Chemistry Commons^™

Earth Field Magnetic Resonance Imaging And Paramagnetic Contrast Agents, Saideh Sadat Mortazavi

Open Access Theses & Dissertations

The goal of this research was to visualize the uptake of copper by plants to aid phyto-remediation research. The hypothesis was that regions of the plant with more copper will have an enhanced NMR signal using copper as a paramagnetic contrast agent.

As the name implies, Earth Field Magnetic Resonance Imaging (EFMRI) spectrometry uses a magnetic field 300,000 times weaker than a 600 MHz Nuclear Magnetic Resonance (NMR) spectrometer. Just like in conventional human MRI, this portable instrument is capable of recording one, two and three dimensional images though the sample size is much smaller.

The enhancement of signal was …

Pressure Induced Phase Transformation Of Sno2: An Ab Initio Constant Pressure Study, Daniel Tesfai Yehdego

Open Access Theses & Dissertations

The behavior of SnO2 under rapid hydrostatic pressures is studied using constant-pressure ab initio simulations. The rutile-type SnO2 gradually transforms into the CaCl2-type structure at 15 GPa. At a pressure of about 20 GPa, a phase transformation into a cubic fluorite-type structure is observed. The orthorhombic Pnma cotunnite-structured phase is observed above 150 GPa. The mechanisms of these phase transformations at the atomistic level are discussed.

Synthesis And Characterization Of Organic-Inorganic Colorants, Kiran A V Adiraju

Open Access Theses & Dissertations

New colorant materials have been found with the interaction of organic dyes and metal alkoxides. Changes in the hue are observed as indigo dye or thioindigo dyes are combined with the ASB (aluminum tri-secbutoxide), when compared to the original indigo or thioindigo dye, due to the binding and geometry change between dye and metal alkoxide. These dyes are combined with the ASB in two different methods of hydrolysis, namely in the air and in water. Similarly, when TTIP (Titanium tetraisopropoxide) is hydrolyzed using the sol gel process, along with the incorporation of thioindigo dye, hue changes were observed. X-ray diffraction …

Design, Synthesis And Study Of The Bridged And Cofacially-Arrayed Poly-P-Phenylene Molecular Wires, Matthew J. Modjewski

Master's Theses (2009 -)

Two novel series of bridged and cofacially-arrayed poly-p-phenylenes have been designed synthesized and studied. The bridged poly-p-phenylenes have been synthesized from a readily available diacetylenic precursor utilizing three high yielding steps, and their structures were determined by 1H/13C NMR spectroscopy as well as X-ray crystallography. The racemization barrier between the two atropoisomers was found to be ~12 Kcal mol-1; the versatility of the synthesis employed was extended to synthesis a triply bridged tetra-p-phenylene and a quadruply bridged penta-p-phenylene.

The cofacially-arrayed poly-p-phenylenes have shown that the X-ray crystal structures of the neutral compounds are largely dominated by C-H--π-interactions interactions while the …

Observed Superspin-Glass Behavior In Ni0.5zn0.5fe2o4 Nanoparticles, Antony Adair

Open Access Theses & Dissertations

In this investigation we seek to identify the magnetic behavior of Ni0.5Zn0.5Fe2O4 nanoparticles though AC-susceptibility and DC-magnetization measurements. Powder x-ray diffraction was performed to determine the purity and average diameter ( ~ 9nm) of the particles. Aditionally, structure was confirmed by comparison through the International Centre for Diffraction Data's Powder Diffraction File [52] (PDF # 08-0234).

