Chemistry Commons^™

Measuring And Modeling Nmr And Emission Spectra To Gain New Insight Into Challenging Organic Compounds, Jacob Powell

Electronic Theses and Dissertations

The advancement of theoretical methods in recent years has allowed the calculation of highly accurate spectroscopic parameters. Comparing these values to the corresponding experimental data can allow molecular structures to be elucidated. This dissertation details the use of experimental and theoretical data from nuclear magnetic resonance (NMR) and fluorescence spectroscopy to determine structure. Herein the NMR focus is on measuring & modeling chemical shift anisotropy and one-bond carbon-carbon J-coupling constants (1JCC). The fluorescence analysis models vibrationally resolved fluorescence spectra. Chemical shift anisotropy techniques were used to study two conflicting crystal structures of the n-alkyl fatty acid, lauric acid. These two …

Two-Component Covalent Inhibitors (Tcci) Of The Human Immunodeficiency Virus Reverse Transcriptase (Hiv-Rt), Carlos Ledezma

Electronic Theses and Dissertations

The traditional design of nucleoside reverse transcriptase inhibitors (NRTI's) involves the synthesis of chain-terminated nucleoside analogs. HIV-RT has relatively low fidelity which facilitates mutations that confer resistance towards NRTI's, also, drug promiscuity from NRTI's result in various side-effects that lead to poor patient adherence to treatment. We designed and tested two-component covalent inhibitors against HIV-RT. Our inhibitor design results in higher specificity due to its binary approach, which has previously been used in biosensing applications, where both components are necessary for therapeutic effect, and lower chances for mutagenesis because of its inhibitory action. The TCCI approach results in up to …

Monitoring Crystal Structure Refinements Using Solid-State Nmr Chemical Shift Tensors, Keyton Kalakewich

Electronic Theses and Dissertations

Inclusion of lattice-fields in density functional theory (DFT) methods has enabled the accurate calculation of solid-state nuclear magnetic resonance (SSNMR) chemical shift tensors. Calculated 13C and 15N tensors (i.e. 3 principle values per nucleus) can be used to monitor crystal structure refinements and to select the correct structure from a large population of computationally generated candidates. In this dissertation, chapter 2 describes a methodology to improve established crystal structures from three different diffraction techniques involving geometric refinement monitored using SSNMR tensor values. The calculated 13C tensors for three relatively simple organic compounds (i.e. acetaminophen, naphthalene, and adenosine) are shown to …

Nitrogen-Containing Materials For Mechanochemical Synthesis, Luminescence Analysis, And Heterogeneous Catalysis, David Nash

Electronic Theses and Dissertations

Various inorganic nitrogen-containing materials have been exploited for their different properties. Several nitride materials are commercially attractive due to their mechanical properties making them suitable for ceramic industries and wide bandgaps fitting for use as semiconductor and insulator materials, as well as optoelectronics. Nitride materials can exhibit versatility in applications such as the use of gallium nitride to make blue LEDs, nitrides of titanium and silicon being utilized as medical implants for their chemical inertness and hardness, and the heavy use of boron nitride as a solid lubricant in the cosmetic industry. Amines have been used as nitrogen-containing organic ligands …

Evaluation Of Earth-Abundant Monometallic And Bimetallic Complexes For Catalytic Water Splitting, Kenneth Kwame Kpogo

Wayne State University Dissertations

The development of affordable water splitting catalysts from Earth-abundant transition metal ions such as Co and Mn is of immense scientific interest. Aiming to develop an efficient water splitting catalyst, a Co(II) complex featuring an asymmetric, pentadentate quinolyl-bispyridine ligand with a phenylenediamine backbone was synthesized and characterized by spectroscopic, spectrometric, and X-ray analysis. The Co ion was selected because of its ability to undergo redox conversions from 3d5 CoIV through 3d8 CoI thereby making it a suitable catalyst that can withstand harsh structural and electronic changes during catalysis. The electrocatalytic water reduction activity of the catalyst at neutral pH gave …

Tnf-R1 And Fadd Mediate Uvb-Induced Activation Of K+ Channels In Corneal Epithelial Cells, Peter M. Boersma, Loren D. Haarsma, Mark P. Schotanus, John L. Ubels

