Chemistry Commons^™

Attempted Synthesis Of 4’-Hydroxyacetophenone-1h-Benzotriazole By Benzyne-Azide Click Chemistry, Kevin Kee-Hoe Cheah

Theses

Ultraviolet light absorber or stabilizer (UVLS) is one of the many additives that is incorporated into a polymer formulation which functions by preferentially absorbing the UV light to prevent its photodegradation. UVLS such as 2-hydroxyphenylbenzotriazole (2H-BZT) and its derivatives are commercially used UV-light absorbers in different polymers. The synthesis of 2H-benzotriazoles solely relies on the two-step azo-coupling of the diazonium salt and reductive cyclization where the former reaction suffers from poor yield.1 The presence of a phenolic hydrogen in the ortho position to the phenyl ring attached to the nitrogen atom on the benzotriazole imparts excellent photochemical stability to the …

Single-Molecule Analysis Of I-Motif Within Self-Assembled Dna Duplexes And Nanocircles, Anoja Megalathan, Bobby D. Cox, Peter D. Wilkerson, Anisa Kaur, Kumar Sapkota, Joseph E. Reiner, Soma Dhakal

Chemistry Publications

The cytosine (C)-rich sequences that can fold into tetraplex structures known as i-motif are prevalent in genomic DNA. Recent studies of i-motif–forming sequences have shown increasing evidence of their roles in gene regulation. However, most of these studies have been performed in short single-stranded oligonucleotides, far from the intracellular environment. In cells, i-motif–forming sequences are flanked by DNA duplexes and packed in the genome. Therefore, exploring the conformational dynamics and kinetics of i-motif under such topologically constrained environments is highly relevant in predicting their biological roles. Using single-molecule fluorescence analysis of self-assembled DNA duplexes and nanocircles, we show that the …

Spatial Variability Of Manganese Oxide In Two Soilscapes: Upland-Lowland, And Riparian Buffer-Wetland Boundary- Wetland, Benjamin Onweni, Richard Griffin, Robert Thomas, Edward Timms, Javon Polk, Annette James

Pursue: Undergraduate Research Journal

Background: This research project describes the development

of a quantitative measurement methodology to determine the

concentration of manganese oxide (MnOx) in two soilscape

positions (Upland- Lowland and Riparian Buffer-Wetland

Boundary-Wetland). Methods: A reaction between the MnOx

in the soil sample and hydrogen peroxide (H2O2) was initiated

to determine the level of MnOx reactivity in the soil sample. Data

was collected from four sites on Soilscape 1 (Upland, Lowland,

and two sites between the Uplands and Lowlands); within each

site, five soil profile depths and three sample replicates were

measured which comprised a total of 60 samples. Additionally,

data was collected …

Fluorogenic Atom Transfer Radical Polymerization In Aqueous Media As A Strategy For Detection, Zachary T. Allen, Jemima R. Sackey-Addo, Madeline P. Hopps, Danyal Tahseen, Joseph T. Anderson, Tyler A. Graf, Christina B. Cooley

Chemistry Faculty Research

The development of novel approaches to signal amplification in aqueous media could enable new diagnostic platforms for the detection of water-soluble analytes, including biomolecules. This paper describes a fluorogenic polymerization approach to amplify initiator signal by the detection of visible fluorescence upon polymerization in real-time. Fluorogenic monomers were synthesized and co-polymerized by atom transfer radical polymerization (ATRP) in water to reveal increasing polymer fluorescence as a function of both reaction time and initiator concentration. Optimization of the fluorogenic ATRP reaction conditions allowed for the quantitative detection of a small-molecule initiator as a model analyte over a broad linear concentration range …

Reduction Of Co2 By A Masked Two-Coordinate Cobalt(I) Complex And Characterization Of A Proposed Oxodicobalt(Ii) Intermediate, L. Roy, M. H. Al-Afyouni, D. E. Derosha, B. Mondal, I. M. Dimucci, K. M. Lancaster, Jason M. Shearer, E. Bill, W. W. Brennessel, F. Neese, S. Ye, P. L. Holland

Chemistry Faculty Research

Fixation and chemical reduction of CO₂ are important for utilization of this abundant resource, and understanding the detailed mechanism of C-O cleavage is needed for rational development of CO₂ reduction methods. Here, we describe a detailed analysis of the mechanism of the reaction of a masked two-coordinate cobalt(i) complex, L^tBuCo (where L^tBu = 2,2,6,6-tetramethyl-3,5-bis[(2,6-diisopropylphenyl)imino]hept-4-yl), with CO₂, which yields two products of C-O cleavage, the cobalt(i) monocarbonyl complex L^tBuCo(CO) and the dicobalt(ii) carbonate complex (L^tBuCo)₂(μ-CO₃). Kinetic studies and computations show that the …