Zero-field cooled and field cooled DC magnetization measurements (bifurcation and blocking temperature), as well as M(H) hysteresis (below and above the blocking temperature) lead us to initially suggest that the material may in fact be superparamagnetic. However, further investigation of the real AC susceptibility …

Synthesis And Characterization Of Acetylenic Derivatives Of The Actinide Extractant (Aryl) N,N Di (Alkyl)Carbamoylmethylphosphine Oxide (Cmpo), Mario Ivan Baeza

Open Access Theses & Dissertations

We have used the reaction between the sodium salt of (diaryl)-N,N-di-(isobutyl)carbamoylmethylphosphine oxides {[Aryl)2P=O][iBu2NC=O]CH}-Na+ and chloromethylacetylenes to produce the first acetylenic derivatives of the carbamoylmethylphosphine oxide (CMPO) actinide extractants. The new compounds - CMPO-CH2C2H (1) {aryl = phenyl}, (2) {aryl = tBu-phenyl}; CMPO-CH2C2Me (3) {aryl = phenyl}; and CMPO-CH2C2CH2Cl (4) {aryl = phenyl}, (5) {aryl = tBu-phenyl} - have been characterized by spectroscopy (1H, 13C, 32P NMR) and also by single crystal X-ray diffraction. These new extractants lead the way to new derivatives aimed at using the materials as both optical and electrochemical actinide and other metal sensors.

Development Of A Novel Humidity Sensor Based On A Polymer Silver Nanoparticle Composite, Aoife Power, John Cassidy, Tony Betts

Conference Papers

Humidity sensing is of particular concern for many industrial applications. Humidity sensors have typically been based on a reversible interaction between a polymer and water vapour. There is work published on gas sensors based on polymer gold nanoparticle composites, where the conductivity of the composite decreases on interaction with the gas. This happens because the swelling of the polymer which increases the electron hopping distance between the gold nanoparticles. The device in this work is a poly vinyl alcohol silver nanoparticle composite cast on an interdigital electrode array. On application of a dc bias, a current develops which is proportional …

Folate-Cyclodextrin Conjugate For Targeted Chemotherapy, Zlata Tofzikovskaya, Orla L. Howe, Mary Mcnamara, Christine O'Connor

Conference Papers

A general disadvantage of chemotherapy is that the drugs cannot discriminate between fast-growing cancer cells and normal healthy cells which causes many side-effects such as hair loss. An ideal solution to current methods of chemotherapy would be the development of a carrier for an anticancer drug which would be able to transport the drug and therefore target only cancer cells and release the drug molecules inside the cells. In this work folic acid (FA) is attached to an aminoalkane derivative of b-cyclodextrin (CDEn) with a view to developing novel drug delivery systems for therapeutic purposes. Cytotoxisity of folate-conjugate (CDEnFA) is …

An Improved Synthesis Of The Hdac Inhibitor Trichostatin A, Joseph Colombo

Master's Theses and Doctoral Dissertations

Histone deacetylase inhibitors (HDIs) have found a wide variety of medicinal uses and are most noted for their specific apoptotic action towards cancer cells. Several hydroxamate HDIs have since been moved on to phase 1 and 2 clinical drug trials, with one having already been approved for treatment of advanced cutaneous T-cell lymphoma. Trichostatin A is one of the most potent known naturally-occurring inhibitors of histone deacetylase. Unfortunately for researchers, the syntheses that have been reported are both long and difficult, which leads to a low overall yield and therefore to a prohibitively expensive product, limiting its medicinal potential. This …

Development Of A Headspace Solid-Phase Microextraction (Hs-Spme) Procedure For The Determination Of Short-Chain Fatty Acids (Scfas) In Activated Sludge By Gc-Fid, Shiyan Cheng

Master's Theses and Doctoral Dissertations

The process of wastewater treatment includes the removal of inorganic solids such as sand and gravel as well as organic materials, phosphorus, and nitrogen. Activated sludge, containing a variety of living organisms, is added into the wastewater treatment system. Short-chain fatty acids (SCFAs), an energy source of the bioorganisms, are produced during activated sludge digestion, and play a significant role in phosphorus and nitrogen removal as well as the removal of organic materials during the process of wastewater treatment. Extensive research has been carried out recently in search of optimized conditions to increase the level of fatty acids in the …

Identification Of Changes In The Surface Of Textiles Subjected To Plasma Chemical Treatment Using Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy, Joslyn Diana Kirkland