University Faculty Publications and Creative Works

The goal of this study was to elucidate the role of Fas, TNF-R1, FADD and cytochrome c in UVB-induced K+ channel activation, an early step in UVB-induced apoptosis, in human corneal limbal epithelial (HCLE) cells. HCLE cells were treated with Fas, TNF-R1 or FADD siRNA and exposed to 80 or 150 mJ/cm2 UVB. K+ channel activation and loss of intracellular K+ were measured using whole-cell patch-clamp recording and ion chromatography, respectively. Cytochrome c was measured with an ELISA kit. Cells in which Fas was knocked down exhibited identical UVB-induced K+ channel activation and loss of intracellular K+ to control cells. …

Endo -/ Exo - And Halogen-Bonded Complexes Of Conformationally Rigid C -Ethyl-2-Bromoresorcinarene And Aromatic N -Oxides, Rakesh Puttreddy, Ngong Kodiah Beyeh, Robin H.A. Ras, John F. Trant, Kari Rissanen

Chemistry and Biochemistry Publications

The host-guest complexes of conformationally rigid C-ethyl-2-bromoresorcinarene with aromatic N-oxides were studied using single crystal X-ray crystallography. Unlike that of the conformationally more flexible C-ethyl-2-methylresorcinarene, the C-ethyl-2-bromoresorcinarene cavity forms endo-complexes only with the small pyridine-N-oxides, such as pyridine N-oxide, 2-methyl-, 3-methyl- and 4-methylpyrdine N-oxide, and quinoline N-oxide. The larger 2,4,6-trimethylpyridine, 4-phenylpyridine and isoquinoline N-oxide, and 4,4-bipyridine N,N′-dioxide and 1,3-bis(4-pyridyl)propane N,N′-dioxide do not fit into the host cavity. Instead endo-acetone complexes are formed. Remarkably, differing from the anti-gauche endo-complex with C-ethyl-2-methylresorcinarene, the flexible 1,3-bis(4-pyridyl)propane N,N′-dioxide guest forms an anti-anti exo-complex with C-ethyl-2-bromoresorcinarene. The endo- and exo-complexes of C-ethyl-2-bromoresorcinarene and studied N-oxides …

Halogen-Bonded Solvates Of Tetrahaloethynyl Cavitands, Lotta Turunen, Fangfang Pan, Ngong Kodiah Beyeh, Mario Cetina, John F. Trant, Robin H.A. Ras, Kari Rissanen

Chemistry and Biochemistry Publications

The formation and structures of halogen-bonded solvates of three different tetrahaloethynyl cavitands with acetone, chloroform, acetonitrile, DMF and DMSO were prepared and investigated. The inclusion and host-guest behaviour of the resorcinarene cavitands was found to be highly dependent on the flexibility of the ethylene-bridging unit.

Joint Small-Angle X-Ray And Neutron Scattering Data Analysis Of Asymmetric Lipid Vesicles, Barbara Eicher, Frederick A. Heberle, Drew Marquardt, Gerald N. Rechberger, John Katsaras, Georg Pabst

Chemistry and Biochemistry Publications

Low- and high-resolution models describing the internal transbilayer structure of asymmetric lipid vesicles have been developed. These models can be used for the joint analysis of small-angle neutron and X-ray scattering data. The models describe the underlying scattering length density/electron density profiles either in terms of slabs or through the so-called scattering density profile, previously applied to symmetric lipid vesicles. Both models yield structural details of asymmetric membranes, such as the individual area per lipid, and the hydrocarbon thickness of the inner and outer bilayer leaflets. The scattering density profile model, however, comes at a cost of increased computational effort …

An Ionic Liquid Based Sensor For Diclofenac Determination In Water, Emma Brennan, Pauline Futvoie, John Cassidy, Benjamin Schazmann

Articles

This paper details a miniaturised, solid state ion-selective electrode selective for diclofenac. The sensor comprises a novel ionic liquid electroactive material – an imidazolium–diclofenac ion associate. The ion associate is present in a plasticised poly(vinyl chloride) (PVC) membrane on planar carbon electrodes, with an intermediate poly(3,4-ethylenedioxythiophene) layer. The sensitivity and selectivity of the sensor were determined using chronopotentiometric methods. In response to diclofenac, a slope of −53.3 ± 3.6 mV/dec was observed. A limit of detection of 2.90 × 10−3 g L−1 is reported, with a linear range of 3.18 × 10−3 g L−1 to 3.18 g L−1. …

