Chemistry Commons^™

Using Natural Resources To Control The Fate Of Contaminants In The Environment, Lucia Rodriguez Freire

Sustainability Seminar Series

Environmental contamination poses an increased health risk to those communities living nearby impacted sites, and it is imperative to find sustainable remediation strategies to restore the natural systems. My research investigates natural biogeochemical processes and the use of ubiquitous materials to the design remediation solutions that are site-specific and take into consideration the needs of the affected communities. The first example is the investigation of uranium (U) accumulation in plants growing along the Rio Paguate, which flows through the Jackpile Mine, and open-pit U mine listed on the National Priority List as a Superfund site. Two villages of the Laguna …

Innovative Monte Carlo Methods For Sampling Molecular Conformations, Aliasghar Sepehri

LSU Doctoral Dissertations

Sampling molecular conformations is an important step in evaluating physical, mechanical, hydrodynamic, and optical properties of flexible molecules especially polymers. One powerful method for this purpose is configurational-bias Monte Carlo in which one random segment of a molecule is chosen, all segments toward one random end are removed, and then regrown segment by segment to produce a new geometry to be accepted/rejected according to probability laws. The advantage of this method is the ability to generate acceptable conformations that are favorable for intra- and intermolecular energies to save computational costs. However, when there are several interdependent energetic terms, trial generation …

Highway Construction Or Stream Destruction: A Water Quality Analysis In The Black Warrior Basin, Walker County, Alabama, Cayla Baughn

Mahurin Honors College Capstone Experience/Thesis Projects

In 2012, residents along Freeman Branch Creek in Eldridge, Alabama observed unusual orange discoloration along the stream and on stream vegetation; an unprecendented black veneer coating pebbles along the streambed; and life in the stream seemed to have vanished. Freeman Branch Creek is located in Walker County, Alabama, which is known for its production of coal and natural gas from the underlying Pennsylvanian-aged Pottsville Formation, which is the uppermost geologic layer within the the Black Warrior Basin. Concerns for environmental safety related to intensive mining operations include the concern that shallow aquifers will be contaminated by mining in deep reservoir …

Expansion Of The (Bb)>Ru Metallacycle With Coinage Metal Cations: Formation Of B-M-Ru-B (M= Cu, Ag, Au) Dimetalacyclodiboryls†, Bennett J. Eleazer, Mark D. Smith, Alexey A. Popov, Dmitry V. Peryshkov

Faculty Publications

In this work, we introduce a novel approach for the selective assembly of heterometallic complexes by unprecedented coordination of coinage metal cations to strained single ruthenium–boron bonds on a surface of icosahedral boron clusters. M(I) cations (M ¼ Cu, Ag, and Au) insert into B–Ru bonds of the (BB)–carboryne complex of ruthenium with the formation of four-membered B–M–Ru–B metalacycles. Results of theoretical calculations suggest that bonding within these metalacycles can be best described as unusual three-center-two-electron B–M/Ru interactions that are isolobal to B–H/Ru borane coordination for M ¼ Cu and Ag, or the pairs of two-center-two electron B–Au and Au–Ru …

Pi Tetrel Bonds, And Their Influence On Hydrogen Bonds And Proton Transfers, Yuanxin Wei, Qingzhong Li, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The positive region that lies above the plane of F2TO (T=C and Si) interacts with malondialdehyde (MDA), which contains an intramolecular H‐bond. The T atom of F2TO can lie either in the MDA molecular plane, forming a T⋅⋅⋅O tetrel bond, or F2TO can stack directly above MDA in a parallel arrangement. The former structure is more stable than the latter, and in either case, F2SiO engages in a much stronger interaction than does F2CO, reaching nearly 200 kJ mol−1. The π‐tetrel bond strengthens/weakens the MDA H‐bond when the bond is formed to the hydroxyl/carbonyl group of MDA, and causes an …

Reaction Chemistry Of Silver(I) Trifluoromethanesulfonate Complexes Of Nitrogen-Confused C-Scorpionates, James R. Gardinier, Kristin J. Meise, Fathiya Jahan, Sergey V. Lindeman

