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Articles 1 - 28 of 28
Full-Text Articles in Physical Sciences and Mathematics
A Synthesis And Analysis Of Anhydrous Hydroxide Ion Conducting Polymer Electrolytes, Stanton Heydinger
A Synthesis And Analysis Of Anhydrous Hydroxide Ion Conducting Polymer Electrolytes, Stanton Heydinger
Honors Theses
This project investigates the synthesis and physical properties of polyethylene glycol monomethyl ether (MePEGn where n=3 or 7) based polymer electrolytes. The two polymer electrolytes explored in the experiments were designed from two different MePEG chains that varied in their overall length and degree of polymerization. The first MePEG backbone contained three polymerized ethoxy groups and the second contained seven. Both MePEGn polymers were modified by substituting an imidazolium group in place of the alcohol functional group at the end of the PEG chain. This modification was made to create a polymer electrolyte with an attached positive charge that could …
Theoretical And Experimental Vibrational Modes Of The Borane Pyridine Complex, Benjamin Stratton
Theoretical And Experimental Vibrational Modes Of The Borane Pyridine Complex, Benjamin Stratton
Honors Theses
Benjamin Wade Stratton: Theoretical and Experimental Vibrational Modes of the Borane Pyridine Complex (Under the direction of Dr. Nathan Hammer) The Borane Pyridine complex is a molecule that contains a dative bond between the boron and nitrogen atoms. A dative bond is a type of covalent bonding that occurs when both electrons come from the same atom. The B-N bond has been studied in several other molecules such as ammonia borane and determining the frequency at which this bond vibrates has been a topic of interest studied in these molecules as well as several others. This complex has another factor …
Blocking Recombinations In Dscs Through Mgo And Pfts Surface Treatments, Kayla Foell
Blocking Recombinations In Dscs Through Mgo And Pfts Surface Treatments, Kayla Foell
Honors Theses
High voltage dye-sensitized solar cells (DSCs) are becoming novel sources in the production of various fuel precursors, such as carbon monoxide and hydrogen, by powering carbon dioxide reduction, water oxidation, and proton reduction catalysts via sunlight. An important task in order to increase overall efficiency of DSC devices is to minimize recombination (electron flow in an undesirable direction) while increasing photovoltage. Surface treatment modifications can be applied to the TiO2 electrodes within DSC devices in an effort to block recombination without negatively effecting the other device performance metrics: fill factor (FF), short-circuit current density (Jsc), and open-circuit photovoltage (Voc). In …
Structures, Energetics, And Vibrational Frequencies Of Microhydrated Hexafluorophosphate, Pf6−(H2o)N=1,2 From Dft And Ab Initio Computations, Yasmeen Abdo
Honors Theses
This study systematically examines an anion commonly used in room temperature ionic liquids, hexafluorophosphate PF6−, and its non-covalent interactions with up to two explicit water molecules (PF6 − (H2 O)n where n = 1, 2). Initial low-energy configurations are identified via a set of relaxed angular scans across the edges and faces of the PF6− octahedron using the global hybrid M06-2X density functional with a triple-ζ correlation consistent basis set augmented with diffuse functions on all non- hydrogen atoms (cc-pVTZ for H and aug-cc-pVTZ for P, O, F; denoted haTZ). Full geometry optimizations are performed on these initial structures using …
Synthesis Of A Novel Tetradentate Ligand And Its Copper Complex For Redox Shuttle Applications, Joseph T. Vaughan
Synthesis Of A Novel Tetradentate Ligand And Its Copper Complex For Redox Shuttle Applications, Joseph T. Vaughan
Honors Theses
With growing energy demands, alternatives to the traditional non-renewable fuel sources are currently being explored. Of these alternative fuel sources, solar energy, particularly dye-sensitized solar cells (DSSC), have garnered considerable interest. Traditional redox mediators within these solar cells have been triiodide/iodide couples, which pose several complications due to their corrosiveness, absorption in the visible range, and efficiency, motivating the development of better redox couples for next generation DSSCs. Thus, transition metal complexes have rapidly gained traction as a potential replacement for this traditional I-/I3- based system. In this study, a novel tetradentate ligand framework and its copper and nickel complexes …