Target Based Design And Synthesis Of Heterocycles In The Potential Treatment Of Cancer And Opportunistic Infection, Shruti Choudhary

Electronic Theses and Dissertations

Dose limiting toxicity and development of multidrug resistance by the tumors are the major limitations of current cancer chemotherapy. Microtubule targeting agents (MTAs) are a structurally diverse set of compounds that disrupt microtubule dynamics and exert their anticancer effect. Among the various classes of such agents, the colchicine site binding agents are particularly important as they circumvent the Pgp and β-III tubulin mediated clinical resistance. These resistance mechanisms, when manifested, are a major reason for the failure of clinically used agents such as taxanes and vinca alkaloids. A series of monocyclic pyrimidine analogs were designed and synthesized as colchicine site …

Heterocycles Via The Pd-Catalyzed Heterofunctionalization Of Alkylidenecyclopropanes, Phillip Roman Lazzara

Dissertations

Natural compounds are often used as inspiration for novel chemical structures that provide medicinal benefits to human health. The unique 3-dimentional structures of these molecules make the majority of them synthetic challenges for organic chemists. While there is great diversity among these molecules, many of these carbon-based compounds exhibit similar key structural features. One of the most common features amongst biologically active molecules is a rigid carbon ring bearing nitrogen or oxygen atoms, which are known as heterocycles. The structural rigidity of heterocycles helps properly align key interactions of the molecule with those of a specific protein, which causes the …

Mild Hydrofunctionalizations Of Olefins Using More Cost-Effective Metal Catalysts, Alexander James Villani-Gale

Dissertations

The focus of this dissertation is the study of alkene hydroaylation reactions. In the first chapter, a review of the relevant literature concerning zinc- and iron-catalyzed hydroarylation of unsaturated bonds is presented. In chapter two, the development of a zinc-catalyzed hydroarylation of alkenes is presented, which is quickly followed by a detailed investigation into the probable mechanism. Chapter three discusses the development of an iron/silver-catalyzed arene prenylation reaction, followed by the development of an iron/zinc-catalyzed arene prenylation reaction. The final section of chapter three discusses the adaptation of the iron/zinc-catalyzed arene prenylation into an undergraduate organic teaching laboratory.

Detection Of Unknown Emerging Contaminants In Natural Water Using Tandem Mass Spectrometry, Qian Wang

Dissertations

Recently, a great deal of concern has been given to the quality of drinking water. Lake Michigan is the drinking water source of Chicago area. It is very important that the quality of drinking water meets the standard setup by the EPA. However, there is a group of chemicals that are not being monitored regularly or are unknown to researchers and are the so-called emerging contaminants.

So the objective of this study is to using tandem-mass spectrometry to detect and identify emerging contaminants. Water samples were obtained along a few locations along the Chicago River and Lake Michigan. By using …

Unusual Acylation Of Chloramphenicol In Lysobacter Enzymogenes, A Biocontrol Agent With Intrinsic Resistance To Multiple Antibiotics, Wei Zhang, Justin Huffman, Shengying Li, Yuemao Shen, Liangcheng Du

Liangcheng Du Publications

Background: The environmental gliding bacteria Lysobacter are emerging as a new group of biocontrol agents due to their prolific production of lytic enzymes and potent antibiotic natural products. These bacteria are intrinsically resistant to many antibiotics, but the mechanisms behind the antibiotic resistance have not been investigated.

Results: Previously, we have used chloramphenicol acetyltransferase gene (cat) as a selection marker in genetic manipulation of natural product biosynthetic genes in Lysobacter, because chloramphenicol is one of the two common antibiotics that Lysobacter are susceptible to. Here, we found L. enzymogenes, the most studied species of this genus, could …

Paper-Based Diagnostic Devices, Spencer A. Schultz, Isabelle C. Noxon, Tyler A. Sisley, Andres W. Martinez

Chemistry and Biochemistry

This chapter will provide an overview of existing diagnostic devices made primarily out of paper and then focus on paper-based microfluidic devices, the next generation of paper-based diagnostic devices that promises to extend the use of paper as a material for fabricating diagnostic devices well into the future.

