mostly molecules containing primary or secondary amine moieties. In the studies highlighted in this dissertation, CNPs were functionalized by selected organic molecules, including especially the use of radical addition reactions, to generate CDots with strong absorption and bright fluorescence emissions. A good demonstration of the approach was the N-ethylcarbazole (NEC) radical addition to CNPs under microwave irradiation. Spectroscopy and microscopy methods were employed to characterize the resulting NEC-CDots, and the results …

Characterizing The Role Of Chemo-Mechanical Couplings In The Activation Process Of Proteins That Undergo Conformational Changes, Ugochi Isu

Graduate Theses and Dissertations

Proteins are not static entities; rather, they are dynamic macromolecules that undergo conformational changes to perform their biological functions. These structural transitions are often coupled to chemical events such as lipid interactions, or changes in the cellular environment. Understanding the intricate interplay between chemical perturbations and the resulting mechanical response is crucial for elucidating the activation mechanisms of proteins. This dissertation aims to characterize the role of chemo-mechanical couplings in the activation process of two G protein-coupled receptors (GPCRs): Cannabinoid Receptor 1 (CB1) and Metabotropic Glutamate Receptor 1 (mGluR1). We employ molecular dynamics simulations to investigate the conformational landscapes of …

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

LSU Doctoral Dissertations

Abstract

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

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

Killing Cancer: Manipulating Hydrophobic Vanadium Complexes To Improve Anti-Cancer Activity, Levi Ausherman, Debbie C. Crans, Peter A. Lay, Maggi Braasch-Turi

SACAD: Scholarly Activities

Hydrophobic vanadium complexes have recently shown improved anti-cancer activities compared to cisplatin. The hydrophobicity and anti-proliferative activity of [VO(Hshed)(dtb)] ([Hshed= N-(salicylideneaminato)-N’-(2-hydroxyethyl)-1,2-ethanediamine and dtb= 3,5-di(tert-butyl)catechol)]) have inspired the development of a library of hydrophobic vanadium complexes. Increasing the steric bulk of the catechol ligand has been shown to have a direct impact on hydrophobicity and anti-proliferative activities. Currently at Fort Hays State University, the Braasch-Turi group is synthesizing VO(HSHED)(dtb) to build up material to support the chemical analysis and biological assay performed by our collaborators at Colorado State University and the University of Sydney, Australia, respectively. In the future, we plan …

Unlocking The Secret To Weight Loss: Discovering The Most Effective Green Tea Products, Seoyeon Kim

SACAD: Scholarly Activities

To find the most effective green tea product that can replace

weight loss drugs, we compared the amount of catechin in six

different green tea products. The result was green tea latte

powder contained a significantly small amount of catechin

compared to other products, and the dried pearl green tea leaves

had the highest amount of catechin. Also, the unexpected result

was that green tea supplements had less amount of catechin

compared to dried leaves or even tea bags that are commonly

sold in markets.

Apigenin Alleviates Autistic-Like Stereotyped Repetitive Behaviors And Mitigates Brain Oxidative Stress In Mice, Petrilla Jayaprakash, Dmytro Isaev, Keun-Hang Susan Yang, Rami Beiram, Murat Oz, Bassem Sadek

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Studying the involvement of nicotinic acetylcholine receptors (nAChRs), specifically α7-nAChRs, in neuropsychiatric brain disorders such as autism spectrum disorder (ASD) has gained a growing interest. The flavonoid apigenin (APG) has been confirmed in its pharmacological action as a positive allosteric modulator of α7-nAChRs. However, there is no research describing the pharmacological potential of APG in ASD. The aim of this study was to evaluate the effects of the subchronic systemic treatment of APG (10–30 mg/kg) on ASD-like repetitive and compulsive-like behaviors and oxidative stress status in the hippocampus and cerebellum in BTBR mice, utilizing the reference drug aripiprazole (ARP, 1 …

Applied Depositional Geosystems Of The Coos Bay Basin, Oregon: Organic Geochemistry, Maturation, Paleoenvironmental Reconstruction And Biostratigraphy Of The Coaledo Delta During The Middle Eocene Climatic Optimum (Meco), Allison K. Barbato

LSU Doctoral Dissertations

The Coos Bay Basin on the southwestern coast of Oregon is a forearc basin that contains exceptionally preserved Eocene to Miocene, tidal to wave-dominated, shallow deltaic to deep marine sediments of the Coaledo Delta. Coastal depositional environments are known to host source, reservoir, and seal rocks. Climate, topographic relief, and geographical position all play an important role in regional vegetation development and oceanic setting. This study assesses 84 outcrop and 12 core samples from Coos Bay for their organic geochemical characteristics and microfossil assemblage to provide source rock characterization information, organofacies descriptions, environmental reconstructions, and age control.