Master's Theses and Doctoral Dissertations

Plasma chemical oxidation has been proposed as a “nondestructive” method for preparing samples from archaeological materials for radiocarbon dating using accelerator mass spectrometry. However, the chemical effects of low-temperature, low-pressure plasma discharges on fragile archaeological materials are not understood. It is believed that reactions only occur at the surface of the treated samples. Therefore, we have used Fourier transform infrared spectroscopy with attenuated total reflectance sampling (ATR-FTIR) to examine changes in the chemical nature of the surface of representative modern and archaeological samples upon plasma treatment. Samples that were treated with destructive wet chemical methods, e.g., treatment with sodium hydroxide …

Role Of Aromatic Pi-Stacking On The Aggregation Of Human Islet Amyloid Polypeptide (Hiapp), Srikanth Reddy Konda

Master's Theses and Doctoral Dissertations

Human islet amyloid polypeptide (hIAPP) is secreted in the β-cells of the pancreas, which also secretes insulin. In type 2 diabetes mellitus, hIAPP undergoes self-aggregation, forming fibrils. This self-aggregation is cytotoxic and is thought to be linked to type 2 diabetes mellitus by causing β-cell membrane destruction. The N-terminus of hIAPP (1-19) contains a binding site (residues 14-18) for self-aggregation. Aggregation is thought to be mediated by pistacking interactions between phenylalanine residues of hIAPP. In this study, the hIAPP 1-19 sequence was modified by replacing phenylalanine with alanine and naphthylalanine, to study if the modification of the aromatic side chain …

Insulin Based Inhibitors Of Human Islet Amyloid Polypeptide (Hiapp) And Their Effect On Hiapp- Mediated Membrane Damage In Type 2 Diabetes Mellitus, Durgaprasad Peddi

Master's Theses and Doctoral Dissertations

Amylin (Islet Amyloid Polypeptide, IAPP) is a 37 amino acid polypeptide, co-secreted with insulin from pancreatic beta cells, that plays a role in the damage of cell membranes by forming amyloid fibrils in Type 2 diabetes. Insulin has been found to inhibit hIAPP (Human Islet Amyloid Polypeptide) aggregation. The HLVEALYLVC amino acid region of insulin contacts hIAPP near the N-terminus. Truncated and modified analogs of insulin containing the binding region (VEALYLV, VEALFLV and EALYLV) were synthesized and purified, and their actions were studied on model lipid membranes in the presence of hIAPP 1-19 and hIAPP 1-37.

Computational Studies Of The Properties Of Copper Oxide Clusters And The Reactions Of Phenol And Chlorinated Phenols With Copper Oxide Clusters, Gyun-Tack Bae

LSU Doctoral Dissertations

We used ab initio simulations and calculations to study the structures and stabilities of copper oxide clusters, CunOn (n=1-8) and CuOn (n=1-6). The lowest energy structures of neutral and charged copper oxide clusters were determined using primarily the B3LYP/LANL2DZ model chemistry. In CunOn clusters with n=1-8, a transition from planar to nonplanar geometries occurs at n=4. In CuOn clusters with n=1-6, all geometries of neutral, positively, and negatively charged clusters are planar or near planar structures. Selected electronic properties, including binding energies, ionization energies, and electronic affinities, were calculated and examined as a function of n. Stabilities were examined by …

A Comparison Of Physical And Electrochemical Properties Of Two Ionic Liquids Containing Different Cations: 1-Butyl-1-Methyl-Pyrrolidinium Beti And 1-Butyl-3-Methyl-Imidazolium Beti, Edward Nelson Kennedy

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A novel ionic liquid, 1,1-butyl-methyl-pyrollidinium bis-pentafluoroehthanesulfonylamide (BMPyrrBeti) was synthesized and characterized. Its physical and electrochemical properties compared to a similar ionic liquid containing the imidazolium cation, 1-methyl-3-butyl-imidizolium bis-pentafluoroehthanesulfonylamide (BMImBeti). The two ionic liquids contain the same anion, bis((pentafluoroethane)sulfonyl)imide (Beti), and the same two alkly group substituents (a methyl and a butyl group). The two ionic liquids differ only by the cation component, and the connectivity of the two substituents (1,1 for the former, and 1,3 for the latter).

