Physical Chemistry Commons^™

Single-Conformation Spectroscopy Of Hydrogen Bonding Networks: Solvation, Synthetic Foldamers, And Neurodegenerative Diseases, Patrick S. Walsh

Open Access Dissertations

The hydrogen bond is one of the most important interactions in natural processes ranging from protein folding to chemical reactions. Two complementary methodologies are applied to understanding this important interaction: top-down and bottom-up. Top-down methods use large molecules, such as proteins, revealing secondary structure information. Bottom-up experiments are performed on small molecules, utilizing high-resolution spectroscopy to reveal underlying quantum mechanical effects. The complexity gap is formed between these two experimental regimes; between large and small molecules; between bulk and individual solvent molecules; between classical mechanics calculations and quantum chemical calculations. This dissertation will focus on the application of gas phase, …

Determination Of Kinetic Parameters Of Equilibrium Peracetic Acid And Hydrogen Peroxide To Calculate Self-Accelerating Decomposition, Ricky Mittiga

Multidisciplinary Studies Theses

Determination of Kinetic Parameters of Equilibrium Peracetic Acid and Hydrogen Peroxide to Calculate Self-Accelerating Decomposition Temperature

Peracetic acid is a simple molecule that works as a powerful oxidant in many applications including food safety and water disinfection. The synthesis of the compound is fairly well understood due to its straightforward synthesis by mixing acetic acid and hydrogen peroxide. However, the decomposition of the compound has not been well studied. Few sources are available to provide kinetic data for the decomposition along with data that shows when the compound will undergo a self-accelerated decomposition that could lead to disastrous effects.

This …

Correlation Of Polymer Performance And Hansen Solubility Parameters, Daniel Jobse Mania

Master's Theses

Ready-to-use (RTU) grout is becoming more important to the finish and remodeling construction industry. Market research shows it is a fast-growing product that not only is creating its own space, but is beginning to supplant existing technology.

The original intent of this research was to investigate formulation parameters and how they affect grout performance. It was learned that particle size and oil absorption (OA) value are important filler properties that affect performance as much as adequate packing density and optimal pigment volume concentration (PVC) without going beyond critical PVC (CPVC).

Polymer architecture was also determined to be extremely important, but …

Preparation And Characterization Of Singlet-Oxygen Generating Thiol-Ene Networks Containing Fullerene And Metallofullerene Derivatives, Emily Matthews Barker

Dissertations

This work explores the derivatization of C₆₀ and Sc₃N@C₈₀ with S-, P-, and C- centered radicals, and is the first exploration into the functionalization of Sc₃N@C₈₀ with sulfur and phosphorous. The number of addends bound to C₆₀, as a function of reaction time and molar ratios, as well as, structure-property relationships including thermal stability, solubility, and singlet oxygen generation were explored. Fullerene derivatives exhibiting enhanced solubility were incorporated into two different thiol-ene polymer matrices at varying thiol-ene monomer concentrations (1:1 or 1:0.75 molar equivalents) and at different C₆₀ loadings (0, …

Characterization Of Etbe + Cl And Isooctane + Cl Combustion Products Using Synchrotron Photoionization, Rong Yao

Master's Theses

The low temperature (298 – 700 K) oxidation characterizations of a series of fuel additives (ETBE and isooctane) were studied at advanced light source in Lawrence Berkley National lab, using a multiplexed chemical kinetics photoionization mass spectrometer with tunable synchrotron radiation. Using Cl atoms as initiators in presence of oxygen, photoionization data were collected. Data analysis was performed via characterization of the reaction species photoionization spectra and kinetic traces, from which the products and also the intermediates were identified. Relevant reaction dynamics on potential energy surfaces were calculated, reaction enthalpies of each individual step were presented using the CBS-QB3 composite …

Structural Behavior Of Nbsexte2-X Superconductors Under High Pressure, Vahe Mkrtchyan

