Thesis (Ph. D.)--Chemical Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Dr. Christopher Jones; Committee Member: Dr. Dennis Hess; Committee Member: Dr. Hang Lu; Committee Member: Dr. Marcus Weck; Committee Member: Dr. Pradeep Agrawal. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Th. doct.--Informatique et réseaux--Paris--ENST, 1991. / Bibliogr. p. 138-142.

Th. doct.--Informatique et réseaux--Paris--ENST, 1995. / Bibliogr. p. 157-163.

Thesis (M.A. in National Security Affairs)--Naval Postgraduate School, Dec. 2004. / Thesis Advisor(s): Abenheim, Don. Includes bibliographical references (p. 89-90). Also available online.

Thesis (M.A. in National Security Affairs)--Naval Postgraduate School, Dec. 2004. / Thesis Advisor(s): Edward Olsen, Lyman Miller. Includes bibliographical references (p. 71-84). Also available online.

Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaves 597-639).

Texte remanié de: Ph. D. Diss.

Dissertação (mestrado) - Universidade Federal de Santa Catarina. Centro de Ciencias Fisicas e Matematicas / Made available in DSpace on 2012-10-16T22:10:59Z (GMT). No. of bitstreams: 0Bitstream added on 2016-01-08T17:55:49Z : No. of bitstreams: 1 90932.pdf: 1736571 bytes, checksum: 9b5e57becaa70fc482282dcd39d1c725 (MD5) / A reação de hidrólise das bases de Schiff N-benzildenoanilina, 4-metóxi-N-benzilidenoanilina, 2-metóxi-N-benzilidenoanilina e 2-(2-etoxi)etóxi-N-benzilidenoanilina foi estudada a 25oC, na presença de sais de metais alcalinos e alcalino-terrosos em diversas concentrações. A força iônica foi mantida constante no meio etanólico aquoso (88%) através da adição de tetrafluoroborato de tetrabutilamônio. Os resultados foram explicados em termos de três fatores: a) o efeito inibitório da complexação do íon metálico com o átomo ligado ao anel; b) o efeito provocado pela associação do cátion com o átomo de nitrogênio imínico; c) o efeito templato, envolvendo a associação do íon metálico com os átomos de oxigênio da cadeia lateral.

This PhD thesis project was concerned with the use of alkali metal amide Brønsted bases and alkali metal alkoxide Lewis bases in (asymmetric) catalysis. The first chapter deals with formal allylic C(sp3)–H bond activation of aromatic and functionalized alkenes for subsequent C–C and C–H bond formations. The second chapter is focused on C(sp3)–Si bond activation of fluorinated pro-nucleophiles in view of C–C bond formations. In the first chapter, a screening of various metal amides, hydrides, and alkyl reagents resulted in the observation that alkali metal amides were effective Brønsted bases to trigger allylic C(sp3)–H bond activation of aromatic alkenes at room temperature. Sodium hexamethyldisilazide was found to be most efficient compared with other s-, p-, d-, and fblock metal amides. This unique transition metal-free methodology was exploited to activate a variety of alkene pro-nucleophiles, which were shown to undergo γ-selective C–C bond formation with various aromatic aldimines as well as one aliphatic substrate. The corresponding homoallylic amine derivatives were obtained in high yields with excellent E:Z ratios. The reaction mechanism was investigated and attempts to detect and/or isolate key intermediates were undertaken. Importantly, it was shown that metal-free superbases of the Schwesinger or Verkade type were not apt to catalyse this challenging C–C bond formation. The asymmetric version of this rare sodium amide catalysis has been achieved by using a commercially available enantiopure bisoxazoline ligand (46% ee). Subsequently, the catalytic use of sodium and potassium amides was applied to the isomerization of terminal aromatic alkenes to generate the thermodynamically more stable internal olefins in excellent yields with high E:Z ratios. Furthermore, functionalized metalloid (B, Si) and metal-free alkenes were found to undergo alkali metal amide-triggered (chemoselective) allylic C(sp3)–H bond activation in view of isomerization and/or C–C bond formation with aldimines. In the second chapter, the catalytic C–Si bond activation of an important difluoromethylation reagent, HCF2SiMe3, was investigated. Here, alkali metal alkoxides were shown to be more effective Lewis base triggers than other metal alkoxides or metal-free superbases. This novel method was successfully used to transfer the nucleophilic difluoromethyl fragment to electrophiles such as a variety of amides and lactams, whereas unsaturated amides failed to undergo the intended conjugate C–C bond formation. In this context, it is noted that the α-hydrogen of certain amides was tolerated. This unprecedented catalytic difluoromethylation of unactivated carbonyl electrophiles was achieved using potassium tert-butoxide at room temperature, and the corresponding fluorinated ‘hemiaminal’ products were obtained in high yields.

It is generally accepted that platinum antitumour drugs bind, preferentially, to Guanine N7 in DNA. Thus the kinetics of formation and the energetics of dissociation of platinum-nitrogen bonding have been investigated, using simple model bases, namely pyridine. pyrimidine. purine and some derivatives. Six complexes of the type cis-PtCl2L2, where L is a N-heterocycle, have been successfully prepared and characterized. The kinetics of the reaction between K2PtCl4 and the N-heterocyclic bases in aqueous solution have beeD studied. This was best achieved by pre-aquating the PtCl4(2-) and measuring the decrease in concentration of platinum or ligand by AA or UV spectroscopy respectively. It was found that the rate of reaction is second order, the rate being dependent on the concentration of both platinum complex and the ligand. The substitution of ligand takes place by direct replacement, involving an associative S.2 mechanism. It was found that the activation entropy and the activation energy for the reactions of platinum complexes in solution are strongly correlated. The energetics of platinum-nitrogen bond dissociation were followed using thermogravimetric analysis. Quantitative data, which enabled calculation of the activation energy for the decomposition process involving the loss of one molecule of ligand was obtained from isothermal studies. No correlation was found between the solid state studies, involving bond breaking, and the syntheses of the complexes, probably because in solution the reaction is complicated by solvent effects. Theoretical studies, which involved Molecular Orbital calculations on the N-heterocyclic bases themselves, were also carried out in an attempt to correlate the kinetic and energetic parameters with the electronic structure of the ligand. Several correlations were attempted but only one was found. This was the relationship between the solid state decomposition energy and the LUMO energy of the quarternized base.