The following physical properties of BMPyrrBeti were measured and compared to the same properties of BMImBeti: conductivity, viscosity, absorption and desorption of …

Synthesis Of 3,6-Bis(5’-Bromo-3’-Indolyl)-1,4-Dimethypiperazine-2,5-Dione, Stephen N. Crooke, C. Michele Davis Mcgibony, Christine R. Whitlock

Chemistry: Faculty Publications (1990-2023)

The one-pot synthesis of 3,6-bis(5’-bromo-3’-indolyl)-1,4-dimethylpiperazine- 2,5-dione is reported. Sarcosine anhydride is brominated and immediately reacted with 5-bromoindole to produce the product, which is characterized by ¹H NMR, MS and microanalysis.

Salsola Kali (Tumbleweed): A Possible Biomonitoring Device For The Detection Of Airborne Heavy Metals, Tenoch Benitez

Open Access Theses & Dissertations

Vehicular congestion generates particulate matter and contaminants such as lead, cadmium, copper, chromium, nickel, and zinc which have been detected in the U.S.-Mexico border region. To overcome the inconvenience of expensive sampling techniques, scientists started to assess air quality by using bioindicator plants, a technique called biomonitoring. Biomonitoring is an inexpensive and environmentally friendly approach to determine inorganic contaminants at trace levels. The purpose of this project was to determine the effectiveness of tumbleweed (Salsola kali) plants, sprayed with chelating agents, as a passive monitoring device to determine the possible presence of heavy metals in the ambient air around international …

In-Situ Ambient Quantification Of Monoterpenes, Sesquiterpenes And Related Oxygenated Compounds During Bearpex 2007: Implications For Gas-And Particle-Phase Chemistry, Nicole Bouvier-Brown

Chemistry and Biochemistry Faculty Works

We quantified ambient mixing ratios of 9 monoterpenes, 6 sesquiterpenes, methyl chavicol, the oxygenated terpene linalool, and nopinone using an in-situ gas chromatograph with a quadrupole mass spectrometer (GC-MS). These measurements were a part of the 2007 Biosphere Effects on AeRosols and Photochemistry EXperiment (BEARPEX) at Blodgett Forest, a ponderosa pine forest in the Sierra Nevada Mountains of California. To our knowledge, these observations represent the first direct in-situ ambient quantification of the sesquiterpenes α-bergamotene, longifolene, α-farnesene, and β-farnesene. From average diurnal mixing ratio profiles, we show that α-farnesene emissions are dependent mainly on temperature whereas α-bergamotene and β-farnesene emissions …

Methyl Chavicol: Characterization Of Its Biogenic Emission Rate, Abundance, And Oxidation Products In The Atmosphere, Nicole Bouvier-Brown

Chemistry and Biochemistry Faculty Works

We report measurements of ambient atmospheric mixing ratios for methyl chavicol and determine its biogenic emission rate. Methyl chavicol, a biogenic oxygenated aromatic compound, is abundant within and above Blodgett Forest, a ponderosa pine forest in the Sierra Nevada Mountains of California. Methyl chavicol was detected simultaneously by three in-situ instruments – a gas chromatograph with mass spectrometer detector (GC-MS), a proton transfer reaction mass spectrometer (PTR-MS), and a thermal desorption aerosol GC-MS (TAG) – and found to be abundant within and above Blodgett Forest. Methyl chavicol atmospheric mixing ratios are strongly correlated with 2-methyl-3-buten-2-ol (MBO), a light- and temperature-dependent …

Water Evaporation From Atmospheric Aerosols, Patrick Louden, Christopher Lawrence

Student Summer Scholars Manuscripts

With the recent discovery of the ubiquity of organic material in tropospheric aerosols, it has been postulated that the rates of water evaporation and condensation into the aerosols could be affected by thin surfactant films, which could ultimately affect cloud formation. Nathanson et al. have begun to study the effect of water evaporation from sulfuric acid solutions through the short-chain surfactant, butanol. They have found that a nearly full monolayer of butanol fails to reduce water evaporation from the acid. This unexpected result raises many questions about the mechanism of water evaporation. We used molecular modeling to help answer some …