Unexpected Outcomes During The Attempted Iodination Of Biphenol, Henry Nguyen
Unexpected Outcomes During The Attempted Iodination Of Biphenol, Henry Nguyen
Honors Theses
The goal of this research was to create a new procedure to iodinate 4,4- biphenol using a ball miller. Iodination of 4,4-biphenol was first attempted in solution using electrophilic aromatic substitution. Several attempts were made to iodinate 4,4-biphenol, but the general insolubility of crude products inhibited progress. Interestingly, NMR analysis of the aqueous ammonia product suggested that 4,4-biphenol dimerized or polymerized with itself to make an ether. The exact mechanism by which the ether dimer was created is unknown, but the reaction may have occurred using a radical mechanism. Though the original goal of the project is left unmet, a …
The Synthesis Of New Donor-Sigma-Acceptor Compounds As Potential Current Rectifiers, Trey Gautier Vaughan
The Synthesis Of New Donor-Sigma-Acceptor Compounds As Potential Current Rectifiers, Trey Gautier Vaughan
Electronic Theses and Dissertations
The zwitterionic D-σ-A’s are characterized by having an anionic donor, a cationic acceptor, an intervening sigma-bond bridge, and an aliphatic tail. The aliphatic tail is of such length as to impart greater solubility in organic solvents since the formal charges on the donor and acceptor lead to poor solubility. Additionally, the aliphatic tail is required for Pockels-Langmuir deposition to facilitate the favorable van der Waal’s packing when combined to form dense monolayer registries. These monolayers may then be suitable for measuring the bulk electrical properties.
A Computational Approach To Predicting And Understanding New Psychoactive Substances (Nps) For Developing A Database For State And Federal Crime Laboratories, Caroline Amelia Spencer
A Computational Approach To Predicting And Understanding New Psychoactive Substances (Nps) For Developing A Database For State And Federal Crime Laboratories, Caroline Amelia Spencer
Electronic Theses and Dissertations
The object of this dissertation was to use a computational approach to predict and understand new psychoactive substances (NPS) to develop a database for state and federal crime. The primary scope of the dissertation was to better understand the interactions that take place between new psychoactive substances and their corresponding receptors. Through analysis of the interactions between the amino acids within the receptors and the NPS an understanding into the pharmacology and toxicology of these drugs can be gained. NPS such as synthetic cannabinoids fentanyl and its analogs and kratom have become more problematic for both state and federal crime …
Electro- And Photocatalytic Carbon Dioxide Reduction And Thermal Isomerization Of Highly Strained Tricyclocompounds, Weiwei Yang
Electro- And Photocatalytic Carbon Dioxide Reduction And Thermal Isomerization Of Highly Strained Tricyclocompounds, Weiwei Yang
Electronic Theses and Dissertations
Anthracene-bridged dinuclear rhenium complexes are reported for electrocatalytic and photocatalytic carbon dioxide (CO2) reduction to carbon monoxide (CO). Related by hindered rotation of each rhenium active site to either side of the anthracene bridge cis and trans conformers have been isolated and characterized. Electrochemical studies reveal distinct mechanisms whereby the cis conformer operates via cooperative bimetallic CO2 activation and conversion and the trans conformer reduces CO2 through well-established single-site and bimolecular pathways analogous to Re(bpy)(CO)3Cl. Higher turnover frequencies are observed for the cis conformer (35.3 s−1) relative to the trans conformer (22.9 s−1) with both outperforming Re(bpy)(CO)3Cl (11.1 s−1). Photocatalytic …
Intramoleculer Hydrogen Bonding In Epoxide, Thiirane, Aziridine And Phosphirane Containing Cyclopentanols, Ben Edward Smith
Intramoleculer Hydrogen Bonding In Epoxide, Thiirane, Aziridine And Phosphirane Containing Cyclopentanols, Ben Edward Smith
Electronic Theses and Dissertations
