Chemistry Commons^™

New Applications Of The Pauson-Khand Reaction And Studies Towards The Synthesis Of The Hamigerans, Christian Emeka Madu

Chemistry & Biochemistry Dissertations - Archive

This dissertation is divided into two parts. The first part describes the dicobalt octacarbonyl mediated synthesis of medium sized rings via intramolecular Pauson-Khand (IMPK) reaction. The cyclization of 1,8-enynes has proved to be difficult via the IMPK reaction due to entropy reasons. To overcome thid limitation we attempted this cyclization in the presence of an ortho- buttressing group (t-butyl group) on the aromatic ring so as to reduce the conformationally allowed volume of the alkene arm of the substrate. The construction of the substrates started with O-alkenylation of the commercially available 3,5 di-tert-butyl-2-hydroxylbenzaldehyde and then the O-alkenylation products were alkynylated …

The Glow Discharge - A Multifaceted Optical Emission Source: From Solids Analysis To Metalloproteins, Timothy Brewer

All Dissertations

Glow discharges (GD) are well known for their application to direct solids elemental analysis of metals and alloys by optical emission spectroscopy (GD-OES). The most successful application of GD-OES has been the analysis of solid materials since the GD provides rapid, direct bulk and depth profiling analysis of solids, metals, powders, polymers, glasses and ceramics. However, solids analysis has typically suffered from the lack of true analytical blanks and the inability to study particulate solids in their native state. An approach for the analysis of solid powdered material entrapped in a sol-gel matrix by radio frequency glow discharge optical emission …

Structural, Magnetic, And Transport Properties Of Zr-Substituted La₀.₇ Sr₀.₃ Mn O₃, Minseob Kim, Jinbo Yang, Qingsheng Cai, William Joseph James, William B. Yelon, Paul Ernest Parris, Satish K. Malik

Chemistry Faculty Research & Creative Works

Zr-substituted perovskites La_0.7Sr_0.3 Mn_1-x Zr_x O₃ with 0 ≤ x ≤ 0.20 were investigated by neutron diffraction (ND), magnetization, electric resistivity, and magnetoresistance measurements. ND refinements reveal that substituted Zr⁴⁺ goes only to the Mn site. Because of its large size, this leads to a Zr-solubility limit at x ≤ 0.10. The x ≤ 0.10 samples exhibit a rhombohedral structure (R3c) from 10 K to room temperature. For the x ≤ 0.10 samples, the cell parameters a and c, and volume increase continuously with increasing Zr content. In addition, the structural distortion of …

Novel Synthesis Of Xanthene And Benzoxanthene Dyes, Corin Michelle Schowalter

Honors Capstones

No abstract provided.

Synthesis Of Hydroxycyclopentenones Via Titanium Complexes, Joeseph David Frasca

Undergraduate Honors Thesis Collection

The electronegativity difference in the titanium-carbon bond has provided a synthetic framework in the formation of a wide range of organic products. Hydroxycyclopentenones are examples of such products and can be synthesized through a titanacyclobutene intermediate via a one-pot procedure. The process involves the incorporation of carbon monoxide into the titanacyclobutene ring with a concomitant addition of an alkyl halide in the presence of samarium diiodide. The synthetic utility of this reaction was explored by varying the alkyl halide. The results of such explorations show a variable tolerance for particular alkyl groups. The details of this project will be discussed.

Local Effective Potential Theory: Nonuniqueness Of Potential And Wave Function, Viraht Sahni, Marlina Slamet, Xiao-Yin Pan

Physics Faculty Publications

In local effective potential energy theories such as the Hohenberg-Kohn-Sham density functional theory (HKS-DFT) and quantal density functional theory (Q-DFT) electronic systems in their ground or excited states are mapped to model systems of noninteracting fermions with equivalent density. From these models, the equivalent total energy and ionization potential are also obtained. This paper concerns the nonuniqueness of the local effective potential energy function of the model system in the mapping from a nondegenerate ground state, the nonuniqueness of the local effective potential energy function in the mapping from a nondegenerate excited state, and in the mapping to a model …

Synthesis Of Polythiophenes Using Oxidative Coupling, Suchismita Datta

Senior Honors Projects

Polythiophenes are polymerization products (also known as polymers) of thiophenes (which are sulfur heterocycles). Polythiophenes become conducting as a result of electron interactions in the conjugated pi-orbitals (of the double bonds) via doping (intentionally adding elemental impurities).This semiconductor-type property of Polythiophenes makes them of special interest to material-science-type applications. They have been dubbed as “synthetic metals”. (www.wikipedia.com) The optical properties of Polythiophenes respond to environment stimuli such as changes in solvent, temperature and applied potential with prominent color shifts. These changes make Polythiophenes attractive sensors. They are also used in the LED display and semiconductor fields. The aim of this …