Modeling Problem Solving: Creating And Evaluating, Kaitlin M. Downey, Nathan Barrows

Student Summer Scholars Manuscripts

The purpose of this project was to create novice-level screencasts and to investigate students’ perceptions and usage of them. A survey of 61 general chemistry students revealed polarity, Lewis structures, molecular geometry, and bond polarity to be topics of greatest concern. Over 25 screencasts were created using Camtasia Studio software and a Dell TabletPC. A blog (http://mi-chemed.net) was created to host the tutorials and monitor student usage. After students registered and logged in to the blog, their viewing patterns were recorded. They were encouraged to comment on the content and technical features of the videos (e.g. animations). Online comments and …

Lipid Metal Organic Networks, Maria Eugenia Martinez

Open Access Theses & Dissertations

Metal–organic frameworks (MOFs) first appeared in the literature in 1991 and consist of three dimensional structures constructed by linking transition metal ions together through highly directional bonding with organic ligands. MOF materials offer the ability to choose from variety of metal centers that allow the tailoring of optical or magnetic properties, as well as control, to some extent, the size of the coordination sphere. Another advantage is the numerous organic ligands form which suitable pore geometries may be constructed with customized functionality among many applications in other areas such a gas storage chemical separations and selective catalysis. The primary objective …

Towards More Reliable Extrapolation Algorithms With Applications To Organic Chemistry, Jaime Nava

Open Access Theses & Dissertations

One of the main objectives of science and engineering is to predict the results of different situations. For example, in Newton's mechanics, we want to predict the positions and velocities of different objects (e.g., planets) at future moments of time.

In this Thesis, as a case study, we take the problem of predicting the properties of new chemical substances. One of the main objectives of chemistry is to design new molecules (and, more generally, new chemical compounds) which are useful for various practical tasks. New substances have already resulted in new materials for buildings and for spaceships, new explosives and …

The Isotopological Homodesmotic Reaction: A Further Refinement To The Quantification Of Aromaticity, Marco Olguin

Open Access Theses & Dissertations

Aromaticity imparts a significant energetic stabilization to various chemical systems as a result of cyclic pi-electron delocalization. One of the most widely used methods for the quantification of the Aromatic Stabilization Energy (ASE) of a molecule is the formulation of a Homodesmotic reaction. The following research employs a refined Homodesmotic approach based on previous work by Herndon and Mills which utilized Isotopological Homodesmotic Reactions (IHR) to determine the Aromatic Stabilization Energy (ASE) of a flourenyl cation. The advantage of employing an IHR for an ASE calculation is that the strain energy contribution from the sigma framework of reactant and product …

Computational Modeling Studies Of The Structures And Properties Of Organotin(Iv) And Stannyl-Thioether Systems With Comparisons To X-Ray Crystallography, Michelle R. Stem Joseph

Open Access Theses & Dissertations

Controlling the toxic effects of organotin(IV) compounds involves engineering the structure of the molecules to optimize their properties. Molecular engineering, coupled with improved capabilities to generate reliable computational optimization models (COMs), will enable researchers to have greater success at harnessing the highly specific cytotoxicity of organotins. For example, as the thio_n ligand phenyl groups were replaced with Cl atoms, the S-Sn intramolecularity was strengthened, the bond distance decreased, and the stannyl tetrahedral structure was deformed from its triphenyl conformation. With each substitution, conformation deformations lowered the damaging bioactivity levels of thio_n. Bonding various ligands to organotin(IV) compounds …

Transition Metal Catalysts For Hydrodesulfurization Reactions Applied To Petroleum Industry, Brenda Torres

