Physical Sciences and Mathematics Commons^™

Synthesis And Characterization Of Starburst Pseudorotaxanes And Their Metallic Derivatives, Shalini D. Kadinappulige

Masters Theses

Mechanically Interlocked Molecules (MIMs) are interlocked molecular architectures, characterized by the fact that they are linked through a mechanical bond. Catenanes, rotaxanes, molecular knots, and Borromean rings are typical examples for these molecules. Since MIMs are not connected by covalent bonds, hydrogen bonding, π- π stacking, and/or electrostatic interactions help bring the components together. Dialkyl-ammonium centers, bis(pyridinium)ethane dications, viologen species, and naphthalenediimide π-deficient groups are well known as recognition motifs for crown ethers. In the research described here, we have synthesized several pseudorotaxanes and their tricyclohexyltin metallic derivatives, based on benzobis(imidazolium) (BBI) salts as axles, in combination with the 15DN38C10 …

Studying Carbon Dioxide Solvent Properties By Microwave Spectroscopic Investigations Of Vinyl Fluoride/Carbon Dioxide Clusters And Developing New Approaches To Decode Rotational Spectra, Prashansa Kannangara

Masters Theses

Supercritical carbon dioxide (sc-C0₂) is an excellent green solvent, but its properties are not thoroughly understood. For example, fluorinated compounds have higher than expected solubility in sc-C0₂. Microwave spectroscopy is one way to learn more about sc-C0₂ because it can be used to determine detailed structures of small clusters of molecules. The purpose of this investigation was to study weak hydrogen bonding interactions in complexes of fluorinated ethylene (solute) with carbon dioxide (C0₂, solvent). Investigations on dimers with one C0₂ molecule and fluorinated ethylene were carried out previously and found two different …

Synthesis Toward A Molecular Container Based On P-Tert-Butylcalix[4]Arene With Gate Features, Balasooriya Appuhamilage Dinesh Madushan Balasooriya

Masters Theses

Nowadays molecular and supramolecular chemistry have endless examples for the development of smart devices. Among those applications, nano-baskets of calixarenes play vital roles in host-guest chemistry. One of the main appealing concepts of this field is the development of host molecules with gate features. These hosts are designed and constructed for the delivery of chemical or biochemical species that are volatile, or reactive, or sensitive to normal solution environment and they are mainly functioned by predefined groups that are responsive toward stimuli such as concentration, temperature, pH and so on. In our previous study, we found that benzyl bromides can …

Removal Of Antimony And Bismuth From Copper Electrorefining Electrolyte By Two Proprietary Solvent Extraction Extractants, Andrew Artzer

Masters Theses

"Antimony and bismuth are two of the most problematic impurities in copper electrorefining (ER). Because of this, much research has been done investigating the ways to remove them. Processes that are currently being used industrially include anode additions, liberators, ion exchange (IX), and solvent extraction (SX). Of these, liberators and anode additions are the most common while SX is the least, mostly being used for arsenic removal. There are other methods that have been evaluated, but are not in commercial use. These include the use of various electrolyte additives, and adsorbents such as bentonite clay and heavy metal sulfates.

Two …

Synthesis, Characterization And Mechanistic Studies Of Biomimetic Dinuclear Copper(Ii) Complexes, Millaniyage Nuwanthaka Prasad Jayaweera

Masters Theses

Dinuclear copper complexes are significant synthetic targets due to their use as model compounds for the active sites of type 3 copper proteins like catechol oxidase. A distinct class of ligands used in these studies are built on a phenol core to witch various donor side-arms were appended at the 2 and 6 positions of the arene ring. In our quest to quantify the influence of electron donating or withdrawing groups attached to the central arene ring, we have designed a set of ligands that, upon coordination to copper(II) centers, would produce complexes of the general structure. During this research …

Developing A Basket-Shaped Host Molecule Based On P-Tert-Butylcalix[4]Arene Featuring Urea Groups For Encapsulating Volatile Guest Molecules, Lokugama Widanelage Vidula Priyadarshana

Masters Theses

Molecular baskets are a group of synthetic host molecules which are designed to govern the inclusion of small guest molecules. The basic structural features of basket-shaped host molecules are a cavity for holding a much smaller guest molecule and tunable gates for keeping the guest molecule inside. These types of gates can be tuned by changing temperature, concentration, pH, etc. In this research group's previous study, a molecular basket of cal ix[ 4]arene with carboxylic acid groups was synthesized by functionalizing calix[4]arene's phenol hydroxyl groups with benzyl bromide building blocks. In the study detailed here, 1 , l '-((5-(bromomethyl)-1,3-phenylene)bis(methylene))bis(3-isopropylurea) was …

