Chemistry Commons^™

Donor-Sigma-Acceptor (D-Sigma-A) Molecules With Perylenebisimide Acceptors Having Alkyl Or Peg Swallowtails With Sulfur Or Hydroxyl Anchors: Synthesis And Applications In Langmuir-Blodgett Films, Single Molecule Spectroscopy (Sms), G-Quadruplex Studies And Passivation Of Gold Nanoparticles, Rajesh Kota

Electronic Theses and Dissertations

Use of single molecules as electronic devices is presently considered a potential alternative to semiconductor-based nanoscale electronics. The ability to study a single molecule or a small group of molecules provides a great opportunity to build electronic devices at the molecular level. It is vital to understand the parameters that control the device properties such as molecular structure, conformation and arrangement at the surface. Ari Aviram and Mark A. Ratner proposed the construction of a single organic molecule as an organic rectifier. Donor-Sigma-Acceptor (D-?-A ) molecules, when arranged with a proper orientation as Langmuir-Blodgett (LB) films and fixed between two …

Investigations Of Noncovalent Interactions Using Raman Spectroscopy And Electronic Structure Computations, Ashley Wright

Electronic Theses and Dissertations

This dissertation research focuses on the effects of noncovalent interactions on vibrational energy levels. Vibrational spectroscopy is a powerful tool for the study of the effects of weak intermolecular interactions such as hydrogen bonding and interactions with the environment, including solvation effects. Changes in the vibrational spectra of interacting molecules allow us to ascertain exactly which atoms and bonds are affected and to what extent they are affected. Quantum mechanical methods, ab initio theory and density functional theory, are employed to model molecular geometries, properties, and subtle interactions between molecules. Much of this research centers on the comparison of these …

Multi-Configurational Investigation Of Thermolytic Pathways Of Highly Strained Ring Systems, Jeffrey Dwayne Veals

Electronic Theses and Dissertations

The isomerization pathways of model high energy structures are of interest because of their relation to high energy density fuels. Electron resonance has been found to greatly affect the relative activation barriers for several isomerization pathways, and the major goal of this research is to accurately describe its role in determining the relative barriers for strain energy release pathways. This research is centered around the potential energy surfaces (PES's) for ? bond breaking and ? bond rotation in these highly strained structures. Of particular interest was how would resonance and or electronegativity affect the allowed/disallonature of the activation barriers in …

Electrochemistry, Transport Properties And Electronic Spectroscopy Of Lanthanide Solutes In Bis(Trifluoromethylsulfonyl)Imide-Based Ionic Liquids, Yunfeng Pan

Electronic Theses and Dissertations

No abstract provided.

Design And Synthesis Of Novel Agrofungicides Based On Naturally Occurring Pbdes, Robert Alexander Smith

Electronic Theses and Dissertations

Cyanobacterial symbionts of Indo Pacific marine sponges, e.g. Dysidea sp., produce hydroxylated (OH-) polybrominated diphenyl ethers (PDBEs) which likely function as chemical deterrents owing to their antifungal and antibacterial properties. Limiting the therapeutic potential and agricultural use of these antimicrobial natural products are the negative connotations associated with non hydroxylated anthropogenic PBDEs. Anthropogenic PBDEs are pervasive global pollutants used as flame retardant additives in many household goods, e.g. furniture, textiles, and electronics. These molecules have a propensity to bioaccumulate in living organisms, they easily traverse the trophic food chains, they are readily passed from mother to offspring, and many of …

Ion Transport, Viscoelastic, And Thermal Properties Of Several Poly(Ethylene Glycol) And Poly(Propylene Glycol) Based Polymer Electrolytes, Benjamin Jacob Yancey

Electronic Theses and Dissertations

This dissertation explores the relationship between ionic conductivity, viscosity, and thermal properties of several MePEG and MePPG based copolymer electrolytes. In particular two main copolymer modifications have been investigated namely copolymerization with "bulky groups" and cross polymerization of MePEG and MePPG monomers. The modifications were made to vary the fractional free volume of the MePEG polymers. All of the copolymers obeyed the Doolittle equation. For both the bulky copolymers and MePEG/MePPG copolymers, increases in the FFV corresponded to increases in the viscosity and decreases in FFV correspond to decreases in viscosity. The FFV and H+ conductivity for these copolymers were …

Design And Construction Of A Reflectron Time Of Flight Mass Spectrometer For Multiphoton Ionization And Vibrational Spectroscopic Studies Of Mass-Selected Clusters, Matthew Dodd Mcdowell

Honors Theses

Mass spectrometry is typically employed for the elucidation and identification of elements and compounds. Its ability to select and isolate specific molecular clusters makes it an ideal tool for the fundamental spectroscopic study of the photophysical and geometric properties of molecules and molecular clusters. The design and construction of a reflectron time of flight mass spectrometer (reflectron TOF-MS) as well as its implementation for electronic and vibrational spectroscopic studies of various molecules and molecular clusters is discussed. The first chapter introduces basic theory related to electronic spectroscopy, multiphoton ionization, and vibrational spectroscopy. The second chapter entails the theoretical aspects of …

Theoretical Characterization Of Non-Covalent Weakly Bound Clusters Through The Application Of Sophisticated Computational Quantum Chemistry Methodologies And The Development Of Integrated Fragmentation Techniques, Desiree Bates

