This thesis continues the study into the synthesis and analysis of metal poly - yndiyl complexes. These molecules have shown promise as model molecular wires. The study provides a general overview of the interest in carbon based molecules and introduces the need for molecular electronics. Some of the most promising classes of molecular wires are described before outlining the methods of evaluation. / Thesis (Ph.D.)--School of Chemistry and Physics, 2006.

Thesis (Ph. D.)--University of California, San Diego, 1983. / Vita. Includes bibliographical references (leaves 101-107).

Thesis (Ph. D.)--University of California, San Diego, 1983. / Vita. Includes bibliographical references (leaves 101-107).

A library of iridium complexes featuring oxazoline and imidazol-2-ylidene ligands were synthesized by reaction of a library of imidazoles with a second library of oxazoline iodides. These complexes were active catalysts for hydrogenations of aryl substituted monoenes. Tri- and 1,1-disubstituted alkenes were hydrogenated quantitatively with ee??s up to 99% at 1 atm hydrogen pressure. Catalyst, substrate, temperature and pressure effects were studied. The iridium complexes were also used for the kinetic study of hydrogenation of 2,3- diphenylbutadiene. This hydrogenation is a stepwise reaction: one double bond was hydrogenated first, then the second one. Both step hydrogenations were zero order in alkene. The consumption of 2,3-diphenylbutadiene was first order in catalyst, and probably first order in hydrogen pressure too. The enantioselectivity for the first step hydrogenation was low. There were match and mismatch catalyst-substrate relationships for the second step hydrogenation, and the enantioselectivities for this step were catalyst controlled. NMR studies indicated that the initiation of the reaction involved both hydrogen and alkene substrate. A competitive experiment was designed to explore the formation of meso-alkane at first step hydrogenation, and the results indicated that the alkane was formed predominantly via an associative mechanism. Four types of conjugate dienes were synthesized and hydrogenated. Different reactivities and selectivities were obtained for each type of dienes. In the best case, a diene was hydrogenated quantitatively with an excellent ent/meso ratio of 20:1.0 and 99% enantioselectivity. The scope, limitation and potential applications of the reactions were discussed. A selection of the dienes was hydrogenated with the Crabtree??s catalyst, for comparison, and the yields, conversions and diastereoselectivities were inferior to those from iridium-oxazoline-imidazol-2-ylidene catalysts.

Thesis (Ph. D.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 61-67).

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

No description available.

Five tri- and tetra-substituted electron-poor olefins containing a β-leaving group, initiated cationic polymerization of p-methoxystyrene with widely varying results. As the electrophilicity of the electron-poor olefins increased, the yields and molecular weights of the polymers formed decreased. The same was true when the excellent leaving group, trifluoromethanesulfonate, was replaced by the poorer leaving group, chloride. Another series of tri-substituted olefins was prepared and reacted with p-methoxystyrene in the presence of excess methyl methacrylate or styrene. Terpolymer was formed as a major product when the electron-poor olefin used contained an α-ester group. The yield of the terpolymer increased with the increasing electrophilicity of the electron-poor olefin. The reactions of methyl α-cyanoacrylate with a number of electron-rich olefins were also studied and found to give new types of adducts, such as Diels-Alder adducts and pyrans. All these reactions were suggested to go through the formation of a tetramethylene intermediate, a resonance hybrid of a zwitterion and spin paired biradical.

No description available.