Results indicate the …

Green Oxidation Of Aromatic Hydrazide Derivatives Using An Oxoammonium Salt, Nidheesh Phadnis, Jessica A. Molen, Shannon M. Stephens, Shayne M. Weierbach, Kyle M. Lambert, John A. Milligan

College of Life Sciences Faculty Papers

Aromatic diazenes are often prepared by oxidation of the corresponding hydrazides using stoichiometric quantities of nonrecyclable oxidants. We developed a convenient alternative protocol for the oxidation of aromatic hydrazides using Bobbitt's salt (1), a metal-free, recyclable, and commercially available oxoammonium reagent. A variety of aryl hydrazides were oxidized within 75 min at room temperature using the developed protocol. Computational insight suggests that this oxidation occurs by a polar hydride transfer mechanism.

Efforts Toward Difunctionalization Of (Hetero)Arenes Enabled By Visible Light, Eric Allen

Master's Theses (2009 -)

Functionalized arenes and heteroarenes are ubiquitous motifs in natural products, pharmaceuticals, and functional materials. As such, methods to place multiple functionalities on (hetero)arenes in one synthetic step create molecular complexity quickly and are highly valued. The vast majority of current strategies are metal-mediated, although others such as utilizing aryne intermediates and cycloadditions have also been reported. The premier challenge in this research area is the difficulty in controlling regioselectivity. Strategies of controlling regioselectivity have included tuning the electronic nature of the substrate, the use of directing groups (DGs), steric influences, ligand control, and photochemically initiated methods. Certain strategies tend to …

Synthesis, Molecular Characteristics, And Antibacterial Assessment Of Marine Hydroid Aqueous Extract-Based Silver Bio-Nanoparticles, Fredryk Mandey, Aulia Rhamdani Arfan, Rugaiyah Andi Arfah

Makara Journal of Science

This investigation aims to synthesize, analyze the molecularity, and test the ability of bacterial inhibition capability of silver nanoparticles that have been synthesized by simply mixing silver nitrate and aqueous extracts of marine natural products with and without the addition of amylum as a stabilizing agent. This research, with and without the addition of amylum as a stabilizing agent, obtained 39.0 and 55.2 mg of solids of round-shaped morphology silver nanoparticles with diameters of 87.9 and 103.0 nm., respectively. In addition, the antibacterial testing assay against Staphylococcus aureus and Escherichia coli showed some considerably good results. S. aureus with the …

Mechanistic Investigation Of C—C Bond Activation Of Phosphaalkynes With Pt(0) Complexes, Roberto M. Escobar, Abdurrahman C. Ateşin, Christian Müller, William D. Jones, Tülay Ateşin

Research Symposium

Carbon–carbon (C–C) bond activation has gained increased attention as a direct method for the synthesis of pharmaceuticals. Due to the thermodynamic stability and kinetic inaccessibility of the C–C bonds, however, activation of C–C bonds by homogeneous transition-metal catalysts under mild homogeneous conditions is still a challenge. Most of the systems in which the activation occurs either have aromatization or relief of ring strain as the primary driving force. The activation of unstrained C–C bonds of phosphaalkynes does not have this advantage. This study employs Density Functional Theory (DFT) calculations to elucidate Pt(0)-mediated C–CP bond activation mechanisms in phosphaalkynes. Investigating the …

Reversible O–H Bond Activation By Tripodal Tris(Nitroxide) Aluminum And Gallium Complexes, Joseph S. Scott , '22, Mika L. Maenaga , '21, Audra J. Woodside , '19, Vivian W. Guo , '26, Alex R. Cheriel , '24, M. R. Gau, Paul R. Rablen, Christopher R. Graves

Chemistry & Biochemistry Faculty Works

Herein, we report the preparation and characterization of the Group 13 metal complexes of a tripodal tris(nitroxide)-based ligand, designated (TriNOx³⁻)M (M = Al (1), Ga (2), In (3)). Complexes 1 and 2 both activate the O–H bond of a range of alcohols spanning a ∼10 pKₐ unit range via an element-ligand cooperative pathway to afford the zwitterionic complexes (HTriNOx²⁻)M–OR. Structures of these alcohol adduct products are discussed. We demonstrate that the thermodynamic and kinetic aspects of the reactions are both influenced by the identity of the metal, with 1 having higher reaction equilibrium constants and proceeding at a …

Group Contribution Revisited: The Enthalpy Of Formation Of Organic Compounds With “Chemical Accuracy” Part V, R. J. Meier, Paul R. Rablen