Chemistry Faculty Research and Publications

Two new C-scorpionate ligands with a bis(3,5-dimethylpyrazol-1-yl)methyl group bound to the 3 position of either an N-tosyl (^TsL*) or an N–H pyrazole (^HL*) ring have been prepared. The silver(I) complexes of these new ligands and the two previously reported analogous ligands with unsubstituted bis(pyrazol-1-yl)methyl groups (^TsL and ^HL) in both 1:1 and 2:1 ligand/metal ratios were investigated to explore the effects of ligand sterics on their physical and chemical properties. The structurally characterized derivatives of the type [Ag(L)₂](OTf) are four-coordinate, where the confused pyrazolyl is not bound to the …

Comparison Of Processed And Non-Processed Biomass Digestion, Richard Bruce Clark Iii

Graduate Theses - Chemistry and Biochemistry

Lignocellulosic ethanol is the main focus of second-generation biofuels [1]. Because cellulose is the most abundant organic material on earth, second-generation biofuels are a more sustainable option than the classical first-generation biofuels that use foodstuffs as the main feedstock in ethanol production [1]. Furthermore, biofuel can be produced not only from unprocessed biomass such as corn husks but also from processed material like paper [1]. Ionic liquids have shown to be quite effective in dissolving naturally occurring, and traditionally insoluble, polymers such as cellulose into solution, and cellulase enzymes have been shown to effectively digest cellulose into simple sugars [2]. …

Molecular Dynamics Of Palmitic Acid And Lead Palmitate In Cross-Linked Linseed Oil Films: Implications From Deuterium Magnetic Resonance For Lead Soap Formation In Traditional Oil Paintings, Jaclyn Catalano, Anna Murphy, Yao Yao, Nicholas Zumbulyadis, Silvia A. Centeno, Cecil Dybowski

Department of Chemistry and Biochemistry Faculty Scholarship and Creative Works

Many oil paintings, dating from the 15th century to the present, are affected by the formation of heavy-metal carboxylates (soaps) that alter the structural integrity and appearance of the works. Through transport phenomena not yet understood, free fatty acids formed from oils used as binders migrate through the paint film and react with heavy-metal ions that are constituents of pigments and/or driers, forming metal carboxylates. The local molecular dynamics of fatty acids and metal carboxylates are factors influencing material transport in these systems. We report temperature-dependent 2H NMR spectra of palmitic acid and lead palmitate as pure materials, in cross-linked …

Novel Fluconazole Derivatives With Promising Antifungal Activity, Nishad Thamban Chandrika, Sanjib K. Shrestha, Huy X. Ngo, Kaitlind C. Howard, Sylvie Garneau-Tsodikova

Pharmaceutical Sciences Faculty Publications

The fungistatic nature and toxicity concern associated with the azole drugs currently on the market have resulted in an increased demand for new azole antifungal agents for which these problematic characteristics do not exist. The extensive use of azoles has resulted in fungal strains capable of resisting the action of these drugs. Herein, we report the synthesis and antifungal activities of novel fluconazole (FLC) analogues with alkyl-, aryl-, cycloalkyl-, and dialkyl-amino substituents. We evaluated their antifungal activity by MIC determination and time-kill assay as well as their safety profile by hemolytic activity against murine erythrocytes as well as cytotoxicity against …

Adsorption Of Tnt, Dnan, Nto, Fox7, And Nq Onto Cellulose, Chitin, And Cellulose Triacetate. Insights From Density Functional Theory Calculations, Guido Todde, Sanjiv K. Jha, Gopinath Subramanian, Manoj K. Shula

Faculty Publications

Insensitive munitions (IM) compounds such as DNAN (2,4-dinitroanisole), NTO (3-nitro-1,2,4-triazol-5-one), NQ (nitroguanidine), and FOX7 (1,1-diamino-2,2-dinitroethene) reduce the risk of accidental explosions due to shock and high temperature exposure. These compounds are being used as replacements for sensitive munition compounds such as TNT (2,4,6-trinitromethylbenzene) and RDX (1,3,5-hexahydro-1,3,5-trinitro-1,3,5-triazine). NTO and NQ in IM compounds are more soluble than TNT or RDX, hence they can easily spread in the environment and get dissolved if exposed to precipitation. DNAN solubility is comparable to TNT solubility. Cellulosic biomass, due to its abundance in the environment and its chemical structure, has a high probability of adsorbing …

