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Thesis (Ph.D.)--University of Melbourne, School of Chemistry, 2009. / Typescript. Includes bibliographical references.

Thesis (Ph. D.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains x, 225 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 113-119).

Thesis (Ph. D.)--University of Florida, 2004. / Title from title page of source document. Document formatted into pages; contains 79 pages. Includes vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1992. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

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Evaporated films of radioactive sodium chloride have been prepared by direct sublimation onto a water cooled quartz substrate at 10-⁵ mm of mercury. These possess specific surfaces of from 30-100 m²/g and show remarkably high exchange reactivity to chlorine. From kinetic studies using ³⁶Cl incorporated in the solid it has been found that the extent of exchange C follows a fractional power of the time C = at[superscript n] and that the rate is independent of surface area, so that the possibility of the rate controlling step involving diffusion is ruled out. These features had been reported in an earlier study but required confirmation with a wider range of specific surface and a modified procedure to measure surface area before reaction. The major part of the work is designed to elucidate the role of electronic defects in the exchange mechanism from the pressure and temperature dependence of the exchange rate and from the effect of introducing electronic defects by X-irradiation or fluoridation. These latter processes cause the kinetics of the reaction to change completely to a second-order law, and provide strong evidence to support an earlier tentative suggestion that electronic defects are involved in the reaction, and that a process of adsorption of a chlorine molecule into a pair of defects is important. Detailed mechanisms are proposed for both the power law and the second-order reactions, largely on the basis of the pressure dependence. Both mechanisms use two species of electronic defect, corresponding to Seitz's models for V₂ and V₄ centres, and the "power law" mechanism requires a transition complex between the two defects. Measurements by X-ray diffraction on the particle size in the evaporated films has shown them to be in the range 250-500 Å, and an estimate of the strain from the same results suggests that roughly one dislocation per particle is present. / Science, Faculty of / Chemistry, Department of / Graduate

The reactions of cobalt halides with lithium dialkylamides have been investigated. The reaction with lithium diethylamide proved to be very unusual. This reaction was fully studied and the main products were shown to be lithium chloride, cobalt metal and bis(4-ethylimino-2-butene-2-ethylamino)Cob~lt(II). The latter product which was a volatile brown liquid was identified by its physical and . . chemical properties and the physical properties of derivatives prepared from the ligand after removal of the cobalt. Bis-(4-ethylimino-2-butene-2-ethylamino)cobalt(II) is a nitrogen analogue of the metal acetylacetonates and shows many similar properties. The ligand 4-ethylimino-2-ethylamino-2-butene • was shown, by the magnetic moment and electronic spectra of the tetrahedral cobalt compound, to produce a very high ligand field. A reaction mechanism has been proposed to explain the products 'of the reaction of cobalt chloride with lithium diethylamide. The reactions of other lithium dialkylamides with cobalt halides haye shown that dialkylamino compounds of cobalt(II) exist but are generally unstable thermally and very oxygen sensitive. The only stable (thermally) dialkylamino cobalt(II) compound prepared was bis-hexamethyldisilylamino cobalt(II). In solution this compound was shown· to be a linear two coordinate compound of cobalt(II). This unusual stereochemistry for cobalt(II) presents many theoretical problems before the magnetic and spectral properties ,are fully understood. It was found that the other dialkylamino cobalt(II) compounds produced were u!lstable.thermally decomposing above room temperature. The most stable compounds were formed when the dialkyl- group produced large steric hindrance. Two new alkolides were prepared from the dialkyamino cobalt(II) compounds. The magnetic and spectral properties of these compounds indicate that they are polymeric. possibly three coordinate compounds of cobalt.