Open Access Theses & Dissertations

Catalysis plays a fundamental role in petroleum refining and basic petrochemical industries creating new routes in the development of industrial processes. Moreover, catalysis has become indispensable to the solution of environmental pollution problems and therefore on public health. World wide concerns for preservation of the environment has motivated the development of "Green" catalyst based technologies, to achieve a better utilization of petroleum resources and demands for cleaner transportation fuels. These environmental concerns have led to increasingly drastic regulations on sulfur, nitrogen and aromatics content in fuels. Sulfur content in the motor and diesel fuels is continuously reduced by regulations to …

Electronic To Vibrational Energy Transfer From Cl* (2P1/2) To Ch4 And Cd4, Brian R. Munson

Browse all Theses and Dissertations

Electronic-to-vibrational (E-V) energy transfer is a significant kinetic channel in the collisional quenching of spin-orbit excited chlorine atoms, Cl^* (²P_1/2, 882 cm^-1), by molecular collision partners. In the present study Cl^* atoms are prepared in the presence of CH₄ or CD₄, under pseudo first-order conditions, by photolysis of ICl at 532 nm with a pulsed Nd:YAG laser. Quenching of Cl^* by CH₄ or CD₄ results in E-V excitation of the ν4 asymmetric bending mode as observed by infrared (IR) fluorescence from the vibrationally excited products. Time-resolved …

Comparison Of The Electrochemical Properties Of Ethanol In Perchloric Acid And Ionic Liquids, Sandra Felix-Balderrama

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1-Ethyl-3-Methylimidazolium Tetrafluroborate (EMImBF₄) and 1-Ethyl-3-Methylimidazlium Bis(trifluoromethanesulfonyl)imide (EMImTFSI) ionic liquids were synthesized and characterized in order to study the electrochemical oxidation of ethanol in these ionic liquids on a platinum surface electrode.

It was found that pure EMImBF₄ exhibits an electrochemical window of 4.4 V,while EMImTFSI exhibits an electrochemical window of 5.0 V.

Electrochemical study of ethanol in perchloric acid showed that the oxidation of ethanol strongly depends on the concentration of ethanol and on the temperature of the solution. The poisoning of the platinum electrode only depends on the concentration of ethanol. At a low concentration of …

Cationic Exchange Reactions Involving Dilithium Phthalocyanine, Morgan M. Hart

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Dilithium phthalocyanine (Li₂Pc) consists of an aromatic macrocycle possessing a doubly negative charge and two Li⁺ counterions. One Li⁺ ion is easily displaceable while the other remains coordinated to the phthalocyanine ring. The displaceable Li⁺ cation can be exchanged with other cations, such as a singly charged tetra-alkyl ammonium cation, by using several variations of a general procedure. It has been demonstrated that tetraalkylammonium lithium phthalocyanines (TAA-LiPcs) can be successfully and reproducibly synthesized with yields ranging from 54.5% up to 64.3%. All TAA-LiPcs demonstrated poor solubilities from approximately <0.2 mg/mL to 5 mg/ml in the solvents tested (with the exception of tetrapropylammonium lithium phthalocyanine and tetrahexylammonium lithium phthalocyanine). All of the TAA-LiPcs synthesized were dark-purple in color, with the exception of tetraheptylammonium lithium phthalocyanine and tetraoctylammonium lithium phthalocyanine. These two compounds were dark - blue in color. Melting points varied greatly from >370.4°C to 157.9°C and depended greatly upon …

Quantum Chemical Investigations Of Nucleophilic Aromatic Substitution Reactions And Acid Dissociations Of Aliphatic Carboxylic Acids, David Henry Schory

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Quantum chemical analysis was used to examine nucleophilic aromatic substitution reactions of fluorinated benzophenones, diphenyl sulfones, and triphenylphosphine oxides. Some experimental results for these compounds were contrary to conventional wisdom, which holds that calculated atomic charges for the aromatic sites and ¹³C-NMR and ¹⁹F-NMR chemical shifts should allow prediction of the preferred sites for aromatic substitution. Density functional theory (B3LYP/6-31+G*//RM1) and semi-empirical (RM1) quantum chemical calculations were employed to study the intermediates in the reaction pathways in order to identify the preferred paths for aromatic substitution. In most cases studied para substitution pathways had the lower energy intermediates …