Solvation Properites Of Supercritical Carbon Dioxide Using Chirped-Pulse Fourier-Transform Microwave Spectra Of Carbon Dioxide / 1, 1-Difluoroethene (Dfe) Mixtures, Tulana Ariyaratne Subasinghe Arachchige

Masters Theses

Supercritical carbon dioxide (sc-C0₂) is a highly utilized industrial substance identified as an excellent solvent and a surfactant, which is cheaper and less hazardous than other typical solvents. The higher solubility of fluorinated hydrocarbons than their hydrocarbon (HC) analogs is not well understood and the theory behind the microsolvation of sc-C0₂ cannot be fully explained with the existing chemical information. Microwave spectroscopy is a good method of identifying the structural arrangement of clusters made from fluorinated HCs and C0₂. I n this project, microwave scans of the four different mixtures of 1 , 1-difluoroethene (DFE) …

Computational Study Of The Nature Of Tetrel Bond, Yama Aman

Masters Theses

For more than a hundred years, the type of a chemical bond has been distinguished according to the relative electronegativities of chemical units at the ends of a bond. Whereas, the bond of unequally electronegative on both ends is called a polar covalent or even ionic bond or a non-polar covalent bond in case of both equal. Regardless the type of bonded elements, the whole idea for the bond was believed to be electron driven only. In the 20th century the development of the idea, that not just the electronic relation but specific elements are also able to characterize the …

Synthesis And Characterization Of Fluorescent Nanojars, Vageesha Warnajith Liyana Gunawardana

Masters Theses

Self-assembly is a powerful tool utilized by synthetic chemists to create large, intricate structures for a variety of applications such as drug delivery, adaptable materials and electronics. In contrast to stepwise synthesis, this process allows the formation of intricate molecular architectures starting from synthetically rudimentary building blocks. Nanojars are class of self-assembling, cyclic copper(II) pyrazolate coordination compounds that encapsulate oxoanions with negative two or three charge. The strong anion binding characteristics of nanojars have potential towards developing novel tools for detecting biologically and environmentally relevant anions such as carbonate, sulfate and phosphate.

This work addresses the design and synthesis of …

Synthesis And Evaluation Of Acetylcholine Molecularly Imprinted Polymers, Nathaniel Donald Thiemann

Masters Theses

Polymers imprinted with acetylcholine during synthesis were prepared in order to evaluate their potential for implementation as a novel recognition element in acetylcholine biosensors. Biosensors, such as the glucose monitor, are used to rapidly detect and quantify a target analyte. Acetylcholine biosensors have already been produced using enzymatic recognition elements, but they are currently expensive and plagued by short viability. Molecularly imprinted polymers are not only cheap and durable, but have also been successfully used as a recognition element in biosensors for other analytes. Therefore, computational tools were used to rationally design acetylcholine molecularly imprinted polymers. Three chemicals, itaconic acid, …

Organocatalyzed Synthesis Of Epoxides From Chalcones Utilizing Amino Acids, Sabrina N. Kegeler

Masters Theses

The epoxide functional group is important throughout the chemical and pharmaceutical industries, as well as in nature. In the chemical industry, epoxides are present in resins and fragrances. In the pharmaceutical industry, epoxide-containing compounds are used as intermediates in the manufacturing of drugs. In nature, many natural products contain epoxide groups and are used for medicinal purposes, and for models to create synthetic molecules.

One approach to epoxide synthesis involves the use of an alkene precursor, a base, and an oxidizing agent. This is where my investigations began. The first step was to optimize the epoxidation reaction, examining substrate scope, …

Research And Development Of Optically Transparent Join With Low Processing Temperatures, Eric Kevin Muskovin

Masters Theses

The purpose of this study was to investigate durable solar cell cover glass joins produced by diffusion bonding with deep eutectic solvents (DES) and to develop a novel process of joining optically transparent materials at low temperatures. A joined PV cell-glass specimen was characterized using Raman, μ-FTIR, SEM-EDS, and thin-film XRD. DESs were created with malonic acid (MAL) and choline chloride (ChCl) of varying composition factors (CF; CF=MAL/ChCl). Joining borosilicate glass coupons was attempted using DESs with CF = 0.65 and 1 at temperatures between 100-150 °C for 20 hours. Joining the glass coupons failed at all temperatures and oxygen …