UNLV Theses, Dissertations, Professional Papers, and Capstones

Niobium chalcogenide compounds have recently gained a great deal of interest due to the fact that a superconducting phase coexists with the charge density wave state (CDW), as well as their potential for numerous applications. Two superconducting compositions, NbSexTe2-x (x=2, 1.5) were prepared by solid state route using high purity Nb, Se, and Te powders. Powder X-ray diffraction patterns collected at ambient conditions for NbSe2 and NbSe1.5Te0.5 showed a single phase with hexagonal crystal structure, with space group P63mmc. High-pressure X-ray diffraction measurements were performed at the Advanced Photon Source at Argonne National Laboratory to investigate structural stability up to …

Development Of Organocatalytic Reactions For The Assembly Of Complex Molecules, Chenguang Yu

Chemistry and Chemical Biology ETDs

Development of efficient organocatalytic reactions for the facile assembly of synthetically and medicinally useful molecules is an important task in modern organic synthesis. Towards this end, my Ph. D. study focuses on the development of novel organocatalytic reactions for the construction of structurally diverse molecular architectures. A chiral bifunctional amine thiourea as promoter has been developed as an efficient solution to a long standing challenging issue in atropo-enantioselective transesterification of the Bringmann lactones. This organocatalytic approach delivers the first highly enantioselective, high yielding dynamic kinetic resolution process for the preparation of axially chiral biaryl compounds with a broad substrate scope …

Molecular Structure And Exciton Dynamics In Organic Conjugated Polymers, Alan K. Thomas

Chemistry and Chemical Biology ETDs

Intermolecular electronic interactions, dipole coupling and orbital overlap, caused by π-π stacking in organic conjugated polymers lead to unique structures and properties that can be harnessed for optoelectronic applications. These interactions define structure-function relationships in amorphous and aggregated forms of polymers in the solid state and determine their efficiencies and functionality in electronic devices, from transistors to solar cells. Organic polymer electronic device performance depends critically upon electronic coupling between monomer units --mediated by conformation and packing characteristics -- that dictates electronic properties like conductivity and capacitance as well as electronic processes, such as charge carrier generation and transport. This …

Synthesis And Applications Of Lanthanide Sulfides And Oxides, Christopher Marin

Department of Chemistry: Dissertations, Theses, and Student Research

This dissertation focuses on two of the key fields where lanthanides find ready application: as optically active materials with a focus on the lanthanide sulfides, and as catalytic materials with a focus on cerium oxide.

The lanthanide sulfides have attracted considerable interest for their potential as solar energy conversion materials, pigments, infrared window materials, and phosphor host media. However, applications of these materials remain limited due to their synthetic difficulty along with their not well understood properties compounded by both their difficulty in manufacturing as well as in simulating largely due to the need to take into account f-shell electrons. …

Development Of Oligo(P-Phenylene Ehynylene)(Ope) Applications Against Chemical And Biological Threats, Suhyun Yoon

Chemistry and Chemical Biology ETDs

Four new applications of oligo-phenylene ethynylene (OPE) and poly-PE (PPE) compounds for detection and destruction of biological and chemical threats have been investigated. Mixed surfaces composed of PPEs and a thermoswitchable polymer were created, and were shown to be able to capture, kill, and reversibly release pathogenic bacteria. In order to develop fluorescent sensors for CW agents, the spectral changes of OPEs with surfactants and malathion (a simulant for nerve agents) were measured. Formation of OPE-dimers in the presence of surfactants can cause fluorescence enhancement (turn-on) or quenching (turn-off). Among six positive and negative OPEs, only OPEs with ethyl ester …

Resonance Raman Studies Of Oxygenated Forms Of Myoglobin And Cyp2b4 And Their Mutants, Ying Wang

Dissertations (1934 -)