Chemistry & Biochemistry Faculty Works

Group Contribution (GC) methods to predict thermochemical properties are eminently important in chemical process design. Following our earlier work in which a Group Contribution (GC) model was presented to account for the gas-phase heat of formation of organic molecules which, for the first time, revealed chemical accuracy (1 kcal/mol or 4 kJ/mol), we here present Group Contribution parameters for a range of additional series of molecules allowing the application to a wider range of molecules whilst, mostly, retaining chemical accuracy. The new classes of molecules include amines, alkylesters, and various substituted benzenes, including t-butyl-benzenes, phenols, methoxybenzenes, anilines, benzaldehydes, and acetophenones, …

3-Chloropropylbis(Catecholato)Silicate As A Bifunctional Reagent For The One-Pot Synthesis Of Tetrahydroquinolines From O-Bromosulfonamides, Noah Brodsky, Nidheesh Phadnis, Mohamed Ibrahim, Isabel M. Andino, Inés Blanc Giro, John A. Milligan

College of Life Sciences Faculty Papers

Bis(catecholato)silicate salts are easily accessible reagents that can be used to install alkyl fragments through photoredox-enabled cross-coupling. These reagents can incorporate various functional groups including pendant alkyl halides. A halogenated organosilicate reagent was leveraged to develop a one-pot synthesis of tetrahydroquinolines from o-bromosulfonamides, where the bifunctional reagent participates in a nickel/photoredox cross-coupling followed by intramolecular nucleophilic substitution. The functional group tolerance of this cross-coupling strategy allowed for the preparation of a series of substituted tetrahydroquinolines.

Purification And Isolation Of Α-Chloro-Β-Lactone Precursor Molecules, Matthew Ellis

ASPIRE 2024

This research investigates the synthesis of α-chloro-β-lactone molecules, focusing on the production, isolation, and purification of two precursor compounds from chloroacetic acid and substituted benzaldehydes. While multiple methods were explored, including EDC, DIC, and DCC catalysis, DCC proved to be most effective in producing higher yields. However, challenges in purification arose due to the formation of byproducts, particularly with DCC, prompting further investigation for efficient extraction and purification techniques. DCC, however, shows a promising route for α-chloro-β-lactone synthesis, despite purification complexities.

Pisa Printing Microneedles With Controllable Aqueous Dissolution Kinetics, Aaron Priester, Jimmy Yeng, Yuwei Zhang, Krista Hilmas, Risheng Wang, Anthony J. Convertine

Chemistry Faculty Research & Creative Works

This study focused on the development of high-resolution polymeric structures using polymer-induced self-assembly (PISA) printing with commercially available digital light-processing (DLP) printers. Significantly, soluble solids could be 3D-printed using this methodology with controllable aqueous dissolution rates. This was achieved using a highly branched macrochain transfer agent (macro-CTA) containing multiple covalently attached CTA groups. In this work, the use of acrylamide as the self-assembling monomer in isopropyl alcohol was explored with the addition of N-(butoxymethyl)acrylamide to modulate the aqueous dissolution kinetics. PISA-printed microneedles were observed to have feature sizes as small as 27 μm, which was close to the resolution limit …

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

Dissertations, Theses, and Capstone Projects

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

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

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

Dissertations, Theses, and Capstone Projects

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

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

The Effect Of Variation Of N-Substituents On Oxidopyridinium Ions In (4+3) Cycloadditions, Zahria Patrick, Madison Clark

Undergraduate Research Symposium

The aim of this research project is to expand the scope of 4 + 3 cycloadduct chemistry by varying functional groups attached to the prerequisite oxidopyridinium ion for each respective cycloadduct product. While N-substitution of the pyridinium precursor is known to proceed smoothly if alkylated by a lone methyl group, we evaluated the effect a larger alkyl group would have on the overall yield of the 4 + 3 cycloadduct product.

Isobutyl triflate, generated from the known reaction between isobutyl alcohol and triflic anhydride, was reacted with ethyl 5-hydroxy-nicotinate to generate the respective N-isobutyl oxidopyridinium ion in quantitative …

Etherification Of Propargylic Alcohol Using Ferrocenium Ions, Cody Amann, Sai Anvesh Bezawada, Eike B. Bauer

Undergraduate Research Symposium

Etherification of Propargylic Alcohol using Ferrocenium Ions

Cody Amann, Sai Anvesh Bezawada and Eike B. Bauer*

Department of Chemistry and Biochemistry, University of Missouri-St.Louis, MO 63121

Our research efforts are directed toward the improvement of iron-based catalyst systems. The Bauer research group recently found that the ferrocenium cation is a catalytically active in the etherification of propargylic alcohols. My research was to compare the effect of two different counteranions of the ferrocenium cation on the catalytic activity. Etherification test reactions were performed using 2-methyl-2-phenol-propargylic alcohol and n-butanol to afford the corresponding propargylic ether substitution products. The complexes used …