Novel Synthetic Routes Toward The Alkaline-Earth Metal Amides, Eli S. Mekhlin

Renée Crown University Honors Thesis Projects - All

Metal organic chemical vapor deposition is a process used in the production of thin, crystalline films. The method involves the transportation of volatile, organometallic precursors to a heated substrate, where it undergoes chemical reactions to produce a thin, metallic layer on the substrate surface. Strontium and barium films of this nature are used as components in semi-conductor device fabrication, including among other things, the cell capacitors in Dynamic Random Access Memory computer chips. Additionally, organoalkaline-earth metal compounds are also desired for their potential to serve as polymerization initiators and reagents to modify polymers. Organocalcium derivatives are currently being explored as …

Groundwater Characterization At Yucca Mountain Task 2: Surface Complexation And Solid Phase Sorption, Kenneth Czerwinski, Anthony Hechanova, Amy J. Smiecinski

Publications (YM)

The purpose and scope of this report is to present an overview of the experiments, methods, results, and conclusions from research performed for the project “Groundwater Characterization at Yucca Mountain Task 2: Surface Complexation and Solid Phase Dissolution”. The impact of surface complexation, alteration phase formation, and solution competition with metal ions on the solubility and speciation of actinide elements (U, Pu, Np) will be examined. In particular the role of iron (as Fe2+ and Fe3+) and silicate (as SO3 2-) concentrations on speciation, solubility, sorption, and secondary phase formation of actinides will be investigated. While a large body of …

Hydrothermal Crystal Growth Of Oxides For Optical Applications, Colin Mcmillen

All Dissertations

There is great interest in obtaining coherent radiation in all regions of the optical spectrum. This dissertation explores the hydrothermal growth of crystals that function in two regions currently inaccessible by solid state devices. The first gap exists in the deep-UV region, particularly below 200 nm. Some materials such as LBO and BBO can generate coherent light at wavelengths as low as 205 nm. The growth of these materials was explored to investigate the feasibility of the hydrothermal method as a new technique for growing these crystals. Particular attention was paid to the descriptive chemistry surrounding these systems, and several …

Adaptive Treatment Of Van Der Waals Interactions In Empirical Bond-Order Potentials With Application To Junction Formation In Carbon Nanotubes, Aibing Liu

All Dissertations

Molecular dynamics (MD) simulation of reactive condensed-phase hydrocarbon systems is a challenging research area. The AIREBO potential is particularly useful in this area because it can simulate bond breaking and bond forming during chemical reactions. It also includes non-bonded interactions for systems with significant intermolecular interactions.

The first part of this dissertation describes a method to adaptively incorporate van der Waals interaction of carbon atoms into the AIREBO force field. In bond-order potentials, the covalent bonding interactions adapt to the local chemical environment, allowing bonded interactions to change in response to local chemical changes.
Non-bonded interactions should adjust to their …

The Effect Of Radiation And Repeated Sub-Culturing On Tgf-Β1 Signaling In Frtl-5 Cells, Cheryl G. Burrell

Loma Linda University Electronic Theses, Dissertations & Projects

From our ongoing in vitro studies using the Fisher Rat Thyroid cell line-5 (FRTL-5) we recorded accelerated growth, reduced follicularization and reduction in thyroxin release that occurred as the cells were repeatedly sub-cultured. We also recorded that these changes occurred earlier and more rapidly following radiation exposure. We determined that TGF-β1 production increased under both conditions. We hypothesized that alteration in the TGF-β1 signaling pathway contributed to the changes observed in the cellular properties of FRTL-5 cells. Our objective was to examine some of the players in the TGF-β1 signaling pathway to determine whether radiation and/or repeated subculturing promoted changes …

Continuous Improvement In E-Learning: Investigating The Effect And Impact Of Our Webct Chemistry Support Initiative (Csi) And Implications For Further Enhancement Of The Virtual Learning Environments (Vles) Developed, Christine O'Connor, Claire M. Mcdonnell, Michael K. Seery

Conference Papers

A Virtual Learning Environment (VLE) was developed using WebCT software and was piloted in 2004 in the School of Chemical and Pharmaceutical Sciences in DIT by the authors. This was one of a number of measures introduced with the aim of supporting and retaining first year undergraduates on the Science ordinary degree programme and was designed as a Chemistry Support Initiative (CSI) for first year Chemistry learning and teaching (O’Connor, 2005). This work was supported through funding from the DIT Learning and Teaching Centre which allowed a summer research assistant to be taken on. Since the launch of the first …

