Chemistry Commons^™

Molecular Recognition In Water: Design, Synthesis, And Characterization Of Rigid Molecular Receptors And Enzymatic Mechanistic Probes, Robert William Hoppe

Theses and Dissertations

Molecular recognition can be defined as a selective and reversible binding between two or more molecules through non-covalent interactions. Multiple weakly attractive intermolecular forces work in concert to achieve selectivity in association. Such discrimination is critical to the physiological processes of catalysis, transport, antigen recognition, and storage. To better understand this phenomenon, acyclic synthetic molecular receptors also known as “molecular tweezers” were made to study the inclusion of small molecule guests from water. Three anionic tweezers derivatives with syn¬- cofacial orientation were constructed from a 1,2:4,5-bis-Trӧger’s Base skeleton that differed in the amount and distribution of negative charge about the …

Structural And Functional Characterization Of Acetoacetate Decarboxylase-Like Enzymes, Lisa Mueller

Theses and Dissertations

The acetatoacetate decarboxylase-like superfamily (ADCSF) is a largely unexplored group of enzymes that may be a potential source of new biocatalysts. Bioinformatic analysis has grouped these approximately 2000 enzymes into seven different families based on comparison of predicted active site residues. To date, only the prototypical ADCs (Family I) that catalyze the decarboxylation of acetoacetate have been studied. Analysis of gene context suggests that Family V contains predominantly enzymes predicted to be involved in secondary metabolism. On average, these share about 20% sequence identity to the true ADCs. To learn more about the diversity of chemistries performed by members of …

The Synthesis Of Fluorescent 3, 6-Dihydroxyxanthones: A Route To Substituted Fluoresceins, Surajudeen Omolabake

Theses and Dissertations

ABSTRACT

THE SYNTHESIS OF FLUORESCENT 3, 6-DIHYDROXYXANTHONES:

A ROUTE TO SUBSTITUTED FLUORESCEIN

by

Surajudeen Omolabake

University of Wisconsin-Milwaukee, 2016

Under the Supervision of Professor Alan W Schwabacher

Xanthones belong to the family of compounds of the dibenzo-γ-pyrone framework. Naturally occurring xanthones have been reported to show a wide range of biological and medicinal activities including antifungal,19 antimalarial,20 antimicrobial,21 antiparasitic,22 anticancer,23 and inhibition of HIV activity in cells.24 Xanthones have also been used as a turn on fluorescent probe for metal ions,32 including use as pH indicators, metal ion sensors, in molecular biology, medicinal chemistry and in the construction of other …

The Function Of Renalase, Brett Allen Beaupre

Theses and Dissertations

Renalase was originally reported to be an enzyme secreted into the blood by the kidney to lower blood pressure and slow heart rate. Despite multiple reports claiming to confirm this activity in vivo there has been considerable discord in regards to the reaction catalyzed by renalase. The structural topology of renalase resembles that of known flavoprotein oxidases, monooxygenases and demethylases, but the conserved active site residues are unique to renalase. It has been reported that the catalytic function of renalase is to oxidize circulating catecholamines, however in vitro studies have failed to demonstrate a catalytic activity in the presence of …

Multipurpose Tenofovir Disoproxil Fumarate Electrospun Fibers For The Prevention Of Hiv-1 And Hsv-2 Infections., Kevin Tyo

Electronic Theses and Dissertations

Sexually transmitted infections affect hundreds of millions of worldwide. Both human immunodeficiency virus (HIV-1 and -2) and herpes simplex virus-2 (HSV-2) remain incurable, urging the development of new prevention strategies. While current prophylactic technologies are dependent on strict user adherence to achieve efficacy, there is a dearth of delivery vehicles that provide discreet and convenient administration, combined with prolonged-delivery of active agents. To address these needs, we created electrospun fibers (EFs) comprised of FDA-approved polymers, poly(lactic-co-glycolic acid) (PLGA) and poly(DL-lactide-co-ε-caprolactone) (PLCL), to provide sustained-release and in vitro protection against HIV-1 and HSV-2. PLGA and PLCL EFs, incorporating the antiretroviral, tenofovir …