Synthesis And Characterization Of Biomimetic Dinuclear And Tetranuclear Copper Complexes, Syed Rahmath Ullah Joy

Masters Theses

Seven new copper(II) complexes were prepared from the condensation reaction of 4-tert-butyl-2,6-diformylphenol with two equivalents of bis(pyrazolyl)ethanamine or 3,5-dimethyl-bis(pyrazolyl)ethanamine moieties in the presence of two equivalents of various copper(II) starting materials having different counter ions (i.e. acetate - AcO^-, perchlorate - CIO₄^-, tetrafluoroborate - BF₄^-, nitrate - NO₃^-, and chloride - Cl^-). The resulting copper(II) complexes were characterized in solid state by single crystal X-ray crystallography, and in solution by UV-Vis and ESI/MS spectroscopies.

X-ray crystallographic studies showed that in solid state two types of …

Pd-Based Photocatalysts For Sonogashira C-C Cross-Coupling Reactions, Komadhie Charuka Dissanayake

Masters Theses

Sonogashira C-C cross-coupling reaction has been heavily used for its simplicity, flexibility and value. Although the original Sonogashira C-C cross coupling reaction conditions entail the use of 0.5 mol% of Pd catalyst, 2 mol% of Cul as co-catalyst at room temperature, the experimental conditions used in laboratories to prepare some compounds vary substantially, especially with respect to the reaction time, temperature and loading amount of the catalysts. The most significant drawback of the conventional Sonogashira reaction is the use of Cul as it leads to the formation of homocoupling product when the reaction is exposed to air or oxidizing agents. …

Apan Production Through Photooxidation Of Isoprene In The Presence Of NoX, Timothy Glidewell

Masters Theses

Peroxyacyl nitrates (PANs, RC(O)OONO₂) are of great importance in atmospheric chemistry. They act as transporters of reactive nitrogen, and radical delivery agents. There are no known natural emission sources of PANs; they are produced through reaction of volatile organic compounds (VOCs) and nitrogen oxides (NO_x) in the atmosphere.

VOCs can enter the atmosphere through biogenic and anthropogenic pathways. It has been estimated that isoprene makes up 70% of the biogenic VOCs (BVOCs) emitted annually. Isoprene has been shown to impact ozone levels in both rural and urban areas by sequestering and transporting NO_x in the form …

The Effect Of Plant Source On Lignin-Based Polyurethanes And The Interdiffusion Dynamics Of Semi-Rigid Polymers, Jason Michael Lang

Masters Theses

The work reported in this thesis increases our understanding of the effect of lignin plant source on the mechanical and morphological properties of lignin-based polyurethanes and the interdiffusion of glassy/liquid bilayer thin films. The interdiffusion of glassy/liquid polymer pairs has received much less attention than liquid/liquid bilayers, leading to conflicting results and unresolved discrepancies. Therefore, the reported study of interdiffusion between polysulfone glassy/liquid polymer layers provides insight into the dynamics of these systems.

This thesis first reports the correlation between the mechanical properties of lignin-based polyurethanes and the lignin plant source. Lignin is a molecule that can be used as …

How The E. Coli Hsp70 Molecular Chaperone, Dnak, Binds A Client Protein, Joseph Tilitsky

Masters Theses

Protein folding is essential for all cellular life. While some proteins are able to reach their folded state reliably using nothing but their amino acid sequence, a great number of essential proteins are unable to do so without the aid of molecular chaperones. One family of molecular chaperone, the Hsp70 family, is found in virtually all cell types and across all domains of life. Certain to the function of Hsp70s are how they bind their client proteins. Substantial effort has been expended to study how Hsp70s work on model peptides as a substrate mimic, but relatively little work has been …

Influence Of Biomimetic Chelating Packaging On Natural Antimicrobial Efficacy, Paul Castrale

Masters Theses

The iron chelating molecule, ethylenediaminetetraacetic acid (EDTA) is used in food applications for the preservation of oxidation prone ingredients. Research has suggested that EDTA is also capable of enhancing the antimicrobial effectiveness of various compounds including naturally-derived antimicrobials. With consumer demand for cleaner food labels, there remains an opportunity to introduce new chelating technology to replace synthetically-derived EDTA. Through photographting and chemical conversion, hydroxamic acid ligands were covalently bound to polypropylene films resulting in polypropylene-graft-poly(hydroxamic acid) (PP-g-PHA). The resulting films demonstrated an ability to chelate 64 nmol/cm² from an iron saturated environment or 163 nmol/cm …