Development And Characterization Of An Inexpensive Single-Particle Fluorescence Spectrometer For Detection And Classification Of Pollen And Other Bioaerosols, Benjamin E. Swanson

Electronic Theses and Dissertations

Atmospheric aerosols are ubiquitous throughout the Earth’s atmosphere and can be important with respect to environmental systems and human health. Pollen particles are a class of primary biological aerosol particles (PBAPs) that cost the United States billions of dollars a year in loss of productivity and healthcare costs due to allergy and respiratory effects. Traditional methods of pollen detection rely on collection and subsequent identification by visual microscopy, yet few measurement stations exist in the United States. As such, current pollen forecasting models have relatively high prediction uncertainty, especially in regions without sampling stations. Recently, laser-induced fluorescence instrumentation has been …

Development Of A Hek293 Cell Line To Show Inhibition Of Tau Aggregation, Justin Ray Shady

Electronic Theses and Dissertations

Intracellular deposition of aggregated tau is the hallmark of several different tauopathies, the most widespread of these being Alzheimer's disease. Tau is a highly soluble, intrinsically disordered, microtubule associated protein. Tau's native function is to stabilize microtubule formation in the axons of neurons. Post translational modification such as hyperphosphorylation as well as several familial mutations allow tau to nucleate and form fibrils. These fibrils can recruit healthy monomers onto their ends in a fashion described as template-assisted growth. Tau has 6 isoforms that vary by the inclusion or exclusion of two N-terminal repeats and the inclusion or exclusion of the …

Conductivity, Viscosity, Spectroscopic Properties Of Organic Sulfonic Acid Solutions In Ionic Liquids, A. T. Tran, J. Tomlin, P. H. Lam, B. L. Stinger, A. D. Miller, D. J. Walczyk, O. Cruz, Timothy Vaden, Lei Yu

College of Science & Mathematics Departmental Research

Sulfonic acids in ionic liquids (ILs) are used as catalysts, electrolytes, and solutions for metal extraction. The sulfonic acid ionization states and the solution acid/base properties are critical for these applications. Methane sulfonic acid (MSA) and camphor sulfonic acid (CSA) are dissolved in several IL solutions with and without bis(trifluoromethanesulfonyl)imine (HTFSI). The solutions demonstrated higher conductivities and lower viscosities. Through calorimetry and temperature-dependent conductivity analysis, we found that adding MSA to the IL solution may change both the ion migration activation energy and the number of “free” charge carriers. However, no significant acid ionization or proton transfer was observed in …

Influence Of Applied Potential And Metal Ion Concentraion On Metal Electrodeposition At Micron Gap Gold Electrodes, Krista Michel Riggins

Online Theses and Dissertations

Zamborini and Coworkers developed, a simple, low cost, and highly parallel electrochemical approach for fabricating nano-scale (metal/metal) or molecular (metal/polymer or self-assembled monolayer (SAM)/metal) junctions that should be useful in preparing working sensors and molecular electronic devices. The fabrication of metal/metal junctions involves metal deposition on one set of electrodes (E1), where the metal grows and becomes connected to a second set of electrodes (E2) of an Au interdigitated array of electrodes with a 5 µm separation. However, when different metals were deposited, they deposited in different fashions. Ag grew in the form of wires and Palladium deposited in the …

Acue Reflection From A Stem Perspective, Ashley Vizenor

Q2S Enhancing Pedagogy

The following document contains reflections from various activities of the ACUE workshop. Activities pertain to syllabus editing, classroom conduct, and effective teaching practices.

Anti-Hypochlorite And Catalytic Activity Of Commercially Available Moringa Oleifera Diet Supplement, Karolina Starzak, Bernadette Creaven, Arkadiusz Matwijczuk, Alicja Matwijczuk, Dariusz Karcz

Articles

Aiming at the assessment of the pro-health, and especially anti-hypochlorite properties of Moringa oleifera species a representative, commercially available Moringaoleifera dietary supplement was used as a substrate for the preparation of aqueous Moringa extract. The anti-hypochlorite activity of the extract was assessed using the hypochlorite-specific coumarin-based fluorescence turn-off sensor, namely 7-diethylamino-coumarin-3-carboxylic acid (7-DCCA). This compound was synthesized via the Knoevenagel condensation of 4-diethylamino-2-hydroxybenzaldehyde with Meldrum’sacidandtheMoringaextractwasemployedasamediumandcatalyst. Moreover,thetotal phenoliccontent(TPC)aswellasthereactiveoxygenspecies(ROS)–scavengingabilityoftheaqueous Moringa extract were determined. The results obtained demonstrated the applicability of Moringa extract as an anti-hypochlorite agent. Additionally, the satisfactory yield of the 7-DCCA obtained suggests the usefulness of the extract as a …