A recent computational analysis of the stabilizing intramolecular OH· · · O contact in 1,2-dialkyl-2,3-epoxycyclopentanol diastereomers has been extended to thiiriane, aziridine and phosphirane analogues. Density functional theory (DFT), second-order Møller-Plesset perturbation theory (MP2) and CCSD(T) coupled-cluster computations with simple methyl and ethyl substituents indicate that electronic energies of the cis isomers are lowered by roughly 3 to 4 kcal mol−1 when the OH group of these cyclopentanol systems forms an intramolecular contact with the O, S, N or P atom on the adjacent carbon. The results also suggest that S and P can participate in these stabilizing intramolecular interactions …
A Study To Regioselectively Access Fluorinated Triazoles And Isoxazoles, Sweta Adhikari
A Study To Regioselectively Access Fluorinated Triazoles And Isoxazoles, Sweta Adhikari
Electronic Theses and Dissertations
The objective of the thesis is to develop regioselective methods for mono-fluorination of disubstituted triazoles, both 1,4- and 1,5-regioisomer, and isoxazoles. These strategies focus on one-pot direct access to final mono-fluorinated triazoles and isoxazoles. Eventually, these fluorinated substrates will be screened against various biological targets. Similarly, the optimization study of a regioselective method to generate 5-fluoro-1,4-disubstituted triazole was conducted. This reaction also utilized 1,3-dipolar cycloaddition to synthesize fluorinated triazole. However, difluoroalkene was used as a synthetic equivalent of fluoroalkyne for this method. This resulted into the inversion of polarity affording a different regioisomer. Here, fluoronitroalkene was identified as a synthetic …
Ligand Effect On Gold Nanomolecules Demonstrated Using Aliphatic, Aromatic And Bulky Thiolate Ligands, Milan Rambukwella
Ligand Effect On Gold Nanomolecules Demonstrated Using Aliphatic, Aromatic And Bulky Thiolate Ligands, Milan Rambukwella
Electronic Theses and Dissertations
Atomically precise thiolate protected gold nanoparticles (AuNPs) known as gold nanomolecules (AuNMs) are intensely pursued owing to their feasibility to elucidate their structure by single crystal X-ray crystallography. They have distinct number of Au atoms (n) and thiolate (-SR, R-hydrocarbon chain) ligands (m) with molecular formula of the form [Aun(SR)m]. AuNMs are made of a gold core protected by a thiolate-monolayer and possess size-dependent properties conferred by quantum confinement. Atomic precision has been achieved in the 1-3 nm range and crystal structures of several AuNMs ranging from 18 to 279gold atoms have been studied. They provide significant insights into the …
The Development Of Novel Rhenium- And Copper-Based Molecular Catalysts For Applications In Energy Conversion Chemistry, Joseph Michael Lee
The Development Of Novel Rhenium- And Copper-Based Molecular Catalysts For Applications In Energy Conversion Chemistry, Joseph Michael Lee
Electronic Theses and Dissertations
Since the Industrial Revolution, the consumption of fossil fuels has increased dramatically worldwide. The combustion of fossil fuels leads to the generation of carbon dioxide (CO2) emissions. CO2 is a greenhouse gas, but also a C1 feedstock that could be utilized for the generation of renewable fuels and commodity chemicals. However, CO2 is chemically inert and typically demands strong chemical reductants or very negative potentials before it undergoes conversion into reduced carbon products. The desire to carry out CO2 conversion in the presence of water presents a significant challenge, as protons may be reduced to hydrogen gas rather than facilitating …
Probing Atypical Noncovalent Interactions Using Electronic Structure Theory, Katelyn Mae Dreux
Probing Atypical Noncovalent Interactions Using Electronic Structure Theory, Katelyn Mae Dreux
Electronic Theses and Dissertations
Some of the most important topics in modern chemistry involve noncovalent interactions in a variety of ways, from pharmacological processes to materials design. Due to the comparatively weak nature of these interactions, they can be difficult to investigate experimentally. Beyond what might be considered the ‘typical’ noncovalent interactions such as hydrogen bonding or London dispersion, there are less well known noncovalent interactions such as coordinate covalent, dihydrogen, and nonconventional hydrogen bonding, which have been the focus of much of this research. Through the use of electronic structure theory, fundamental information about the structure, energetics, and molecular properties of noncovalently bound …