Important oxidative heme enzymes use hydrogen peroxide or activate molecular oxygen to generate highly reactive peroxo-, hydroperoxo- and feryl intermediates resulting from heterolytic O-O bond cleavage. Members of the cytochrome P450 superfamily catalyze difficult chemical transformations, including hydroxylations and C-C bond cleavage reactions. In mammals, these enzymes function to reliably produce important steroids with the required high degree of structural precision. On the other hand, certain other mammalian P450s serve a different role, efficiently metabolizing xenobiotics, including pharmaceuticals and environmental pollutants. Though so important, the precise mechanisms involved in such transformations are incompletely understood, because of difficulties in structurally characterizing …

Synthesis, Structural Diversity, And Redox Control Of Cyclometalated Monoruthenium Complexes, Zhong-Liang Gong, Jiang-Yang Shao, Yu-Wu Zhong

Journal of Electrochemistry

Cyclometalated ruthenium complexes have received increasing attractions recently due to their excellent redox and photophysical properties. One structural feature of these complexes is that there is a ruthenium-carbon (Ru-C) σ bond presented in the molecule. Three common methods, namely, the “late metalation”, “early metalation”, and “transmetalation” methods, for the synthesis of cyclometalated ruthenium complexes are discussed and summarized. General strategies for the design of cyclometalating ligand and cyclometalated ruthenium complexes are introduced. By using different ancillary ligands, such as pyridine, imidazole, triazole, and pyrimidine, a great number of ruthenium complexes can be prepared. The presence of the Ru-C bond significantly …

Electrochemical And In Situ X-Ray Absorption Fine Structure Study Of Li-Rich Cathode Materials, Meng-Yan Hou, Hong-Liang Bao, Ke Wang, Jian-Qiang Wang, Yong-Yao Xia

Journal of Electrochemistry

A series of the lithium-rich and manganese-based layered structure xLi₂MnO₃•(1-x)LiMn_1/3Ni_1/3Co_1/3O₂ (x = 0.3,0.5,0.7) materials were synthesized by a co-precipitation method, and followed by a solid-state reaction process. By comparing the first cycle efficiency, the reversible discharge capacity, the cycling stability and the voltage decay during the charge/discharge cycling process, the material with the composition of 0.5Li₂MnO₃•0.5LiMn_1/3Ni_1/3Co_1/3O₂was found to show the best electrochemical performance. The lithium storage mechanism and thermal stability of the de-lithiated compound were also investigated …

The Progress Of Order-Structured Membrane Electrode Assembly, Shang-Feng Jiang, Bao-Lian Yi

Journal of Electrochemistry

Performances of proton exchange membrane fuel cells (PEMFCs) have been recently improved. However, the cost and Pt loading must be further reduced for the commercialization of PEMFCs. Previous researches have proved that the order-structured electrode is beneficial to the effective utilization of Pt-based catalysts, decreasing the Pt loading and increasing the three-phase boundary for reaction. Especially, the nanostructure thin films (NSTFs) electrode, an ultra-thin catalytic layer developed by 3M Company, demonstrates high performance and durability. Besides, some other researchers have employed the high conductive carbon nanotube arrays or high stable metal oxide arrays as the order-structured catalyst supports for fundamental …

Recent Progress In Solid-State Nmr Study Of Electrode/Electrolyte Materials For Lithium/Sodium Ion Batteries, Gui-Ming Zhong, Zi-Geng Liu, Da-Wei Wang, Qi Li, Ri-Qiang Fu, Yong Yang

Journal of Electrochemistry

Solid state NMR technique is a powerful tool for characterizing the local structure and compositions of solid materials quantitatively. A comprehensive understanding of the structure evolution during the electrochemical reactions of the materials for lithium/sodium ion batteries will be obtained with the combination of solid state NMR, XRD, and XAS methods. Through analyzing solid state NMR spectra, we can obtain the compositions, local structures and ion diffusion dynamics of electrodes, electrolytes and surface layers for lithium/sodium ion batteries, providing an important theoretical support for the design and development of high-performance materials for batteries. In this paper, we review the recent …

