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  Partner: UNT Libraries
 Decade: 2010-2019
 Degree Discipline: Chemistry
 Degree Level: Master's
 Collection: UNT Theses and Dissertations
Characterization of Ionic Liquid As a Charge Carrier for the Detection of Neutral Organometallic Complexes Using Electrospray Ionization Mass Spectrometry

Characterization of Ionic Liquid As a Charge Carrier for the Detection of Neutral Organometallic Complexes Using Electrospray Ionization Mass Spectrometry

Date: August 2012
Creator: Joshi, Ubisha
Description: A novel application of ionic liquid as a charge carrier for the analysis and detection of neutral organometallic complexes using a mass spectrometer has been presented. The mass spectrometer detects only charged compounds which raise a difficulty in analyzing a neutral molecule that lacks a basic site to associate with charge. Therefore, an effective way of providing charge has always been an area of keen interest in the field of mass spectrometry. Ionic liquids have a very fascinating property of forming a cation-? interaction with other molecules to give a charged complex. In order to take advantage of this, it is important to know the geometric structure of the complex. Advanced methodologies like hydrogen-deuterium exchange and computational calculations have been used assisting in better understanding of the structure of the ionic liquid complexes.
Contributing Partner: UNT Libraries
Effect of fluorine and hydrogen radical species on modified oxidized Ni(Pt)Si

Effect of fluorine and hydrogen radical species on modified oxidized Ni(Pt)Si

Date: May 2010
Creator: Gaddam, Sneha Sen
Description: NiSi is an attractive material in the production of CMOS devices. The problem with the utilization of NiSi, is that there is no proper method of cleaning the oxide on the surface. Sputtering is the most common method used for the cleaning, but it has its own complications. Dry cleaning methods include the reactions with radicals and these processes are not well understood and are the focus of the project. Dissociated NF3 and NH3 were used as an alternative and XPS is the technique to analyze the reactions of atomic fluorine and nitrogen with the oxide on the surface. A thermal cracker was used to dissociate the NF3 and NH3 into NFx+F and NHx+H. There was a formation of a NiF2 layer on top of the oxide and there was no evidence of nitrogen on the surface indicating that the fluorine and hydrogen are the reacting species. XPS spectra, however, indicate that the substrate SiO2 layer is not removed by the dissociated NF3 and NiF2 growth process. The NiF2 over layer can be reduced to metallic Ni by reacting with dissociated NH3 at room temperature. The atomic hydrogen from dissociated ammonia reduces the NiF2 but it was determined that the ...
Contributing Partner: UNT Libraries
Kinetic Investigation of the Gas Phase Atomic Sulfur and Nitrogen Dioxide Reaction

Kinetic Investigation of the Gas Phase Atomic Sulfur and Nitrogen Dioxide Reaction

Date: May 2011
Creator: Thompson, Kristopher Michael
Description: The kinetics of the reaction of atomic sulfur and nitrogen dioxide have been investigated over the temperature range 298 to 650 K and pressures from 14 - 405 mbar using the laser flash photolysis - resonance fluorescence technique. The overall bimolecular rate expression k (T) = (1.88 ± 0.49) x10-11 exp-(4.14 ± 0.10 kJ mol-1)/RT cm3 molecule-1 s-1 is derived. Ab initio calculations were performed at the CCSD(T)/CBS level of theory and a potential energy surface has been derived. RRKM theory calculations were performed on the system. It is found that an initially formed SNO2 is vibrationally excited and the rate of collisional stabilization is slower than the rate of dissociation to SO + NO products by a factor of 100 - 1000, under the experimental conditions.
Contributing Partner: UNT Libraries
Microwave-Assisted Synthesis, Characterization, and Photophysical Properties of New Rhenium(I) Pyrazolyl-Triazine Complexes

Microwave-Assisted Synthesis, Characterization, and Photophysical Properties of New Rhenium(I) Pyrazolyl-Triazine Complexes

Date: May 2010
Creator: Salazar Garza, Gustavo Adolfo
Description: The reaction of the chelating ligand 4-[4,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)-1,3,5-triazin-2-yl]-N,N-diethyl-benzenamine, L, with pentacarbonylchlororhenium by conventional heating method produces the complexes fac-[ReL(CO)3Cl2] and fac-[Re2L(CO)6Cl2] in a period of 48 hours. The use of microwaves as the source of heat and the increase in the equivalents of one of the reactants leads to a more selective reaction and also decreases the reaction time to 1 hour. After proper purification, the photophysical properties of fac-[ReL(CO)3Cl] were analyzed. The solid-state photoluminescence analysis showed an emission band at 628 nm independent of temperature. However, in the solution studies, the emission band shifted from 550 nm in frozen media to 610 nm when the matrix became fluid. These results confirm that this complex possess a phenomenon known as rigidochromism.
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The Pure Rotational Spectra of Diatomics and Halogen-Addition Benzene Measured by Microwave and Radio Frequency Spectrometers

The Pure Rotational Spectra of Diatomics and Halogen-Addition Benzene Measured by Microwave and Radio Frequency Spectrometers

Date: August 2010
Creator: Etchison, Kerry C.
Description: Two aluminum spherical mirrors with radii of 203.2 mm and radii of curvature also of 203.2 mm have been used to construct a tunable Fabry-Perót type resonator operational at frequencies as low as 500 MHz. The resonator has been incorporated into a pulsed nozzle, Fourier transform, Balle-Flygare spectrometer. The spectrometer is of use in recording low J transitions of large asymmetric molecules where the spectra are often greatly simplified compared to higher frequency regions. The resonators use is illustrated by recording the rotational spectra of bromobenzene and iodobenzene. In related experiments, using similar equipment, the pure rotational spectra of four isotopomers of SrS and all three naturally occurring isotopomers of the actinide-containing compound thorium monoxide have been recorded between 6 and 26 GHz. The data have been thoroughly analyzed to produce information pertaining to bond lengths and electronic structures.
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Synthesis and Characterization of Copper Releasing Polymer Nanoparticles

Synthesis and Characterization of Copper Releasing Polymer Nanoparticles

Date: May 2011
Creator: Harris, Alesha N.
Description: Polymeric nanoparticles were synthesized and loaded with Cu²⁺ to explore the therapeutic potential for catically active transition metal ions and complexes other than cisplatin. Two types of nanoparticles were synthesized to show the potential for polymer based vectors. Copper loading and release were characterized via inductively coupled plasma mass spectrometry (ICP MS), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and elemental analysis. Results demonstrated that Cu could be loaded to the nano-sized carriers in an aqueous environment, and that the release was pH-dependent. The toxicity of these particles was measured in HeLa cells where significant toxicity was observed in vitro via dosing of high Cu-loaded nanoparticles. No significant toxicity was observed in cells dosed with Cu-free nanoparticles.
Contributing Partner: UNT Libraries