Flavour Chemicals In A Sample Of Non-Cigarette Tobacco Products Without Explicit Flavour Names Sold In New York City In 2015, Shannon M. Farley, Kevin R.J. Schroth, Victoria Grimshaw, Wentai Luo, Julia Lynn Degagne, Peyton A. Tierney, Kilsun Kim, James F. Pankow

Chemistry Faculty Publications and Presentations

Background Youth who experiment with tobacco often start with flavoured products. In New York City (NYC), local law restricts sales of all tobacco products with ‘characterising flavours’ except for ‘tobacco, menthol, mint and wintergreen’. Enforcement is based on packaging: explicit use of a flavour name (eg, ‘strawberry’) or image depicting a flavour (eg, a fruit) is presumptive evidence that a product is flavoured and therefore prohibited. However, a tobacco product may contain significant levels of added flavour chemicals even when the label does not explicitly use a flavour name.

Methods Sixteen tobacco products were purchased within NYC in 2015 that …

Rapid Adsorption Of Proinflammatory Cytokines By Graphene Nanoplatelets And Their Composites For Extracorporeal Detoxification, Yishan Zheng, Nicholas Pescatore, Yury Gogotsi, Boris Dyatkin, Ganesh Ingavle, Vadym Mochalin, Tochukwu Ozulumba, Sergey Mikhalovsky, Susan Sandeman

Chemistry Faculty Research & Creative Works

Sepsis is a complex clinical syndrome that features excessive release of cytokines and other inflammatory mediators that could lead to organ dysfunction. Despite different treatment and management options, sepsis associated high morbidity and mortality rates remain. This has prompted intensive research into alternative therapeutic approaches such as targeted removal of sepsis related molecules using extracorporeal hemoperfusion. In this study, we explore the use of graphene nanoplatelets (GNP) as low-cost alternative hemosorbents for rapid removal of a broad spectrum of proinflammatory cytokine markers. Firstly, the physical characteristics, cytotoxicity, and cytokine marker adsorption profile of GNP were assessed. The results not only …

Undergraduate Research In Petrology Approached Through Computer Modeling Of Fabric Evolution In Igneous Rocks, Michael C. Leopold, M. J. Bonder, C. W. Holyoke, T. G.M. Krohn, R. V. Amenta

Chemistry Faculty Publications

Undergraduate research is an important part of the curriculum in many geology departments but, in recent years, it has become more difficult to attract students into projects dealing with solid-earth studies due to the limited employment prospects in these areas compared to those in environmental geology. This report describes how petrologic research can be made more attractive to students by an approach using C programming to model crystal growth and fabric development in poly crystalline solids. This topic has broad appeal to students in the other sciences as well as geology, and the computer skills learned have wide practical utility …

Systematic Size Control In The Synthesis Of Zero-Valent Iron Nanoparticles, Grant C. Bleier

Chemistry and Chemical Biology ETDs

A novel synthetic method for the production of highly magnetic, low size-dispersity nanoparticles through reversible magnetic agglomeration is introduced and studied in detail. Initially, a weakly coordinating surfactant (3-octadecyl-2,4-pentanedione) is employed to produce a wide range of nanoparticle sizes ranging from 8 to 20 nm in diameter. The kinetics faced in these reactions by cheap and widely available iron complex precursors can be avoided in this method with the introduction of thermodynamic control, which occurs in the form of a magnetic precipitation event that essentially halts nanoparticle growth. Utilizing this synthetic method, the length of the alkyl chain on the …

Investigation Of Novel Electrolytes For Use In Lithium-Ion Batteries And Direct Methanol Fuel Cells, Kartik Pilar