Uniform Nanoshells For Functional Materials: Constructions And Applications, Shu-Yi Duan, Wei Zhang, Jun-Yu Piao, An-Min Cao, Li-Jun Wan

Journal of Electrochemistry

As a significant protocol for materials treatment, surface modification has found broad applications in different fields including catalyst, photochemistry, and electrochemistry. Herein, we introduced the representative synthetic methodologies for the constructions of different functional materials with a focus on their core-shell structures. By taking the electrode materials in lithium ion batteries as an example, we demonstrated the importance of surface modification on the electrode materials. Different coating materials ranging from metal oxides, metal phosphates to carbon have been discussed. We also showed that an accurate control on the surface layer can be crucial for optimizing the electrochemical performances of the …

3, 4-Ethylenedioxythiophene Monomer As Safety-Enhancing Additive For Lithium Ion Batteries, Wei-Xiao Ji, Feng Wang, Jiang-Feng Qian, Yu-Liang Cao, Xin-Ping Ai, Han-Xi Yang

Journal of Electrochemistry

Safety concern is a major obstacle hindering the wide applications of large-capacity lithium ion batteries (LIBs) in electric vehicles. In this paper, a polymerizable monomer of 3, 4-ethylenedioxythiophene (EDOT) was proposed and tested as an electrolyte additive for enhancing the safety of LIBs. The electro-oxidative polymerization behaviors and influence of PEDOT additive on the thermal behavior of LiCoO₂ cathode, as well as the safety performance and electrochemical properties of LiCoO₂-based LIBs were investigated. The results from cyclic voltammetry (CV) and transmission electron microscope (TEM) characterizations indicated that the monomer additive can be electro-oxidatively polymerized to form a …

Reduced Graphene Oxide (Rgo) Hollow Network Cages For High-Performance Electrochemical Energy Storage, Chi Zhang, Xu-Jun He, Gao-Ren Li

Journal of Electrochemistry

The reduced graphese oxide (RGO) hollow network cages were synthesized via zinc oxide (ZnO) template-assisted electrodeposition. The as-prepared RGO hollow network cages exhibited the multi-level architectures, from nano sheets, porous structures, networks, to 3D microscaled hollow cages, which can simultaneously optimize transport of electroactive species, utilization rate of electrode material, and super capacitive performance. Electrochemical measurements confirmed the superior performance of RGO hollow network cages for supercapacitors (SCs), such as high Csp (393 F⋅g^-1 at 1.0 A⋅g^-1), excellent rate capability (21.2% Csp loss from 1.0 to 20 A⋅g^-1), and superior cycling stability (< 1% Csp loss after 10000 cycles).

Electrochemiluminescence Immunosensor Based On Platinum Nanoparticles For The Determination Of Apolipoprotein A1, Ni Liao, Ying Zhuo, Ruo Yuan

Journal of Electrochemistry

In this paper, a novel electrochemiluminescence (ECL) immunosensor for the detection of apolipoprotein A1 was constructed based on flower-like platinum nanoparticles (PtNFs) via a one-pot chemical synthesis method. The PtNFs was used to immobilize the secondary antibody and enzyme (GOD). Then the prepared bioconjugates were introduced onto the electrode via sandwich immunoreactions. Accordingly, the ECL luminophore peroxydisulfate (S₂O₈^2-) was presented in the working buffer solution containing an appropriate amount of glucose. Through the ECL responses of S₂O₈^2- and O₂, a dramatically amplified ECL signal was obtained for the reason …

The Electrochemical Behavior Of Li+ In Lif-Baf2-Licl Molten Salt System, Shao-Hua Yang, Jun Wang, Xiao-Hui Lai, Hao-Ran Wang