Electrochemical Enzyme-Linked Immunosorbent Assay (E-Elisa) For Parasitic Nematode: Ostertagia Ostertagi (Brown Stomach Worm) Infections In Dairy Cattle, Baljit Singh, Evangelia Flampouri, Eithne Dempsey

Articles

A sensitive electrochemical immunoassay (e-ELISA) has been developed for the detection of the gastrointestinal parasitic nematode Ostertagia ostertagi (brown stomach worm) in infected and control serum samples. An antigen-indirect immunoassay format was employed to detect the presence of O. ostertagi antibodies, coupled with an anti-species monoclonal horseradish peroxidase (HRP) conjugate. ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)) and TMB (3,3',5,5'-tetramethylbenzidine/hydrogen peroxide) were investigated as both chromogenic visualising reagents for optical ELISA and electroactive substrates for electrochemical ELISA in the HRP catalysed oxidation reaction. Coulometry was applied for the detection of O. ostertagi antibodies (via TMB electrochemistry) and compared with the commercial optical ELISA (ABTS …

Ua66/1/4 Ogden College Of Science & Engineering Dean's Office Student & Faculty Organizations, Wku Archives

WKU Archives Collection Inventories

Records created by and about student and faculty organizations in the Ogden College of Science & Engineering.

Ua84 Sigma Chi, Wku Archives

WKU Archives Collection Inventories

Records created by and about the WKU chapter of Sigma Xi.

Ua66/7/1 Ogden College Of Science & Engineering Chemistry Administration, Wku Archives

WKU Archives Collection Inventories

Records created by and about the Chemistry department.

Ua66/7/2 Ogden College Of Science & Engineering Chemistry Publications, Wku Archives

WKU Archives Collection Inventories

Publications created by and about the WKU Chemistry department.

Photoassisted Synthesis Of Complex Polyheterocycles Via Esipt-Driven Dearomative Intramolecular Cycloadditions, Dmitry Kuznetsov

Electronic Theses and Dissertations

This research is focused on the development of novel photoassisted synthetic methodologies that provide straightforward access to complex and diverse libraries of polyheterocycles from modularly assembled precursors. All methods are based on the dearomative cycloadditions between two components: (i) o-azaxylylenes, generated by the excited-state intramolecular proton transfer, and (ii) tethered arene groups.

We have demonstrated the synthetic utility of four new photoinduced processes that yield complex products amenable for post-photochemical modifications:

• [4+4] Cycloaddition of o-azaxylylenes to 1,3,4-oxadiazoles with subsequent dinitrogen extrusion. This reaction furnishes compounds outfitted with epoxide fragments, which undergo ring-openings with various nucleophiles; furthermore, the oxidized products …

Inhibition Of Pseudomonas Aeruginosa Biofilm Formation With Surface Modified Polymeric Nanoparticles, Tyler R. Flockton, Logan Schnorbus, Agustin Araujo, Jill Adams, Maryjane Hammel, Lark Perez

College of Science & Mathematics Departmental Research

The gram-negative bacterial pathogen Pseudomonas aeruginosa represents a prominent clinical concern. Due to the observed high levels of antibiotic resistance, copious biofilm formation, and wide array of virulence factors produced by these bacteria, new treatment technologies are required. Here, we present the development of a series of P. aeruginosa LecA-targeted polymeric nanoparticles and demonstrate the anti-adhesion and biofilm inhibitory properties of these constructs.

In Vitro Uptake And Biodistribution Of Silver Nanoparticles In Vero 76 Cells, Miriam A. Crane

Browse all Theses and Dissertations

The number of consumer products containing nanomaterials over the last eight years has increased over two-fold. Silver is one of the most commonly used materials in consumer goods nanoparticle fabrication.1 Thus, the uptake and biodistribution of silver nanoparticles (AgNPs) within mammalian cells can provide insight into their possible toxicological effects. In this study, starch-capped AgNPs of an average diameter of 9 ± 5 nm were synthesized via a bottom-up method, and characterized by Raman spectroscopy, transmission electron microscopy (TEM), inductively couple plasma optical emission spectroscopy (ICP-OES), and absorption spectroscopy. Vero 76 cells were incubated with 0.0, 0.1, 1.0, and 3.0 …

Molecular Dynamics Simulations In First-Semester General Chemistry: Visualizing Gas Particle Motion And Making Connections To Mathematical Gas Law Relationships, Chrystal D. Bruce

2019 Faculty Bibliography

Implementation of a freely available molecular dynamics (MD) software program in a general chemistry class to assist students in learning the relationship among particle motion, macroscopic properties, and mathematical gas laws is described. In this activity, students acquire skills in data analysis while developing a deeper understanding of the origin of macroscopic physical properties of gases. The activity is easy to implement and does not require significant expertise in computational chemistry on the part of the instructor.