Dissertations, Theses, and Capstone Projects

Energy storage and conversion plays a critical role in the efficient use of available energy and is crucial for the utilization of renewable energy sources. To achieve maximum efficiency of renewable energy sources, improvements to energy storage materials must be developed. In this work, novel electrolytes for secondary batteries and fuel cells have been studied using nuclear magnetic resonance and high pressure x-ray scattering techniques to form a better understanding of dynamic and structural properties of these materials. Ionic liquids have been studied due to their potential as a safer alternative to organic solvent-based electrolytes in lithium-ion batteries and composite …

Parp Pet Imaging Agents, Brandon Carney

Dissertations, Theses, and Capstone Projects

The poly (adenosine-diphosphate (ADP) ribose) polymerase (PARP) family of enzymes has been of interest to researchers and clinicians for over fifty years, especially the first member of the family, PARP1. This enzyme has become a target for cancer therapeutics due the reliance of highly proliferating cells on PARP1 for genomic maintenance. In the coming age of individualized medicine, however, highly specific therapeutic agents like PARP inhibitors are in need of similarly highly specific companion diagnostic agents. These kind of agents have been made possible with the quickly progressing field of molecular imaging. Specifically, positron emission tomography (PET) has enabled the …

Nanoporous Carbon-Based Co2 Reduction Catalysts: Exploring The Combined Effects Of Surface Chemistry And Porosity, Wanlu Li

Dissertations, Theses, and Capstone Projects

For the first-time sulfur-doped, nitrogen-doped and sulfur, nitrogen-codoped nanoporous carbons were systematically studied as catalysts for CO₂ electrochemical reduction reaction (CO₂ERR). The Faradaic efficiencies (FE) of CO and CH₄ formation were calculated to evaluate the performance of these carbons. The best catalysts showed the FE of CO and CH₄ formation of 29% and 0.76%, respectively. It was found that the overall performance in CO₂ERR dramatically increased upon the reduction pretreatment of the carbons in N₂-saturated electrolyte before the CO₂ reduction process. The pretreated carbon showed the maximum FE of CO …

Discovery And Development Of A Three-Component Oxidopyrylium Cycloaddition And Its Application Towards Alpha-Hydroxytropolone Synthesis, Michael P. D'Erasmo

Dissertations, Theses, and Capstone Projects

Historically, natural products have provided unique research opportunities and challenges for organic synthesis, chemical biology, and medicinal chemistry due to their molecular complexity and effects on physiological systems. The total synthesis of natural products has not only produced novel reaction methods and strategies capable of efficiently generating complex structural motifs but also granted access to sufficient quantities of otherwise scarce natural product material for clinical evaluation. These synthetic efforts have facilitated the formation of a transdisciplinary partnership between chemistry, biology, and medicine that has been paramount in elucidating the chemical and pharmaceutical utility of natural products. Chapter I of this …

Development Of Nanomaterials: Complex Mesoporous Silicas And Highly Functional Multi-Responsive Hybrid Nanogels, Jinhui Yi

Dissertations, Theses, and Capstone Projects

The research work in this dissertation describes the study of the applications of polymers in several important areas. Two synthesis methods for bicontinuous cubic KIT6 silicas with block copolymer Pluronic P123 as templates were developed, expanding the range of available pore size and enchancing mesopore volume. In addition, two types of drug delivery systems were developed based on polymer nanoparticles.

In Chapter 2, it was shown that the addition of a suitable swelling agent at temperatures somewhat lower than those typically used in the syntheses of silicas with cubic Ia3d structure (19−25 °C vs 30−35 °C) allows one to induce …

The Therapeutic Potential Of Natural Products From Vaccinium Berries For Viral And Lung Diseases Through An Improved Lc-Ms-Based Chemometric Approach, Vanya I. Petrova

Dissertations, Theses, and Capstone Projects

Smoking is a global epidemic that creates serious health and economic burden. It is the primary, preventative factor for the majority of causes of death worldwide. Analysis of publicly available data revealed that smoking prevalence rates among the youth in developing countries, especially in Bulgaria, are alarmingly high. The Bulgarian population has one of the highest percentages of smokers and the second highest rate among teenage girls. Consequently, chronic diseases affected by smoking, such as chronic obstructive pulmonary disorder (COPD), have been increasing there in the last five years. Poland, on the other hand, is an exemplary outlier for the …