Journal of Electrochemistry

The electrochemical reduction process and rate determining step of Li ion on a tungsten electrode at 1203 K in a LiF-BaF₂-LiCl molten system were studied by cyclic voltammetry, chronoamperometry and chronopotentiometry methods using a three-electrode system and electrochemical workstation AUTOLAB. The results showed that the reduction potential of Li ion was at around -1.0 V on a tungsten electrode as compared with a platinum electrode. The reduction process of Li ion on a tungsten electrode occurred in a single step with the exchange of one electron. Chronoamperograms indicated that the cathode process was controlled by the diffusion step …

Developments Of Photo-Assisted Fuel Cells, Ling-Ling Zhang, Shao-Jun Dong

Journal of Electrochemistry

The exploitation and utilization of fossil fuels have led to serious energy crisis and environmental pollution. In this case, the development of renewable energy is an alternative to traditional energy consumption. Fuel cells (FCs) can convert chemical energy into electricity via the electrochemical reaction, which is green and environment-friendly. Photo-assisted FCs integrate photo-responsive components into FCs, leading to the dual routes of energy conversion including light energy to electricity and chemical energy to electricity, and thus, improving the energy utilization efficiency. The development of photo-assisted FCs is significant for practical application and promising to solve the coming energy crisis. In …

Aqueous Photochemistry Of Glyoxylic Acid, Alexis J. Eugene, Sha-Sha Xia, Marcelo I. Guzman

Chemistry Faculty Publications

Aerosols affect climate change, the energy balance of the atmosphere, and public health due to their variable chemical composition, size, and shape. While the formation of secondary organic aerosols (SOA) from gas phase precursors is relatively well understood, studying aqueous chemical reactions contributing to the total SOA budget is the current focus of major attention. Field measurements have revealed that mono-, di-, and oxo-carboxylic acids are abundant species present in SOA and atmospheric waters. This work explores the fate of one of these 2-oxocarboxylic acids, glyoxylic acid, which can photogenerate reactive species under solar irradiation. Additionally, the dark thermal aging …

Rotational And Hyperfine Analysis Of Aus, Ian A. Wyse

Macalester Journal of Physics and Astronomy

Gas phase diatomic gold sulfide, AuS, was analyzed using optical spectroscopy. High-resolution spectra were collected and characterized and a global fit of the A²∑⁺-X²∏_3/2 (0,0), B²∑^–-X²∏_3/2 (0,0), and C²Δ_3/2-X²∏_1/2 (0,0) transitions at 15570 cm^-1, 16290 cm^-1, and 17670 cm^-1 was compiled and resulted in rotational constant determinations for the A²∑⁺((2σ)¹(4π)⁴), B²∑^–((2σ)²(4π)²(2σ*)¹), and C²Δ_{3/2 …}

Structural Analysis Of Transient Receptor Potential Vanilloid Type 1 (Trpv1) Channel Protein And Proline Mimics Using Computational Techniques, Kelly A. Raymond

Seton Hall University Dissertations and Theses (ETDs)

Chapter I

The Transient Receptor Potential (TRP) family of ion channels encompasses more than 30 members, which are expressed in many different tissues and cell types.¹ Transient Receptor Potential Vanilloid Type 1 (TRPV1) is part of the TRP family gated by vanilloids, heat and protons.² Molecular modeling will be used in order obtain structural and functional data on TRPV1 in its membrane bound environment. In particular, the transmembrane and C-terminal domain regions of TRPV1 are of particular interest. The S1-S4 region of the channel is the putative ligand-binding segment, while the C-terminal domain is suggested to respond to …

Functionalization Of Metal Oxide Surfaces Through Chemical Reactions And Physical Adsorption, Gabriel C. Graffius

Seton Hall University Dissertations and Theses (ETDs)

The synthesis of high surface area metal oxides is an area of extensive research with potential applications in catalysis, adsorption, and materials chemistry. The functionalization of a material’s surface can dramatically change its physical and chemical properties. The research described herein is built on the foundation of traditional techniques used for synthesis, characterization, and functionalization of metal oxides and develops new mechanisms and materials for the functionalization of surfaces.