Past, Present, And Future Of Waste Cooking Oil (Beyond Biofuel), Jihyun Kim

Open Educational Resources

In this project, students in “General Chemistry” will explore the development of a facile, eco-friendly, and simple preparation method of fluorescent carbon dots (CDs) from a mixture of waste cooking oil and orange waste peels. Orange waste peels are one of the most underutilized bio-waste residues on earth, therefore, it would make better sense to utilize a mixture of the two wastes.

Anchoring Cu 1 Species Over Nanodiamond-Graphene For Semi-Hydrogenation Of Acetylene, Fei Huang, Yuchen Deng, Yunlei Chen, Xiangbin Cai, Mi Peng, Zhimin Jia, Jinglin Xie, Dequan Xiao, Xiaodong Wen, Ning Wang, Zheng Jiang, Hongyang Liu, Ding Ma

Chemistry and Chemical Engineering Faculty Publications

The design of cheap, non-toxic, and earth-abundant transition metal catalysts for selective hydrogenation of alkynes remains a challenge in both industry and academia. Here, we report a new atomically dispersed copper (Cu) catalyst supported on a defective nanodiamondgraphene (ND@G), which exhibits excellent catalytic performance for the selective conversion of acetylene to ethylene, i.e., with high conversion (95%), high selectivity (98%), and good stability (for more than 60 h). The unique structural feature of the Cu atoms anchored over graphene through Cu-C bonds ensures the effective activation of acetylene and easy desorption of ethylene, which is the key for the outstanding …

A Versatile Route To Fabricate Single Atom Catalysts With High Chemoselectivity, Xiaohui He, Qian He, Yuchen Deng, Mi Peng, Hongyu Chen, Ying Zhang, Siyu Yao, Mengtao Zhang, Dequan Xiao, Ding Ma, Binghui Ge, Hongbing Ji

Chemistry and Chemical Engineering Faculty Publications

Preparation of single atom catalysts (SACs) is of broad interest to materials scientists and chemists but remains a formidable challenge. Herein, we develop an efficient approach to synthesize SACs via a precursor-dilution strategy, in which metalloporphyrin (MTPP) with target metals are co-polymerized with diluents (tetraphenylporphyrin, TPP), followed by pyrolysis to N-doped porous carbon supported SACs (M₁/N-C). Twenty-four different SACs, including noble metals and non-noble metals, are successfully prepared. In addition, the synthesis of a series of catalysts with different surface atom densities, bi-metallic sites, and metal aggregation states are achieved. This approach shows remarkable adjustability and generality, providing …

Rigorous Computational And Experimental Investigations On Mdm2/Mdmx-Targeted Linear And Macrocyclic Peptides, David J. Diller, Jon Swanson, Alexander S. Bayden, Chris J. Brown, Dawn Thean, David P. Lane, Anthony W. Patridge, Tomi K. Sawyer, Joseph Audie

Chemistry & Physics Faculty Publications

There is interest in peptide drug design, especially for targeting intracellular protein–protein interactions. Therefore, the experimental validation of a computational platform for enabling peptide drug design is of interest. Here, we describe our peptide drug design platform (CMDInventus) and demonstrate its use in modeling and predicting the structural and binding aspects of diverse peptides that interact with oncology targets MDM2/MDMX in comparison to both retrospective (pre-prediction) and prospective (post-prediction) data. In the retrospective study, CMDInventus modules (CMDpeptide, CMDboltzmann, CMDescore and CMDyscore) were used to accurately reproduce structural and binding data across multiple MDM2/MDMX data sets. In the prospective study, CMDescore, …

