Chemistry Commons^™

Tellurorhodamine Photocatalysts In Aerobic Oxidation Reactions: Development Of Synthetic Methods And Reaction Mechanisms, Irving D. Rettig

Dissertations and Theses

Aerobic oxidation photocatalysis involves the use of oxygen as an oxidant species, coupled to a light driven catalyst to achieve useful chemical transformations. Catalytic aerobic oxidation reactions can be defined as either oxidase-like, in which O₂ acts as an electron donor/acceptor but is not incorporated into the reaction products, or oxygenase-like where O₂ acts as an electron donor/acceptor and is incorporated into the reaction products. A multitude of inorganic catalysts have been developed that can achieve a wide scope of oxidase-like or oxygenase-like reactivity, however, it is rare for a catalyst to be capable of both. We report …

Analytical Survey Of Tattoo Inks—A Chemical And Legal Perspective With Focus On Sensitizing Substances, Xuying Wang, Leila Josefsson, Silvia Meschnark, Marie-Louise Lind, Åsa Emmer, Walter Goessler, Yolanda S. Hedberg

Chemistry Publications

Background

Tattoo inks have been reported to elicit allergic contact dermatitis.

Objectives

To investigate the labels and the contents of metals and pigments in tattoo inks, considering restrictions within the European Union.

Methods

Seventy-three tattoo inks currently available on the market, either bought or donated (already used), were investigated for trace metals and pigments by inductively coupled plasma mass spectrometry and by matrix-assisted laser desorption/ionization time of flight tandem mass spectrometry.

Results

Ninety-three percent of the bought tattoo inks violated European, legal requirements on labeling. Fifty percent of the tattoo inks declared at least one pigment ingredient incorrectly. Sixty-one percent …

Colossal Density-Driven Resistance Response In The Negative Charge Transfer Insulator Mns2, Dylan Durkee, Nathan Dasenbrock-Gammon, G. Alexander Smith, Elliot Snider, Dean Smith, Christian Childs, Simon A.J. Kimber, Keith V. Lawler, Ranga P. Dias, Ashkan Salamat

Chemistry and Biochemistry Faculty Research

A reversible density driven insulator to metal to insulator transition in high-spin MnS2 is experimentally observed, leading with a colossal electrical resistance drop of 108 ω by 12 GPa. Density functional theory simulations reveal the metallization to be unexpectedly driven by previously unoccupied S22- σ3p∗ antibonding states crossing the Fermi level. This is a unique variant of the charge transfer insulator to metal transition for negative charge transfer insulators having anions with an unsaturated valence. By 36 GPa the emergence of the low-spin insulating arsenopyrite (P21/c) is confirmed, and the bulk metallicity is broken with the system returning to an …

Investigations Into Size And Surface Control Of Silicon Nanocrystals For Improved Optical Properties, James Donald Barnes

Dissertations and Theses

The discovery of visible photoluminescence (PL) from nanocrystalline porous silicon in 1990 led to extensive research into the mechanisms of the emergent properties, and optimization of these properties, for use in applications. The widespread use of silicon nanoparticles (Si NPs) in commercial applications is currently limited by three main factors: 1) poor radiative recombination efficiency of the interband transition, 2) instability of the interband photoluminescence, and 3) a lack of scalable methods for producing Si NPs that are both highly crystalline and size monodisperse.

To address these limitations, this dissertation correlates changes in the photoluminescence properties of hydrogen passivated silicon …

The 2021 Flexible And Printed Electronics Roadmap, Yvan Bonnassieux, Christoph J. Brabec, Yong Cao, Tricia Breen Carmichael, Michael L. Chabinyc, Kwang Ting Cheng, Gyoujin Cho, Anjung Chung, Corie L. Cobb, Andreas Distler, Hans Joachim Egelhaaf, Gerd Grau, Xiaojun Guo, Ghazaleh Haghiashtiani, Tsung Ching Huang, Muhammad M. Hussain, Benjamin Iniguez, Taik Min Lee, Ling Li, Yuguang Ma, Dongge Ma, Michael C. Mcalpine, Tse Nga Ng, Ronald Österbacka