Intramolecular 1,5-C(Sp3)–H Radical Amination Via Co(Ii)-Based Metalloradical Catalysis For Five-Membered Cyclic Sulfamides, Hongjian Lu, Kai Lang, Huiling Jiang, Lukasz Wojtas, X Peter Zhang

Chemistry Faculty Publications

Co(II)-based metalloradical catalysis (MRC) proves effective for intramolecular 1,5-C–H amination of sulfamoyl azides under neutral and nonoxidative conditions, providing a straightforward approach to access strained 5-membered cyclic sulfamides with nitrogen gas as the only byproduct. The metalloradical amination system is applicable to different types of C(sp³)–H bonds and has a high degree of functional group tolerance. Additional features of the Co(II)-catalyzed 1,5-C–H amination include excellent chemoselectivity toward allylic and propargylic C–H bonds. The unique reactivity and selectivity profile of the Co(II)-catalyzed 1,5-C–H amination is attributed to the underlying radical mechanism of MRC.

Multiple New-Particle Growth Pathways Observed At The Us Doe Southern Great Plains Field Site, Anna L. Hodshire, Michael J. Lawler, Jun Zhao, John Ortega, Coty Jen, Taina Yli-Juuti, Jared F. Brewer, Jack K. Kodros, Kelley C. Barsanti, Dave R. Hanson, Peter H. Mcmurry, James N. Smith, Jeffery R. Pierce

Civil and Environmental Engineering Faculty Publications and Presentations

New-particle formation (NPF) is a significant source of aerosol particles into the atmosphere. However, these particles are initially too small to have climatic importance and must grow, primarily through net uptake of low volatility species, from diameters ∼ 1 to 30–100 nm in order to potentially impact climate. There are currently uncertainties in the physical and chemical processes associated with the growth of these freshly formed particles that lead to uncertainties in aerosol-climate modeling. Four main pathways for new-particle growth have been identified: condensation of sulfuric-acid vapor (and associated bases when available), condensation of organic vapors, uptake of organic acids …

Development And Optimization Of Solid Polymer Electrolyte For Lithium Ion Batteries, Ladan Eskandarian

Electronic Thesis and Dissertation Repository

This thesis focuses on the development of new poly(ethylene oxide) (PEO)-based solid polymer electrolytes (SPEs) in order to enhance their ionic conductivity at ambient temperature and fabricate the prototypes of novel Li ion batteries using these SPEs. Different types of SPEs have been developed: (i) blends of high molecular weight PEO and low molecular weight poly(vinyl acetate) (PVAc); (ii) composites of high molecular weight PEO and titanium dioxide (TiO₂)nanoparticles; and (iii) blend-based composite electrolytes consisting of PEO and PVAc with dispersed TiO₂. The SPEs were characterized by scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), and …

Minimizing Corrosion Of Outdoor Metalworks Using Dispersed Chemically Stabilized Nanoclays In Polyvinylidene Fluoride Latex Coatings, Natasja Alexandria Swartz, Capri A. Price, Tami Lasseter Clare

Chemistry Faculty Publications and Presentations

Nanoclays are small enough to appear optically transparent, yet they have large surface-to-volume and high aspect ratios that can significantly inhibit water diffusion when incorporated into protective coatings. Clear coatings, which minimally affect the aesthetics of metalworks, are commonly applied to outdoor metalworks, such as sculptures, to prevent and slow corrosion. In recent years, waterborne clear coatings, rather than solvent-based clear coatings, are increasingly used in many applications to reduce the quantity of volatile organic components in the formulation, yet the performance of dry films produced from waterborne colloidal suspensions is generally poorer. In this work, we aim to improve …

Binding Properties Of Large Antiviral Polyamides (Pa1 And Pa25) And Natural Product Derivatives As Inhibitors Of Serine Hydrolases, Elena Vasilieva