Bioengineering Of Protein Nanotubes And Protein Nanomaterial Composites, Thilak Kumara Mudalige

Dissertations

Flagella of Mesophilic bacteria such as E. coli are extremely ordered structures consisting of self-assemblies of flagellin 11-mers resulting in protein nanotubes of 2--3 nm inner diameter, 23 nm outer diameter, several microns in length and 5.4 nm separation between 11-mer segments. They are as a result attractive scaffolds and templates for the generation of uniform nanotubes and ordered array of nanoparticles. In this study fusion protein of bacterial flagellin (Fli C) and core thioredoxin (Trx), pFliTrx was used as peptide display on bacterial flagella. This was accomplished in the current research by introducing various peptide loops such as cysteine, …

Analysis Of Nutraceuticals For Toxic Metals: Development And Validation Of Sample Preparation Method, Julia Cooper

All Theses

With increasing numbers of health-conscious consumers purchasing nutraceutical supplements, total sales in the nutrition industry have soared to over $200 billion in 2006. It is important to assess the safety of these nutraceutical products, with specific regards to toxic metals, including arsenic, cadmium, lead, and mercury. Because species of these metals may be more toxic than others, they can have hazardous health effects if ingested in excess quantities. The work described in this thesis focuses on the development of a sample preparation method for nutraceutical products, specifically ethanolic tinctures and glycerin-based matrices, and analysis of these products by inductively coupled …

Functionalized Nanomaterials: Synthesis, Characterization, And Applications, Liangwei Qu

All Dissertations

Due to their unique electronic, optical, catalytic and mechanical properties, nanomaterials (nanoparticles and nanotubes) have been attracting much attention over the past decades. In this dissertation, polymeric nanoparticles bearing derivatized D-mannose and galactose molecules were prepared via dispersion polymerization and their interactions with various bacterial cells were studied. The results show that there are strong adhesin-specific interactions of the nanoparticles with E. coli cells, resulting significant nanoparticles-madiated cell agglutination.
Poly(ethylene glycol)-coated magnetic polymer nanoparticles were synthesized through miniemulsion polymerization by using macromonomer as both a comonomer and a surfactant. The resulting magnetic polymer nanoparticles were successfully used for bio-detection and …

Synthesis And Characterization Of Platinum – Selenium Derivatives: X-Ray Structure Of Trans-Pt(Pet3)2(Seph)2, Martin D. Rudd, Sergey V. Lindeman

Chemistry Faculty Research and Publications

The crystal structure of trans-[((bis)triethylphosphine)(bis(phenylselenato))platinum (II)] has been determined by single crystal X-ray diffraction. Crystallization occurs in the triclinic space group P-1 (No. 2) with a = 8.9964(2) Å, b = 11.5103(2) Å, c = 14.9335(3) Å; α = 85.8750(10)°, β = 72.5350(10)°, γ = 68.4450(10)°. Details of the structure and spectroscopic results are presented and discussed and comparisons are made with related square planar platinum (II) structures.

High Temperature Heat Exchanger Project: Quarterly Progress Report January 1, 2007 Through March 31, 2007, Anthony Hechanova

Publications (NSTD)

• The variation of sulfur dioxide production (throughput) of the baseline design of the Ceramatec sulfuric acid decomposer with total mass flow rate of reacting flow has been calculated. According to the calculations, the sulfur dioxide production increases as the total mass flow rate of reacting flow increases regardless of the fact that decomposition percentage of sulfuric trioxide decreases. A parametric study of the baseline design of the Ceramatec sulfuric acid decomposer was performed.

• The thermal performance using various channel geometries for the decomposer was studied. The baseline design (straight channels) has 89.5% thermal efficiency while the thermal efficiency …

The High-Resolution Nmr Structure Of The R21a Spc-Sh3:P41 Complex: Understanding The Determinants Of Binding Affinity By Comparison With Abl-Sh3, Salvador Casares, Eiso Ab, Hendrik Eshuis, Obdulio Lopez-Mayorga, Nico A.J. Van Nuland, Francisco Conejero-Lara