Chapter Contents:

• 2.1 Introduction
• 2.2 Current paper-based diagnostic devices
• 2.2.1 Dipstick devices
• 2.2.2 Lateral-flow devices
• 2.2.2.1 Vertical-flow devices
• 2.2.3 Paper-based arrays
• 2.3 Paper-based microfluidic devices
• 2.3.1 Fabrication of paper-based microfluidic devices
• 2.3.2 Applications of paper-based microfluidic devices
• 2.4 Conclusions
• References

Criegee Intermediate-Hydrogen Sulfide Chemistry At The Air/Water Interface, Manoj Kumar, Jie Zhong, Joseph S. Francisco, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

We carry out Born–Oppenheimer molecular dynamic simulations to show that the reaction between the smallest Criegee intermediate, CH₂OO, and hydrogen sulfide (H₂S) at the air/water interface can be observed within few picoseconds. The reaction follows both concerted and stepwise mechanisms with former being the dominant reaction pathway. The concerted reaction proceeds with or without the involvement of one or two nearby water molecules. An important implication of the simulation results is that the Criegee-H₂S reaction can provide a novel non-photochemical pathway for the formation of a C–S linkage in clouds and could be a …

Probing The Structural Evolution Of Gold−Aluminum Bimetallic Clusters (Au2AlN−, N = 3−11) Using Photoelectron Spectroscopy And Theoretical Calculations, Navneet S. Khetrapal, Tian Jian, Gary V. Lopez, Seema Pande, Lai-Sheng Wang, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

We report a combined photoelectron spectroscopy and theoretical study of the structural evolution of aluminum cluster anions doped with two gold atoms, Au₂Al_n^– (n = 3−11). Well-resolved photoelectron spectra have been obtained at several photon energies and are used to compare with theoretical calculations to elucidate the structures of the bimetallic clusters. Global minima of the Au₂Al_n^– clusters were searched using the basin-hopping method combined with density functional theory calculations. Vertical detachment energies were computed for the low-lying isomers with the inclusion of spin−orbit effects and were used to generate simulated …

Deciphering Of Interactions Between Platinated Dna And Hmgb1 By Hydrogen/Deuterium Exchange Mass Spectrometry, Yuanyuan Wang, Zhifeng Du, Wei Zheng, Kui Wu, Decheng Xu, Qun Luo, Yao Zhao, Juanjuan Han, Yangzhong Liu, Fuyi Wang

Chemistry Publications

A high mobility group box 1 (HMGB1) protein has been reported to recognize both 1,2-intrastrand crosslinked DNA by cisplatin (1,2-cis-Pt-DNA) and monofunctional platinated DNA using trans-[PtCl2(NH3)(thiazole)] (1-trans-PtTz-DNA). However, the molecular basis of recognition between the trans-PtTz-DNA and HMGB1 remains unclear. In the present work, we described a hydrogen/deuterium exchange mass spectrometry (HDX-MS) method in combination with docking simulation to decipher the interactions of platinated DNA with domain A of HMGB1. The global deuterium uptake results indicated that 1-trans-PtTz-DNA bound to HMGB1a slightly tighter than the 1,2-cis-Pt-DNA. The local deuterium uptake …

Amino Acid Catabolism In Staphylococcus Aureus And The Function Of Carbon Catabolite Repression, Cortney R. Halsey, Shulei Lei, Jacqueline K. Wax, Mckenzie K. Lehman, Austin S. Nuxoll, Laurey Steinke, Marat Sadykov, Robert Powers, Paul D. Fey

Chemistry Department: Faculty Publications

Staphylococcus aureus must rapidly adapt to a variety of carbon and nitrogen sources during invasion of a host. Within a staphylococcal abscess, preferred carbon sources such as glucose are limiting, suggesting that S. aureus survives through the catabolism of secondary carbon sources. S. aureus encodes pathways to catabolize multiple amino acids, including those that generate pyruvate, 2-oxoglutarate, and oxaloacetate. To assess amino acid catabolism, S. aureus JE2 and mutants were grown in complete defined medium containing 18 amino acids but lacking glucose (CDM). A mutation in the gudB gene, coding for glutamate dehydrogenase, which generates 2-oxoglutarate from glutamate, significantly reduced …