Dissertations

Polyamides are a class of DNA minor groove binders that were developed from the natural product Distamycin A. PA25 (20-ring PA) showed better activity (3-fold) in the elimination of HPV16 episomes than PA1 (14-ring PA). Binding studies of PA1 and PA25 were performed in the long control region of HPV16 (7348-122 bp). PA1 showed similar binding affinity to perfect match and single mismatch binding sites. PA1 bound to double, triple, and quadruple mismatch sites with lower affinity. PA25 bound with similar binding affinity to perfect through triple mismatch binding sites. PA25 bound quadruple mismatch sites and nonspecifically. Therefore, it was …

Fulleretic Well-Defined Scaffolds: Donor–Fullerene Alignment Through Metal Coordination And Its Effect On Photophysics, Derek E. Williams, Ekaterina A. Dolgopolova, Danielle C. Godfrey, Evgeniya D. Ermolaeva, Perry J. Pellechia Dr., Andrew B. Greytak Prof. Dr., Mark Smith Dr., Stanislav M. Avdoshenko, Dr., Alexey A. Popov Dr., Natalia B. Shustova Prof. Dr.

Faculty Publications

Herein, we report the first example of a crystalline metal–donor–fullerene framework, in which control of the donor–fullerene mutual orientation was achieved through chemical bond formation, in particular, by metal coordination. The 13C cross-polarization magic-angle spinning NMR spectroscopy, X-ray diffraction, and time-resolved fluorescence spectroscopy were performed for comprehensive structural analysis and energy-transfer (ET) studies of the fulleretic donor–acceptor scaffold. Furthermore, in combination with photoluminescence measurements, the theoretical calculations of the spectral overlap function, Förster radius, excitation energies, and band structure were employed to elucidate the photophysical and ET processes in the prepared fulleretic material. We envision that the well-defined fulleretic donor–acceptor …

Mida Boronates Are Hydrolysed Fast And Slow By Two Different Mechanisms, Jorge A. Gonzalez, O. Maduka Ogba, Gregory F. Morehouse, Nicholas Rosson, Kendall N. Houk, Andrew G. Leach, Paul H.-Y. Cheong, Martin D. Burke, Guy C. Lloyd-Jones

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

MIDA boronates (N-methylimidodiacetic boronic acid esters) serve as an increasingly general platform for building-block-based small molecule construction, largely due to the dramatic and general rate differences with which they are hydrolysed under various basic conditions. Yet the mechanistic underpinnings of these rate differences have remained unclear, hindering efforts to address current limitations of this chemistry. Here we show that there are two distinct mechanisms for this hydrolysis: one is base-mediated and the other neutral. The former can proceed more than three orders of magnitude faster, and involves rate-limiting attack at a MIDA carbonyl carbon by hydroxide. The alternative ‘neutral’ hydrolysis …

Corn Stalk Nitrate Interpretation, John E. Sawyer

John E. Sawyer

You’ve gotten results from corn stalk nitrate samples collected this fall. (Corn stalk nitrate analysis form.) Now, what do the results mean? The stalk nitrate test is based on the concentration of nitrate-N in the lower corn stalk (8 inch segment from 6 to 14 inches above the ground) when the plant reaches maturity (See Cornstalk testing to evaluate nitrogen management, PM 1584). In general, a larger amount of plant-available N in the soil during the time period before plant maturity results in a greater concentration of nitrate in the lower stalk. However, the stalk nitrate-N concentration …

Corn Stalk Nitrate Interpretation, John E. Sawyer

John E. Sawyer

You’ve gotten results from corn stalk nitrate samples collected this fall. (Corn stalk nitrate analysis form.) Now, what do the results mean? The stalk nitrate test is based on the concentration of nitrate-N in the lower corn stalk (8 inch segment from 6 to 14 inches above the ground) when the plant reaches maturity (See Cornstalk testing to evaluate nitrogen management, PM 1584). In general, a larger amount of plant-available N in the soil during the time period before plant maturity results in a greater concentration of nitrate in the lower stalk. However, the stalk nitrate-N concentration can be greatly …