Characterization Of Hydrogen Bonding, Halogen Bonding And Argyrophilic Interactions Using Computational Modeling, Sarah Nicole Arradondo
Characterization Of Hydrogen Bonding, Halogen Bonding And Argyrophilic Interactions Using Computational Modeling, Sarah Nicole Arradondo
Electronic Theses and Dissertations
Non-covalent interactions govern multiple important chemical processes throughout nature from those within the human body to the complex environment of the atmosphere. Quantum mechanical electronic structure modeling of these relatively weak interactions can provide molecular level insight that can further our understanding of specific macroscopic properties. In the present work different non-covalent interactions are computationally evaluated within four systems. A small prototypical hydrogen bonded system and the various structural motifs that promoted proton transfer within concentrated acid and water clusters are characterized with sophisticated wavefunction based methods and large robust basis sets in order to accurately predict the structures energies …
Effects Of Halogen Bonding And Nir Tuning Of Dyes For Dye-Sensitized Solar Cells, Alexandra Baumann
Effects Of Halogen Bonding And Nir Tuning Of Dyes For Dye-Sensitized Solar Cells, Alexandra Baumann
Electronic Theses and Dissertations
With current energy demands being met through the utilization of energy sources such as petroleum, natural gas, and coal, the non-renewable nature of these sources will eventually approach depletion as world wide energy consumption increases yearly. As a result the need for a renewable energy alternative has become imminent. One appealing alternative that has gained considerable attention since its development due to a low cost and a high solar to electric conversion efficiency are dye-sensitized solar cells (DSCs). This dissertation describes efforts to design and synthesize improved organic dyes utilizing three analogous methods: first, through decreasing non-productive pathways such as …
Bulky Thiolated Gold Nanomolecules: Synthesis, Characterization, Optical Properties, And Atomic Structure, Tanya Clorise Jones
Bulky Thiolated Gold Nanomolecules: Synthesis, Characterization, Optical Properties, And Atomic Structure, Tanya Clorise Jones
Electronic Theses and Dissertations
Gold nanomolecules (NMs) have a distinct number of gold atoms and thiolate ligands, Aux(SR)y, with unique spectroscopic, electrochemical, and chiral properties which are dependent on “x” and “y”. The properties of NMs are dictated by the type of capping ligand. The overall structure, size, surface percentage of ligands, and structure of an entire gold NM is changed based on the type of ligand used to synthesize it. Ligand type, such as aliphatic, aromatic or bulky play a crucial role in determining the size and composition of such NMs. A NM’s composition and properties vary widely depending on the type of …
High Voltage Dye-Sensitized Solar Cells And Molecular Photocatalysis For Co2 Reduction, Roberta Ramalho Rodrigues
High Voltage Dye-Sensitized Solar Cells And Molecular Photocatalysis For Co2 Reduction, Roberta Ramalho Rodrigues
Electronic Theses and Dissertations
The development of high voltage solar cells is an attractive way to use sunlight to power electrocatalysts for water oxidation, electrocatalysts for CO2 reduction, and consumer electronics. Through careful molecular dye engineering and redox shuttle pairing, our group has reported a single-junction dye-sensitized solar cell (DSC) employing, for the first time, an iron redox mediator (Fe(bpy)33+/2+) in conjunction with a novel wide band gap dye (RR9). This system generates a high photovoltage of 1.42 V. To the best of our knowledge, this system is the highest photovoltage achieved by a single-junction DSC device without metal oxide doping. The RR9/Fe(bpy)33+/2+ redox …
X-Ray Crystal Structure Of Au36(Sph-Pch3)24 Nanomolecules, Vigneshraja Ganeshraj
X-Ray Crystal Structure Of Au36(Sph-Pch3)24 Nanomolecules, Vigneshraja Ganeshraj
