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High Valent Palladium Complexes And Their Role In C-C And C-X Bond Formation Chemistry., Fengrui Qu

All Theses and Dissertations (ETDs)

Energy is the currency of the universe. Without energy everything will come to a stall. According to the Energy Information Administration, in 2007 over 80 % of energy came from fossil fuel. When the fossil fuel will eventually run out at the current consumption rate, then what can we use for energy? While finding alternative energy sources is our ultimate goal, our research focus on the basic study of the role metal ions play in the catalysis of energy related process. Namely, the water oxidation catalysis and methane oligomerization process.

Water oxidation is a multi-electron process, which requires multiple single …

Mri Characterization Of Radiation Necrosis In An Animal Model: Time To Onset, Progression, And Therapeutic Response, Xiaoyu Jiang

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Radiation necrosis is a severe, but late occurring type of injury to normal tissue, within and surrounding a radiation treatment field, which can lead to significant complications for neurooncology patients. Radiation necrosis is difficult to distinguish from recurrent tumor by either neurologic examination or clinical imaging protocols. Concerns for the development of radiation necrosis often limit therapeutic radiation doses. Current treatment options for radiation necrosis are limited. The development of solutions to these clinical challenges has been hampered by an appropriate animal model of radiation necrosis.

With a novel mouse model of radiation necrosis developed in our lab employing a …

Photoelectron Imaging Of Iodide Centered Alkyl Halide Cluster Anions, Joshua S. Lasinski

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This dissertation presents results from cluster anion photodetachment experiments of the solvated iodide anion as a means of investigating electron molecule interaction. Due to the localization of the excess charge on the iodine atom, these experiments proceed analogously to electron scattering experiments, in that exposure to sufficient photon energy detaches the electron, which may or may not interact with the target molecule before being detected. Such interactions are related to temporary electron capture into the σ* orbital of the target molecule.

This dissertation begins with an analysis of the previously published I−·CH3X: X = I, Br, Cl) photodetachment results. These …

Molecular Design And Photophysical Characterization Of Synthetic Bacteriochlorins For Solar Energy Conversion And Photodynamic Therapy, Eunkyung Yang

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The design, photophysical characteristics and some potential applications of synthetic bacteriochlorins are discussed. Bacteriochlorins: e.g., bacteriochlorophylls) are tetrapyrrole macrocycles with two reduced pyrrole rings, whereas chlorins: e.g., chlorophylls) and porphyrins: e.g., hemes) have one and zero reduced pyrrole rings. Molecular design characteristics are revealed by understanding the effects of substituent types and patterns and the central metal ion on the photophysical properties and electronic structure. These effects are elucidated via studies of the optical absorption and emission spectra and excited-state decay pathways, and analysis of the molecular-orbital characteristics within the four-orbital model. The studies also encompass analysis of the properties …

Energetics And Dynamics In Quantum Confined Semiconductor Nanostructures, Jessica Hoy

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The ability to tune the band-gap energies of semiconductor quantum dots, nanoplatelets, and quantum wires, their significant absorption cross sections, and high photoluminescence quantum yields make these nanostructures promising moieties for use in optoelectronic devices, solar concentrators, chemical sensors, and biological labels. The variable dynamics of the electron-hole pairs that occur within semiconductor nanostructures, however, can complicate the utility of these devices. The variability of the dynamics is born from the different paths accessible for the charge carriers to undergo. In this work, three pathways are proposed to be of primary consequence, namely, electronic intraband relaxation, coupling to surface-mediated processes, …

Rapid, Efficient And Versatile Strategies For Functionally Sophisticated Polymers And Nanoparticles: Degradable Polyphosphoesters And Anisotropic Distribution Of Chemical Functionalities, Shiyi Zhang

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The overall emphasis of this dissertation research included two kinds of asymmetrically-functionalized nanoparticles with anisotropic distributions of chemical functionalities, three degradable polymers synthesized by organocatalyzed ring-opening polymerizations, and two polyphosphoester-based nanoparticle systems for various biomedical applications.

Inspired by the many hierarchical assembly processes that afford complex materials in Nature, the construction of asymmetrically-functionalized nanoparticles with efficient surface chemistries and the directional organization of those building blocks into complex structures have attracted much attention. The first method generated a Janus-faced polymer nanoparticle that presented two orthogonally click-reactive surface chemistries, thiol and azido. This robust method involved reactive functional group transfer by …

Use Of Self-Assembled Monolayers To Tailor Surface Properties: From Lubrication To Neuronal Development, Natalie Ann Lafranzo

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The subsequent work describes advances in modifying the chemical properties of various substrates to tailor the surface properties for specific applications. This is achieved by making use of a molecular assembly known as self-assembled monolayers, or SAMs. SAMs are composed of tightly packed organic molecules that form a well-ordered structure on a substrate. Typically, the head group of the monomer is covalently anchored to the substrate, and monolayer order and self-assembly is achieved through van der Waals interactions between the long alkyl chains of the monomer's tail group. Monolayers containing head groups consisting of thiols, siloxanes, and phosphonates have been …

Discovery And Identification Of New Dna Photoproducts And Investigation Of The Redox Mechanism Of Human Apurinic/Apyrimidinic Endonuclease 1 (Hape1) Protein, Dian Su

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Exposure of cells to ultraviolet light results in the formation of DNA photoproducts, many of which have been linked to skin cancer. The majority of these photoproducts arise from a photoreaction between two pyrimidines. Irradiation of double stranded B form DNA under physiological conditions mainly produces adjacent dimers. Nonadjacent photodimers of both intrastrand and interstrand types are much rarer. Intrastrand-type nonadjacent dimers form when one or more nucleotides between two pyrimidines become extrahelical owing to the formation of single strand DNA or a slipped structure. This allows the two pyrimidines to photodimerize in a colinear arrangement, as if the intervening …