C60 And Sc3N@C80(Tmb-Ppo) Derivatives As Constituents Of Singlet Oxygen Generating, Thiol-Ene Polymer Nanocomposites, Emily M. Barker, Ashli R. Toles, Kyle A. Guess, J. Paige Buchanan

Faculty Publications

Numerous functionalization methods have been employed to increase the solubility, and therefore, the processability of fullerenes in composite structures, and of these radical addition reactions continue to be an important methodology. C₆₀ and Sc₃N@C₈₀ derivatives were prepared via radical addition of the photodecomposition products from the commercial photoinitiator TMB-PPO, yielding C₆₀(TMB-PPO)₅ and Sc₃N@C₈₀(TMB-PPO)₃ as preferred soluble derivatives obtained in high yields. Characterization of the mixture of isomers using standard techniques suggests an overall 1PPO:6TMB ratio of addends, reflecting the increased reactivity of the carbon radical. Although, a higher …

Expanding The Versatility Of Nano Assembled Capsules As Platform Of Potential High Payload Mri Contrast Agents, Annah Farashishiko

Dissertations and Theses

Magnetic resonance imaging (MRI) has become a powerful clinical modality in diagnostic medicine. It is non-invasive and offers high spatial and temporal resolution. The goal of molecular imaging is to reveal the pathophysiology underlying the observed anatomy and diagnose diseases. The detection of pathological biomarkers can lead to early recognition of diseases and improved monitoring for recurrence. Clinically available contrast agents are limited in their discrimination of contrast between tissues and they tend to have very high detection limits. Because biomarkers are very low in concentration there is a need for high payload deposition of contrast agent (CA) and targeted …

A New Science, And A New Profession: Sugar Chemistry In Louisiana, 1885-1895, John Alfred Heitmann

John A. Heitmann

Between 1885 and 1895 the Louisiana sugar industry experienced a scientific and technological revolution in methods, process apparatus, and scale of operations. The animal-powered mills and open kettles characteristic of the antebellum period were supplanted by large, technically designed, and scientifically controlled central factories . In 1880 there were approximately 1,000 sugar houses in Louisiana with an average annual production of 110 long tons of sugar per house. By 1900 fewer than 300 factories constituted the state's sugar industry, but yearly production averaged over 980 long tons for each sugar house. One commentator of the period, Mark Twain, described a …

Effects Of Angular Deformation On The Energetics Of The Sn2 Reaction, Vincent De Paul Nzuwah-Nziko, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Quantum calculations are applied to a number of model SN2 reactions. The halides F-, Cl-, and Br- were allowed to attack the central C atom of a set of CH2RI molecules, with R= H, CH3, CH=CH2, C≡CH, and C≡N. For each system the X∙∙C∙∙I angle was distorted in set increments from the optimized value, and the activation energy computed for each angle. The energy of the transition state rose in conjunction with this deformation. However, the distortion energy of the initial X-∙∙CH2RI reaction complex was similar in magnitude. As a result, the activation energy of the reaction was quite insensitive …

Interpretation Of Spectroscopic Markers Of Hydrogen Bonds, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Quantum calculations are used to examine whether a AH∙∙D H-bond is unambiguously verified by a downfield shift of the bridging proton’s NMR signal or a red (or blue) shift of the AH stretching frequency in the IR spectrum. It is found that such IR band shifts will occur even if the two groups experience weak or no attractive force, or if they are drawn in so close together that their interaction is heavily repulsive. The mere presence of a proton-acceptor molecule can affect the chemical shielding of a position occupied by a proton-donor by virtue of its electron density, even …

58th Annual Rocky Mountain Conference On Magnetic Resonance

Rocky Mountain Conference on Magnetic Resonance

Final program, abstracts, and information about the 58th annual meeting of the Rocky Mountain Conference on Magnetic Resonance, co-endorsed by the Colorado Section of the American Chemical Society and the Society for Applied Spectroscopy. Held in Breckenridge, Colorado, July 17-21, 2016.