Chemistry and Biochemistry Publications

This roadmap includes the perspectives and visions of leading researchers in the key areas of flexible and printable electronics. The covered topics are broadly organized by the device technologies (sections 1–9), fabrication techniques (sections 10–12), and design and modeling approaches (sections 13 and 14) essential to the future development of new applications leveraging flexible electronics (FE). The interdisciplinary nature of this field involves everything from fundamental scientific discoveries to engineering challenges; from design and synthesis of new materials via novel device design to modelling and digital manufacturing of integrated systems. As such, this roadmap aims to serve as a resource …

Conducting Materials As Building Blocks For Electronic Textiles, Anja Lund, Yunyun Wu, Benji Fenech-Salerno, Felice Torrisi, Tricia Breen Carmichael, Christian Müller

Chemistry and Biochemistry Publications

Abstract: To realize the full gamut of functions that are envisaged for electronic textiles (e-textiles) a range of semiconducting, conducting and electrochemically active materials are needed. This article will discuss how metals, conducting polymers, carbon nanotubes, and two-dimensional (2D) materials, including graphene and MXenes, can be used in concert to create e-textile materials, from fibers and yarns to patterned fabrics. Many of the most promising architectures utilize several classes of materials (e.g., elastic fibers composed of a conducting material and a stretchable polymer, or textile devices constructed with conducting polymers or 2D materials and metal electrodes). While an increasing number …

Pressure Driven Desalination Membranes: Lyotropic Liquid Crystals Containing Single Walled Carbon, Matteo A. Del Giudice, Samantha Castillo Merigold

Materials Engineering

This project presents a potential alternative desalination technique that utilizes the ion rejection properties of single walled carbon nanotubes dispersed in a lyotropic liquid crystal (LLC) matrix. Previous research has pointed to the polymerizable surfactant methacryloxy ethyl hexadecyl dimethyl ammonium bromide (C16MA) having capabilities of filtering molecular components smaller than a nanometer, when oriented in cylindrical micelles. SWCNTs were dispersed in deionized water by probe sonication and addition of surfactant cetyltrimethylammonium bromide (CTAB) due to SWCNTs’ hydrophobic properties. Membranes were produced containing 55wt% C16MA, 37wt% DI water, 0.1wt% with respect to the monomer (WRM) SWCNTs, 1.9 wt% WRM 2,2-dimethoxy-2-phenylacetophenone (photointiator), …

College Of Natural Sciences Newsletter, June 2021, College Of Natural Sciences

College of Natural Sciences Newsletters and Reports

Volume 2, Issue 6.

Page 1 Dean's Message
Page 2-6 Remembering the Life of Dr. Pengra and Celebrating His legacy for Entire Generations to Come.

Repurposing Drugs To Treat Heart And Brain Illness, Maranda S. Cantrell, Alejandro Soto-Avellaneda, Jackson D. Wall, Aaron D. Ajeti, Brad E. Morrison, Lisa R. Warner, Owen M. Mcdougal

Chemistry and Biochemistry Faculty Publications and Presentations

Drug development is a complicated, slow and expensive process with high failure rates. One strategy to mitigate these factors is to recycle existing drugs with viable safety profiles and have gained Food and Drug Administration approval following extensive clinical trials. Cardiovascular and neurodegenerative diseases are difficult to treat, and there exist few effective therapeutics, necessitating the development of new, more efficacious drugs. Recent scientific studies have led to a mechanistic understanding of heart and brain disease progression, which has led researchers to assess myriad drugs for their potential as pharmacological treatments for these ailments. The focus of this review is …

Linear Discriminant Analysis Based On Gas Chromatographic Measurements For Geographical Prediction Of Usa Medical Domestic Cannabis, Ramia Z. Al Bakain, Yahya S. Al-Degs, James V. Cizdziel, Mahmoud A. Elsohly

