Thesis (Ph. D.)--Lehigh University, 2005. / Includes bibliographical references and vita.

Thesis (M.Sc.)(Chemistry)--University of Pretoria, 2004. / Title from opening screen (Viewed March 22, 2006). Includes summary. Includes bibliographical references.

Thesis (Ph. D.)--State University of New York at Binghamton, Department of Chemistry, 2005. / Includes bibliographical references.

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2006. / Includes bibliographical references. Also available in electronic version.

Thesis (B.S.) Magna Cum Laude--Butler University, 2007. / Includes bibliographical references (leaf 20).

Thesis (Ph. D.)--Oregon Graduate Center, 1988.

Thesis (Ph. D.)--University of Washington, 1985. / Vita. Bibliography: leaves [34]-35.

Thesis (Ph.D.)--Boston University. / Earlier work has shown that alumina at 350° acts on tetrahydrofurfuryl alcohol labeled at its external methylene group with carbon-14, as well as on dihydropyran ([delta^2]-dihydropyran) labeled at its 6 position with carbon-14 to produce an equimolecular mixture of dihydropyran2-C14 and dihydropyran-6-C14. The present work inquires into the possibility of oxygen and of hydrogen exchange in dihydropyran in contact with alumina under the same conditions. Dihydropyran-O18 was synthesized for use in oxygen exchange experiments. Tetrahydrofurfuryl chloride, prepared from the correspondingalcohol with thionyl chloride and pyridine, was treated with sodium to give 4-penten-1-ol. This alcohol was converted to 1-bromo-4-pentene with phosphorus tribromide in pyridine. Reaction of the Grignard derivative of the bromo compound with formaldehyde-O18 gave 5-hexen-1-o1-O18s · The labeled formaldehyde was obtained by pyrolyzing labeled paraformaldehyde, which in turn was prepared from ordinary paraformaldehyde by depolymerization to formaldehyde, exchange of oxygen with water-O18, and repolymerization. A mixture of 5-hexen-1-o1-O18 and 5-hexen-1-ol-1-C14 was ozonized and the product dehydrated to give dihydropyran labeled with oxygen-18 and (at position 6) with carbon-14 [TRUNCATED]

M.Sc. (Chemistry) / Please refer to full text to view abstract

M.Sc. / This study comprises the preparation and characterisation of new azolinylidene- and divinylcarbene complexes of chromium, molybdenum and tungsten, from 1- phenylpyrawle, 1-methylimidazole and 4,4-dimethyl-2,2-thienyloxazoline precursors. The reaction of 1-phenylpyrazolyllithium with (C0) 6M (M Cr, Mo or W) yields after alkylation with CH3S03CF3 in THE the two products (C0)5M[C(OCH3X(ONPhNCHC(H)] and (C0)5M[C(0{CH2}40C113)(aNPhNCH6H)]. A 'H NMR study indicates the existence of two isomers for each of the two tungsten CO'cli•lexes. 1-Methylimidazolyllithiura reacts with (CO)6M (M = Cr, Mo or W) to give the carbene complexes (C0)5MK'N(CH3)CHCH14(C I i 3)] after alkylation with CH3S03CF3, and the imine complexes (C0)5MOCHN(CH3)CH6H] after protonation with SO3CF3. Reaction of 1-methylimidazolyllithium with the anionic salt (C0)5 Cl = Cr or W), followed by alkylation with CH3S03CF3 affords both the mono- and bis(carbene) complexes, (CO)5M[CN(CH3)CHCHN(CH3)] and (C0)41v1[6N(CH3)CHCIRA(CH3)]2. The complex (C0)5W[C(0 {CH2 } 40C113)(t‘NPhNaldH)] reacts with phenylethynthiolate to furnish an anionic organometallic synthon that can either be alkylated or protonated. Protonation leads to two isomeric forms of the metal-coordinated thioaldehyde, (C0)5W4—SHC(Ph)=C(OCH3)(oNPhNCHell), whilst alkylation with various electrophilic reagents produces the metal coordinated dithio-esther (C0)5 W4--S=C [ SCH3] [C(Ph)=C(OCH3)(tNPhNaldH)]. The neutral divinylcarbene complexes (C0)5Cr{cC(a0CH2CMe2N)SC CH} (a) and (C0)5W{cC(COCH2CMe214)SCH9H} (19) are prepared by reaction of (C0)5MCr with the 3-lithiated thienyloxazoline, followed by alkylation with CH3S03CF3 . These complexes are the first examples of coordinated 'divinylcarbenes utilizing the group 6 transition metals, where the carbene carbon shows carbene character. They are also in another sense unique since the nucleopbutlic heteroatom where alkylation occurs, is situated outside the coordinated ring-system, and, therefore, more than two bonds removed fro the carbene carbon atom.