Organic Photochemistry: Remote Delivery Of Reactive Oxygen Intermediates Via A Heterogeneous Approach, Niluksha Walalawela Abeykoon

Dissertations, Theses, and Capstone Projects

Photosensitized oxidation reactions produce a number of intermediates species, which are generated in varying amounts over time. This complexity presents major challenges in the study of oxidation processes. Mechanistic efforts to separate and deliver reactive oxygen intermediates enable their controlled use in processes such as bacterial inactivation. This thesis describes a heterogeneous reaction approach taken to control the generation and delivery of reactive oxygen intermediates. The mechanistic details of photosensitized reactions were elucidated via synthetic, materials, and physical organic techniques to optimize the delivery of reactive oxygen intermediates. This thesis contains six chapters as described below.

Chapter 1 gives a …

Lanthanum-Mediated Dehydrogenation Of Butenes: Spectroscopy And Formation Of La(C4H6) Isomers, Wenjin Cao, Dilkrushi Hewage, Dong-Sheng Yang

Chemistry Faculty Publications

La atom reactions with 1-butene, 2-butene, and isobutene are carried out in a laser-vaporization molecular beam source. The three reactions yield the same La-hydrocarbon products from the dehydrogenation and carbon-carbon bond cleavage and coupling of the butenes. The dehydrogenated species La(C₄H₆) is the major product, which is characterized with mass-analyzed threshold ionization (MATI) spectroscopy and quantum chemical computations. The MATI spectrum of La(C₄H₆) produced from the La+1-butene reaction exhibits two band systems, whereas the MATI spectra produced from the La+2-butene and isobutene reactions display only a single band system. Each of these …

Par1 Agonists Stimulate Apc-Like Endothelial Cytoprotection And Confer Resistance To Thromboinflammatory Injury, Karen De Ceunynck, Christian G. Peters, Abhishek Jain, Sarah J. Higgins, Omozuanvbo Aisiku, Jennifer L. Fitch-Tewfik, Sharjeel A. Chaudhry, Chris Dockendorff, Samir M. Parikh, Donald E. Ingber, Robert Flaumenhaft

Chemistry Faculty Research and Publications

Stimulation of protease-activated receptor 1 (PAR1) on endothelium by activated protein C (APC) is protective in several animal models of disease, and APC has been used clinically in severe sepsis and wound healing. Clinical use of APC, however, is limited by its immunogenicity and its anticoagulant activity. We show that a class of small molecules termed “parmodulins” that act at the cytosolic face of PAR1 stimulates APC-like cytoprotective signaling in endothelium. Parmodulins block thrombin generation in response to inflammatory mediators and inhibit platelet accumulation on endothelium cultured under flow. Evaluation of the antithrombotic mechanism showed that parmodulins induce cytoprotective signaling …

Elucidating Charge Separation Dynamics In A Hybrid Metal–Organic Framework Photocatalyst For Light-Driven H2 Evolution, Sizhuo Yang, Donghua Fan, Wenhui Hu, Brian Pattengale, Cunming Liu, Xiaoyi Zhang, Jier Huang

Chemistry Faculty Research and Publications

Metal–organic frameworks (MOFs) have emerged as novel scaffolds for artificial photosynthesis due to their unique capability in incorporating homogeneous photosensitizer and catalyst to their robust heterogeneous matrix. In this work, we report the charge separation dynamics between molecular Ru-photosensitizer and Pt-catalyst, both of which were successfully incorporated into a Zr-MOF that demonstrates excellent activity and stability for light-driven H₂ generation from water. Using optical transient absorption (OTA) spectroscopy, we show that charge separation in this hybrid MOF occurs via electron transfer (ET) from Ru-photosensitizer to Pt-catalyst. Using Pt L₃-edge X-ray transient absorption (XTA) spectroscopy, we observed the …

Exploiting Anisotropy Of Plasmonic Nanostructures With Polarization-Modulation Infrared Linear Dichroism Microscopy (Μpm-Irld)., Gregory Q. Wallace, Stuart Read, Danielle M. Mcrae, Scott Rosendhal, Francois Lagugne-Labarthet