Faculty and Student Publications

Fifty four domestically produced cannabis samples obtained from different USA states were quantitatively assayed by GC-FID to detect 22 active components: 15 terpenoids and 7 cannabinoids. The profiles of the selected compounds were used as inputs for samples grouping to their geographical origins and for building a geographical prediction model using Linear Discriminant Analysis. The proposed sample extraction and chromatographic separation was satisfactory to select 22 active ingredients with a wide analytical range between 5.0 and 1,000 μg/mL. Analysis of GC-profiles by Principle Component Analysis retained three significant variables for grouping job (Δ9-THC, CBN, and CBC) and the modest discrimination …

Photosensitization And Analytical Study On Reactive Oxygen Intermediates: Self-Sorting Surface Radicals And “On-Off” Sensitizer Function Mechanisms, Sarah J. Belh

Dissertations, Theses, and Capstone Projects

This thesis consists of four chapters which are detailed below. Chapter 1 is an introductory chapter, which lays out the background and purpose of the research.

Chapter 2 describes a study of the mobility of alkoxy radicals on a surface by detection of their recombination product. A novel method called symmetrical product recombination (SRP) utilizes an unsymmetrical peroxide that upon sensitized homolysis recombines to a symmetrical product [R'OOR → R'O•↑ + •OR → ROOR]. This allows for self-sorting of the radical to enhance the recombination path to a symmetrical product, which has been used to deduce surface migratory aptitude. SPR …

Tailored Porous Carbons Enabled By Persistent Micelles With Glassy Cores, Eric R. Williams, Paige L. Mcmahon, Joseph E. Reynolds Iii, Jonathan L. Snider, Vitalie Stavila, Mark Allendorf, Morgan Stefik

Faculty Publications

Porous nanoscale carbonaceous materials are widely employed for catalysis, separations, and electrochemical devices where device performance often relies upon specific and well-defined regular feature sizes. The use of block polymers as templates has enabled affordable and scalable production of diverse porous carbons. However, popular carbon preparations use equilibrating micelles which can change dimensions in response to the processing environment. Thus, polymer methods have not yet demonstrated carbon nanomaterials with constant average template diameter and tailored wall thickness. In contrast, persistent micelle templates (PMTs) use kinetic control to preserve constant micelle template diameters, and thus PMT has enabled constant pore diameter …

Formulating 3-Chloropropyltriethoxysilane Modified Silica Nanoparticle Sprays As Hydrophobic Transparent Coatings Onto Cotton Textiles, Mikaela C. S. Mendoza, Gilbert U. Yu

Chemistry Faculty Publications

Cotton textiles were transformed into hydrophobic fabrics via the application of 3-chloropropylthriethoxysilane-functionalized silica nanoparticle spray coatings. Silica particles were measured to be < 50 nm, as determined by dynamic light scattering (DLS). The incorporation of hexadecyltrimethylammonium bromide (HTAB), a surfactant, into the nanosilica alcohol-based sprays resulted in a suspension that was stable for at least a week. Stability and turbidity tests of samples point to smaller particle size (silica nanoparticles = 24.3 ± 8.5 nm) as the main contributor to possibly providing transparency, as evidenced when sprayed in colored (black) textiles, while still contributing to hydrophobicity/ superhydrophobicity of the cloth.

Iron And Iodine-Mediated Reactions, Xiaochen Liu

Dissertations, Theses, and Capstone Projects

This thesis work focuses on developing facile, low-cost, and environmentally friendly reactions, specifically the iron and iodine-mediated reactions, including (1) iron-catalyzed reductive ring-opening of 3,5-disubstituted isoxazoles and isoxazolines in aged N-methyl-2-pyrrolidone (NMP*), (2) iodine-mediated C-N bond cross-coupling reactions between amides and aldehydes, and (3) ICl-mediated functionalization of β-alkoxy alkynes – synthesis of α-iodo-γ-chloro-ketones.