Electronic Theses and Dissertations
Au36(SR)24 is one of the most comNanomolecules (NM) in gold NM field and crystal structures of Au36(SR)24 with different thiolate protecting ligand such as tert-butylbenzene thiol, thiophenol and cyclopentane thiol have been reported. It has been predicted that aromatic thiol protected Au36(SR)24 NM have same core structures like the other reported Au36(SR)24 NMs. Due to the steric and electronic conjugation effects the staples on the gold core exhibit minor changes in the bond length without affecting the gold core. By varying the Gold:Thiol ratio the NM size can be controlled. Herein, we report the synthesis, isolation and characterization of two …
Organic Sensitizers For High Efficiency Dye-Sensitized Solar Cells, Adithya Peddapuram
Organic Sensitizers For High Efficiency Dye-Sensitized Solar Cells, Adithya Peddapuram
Electronic Theses and Dissertations
After the industrial revolution in 19th-century energy, demand has increased exponentially. Relying on fossil fuels long term is not a good option due to their non-renewable nature and concerns about burning fossil fuels raising carbon dioxide levels in atmosphere. This dissertation describes, utilizing sunlight for electricity production with dye-sensitized solar cells (DSCs). DSCs are an attractive solar technology due to processing advantages over traditional solar cells. To improve the stability of DSCs, strong surface binding dyes are important. This work studies the dual anchor dual donor (DD-π-AA) dye framework with various donors (electron rich π-systems) and π-bridges (electron neutral π-systems). …
Near-Infrared High Efficiency Organic Dye Sensitized Solar Cells (Dscs) And Biological Fluorescent Imaging Dyes, Yanbing Zhang
Near-Infrared High Efficiency Organic Dye Sensitized Solar Cells (Dscs) And Biological Fluorescent Imaging Dyes, Yanbing Zhang
Electronic Theses and Dissertations
With the energy consumption increase every year, the non-renewable energy sources such as fossil fuels, natural gas, and coal will not sustain forever. In this case, searching for a way to develop a renewable energy source is an emergency. For decades, dye-sensitized solar cells (DSCs) have received intensive attention due to their high power conversion efficiency and low material cost. This dissertation describes efforts to design and synthesize near-infrared organic dyes to apply to two systems: first, for use in the improvement of DSCs by the optimization of electron rich components such as ullazine and cross-conjugated -bridges to increase photon-to-electricity …
Development Of Cobalt And Iron Catalysts Bearing Rigid Polydentate Ligands For Proton Reduction And C-H Bond Oxidation, Lizhu Chen
Electronic Theses and Dissertations
The demand for energy consumption has increased exponentially since the Industrial Revolution. The major source of this energy has been and continues to be fossil fuels. The depletion of fossil fuels and environmental concerns associated with their combustion has motivated us to develop a renewable energy alternative to meet future energy demands. Hydrogen is a clean energy alternative to fossil fuels, which can be generated from solar-driven water splitting. However, more efficient and inexpensive catalysts for the hydrogen evolution reaction (HER) are needed. In this context, hydrogen production has been investigated with a stable and highly reactive cobalt-based catalyst. While …
Electrochemical Studies Involving Co2 Reduction With Rhenium-Based Catalysts And For Guanosine Monophosphate Oxidation, Kayla A. Milano
Electrochemical Studies Involving Co2 Reduction With Rhenium-Based Catalysts And For Guanosine Monophosphate Oxidation, Kayla A. Milano
Electronic Theses and Dissertations
The following chapter of this thesis will cover the oxidation of guanine monophosphate (GMP). GMP has been linked to numerous conditions when it is oxidized or damaged. There have been two oxidation pathways suggested in association to the oxidation of GMP: EPT and MS-EPT. The ideal conditions for GMP’s oxidation is still be studied and collected. The study focuses on the acetate versus phosphate buffer, varying base concentration in phosphate buffer, and the varying concentration of ruthenium complex, a redox mediator.