Microtransplantation Of Rat Brain Neurolemma Into Xenopus Laevis Oocytes To Study The Effect Of Environmental Toxicants On Endogenous Voltage-Sensitive Ion Channels, Edwin Murenzi

Masters Theses

Microtransplantation of mammalian neurolemma into Xenopus laevis oocytes has been used to study ion channels in terms of their structure and function in the central nervous system. Use of microtransplanted neurolemma is advantageous in that tissue can be obtained from various sources, ion channels and receptors are present in their native configuration and they can be used to evaluate numerous channelpathies caused by environmental toxicants. Here we show that Xenopus oocytes injected with fragments of rat brain neurolemma successfully express functional native ion channels that are assembled in their own plasma membrane. Using a high throughput two electrode voltage clamp …

Novel Spectroscopic Tools To Differentiate Drug-Dna Binding Interactions, Fadwa Dhafer Hamad

Masters Theses

DNA-drug interactions play a major role in therapeutics, diagnostics, forensics and imaging. Drugs bind to DNA in several ways based on the mode of interaction and they alter protein-DNA interactions or breaks/cleaves DNA that can lead to the cure of the disease. The major goal of the research carried out in this thesis is to develop novel optical spectroscopic tools that can differentiate Drug-DNA binding interactions mode whether its intercalation or minor-groove binding. To achieve this goal, we developed two-photon absorption (2PA) cross-section based technique to differentiate between Drug-DNA binding modes. The investigations were carried out on two drug molecules, …

Characterization Of Γ-Butyrolactone Rings: A Computational And Toxicological Study, Donald C. Kidd

Masters Theses

Given the declining state of the natural environment, identifying green methodologies in synthetic chemistry is becoming paramount. An under explored area of green chemistry, is the use of catalytic systems in green solvents. One interesting concept in green chemistry is the use of N-Heterocyclic Carbenes (NHCs) as organocatalysts.

Thiamine or vitamin B1 was one of the first NHCs recognized. Thiamine is required for carbohydrate metabolism and helps the cell produce adenosine triphosphate (ATP). Over the last 20 years NHCs have been found to be efficient catalysts in carbon-carbon bond forming reactions.

But to date, little research has been done exploring …

Development Of Nuclear Underground Engineered Test Surrogates For Technical Nuclear Forensics Exploitation, Robert Boone Gilbreath

Masters Theses

A method for formulation and production of Nuclear UnderGround Engineered Test Surrogates (NUGETS) based on notional improvised nuclear device (IND) detonations in an underground environment analogous to the Nevada National Security Site (NNSS) is presented. Extensive statistical analyses of precursory geochemical and geophysical characteristics are combined with an augmented surrogate debris cooling technique and predictive IND contributions from the ORIGEN Fallout Analysis Tool. Precursory and resultant elemental compositions, cooling curve calculations, and visual comparison of NUGETS to genuine underground debris are reported. Application of NUGETS methodology to future studies in urban, underground post-detonation technical nuclear forensic (TNF) analysis is suggested.

Red Emissive Bodipy Dyes As Sensitizers For Near-Infrared Emission Of Lanthanide Complexes & Structural & Spectroscopic Studies Of Quinoline-Functionalized Bodipy Dyes, Adedayo Ayodeji Kukoyi

Masters Theses

Bioimaging has become a significant tool for the visualization of biological events and the detection of numerous biomarkers. However, detection sensitivity is compromised by background signal from the biofluid which interferes with signals from the probes that usually emit in the visible region Alternative probes such as those that emit in the near-infrared (NIR) region are necessary to overcome these shortcomings. Lanthanide ions have demonstrated efficiency with sharp characteristic emission in the visible and (NIR) region. Emission however is mostly achieved by indirect sensitization process in which energy from the triplet state of a sensitizer is transferred to the excited …

Bodipy-Based Red Sensitizers For Near-Infrared Emission Of Lanthanide Complexes, Priyangika Prasadini Senevirathne