Chapter I provides a background introduction on previous synthesis and applications of β-enaminones and 1,3-diketones that play as synthons or ligands. Ring-openings of heterocycles, such as isoxazoles and isoxazolines have attracted great attentions. A newly developed iron-catalyzed reductive system was established upon our previous palladium-catalyzed research. …

Mechanistic And Synthetic Studies Of Oxidopyrylium Cycloaddition Reactions, Lauren P. Bejcek

Dissertations, Theses, and Capstone Projects

Cycloaddition chemistry has historically served as a robust route to stereo-rich and highly functionalized cyclic and heterocyclic compounds. Herein we describe our examination of 3-hydroxy-4-pyrone-derived oxidopyrylium cycloadditions in both mechanistic considerations as well as the unique synthetic advancements of their corresponding cycloadducts. Chapter 1 is a literature review where we specifically outline the use of oxidopyrylium cycloadditions in the synthesis of natural products. This includes the mention of previous syntheses prior to 2008, and a more thorough examination of the natural products synthesized from 2008 to present. The work exploits this chemistry as a facile route to highly complex 7-membered …

Design, Synthesis And Evaluation Of Molecules With Selective And Poly-Pharmacological Actions At D1r, D3r And Sigma Receptors, Pierpaolo Cordone

Dissertations, Theses, and Capstone Projects

The dopamine D3 receptor (D3R) is one of the most studied receptors involved in drug addiction. One of the most common strategies to treat substance use disorders is via D3R antagonism. The majority of the D3R antagonists synthesized so far have poor pharmacokinetic properties and/or lack selectivity toward D3R. In this thesis, the design, synthesis and biological evaluation of novel molecules that target the dopamine D1 receptor (D1R), D3R and the serendipitous discovery of molecules that target s receptors will be described.

Chapter 1 presents a survey of the fundamental pharmacology of D1R, D3R and s receptors and the therapeutic …

Computational Modeling Of Water And Proteins In Drug Discovery, Anthony Cruz Balberdy

Dissertations, Theses, and Capstone Projects

This thesis aims to improve how structural and thermodynamic properties of water on protein surfaces can be exploited to aid early stage drug discovery and lead optimization. We first discuss our development of SSTMap, a public domain software suite that maps out the properties of water on biomolecular surfaces. We then show the utility of these maps in describing differences in binding affinities between congeneric pairs of ligands. We then discuss our use of solvation maps in the prospective discovery of novel binders to cytochrome C peroxidase. Finally, we present our creation and validation of a homology model of Interleukin-24 …

Synthetic And Biological Studies On Benzazepine Derivatives As Dopamine Receptor Ligands, Rajan Giri

Dissertations, Theses, and Capstone Projects

Dopamine (DA) receptors, members of the G-protein coupled receptors (GPCRs) family, are divided in two groups based on their transmembrane structural homology domains: D1R-like (D1R, D5R sub-types) and D2R-like DA receptors (D2R, D3R and D4R sub-types). Disturbances in dopaminergic neurotransmission are associated with several CNS disorders. Hence, DA receptor selective ligands have been sought as pharmacological agents to normalize perturbations in the dopaminergic system. Despite several notable efforts, the discovery of highly selective ligands for dopamine receptor sub-types has proved challenging due to close transmembrane structural similarity, especially between DA receptor sub-types within the same group.

The 1-phenylbenzazepine scaffold is …

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 …

Reconstituting The Cyanobacterial Circadian Clock In Vitro, Pyong Hwa Kim

Dissertations

Cyanobacteria are photosynthetic organisms that are known to be responsible for oxygenating Earth’s early atmosphere. Having evolved to ensure optimal survival in the periodic light/dark cycle on this planet, their genetic codes are packed with various tools, including a sophisticated biological timekeeping system. Among the cyanobacteria is Synechococcus elongatus PCC 7942, the simplest clock-harboring organism with a powerful genetic tool that enabled the identification of its intricate timekeeping mechanism. The three central oscillator proteins—KaiA, KaiB, and KaiC—drive the 24 h cyclic gene expression rhythm of cyanobacteria, and the "ticking" of the oscillator can be reconstituted inside a test tube just …