Department of Chemistry and Biochemistry Faculty Scholarship and Creative Works

Background. SH3 domains are small protein modules of 60-85 amino acids that bind to short proline-rich sequences with moderate-to-low affinity and specificity. Interactions with SH3 domains play a crucial role in regulation of many cellular processes (some are related to cancer and AIDS) and have thus been interesting targets in drug design. The decapeptide APSYSPPPPP (p41) binds with relatively high affinity to the SH3 domain of the Abl tyrosine kinase (Abl-SH3), while it has a 100 times lower affinity for the α-spectrin SH3 domain (Spc-SH3). Results. Here we present the high-resolution structure of the complex between the R21A mutant of …

Slow Turning Reveals Enormous Quadrupolar Interactions (Streaqi), John Persons, Gerard S. Harbison

Gerard S. Harbison Publications

We introduce a new solid-state NMR method, which uses very slow sample rotation to visualize NMR spectra whose width exceeds feasible spectrometer bandwidths. It is based on the idea that if we reorient a tensor by a known angle about a known axis, the shifts in the NMR frequencies observed across the spectral width allow us to reconstruct the entire tensor. Called STREAQI (Slow Turning Reveals Enormous Anisotropic Quadrupolar Interactions), this method allows us to probe NMR nuclei that are intractable to current methods. To prove the concept and demonstrate its promise we have implemented the method for several 79Br …

Kinetic Studies Of 6-Halopurine Nucleoside In Snar Reactions; 6-(Azolyl, Alkylthio And Fluoro)-Purine Nucleosides As Substrates For Suzuki Reactions, Jiangqiong Liu

Theses and Dissertations

In chapter 1, we describe development of a mild and efficient method for SNAr iodination of 6-chloropurine 2'-deoxynucleosides and nucleosides. Our studies demonstrate that 6-iodopurine nucleosides are excellent substrates for certain transition metal-catalyzed cross-coupling reactions. In chapter 2, we describe synthesis of protected 6-fluoro, 6-chloro, 6-bromo and 6-sulfonylpurine nucleosides. Comparisons among 6-fluoro-, 6-chloro-, 6-bromo, 6-iodo and 6-sulfonylpurine nucleosides for SNAr reactions with various N, O and S nucleophiles were investigated. Our results demonstrate that the 6-fluoropurine nucleoside is the best substrate for SNAr reactions among the four 6-halopurine nucleosides with oxygen, sulfur and aliphatic amine nucleophiles, and also with an …

Dna-Templated Nanomaterials, Hector Alejandro Becerril-Garcia

Theses and Dissertations

Nanomaterials display interesting physical and chemical properties depending on their shape, size and composition. Self assembly is an intriguing route to producing nanomaterials with controllable compositions and morphologies. DNA has been used to guide the self assembly of materials, resulting in: (1) metal nanowires; (2) metal or semiconductor nanorods; (3) carbon nanotubes; and (4) semiconductor, metal or biological nanoparticles. My work expands the range of DNA templated nanomaterials and develops novel ways of using DNA to pattern nanostructures on surfaces. I have performed the first synthesis of silver nanorods on single stranded DNA, an attractive material for localizing DNA coupled …

Understanding Atomic (Hydrogenic) Orbitals, Part 2, D-Orbitals, Carl W. David

Chemistry Education Materials

This material extends earlier discussions to the d-orbitals.

Reliable Structures And Energetics For Two New Delocalized Π⋯Π Prototypes: Cyanogen Dimer And Diacetylene Dimer, Brian W. Hopkins, Adel M. Elsohly, Gregory S. Tschumper

Chemistry Faculty Research & Creative Works

Two new prototypes delocalized π⋯π complexes are introduced: the dimers of cyanogen, (N≡C-C≡N)2, and diacetylene, (HC≡C-C≡CH)2. These dimers have properties similar to larger delocalized π⋯π systems such as benzene dimer but are small enough that they can be probed in far greater detail with high accuracy electronic structure methods. Parallel-slipped and T-shaped structures of both cyanogen dimer and diacetylene dimer have been optimized with 15 different procedures. The effects of basis set size, theoretical method, counterpoise correction, and the rigid monomer approximation on the structure and energetics of each dimer have been examined. MP2 and CCSD(T) optimized geometries for all …