Electronic Theses and Dissertations

Non-covalent, weakly bound clusters have been and remain of significant interest to many researchers. However, with computational studies, accurate description of these interactions requires sophisticated electronic structure methods employing large basis sets. This methodology becomes extremely computationally demanding as the size of the system increases. This work presents benchmark data and explores methods for obtaining highly accurate ab initio results for larger systems at greatly reduced computational costs. CCSD(T) complete basis set limit interaction energies are presented for a variety of parallel-slipped π...π dimers and low-lying isomers of (h₂o)₆. The calibration of a 2-body:Many-body fragmentation method …

Characterization Of Intermolecular Pi-Type Interactions Using Sophisticated Quantum Mechanical, Electronic Structure Computations, Emily Joy Carrell

Electronic Theses and Dissertations

Much like the instrumentation in an experimental lab, computational chemists use computers to solve the mathematical equations that describe the physics of electrons to understand the chemistry involved. The combination of the two main components of computational chemistry, the basis set and method, determines the ``cost'' (disk, memory, and CPU time) of a computation. A variety of basis sets and methods have been developed in the past century. The focus of this report is to accurately describe non-covalent interactions with the use of various quantum computational techniques. In Chapter 1 a brief discussion on the theory behind computational chemistry is …

Approaches Towards The Synthesis Of Bradyoxetin, Vanildo Martins Lima Braga

Electronic Theses and Dissertations

Quorum sensing bacteria produce and release chemical signal molecules (like N-acyl homoserine lactones, AHL) that increase in concentration as a function of cell density. The responses cover a large spectrum of process such as the virulence in Staphylococcus aureus, competence for DNA-uptake in Bacillus subtilis and Streptococcus pneumoniae, sporulation in Bacillus subtilis, conjugal plasmid transfer in Enterococcus faecalis, and bacteriocin production in lactic acid bacteria. The collapse of (AHL) signaling system in bacteria represents an attractive therapeutic approach towards the development of new antibiotics. Recently, a new extracellular modulator was isolated from a symbiotic bacterium (Bradyrhizobium japonicum) that nodulates soybean. …

Development Of A Laser-Induced Breakdown Spectrometer For Lead-Free Gunshot Residue Analysis, Ryan Alexander Gregg

Honors Theses

Research has demonstrated that Laser‐Induced Breakdown Spectroscopy (LIBS) can be used as an effective method of screening for the common elemental components in gunshot residue. Barium (Ba), lead (Pb), and antimony (Sb) make up the primer cap of most ammunition involved in forensic gunshot residue analysis. Recently, ammunition manufacturers have started producing and popularizing ammunition with zinc (Zn), titanium (Ti), and gadolinium (Gd) primer components that are non‐toxic to the environment. This paper discusses the development of the Ole Miss Department of Chemistry and Biochemistry's first LIBS instrument for forensic analysis of lead‐free using Gd as a tracer element for …

Developing The Techniques For Raman, Surface-Enhanced Raman Scattering (Sers), And Fluorescence Spectroscopies Of Organic Molecules In Isolation, Jonathan Wolfe

Honors Theses

The nature of matter and light has been a subject of philosophical debate since antiquity. However, by the end of the nineteenth century, much of the scientific community believed that most of the significant principles that govern the natural world had been discovered. Classical physics was able to explain complex phenomena such as planetary motions, elasticity, and hydrodynamics. The field of thermodynamics had been developed nearly to completion by James Joule, Sadi Carnot, Josiah Gibbs, et al. The magnetic and electronic nature of light had been demonstrated by James Clerk Maxwell's famous equations. In the neighboring field of chemistry, a …

Synthesis Of Analogues Based On The Opioid Alkaloid Mitragynine, Marco A. Arribas

Electronic Theses and Dissertations

Opioid analgesics such as morphine and its derivatives are the most frequently prescribed narcotics for the treatment of severe and chronic pain. Among other side effects caused by the administration of these opioid analgesics, physical dependence and addiction are the most undesirable ones. Currently, pharmacological approaches to treat opioid dependence include mainly methadone and LAAM (mu-agonists), buprenorphine (mu-partial agonist) and clonidine (alpha2-adrenergic agonist). Considering the negative aspects of the relapsing nature correlated to opioid dependence, it is important to search for new ways to overcome this problem. The scope of this work is to study novel compounds based on the …

Upgrade Of A Raman Spectrometer With Modern Computer Control And Data Acquisition For Studies Of Hydrogen Bonding In Pyrimidine, Austin Howard

Honors Theses

The restoration of a Cold War era high resolution Raman spectrometer to working order as well as its control and data acquisition upgrade using a Labview program authored for this purpose are discussed. The restored Raman spectrometer was used in an investigation of intermolecular interactions involving pyrimidine. Following in this manuscript are three chapters. The first chapter is a brief description of the history and theory of Raman spectroscopy as well as some details of the instrumentation used in Raman spectroscopy. The second chapter contains technical details of the restoration and upgrade of the high resolution Raman spectrometer. The third …

Concomitant Ordering In First Row Transition Metal Fluorides, Ajay Shah

Electronic Theses and Dissertations

Type of Compounds Investigated

First row transition metal fluorides with a general formula, A_xM²⁺_xM’³⁺_1-xF₃, where A = alkali metal ion, M,M' = First row transition metal ions, and x = 0 - 1 ate reported to form, ReO₃, perovskite, GdFeO₃, tetragonal tungsten bronze (TTB), hexagonal tungsten bronze (HTB), and, modified pyrochlore type structures. Compounds of the type LiM^IIM^IIIF₆ have been reported to form rutile and trirutile type structures. These compounds display ionic, electronic, and magnetic ordering.

Formation of TTB Structure and …