Chemistry Publications

Metallic nanostructures that exhibit plasmon resonances in the mid-infrared range are of particular interest for a variety of optical processes where the infrared excitation and/or emission could be enhanced. This plasmon-mediated enhancement can potentially be used towards highly sensitive detection of an analyte(s) by techniques such as surface-enhanced infrared absorption (SEIRA). To maximize the SEIRA enhancement, it is necessary to prepare highly tuned plasmonic resonances over a defined spectral range that can span over several microns. Noteworthy, nanostructures with anisotropic shapes exhibit multiple resonances that can be exploited by controlling the polarization of the input light. This study demonstrates the …

Informing Efforts To Develop Nitroreductase For Amine Production, Anne-Frances Miller, Jonathan T. Park, Kyle L. Ferguson, Warintra Pitsawong, Andreas S. Bommarius

Chemistry Faculty Publications

Nitroreductases (NRs) hold promise for converting nitroaromatics to aromatic amines. Nitroaromatic reduction rate increases with Hammett substituent constant for NRs from two different subgroups, confirming substrate identity as a key determinant of reactivity. Amine yields were low, but compounds yielding amines tend to have a large π system and electron withdrawing substituents. Therefore, we also assessed the prospects of varying the enzyme. Several different subgroups of NRs include members able to produce aromatic amines. Comparison of four NR subgroups shows that they provide contrasting substrate binding cavities with distinct constraints on substrate position relative to the flavin. The unique architecture …

Polysaccharide-Mediated Synthesis Of Melanins From Serotonin And Other 5-Hydroxy Indoles, Koen Vercruysse, Astiney Clark, Noor Alattas, Dylan Brooks, Nafisa Hamza, Margaret Whalen

Chemistry Faculty Research

Aim: As a continuation of our research on the melanin formation from catecholamines, we studied the polysaccharide-mediated oxidation of serotonin and other 5-hydroxy indoles into melanin-like materials. As for the catecholamines, we observed that many polysaccharides promote the oxidation of such compounds, particularly in the presence of Cu²⁺. Methodology: The reactions were monitored using reverse phase-HPLC and size-exclusion chromatography techniques. Melanin-like materials were purified through dialysis and characterized using UV-Vis and Fourier transform IR spectroscopic techniques. Results: One such material, synthesized from chondroitin sulfate type A and serotonin in the presence of Cu²⁺ was found to affect …

A High Throughput Approach For The Generation Of Orthogonally Interacting Protein Pairs, Justin Lawrie, Xi Song, Wei Niu, Jiantao Guo

Department of Chemistry: Faculty Publications

In contrast to the nearly error-free self-assembly of protein architectures in nature, artificial assembly of protein complexes with pre-defined structure and function in vitro is still challenging. To mimic nature’s strategy to construct pre-defined three-dimensional protein architectures, highly specific proteinprotein interacting pairs are needed. Here we report an effort to create an orthogonally interacting protein pair from its parental pair using a bacteria-based in vivo directed evolution strategy. This high throughput approach features a combination of a negative and a positive selection. The newly developed negative selection from this work was used to remove any protein mutants that retain effective …

Chemistry And Biochemistry News, Georgia Southern University

Biochemistry, Chemistry & Physics: News & Publications (2012-2023)

• Faculty Highlight: Ryan Fortenberry

Biomedical Applications Of Hydrogels And Gumbos, Kelsey Elizabeth Mcneel

LSU Doctoral Dissertations

Sodium deoxycholate (NaDC) is a small bile salt that was used in this dissertation to produce gelation of tris(hydroxymethyl)amino-methane (TRIS) solutions above, below, and near the pKa of NaDC. These solutions respectively yielded a neutral gelator, a charged gelator, and a mixture of each. Impacts of ionic interactions on gel formation were studied in detail and showed that pH can be used to modify many hydrogel properties including sol-gel temperature, crystallinity, and mechanical strength. It was also observed that pH modification of the hydrogels affected nanoparticle formation. Nanoparticles derived from a Group of Uniform Materials Based on Organic Salts (nanoGUMBOS), …