We began with Methyl-terminated poly(dimethylsiloxanes) (PDMSs), which are typically considered to be inert and not suitable for surface functionalization reactions because of the absence of readily hydrolysable groups. Nevertheless, these siloxanes …

2016-01-A3dsrinp-Csc-Sta-Cmb-522-Bps-542, Raymond Pulver, Neal Buxton, Xiaodong Wang, John Lucci, Jean Yves Hervé, Lenore Martin

Bioinformatics Software Design Projects

Cholesterol is carried and transported through bloodstream by lipoproteins. There are two types of lipoproteins: low density lipoprotein, or LDL, and high density lipoprotein, or HDL. LDL cholesterol is considered “bad” cholesterol because it can form plaque and hard deposit leading to arteries clog and make them less flexible. Heart attack or stroke will happen if the hard deposit blocks a narrowed artery. HDL cholesterol helps to remove LDL from the artery back to the liver.

Traditionally, particle counts of LDL and HDL plays an important role to understanding and prediction of heart disease risk. But recently research suggested that …

A Direct Mechanism Of Ultrafast Intramolecular Singlet Fission In Pentacene Dimers, Eric G. Fuemmeler, Samuel N. Sanders, Andrew B. Pun, Elango Kumarasamy, Tao Zeng, Kiyoshi Miyata, Michael L. Steigerwald, X.-Y. Zhu, Matthew Y. Sfeir, Luis M. Campos, Nandini Ananth

Publications and Research

Interest in materials that undergo singlet fission (SF) has been catalyzed by the potential to exceed the Shockley–Queisser limit of solar power conversion efficiency. In conventional materials, the mechanism of SF is an intermolecular process (xSF), which is mediated by charge transfer (CT) states and depends sensitively on crystal packing or molecular collisions. In contrast, recently reported covalently coupled pentacenes yield ∼2 triplets per photon absorbed in individual molecules: the hallmark of intramolecular singlet fission (iSF). However, the mechanism of iSF is unclear. Here, using multireference electronic structure calculations and transient absorption spectroscopy, we establish that iSF can occur via …

Surface And Interfacial Design And Control Of High Performing Thermoplastics: Polysulfones And Beyond, Katrina Marie Knauer

Dissertations

The study of a class of materials almost always begins with the development of an understanding of properties in the bulk state. However, it is the study of surface critical phenomena that has led to a number of new important insights into polymer behavior. A systematic understanding of physical properties in the immediate vicinity of surface and interfacial layers, which cannot be deduced by simple extrapolation of bulk properties, is of significant importance for advancements in polymer applications where the interface drives performance, such as in membranes, coatings, drug-delivery systems, medical devices, and composites.

First, the surface and interfacial modification …

Energy Transfer And Localization In Molecular Crystals, Mitchell A. Wood

Open Access Dissertations

With the aim of developing new technologies for the detection and defeat of energetic materials, this collection of work was focused on using simulations to characterize materials at extremes of temperature, pressure and radiation. Each branch of the work here is collected by which material response is potentially used as the detectable signal.

Where the chemical response is of interest, this work will explore the possibility of non-statistical chemical reactions in condensed-phase energetic materials via reactive molecular dynamics (MD) simulations. We characterize the response of three unique high energy density molecular crystals to different means of energy input: electric fields …

The Effects Of Hydrogen Bonding On The Reactivity Of Synthetic Ada Repair Protein Analogues, Josiah G. Elsberg

Boise State University Theses and Dissertations

The study of bioinorganic chemistry is an important field, as it can provide insight as to why Nature has chosen certain active sites and structures within different kinds of metalloproteins. Ada repair protein, a zinc-containing metalloprotein, is one such topic of interest. Although it is known that Ada RP is able to repair methyl-phosphotriester backbone damage by self-methylation of one of its cysteine groups, the mechanism is not fully understood. Two pathways have been proposed: a dissociative pathway where the Zn-S bond becomes a zinc/sulfur ion pair, and an associative pathway where a four ringed σ-metathesis occurs. Previous research has …