Reaction Mechanism Between Small-Sized Ce Clusters And Water Molecules: An Ab Initio Investigation On CeN+H2O, Rulong Zhou, Yang Yang, Seema Pande, Bingyan Qu, Dongdong Li, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Reactions of small-sized cerium clusters Ce_n (n = 1–3) with a single water molecule are systematically investigated theoretically. The ground state structures of the Ce_n/H₂O complex and the reaction pathways between Ce_n + H₂O are predicted. Our results show the size-dependent reactivity of small-sized Ce clusters. The calculated reaction energies and reaction barriers indicate that the reactivity between Ce_n and water becomes higher with increasing cluster size. The predicted reaction pathways show that the single Ce atom and the Ce₂ and Ce₃ clusters can all easily react with H …

Coherent Vibrational And Dissociation Dynamics Of Polyatomic Radical Cations, Katharine M. Tibbetts

Chemistry Publications

The ultrafast dynamics of polyatomic radical cat- ions contribute to important processes including energy transfer in photovoltaics, electron transfer in photocataly- sis, radiation-induced DNA damage, and chemical reac- tions in the upper atmosphere and space. Probing these dynamics in the gas phase is challenging due to the rapid dissociation of polyatomic radical cations following elec- tron removal, which arises from excess electronic excita- tion of the molecule during the ionization process. This Concept article introduces the reader to how the pump- probe technique of femtosecond time-resolved mass spectrometry (FTRMS) can overcome this challenge to capture coherent vibrational dynamics on the …

Probing Coherent Vibrations Of Organic Phosphonate Radical Cations With Femtosecond Time-Resolved Mass Spectrometry, Derrick Ampadu Boateng, Mi'kayla D. Word, Katharine M. Tibbetts

Chemistry Publications

Organic phosphates and phosphonates are present in a number of cellular components that can be damaged by exposure to ionizing radiation. This work reports femtosecond time-resolved mass spectrometry (FTRMS) studies of three organic phosphonate radical cations that model the DNA sugar-phosphate backbone: dimethyl methylphosphonate (DMMP), diethyl methylphosphonate (DEMP), and diisopropyl methylphosphonate (DIMP). Upon ionization, each molecular radical cation exhibits unique oscillatory dynamics in its ion yields resulting from coherent vibrational excitation. DMMP has particularly well-resolved 45 fs (732 ± 28 cm−1) oscillations with a weak feature at 610–650 cm−1, while DIMP exhibits bimodal oscillations with a period of ∼55 fs …

Multifaceted Water Dynamics In Spherical Nanocages, M. Von Domaros, D. Bratko, B. Kirchner, G. Hummer, A. Luzar

Chemistry Publications

We present a new method to study position- dependent, anisotropic diffusion tensors inside spherically confined systems—a geometry that is common to many chemical nanoreactors. We use this method to elucidate the surprisingly rich solvent dynamics of confined water. The spatial variation of the strongly anisotropic diffusion predicted by the model agrees with the results of explicit molecular dynamics simulations. The same approach can be directly transferred to the transport of solutes to and from reaction sites located at nanoreactor interfaces. We com- plement our study by a detailed analysis of wa- ter hydrogen bond kinetics, which is intimately coupled to …

Molecular Polarizability In Open Ensemble Simulations Of Aqueous Nanoconfinements Under Electric Field, F. Moucka, S. Zamfir, D. Bratko, A. Luzar

Chemistry Publications

Molecular polarization at aqueous interfaces involves fast degrees of freedom that are often averaged-out in atomistic-modeling approaches. The resulting effective interactions depend on a specific environment, making explicit account of molecular polarizability particularly important in solutions with pronounced anisotropic perturbations, including solid/liquid interfaces and external fields. Our work concerns polarizability effects in nanoscale confinements under electric field, open to an unperturbed bulk environment. We model aqueous molecules and ions in hydrophobic pores using the Gaussian-charge-on-spring BK3-AH representation. This involves nontrivial methodology devel- opments in expanded ensemble Monte Carlo simulations for open systems with long-ranged multibody interactions and necessitates further improvements …

Role Of Water On The Rotational Dynamics Of The Organic Methylammonium Cation: A First Principles Analysis, Ross D. Hoehn, Joseph S. Francisco, Sabre Kais, Ali Kachmar

Department of Chemistry: Faculty Publications

Understanding the degradation mechanisms of lead-halide perovskites (CH₃NH₃PbI₃) under exposure to liquid/aerosol water is an essential problem within the photovoltaic community. Herein we investigate both the static and the dynamic properties of the methylammonuim cation (MA) as it coordinates with invading water molecules (MA.(H₂O)_n, n = 1, 2, 3, 4) using both stationary state quantum mechanics and first principle molecular dynamics simulations. Various solvation structures of MA were characterized by their stabilization energies, dipoles, and Maximally-Localized Wannier Function (MLWF) centers. Calculation – and analysis – of vibrational shifts in the …