Investigation Of Novel Microseparation Techniques, Yansheng Liu

Theses and Dissertations

Ultrahigh pressure liquid chromatography (UHPLC) makes it possible to use very small particles (< 2 µm) as packing materials to provide high column efficiencies. Results from a careful comparison of small porous and nonporous particles show that when the particle size is small enough (< 2 µm), both porous and nonporous particles give excellent performance, and the differences in column efficiencies between porous and nonporous particles become insignificant. Columns packed with bare diamond particles could separate small molecules, especially polar molecules, however, severe tailing occurred for less polar compounds. The polybutadiene coated diamond particles gave greater retention and better separation of small molecules compared to bare particles, although no improvement in column efficiency was observed. Changes in surface bonding of thermally hydrogenated diamond particles was achieved by chemical modification using various organic peroxides with or without reagents containing long carbon chain functional groups. It appears that the alkyl groups were attached onto the diamond surface with limited coverage. LC experiments did not demonstrate good separation; however, changes in LC behavior were observed. A repetitive solvent programming approach was successfully applied to the analysis of a continuous sample stream in microbore LC. Each analysis cycle consisted of three steps: pseudo-injection, elution and rinse. In the pseudo-injection step, elution with a non- or poor-eluting solvent produced a concentrated sample plug due to on-column focusing. Factors influencing peak symmetry, resolution and analysis cycle length were investigated. Quantitative analysis of a continuous sample stream is possible under certain operating conditions. Electric field gradient focusing (EFGF) devices with distributed resistor substrates could focus proteins in the separation channel, however, the focused bands were not stable, and the repeatability was poor due to the formation of bubbles and pH gradient in the separation channel. Both fiber-based and porous glass capillary-based planar EFGF devices with changing cross-sectional area (CCSA) channels were constructed and evaluated with the aid of a home-made scanning laser-induced fluorescence detection system. The fiber-based CCSA EFGF devices gave poorer performance compared with glass capillary based devices. Porous glass capillary-based EFGF devices could focus single proteins and separate mixtures of two to three proteins.

Computation Of Correlation Functions And Wave Function Projections In The Context Of Quantum Trajectory Dynamics, Sophya Garashchuk

Faculty Publications

The de Broglie-Bohm formulation of the Schrödinger equation implies conservation of the wave function probability density associated with each quantum trajectory in closed systems. This conservation property greatly simplifies numerical implementations of the quantum trajectory dynamics and increases its accuracy. The reconstruction of a wave function, however, becomes expensive or inaccurate as it requires fitting or interpolation procedures. In this paper we present a method of computing wave packet correlation functions and wave function projections, which typically contain all the desired information about dynamics, without the full knowledge of the wave function by making quadratic expansions of the wave function …

1,3-Bi-9-Anthrylpropane, Mustafa Arslan, Erol Asker, John Masnovi, Ronald J. Baker

Chemistry Faculty Publications

The title compound, C₃₁H₂₄, with three molecules in the asymmetric unit. The crystal packing is mainly stabilized by weak C—H⋯π inter­actions in addition to van der Waals forces.

Ua66 2007 Student Awards Ceremony, Wku Ogden College Of Science & Engineering

WKU Administration Documents

Program recognizing Ogden College students with brief list of activities for each student.

Biophysical Characterization Of A Beta-Peptide Bundle: Comparison To Natural Proteins, E. James Petersson, Cody J. Craig, Douglas S. Daniels, Jade X. Qiu, Alanna S. Schepartz

Chemistry Faculty Publications

We recently described the high-resolution X-ray structure of a helical bundle composed of eight copies of the β-peptide Zwit-1F. Like many proteins in Nature, the Zwit-1F octamer contains parallel and antiparallel helices, extensive inter-helical electrostatic interactions, and a solvent-excluded hydrophobic core. Here we explore the stability of the Zwit-1F octamer using circular dichroism (CD) spectroscopy, analytical ultracentrifugation (AU), differential scanning calorimetry (DSC), and NMR. These studies demonstrate that the thermodynamic and kinetic properties of Zwit-1F closely resemble those of α-helical bundle proteins. Together these studies should provide a model for the design of β-peptide proteins with biological functions.

Accumulation Of Pathological Tau Species And Memory Loss In A Conditional Model Of Tauopathy, Zdenek Berger, Hanno Roder, Amanda Hanna, Vijayaraghavan Rangachari, Mei Yue, Zbigniew Wszolek, Karen Ashe, Joshua Knight, Dennis Dickson, Cathy Andorfer, Terrone L. Rosenberry, Jada Lewis, Mike Hutton, Christopher Janus

Faculty Publications

Neurofibrillary tangles (NFTs) are a pathological hallmark of Alzheimer's disease and other tauopathies, but recent studies in a conditional mouse model of tauopathy (rTg4510) have suggested that NFT formation can be dissociated from memory loss and neurodegeneration. This suggests that NFTs are not the major neurotoxic tau species, at least during the early stages of pathogenesis. To identify other neurotoxic tau protein species, we performed biochemical analyses on brain tissues from the rTg4510 mouse model and then correlated the levels of these tau proteins with memory loss. We describe the identification and characterization of two forms of tau multimers (140 …