Theranostics Based On Linear Dendritic Block Copolymers, Jon Williams
Theranostics Based On Linear Dendritic Block Copolymers, Jon Williams
Electronic Theses and Dissertations
When combining imaging and therapeutic motifs, known as theranostics, amphiphilic diblock copolymers have a strong precedent of success. These polymers can self-assemble into a variety of morphologies that are known to concentrate in areas of inflammation such as tumors. However, prediction of size and morphology from polymer structure still remains an open challenge. Another system with promise of therapeutic efficacy are tree-like struc- tures known as dendrimers, such as poly(amidoamine) (PAMAM) and bis-(hydroxymethyl) propionic acid (bMPA), which can uptake drugs and dyes into their branches. It is desireable to combine these two motifs, using linear-dendritic block copolymers (LDBCs). These represent …
Ni And Au Transition Metal Complexes In The Photocatalytic Co2 Reduction Reaction, Shakeyia Davis
Ni And Au Transition Metal Complexes In The Photocatalytic Co2 Reduction Reaction, Shakeyia Davis
Electronic Theses and Dissertations
The production of renewable fuels by the conversion of solar energy into chemical energy is a challenge. Photocatalytic and electrocatalytic conversion of CO2 to usable fuel precursors are approaches to overcoming this challenge. The two-electron reduction of carbon dioxide to carbon monoxide is an appealing process because CO can be used as a commodity chemical in industrial processes. Many molecular CO2 reduction catalysts have been reported and commonly use expensive late transition metals. These systems are inspired by natural photosynthesis and generally combine a photosensitizer, a catalyst, and a sacrificial electron donor. This work focuses nickel and gold complexes as …
Physical And Chemical Trace Evidence From 3d-Printed Firearms, And Use Of A Quadcopter For Targeted Sampling Of Gaseous Mercury In The Atmosphere, Oscar Beauchamp Black
Physical And Chemical Trace Evidence From 3d-Printed Firearms, And Use Of A Quadcopter For Targeted Sampling Of Gaseous Mercury In The Atmosphere, Oscar Beauchamp Black
Electronic Theses and Dissertations
My forensic research resulted in the first peer-reviepaper to address the forensic challenges presented by 3D-printed polymer firearms. The work involved a systematic approach to the analysis of evidence stemming from 3D-printed firearms filling a critical void in current forensic knowledge. We used DART-MS to characterize the polymer evidence left behind by 3D-printed firearms as well as an evaluation of pre-existing firearm and toolmark techniques and fingerprint analysis. We demonstrated that 3D-printed firearms leave behind characteristic polymer residue on cartridge cases bullets and the receiving surface which can be identified using DART-MS. The culmination of the work includes a database …
Design And Development Of Chemically And Biologically Stable Salvinorin-Based Ligands For Opioid Receptors, Tanner Neilson
Design And Development Of Chemically And Biologically Stable Salvinorin-Based Ligands For Opioid Receptors, Tanner Neilson
Honors Theses
The number of opioid prescriptions as a method in pain management increased dramatically in the mid 1990’s following Dr. James Campbell’s 1995 Presidential address to the American Pain Society, where he called for patient pain to be included as a vital sign. The rapid increase in prescriptions in the early 2000’s coupled with a massive effort by pharmaceutical companies to downplay the addictiveness of these drugs has led to a consistent increase in opioid-related drug overdoses, with 47,600 of 70,237 drug related deaths involving opioids in 2017. Opioid analgesics most commonly act upon the mu-opioid receptor (MOR), which is one …
Solvation Of Isoelectronic Halide And Alkali Metal Ions By Noble Gas Atoms, Carly A. Rock
Solvation Of Isoelectronic Halide And Alkali Metal Ions By Noble Gas Atoms, Carly A. Rock
Honors Theses
Alkali metal cations (M+ = Li+, Na+, K+, and Rb+), as well as their corresponding isoelectronic atomic anions (X− = H−, F−, Cl−, and Br−) were solvated with argon atoms (i.e., M+Arn and X−Arn where n=1−6). Full geometry optimizations were performed using the MP2 electronic structure method with a series of correlation consistent basis sets augmented with diffuse functions on argon and the anions (aug-cc-pVXZ) and weighted core valence basis sets were used for the cations (cc-pwCVXZ) that include the appropriate pseudopotentials for K+ and Rb+ (cc-pwCVXZ-PP). The basis sets for a particular cluster are, hereafter, simply denoted as XZ …