Masters Theses

During the past 20 years there has been a remarkable growth in the use of the fluorescence technique in biological studies. Fluorescence and time-resolved fluorescence spectroscopy are considered primary research tools in the field of biochemistry. Currently, fluorescence spectroscopy is a dominant methodology and used widely in biotechnology and medical diagnosis process. One impediment in using fluorescent probes is the fluorescence of biological substrates and fluorescence of diagnostic probes are significantly overlapped, and it decreases the detection sensitivity. Also, commercially available probes require UV or near-UV light excitation, causing severe degradation of biological substrates. Near-infrared emitting lanthanide complexes can overcome …

In Situ Ph Determination Based On The Nmr Analysis Of ¹H-Nmr Signal Intensities And ¹⁹F-Nmr Chemical Shifts, Ming Huang

Masters Theses

"The pH of an NMR sample can be measured directly by NMR experiments of signal intensities, chemical shifts, or relaxation time constants that depend on the pH. The ¹H NMR peak intensities of the pH indicator phenolphthalein change as it changes from the OH-depleted form to the OH-rich form in the range of pH = 11.1 to 12.7. Because this range is rather small, another NMR technique was utilized based on ¹⁹F chemical shifts. The shift of F^- in an aqueous solution of NaF changes in the alkaline range between pH = 11.0 and 14.0 and even …

Functionalized Bodipy Dyes For Near-Infrared Emission Of Lanthanide Complexes, Rukshani Wickrama Arachchi

Masters Theses

For many decades, fluorophores have been used to investigate natural systems, but autofluorescence and photobleaching diminish the detection capacity. Recently, BODIPY based lanthanide complexes have been synthesized and their photophysical properties have been investigated. These complexes exhibit higher emission efficiencies at NIR region with longer NIR lifetimes upon exciting at longer wavelength.

In this study, two BODIPY based lanthanide complexes were synthesized and their photophysical properties were evaluated. BODIPY based ligands were synthesized with phenanthroline as the ligand binding group. These ligands exhibit strong absorption at 527 nm and 532 nm, fluorescence at 540 nm and 548 nm with 0.55 …

Behavior Of Different Sizes Of Strontium Titanate Substrates In Electrochemical Modifications, Shuxin Luo

Masters Theses

In our previous atomic force microscopy (AFM) studies of 5 mm x 5 mm single crystal SrTiO₃ (STO(100)) substrates, rutile TiO₂ crystals were found on the substrates surfaces after electrochemical modification. These crystals were found mainly in the area of contact between the substrate and the gold-coated alligator clip that was not supposed to be immersed into the electrolyte and that served as a connection between the STO working electrode and the potentiostat circuit. The size and density of the crystals were found to depend on electrochemical potential, its polarity, the length of modifying time, and the total …

Molecular Recognition Profiles Of Molecular Cocrystals, Ian C. Tinsley

Masters Theses

The manner in which molecules recognize each other holds critical importance to nearly every area of science. This significance stems from the key underpinning of molecular assembly to our most basic understanding of chemical processes. Whether these interactions relate to small-molecule catalytic transformations or complex physiological processes, the structural features responsible for molecular association play into the well-known adage that form follows function where material property arises from the collective structural features of the molecular components. Because the form of chemical systems is derived from a complex blend of covalent and non-bonded contacts, codifying each contributor has become essential for …

Synthesis And Characterization Of Cu(Ii)-Cu(I) Mixed Valence Complexes, Hansani T. Lekam Wasam Liyanage

Masters Theses

Our study was focused on synthesis and characterization of new family of metal complexes that mimic the active site of copper containing enzymes. Our approach focused on preparing a series of metalloligands which vary systematically in structure and use them in combination with additional metallic centers to synthesize our desired complexes.

We synthesized a main ligand, which is named as HL^Q 2Pz, which contain a quinoline body, one amide bond and two pyrazolyl rings. We synthesized a copper complex by deprotonating HL^Q 2Pz using KOH. The ligand coordinated to the copper(II) center through its quinoline nitrogen, two of …

Three Body Interactions Of Rare Gas Solids Calculated Within The Einstein Model, Dan D'Andrea

Masters Theses

Three body interactions can become important in solids at higher pressures and densities as the molecules can come into close contact. At low temperatures, accurate studies of three body interactions in solids require averaging the three-body terms over the molecules' zero point motions. An efficient, but approximate, averaging approach is based on a polynomial approximation of the three-body term. The polynomial approximation can be developed as a function of the symmetry coordinates of a triangle displaced from its average geometry and also as a function of the Cartesian zero point displacements from each atom’s average position. The polynomial approximation approach …