Thesis (Ph. D.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains xi, 120 p. : ill. Includes abstract. Includes bibliographical references (p. 115-120).

Thesis (Ph. D.)--Hong Kong University of Science and Technology, 2003. / Includes bibliographical references (leaves 196-207). Also available in electronic version. Access restricted to campus users.

Thesis (M.S.)--University of North Carolina at Wilmington, 2003. / Includes bibliographical references (leaves : [85]-87).

No description available.

Ferroelectric liquid crystals (FLCs) exhibit a bulk electric polarization (PS) that can be coupled to an electric field to produce an ON-OFF light shutter, and are being investigated as an alternative to nematic liquid crystals in display applications. Commercial FLC mixtures normally consist of a small amount of chiral dopant in an achiral smectic C (SmC) liquid crystal host. Because the switching time of FLC display is inversely proportional to the induced polarization, the design of chiral dopants with high polarization powers (p) is a key aspect of FLC research. Such work requires an understanding of the relationship between molecular structure and polar order in the chiral SmC* phase. Previous work in the Lemieux group focused on 2,2’-spirobiindan-1,1’-diones dopants, and a conformational model was proposed to explain the observed host dependence of the polarization power (p) of these dopants. In order to test this model, the 2,2’-spirobiindan-1,1’-dione core has been modified by introducing polar substituents and by modifying the functional groups linking the core to the alkyl side-chains. Specifically, this thesis focuses on implementing this approach via the synthesis and characterization of chloro- and methyl-substituted 2,2’-spirobiindan-1,1’-dione dopants. Four chiral dopants (2.1a, 2.1b, 2.2a and 2.2b) were synthesized, resolved and their absolute configurations assigned by CD spectroscopy. Their polarization powers were measured in four SmC hosts with different core structures. For both the ether-linked and ester-linked dopants, the addition of a substituent at the 6-position of one indanone ring results in lower polarization powers regardless of the size and polarity of the substituent, which is contrary to the original conformational distribution model. A comparative study of the data suggests that the ester-linked dopants exert much stronger perturbations on the host environment than the ether-linked dopants, especially when the 6-position is substituted. We postulate that this perturbation is chiral in nature, and that the feedback effect of chirality transfer causes a shift in the conformational distribution of the dopant favoring conformers with negative polarity. Probe experiments were performed to detect the effect of chirality transfer feedback (CTF) in the case of the chloro-substituted diester dopant (2.1b), showing consistent results with the postulate. / Thesis (Master, Chemistry) -- Queen's University, 2007-09-28 12:26:06.486

Chirality can be induced in achiral solvent molecules located near a chiral molecule or surface, but there have been very few systematic studies in this field either experimentally or theoretically. The focus of this thesis is to study the chirality transfer from chiral molecules to achiral solvents. To capture the chirality transfer in solvent molecules, a solvent model that is sensitive to the changes in the environment is needed. We developed new polarizable and flexible models based on an extensive series of ab initio calculations and molecular dynamics simulations. The models include electric field dependence in both the atomic charges and the intramolecular degrees of freedom. Modified equations of motion are required and we have implemented a multiple time step algorithm to solve these equations. Our methodology is general and has been applied to ethanol as a test. For other solvents in our simulations, such as 2-propanol, limited models are used. The chirality transfer from chiral solutes to achiral solvents and its dependence on the solute and solvent characteristics are then explored using the new polarizable models in molecular dynamics simulations. The chirality induced in the solvent is assessed based on a series of related chirality indexes originally proposed by Osipov[Osipov et al., Mol. Phys.84, 1193(1995)]. Two solvents are considered: Ethanol and benzyl alcohol. The solvation of three chiral solutes is examined: Styrene oxide, acenaphthenol, and n-(1-(4-bromophenyl)ethyl)pivalamide (PAMD). All three solutes have the possibility of hydrogen-bonding with the solvent, the last two may also form π-π interactions, and the last has multiple hydrogen bonding sites. The chirality transfer from chiral surfaces to achiral solvents is also explored. Emphasis is placed on the extent of this chirality transfer and its dependence on the surface and solvent characteristics is explored. Three surfaces employed in chiral chromatography are examined: The Whelk-O1 interface; a phenylglycine-derived chiral stationary phase (CSP); and a leucine-derived CSP. The solvents consist of ethanol, a binary n-hexane/ethanol solvent, 2-propanol, and a binary n-hexane/2-propanol solvent. Molecular dynamics simulations of the solvated chiral interfaces form the basis of the analysis and position dependent chirality indexes are analyzed in detail. / Thesis (Ph.D, Chemistry) -- Queen's University, 2009-09-24 00:25:15.174

This thesis described investigations into the synthesis and reactions of chiral monophosphines, in five chapters. Chapter 1 introduces asymmetric catalysis, Chapter 2 and 3 describe the synthesis of enantiomerically pure monophosphine via an oxide and borane route respectively. Chapter 4 describes the organometallic reactions of these monophosphines and Chapter 5 contains experimental details of the reactions. <strong>Chapter 1</strong> describes the importance of chirality and significant asymmetric processes. The literature methods of producing homochiral monophosphines are detailed. <strong>Chapter 2</strong> describes the synthesis of enantiomerically enriched monophosphine oxides. Diastereomerically pure (2R, 4S, 5R)-2-chloro-5-phenyl-3,4-dimethyl-1,3,2-oxazaphospholidine was prepared from PCl₃ and (-)-ephedrine. This compound was reacted with 2-adamantyl magnesium bromide to afford (2R, 4S, 5R) and (2S, 4S, 5R)-3,4-dimethyl-2-2-adamantyl-5-phenyl-1,3,2-oxazaphospholidin-2-oxide after oxidation with ^tBuOOH. An X-ray crystal structure was obtained of the R_P diastereoisomer and a detailed NMR study carried out on the S_P diastereoisomer. The R_P diastereoisomer was reacted with 2-methoxyphenylmagnesium bromide to give R_P-N-methyl-N-(1S,2S)-(1-methyl-2-hydroxy-2-phenyl)-ethyl-P-(2-methoxyphenyl)-P-(2-adamantyl)phosphinamide in 68% yield and 95% d.e. The ephedrinyl residue was replaced by O-methyl under acid catalysis with inversion of configuration and with >85% e.e. Displacement of the methoxy group using phenyl lithium occurred with inversion of configuration to give the corresponding phosphine oxide in 65% e.e., which could be reduced under forcing conditions using polymethylhydrosiloxane in the presence of Ti(OⁱPr)₄. <strong>Chapter 3</strong> describes the synthesis of enantiomerically enriched monophosphines via phosphine borane complexes. Diastereomerically pure (2R, 4S, 5R)-2,5-diphenyl-3,4-dimethyl-1,3,2-oxazaphospholidine borane was prepared directly from PhPCl₂ and (-)-ephedrine, followed by oxidation with BH₃.Me₂S. This compound reacted regiospecifically with ortho-anisyl lithium to afford the product formed by P-O cleavage with >96% d.e. and with retention of configuration at phosphorus. The ephedrinyl residue was replaced by O-methyl under acid conditions with inversion of configuration and with >98% e.e. Ferrocenyl, 1-adamantyl and tert-butyl lithium reagents displaced the methoxy group with inversion of configuration and with >92% e.e., as determined by ¹H NMR methods. The phosphine borane complexes were then reduced quantitatively with Et₂NH with retention of configuration and with >98% e.e. <strong>Chapter 4</strong> describes the synthesis of indium and rhodium complexes of (S)-t-butyl-(2-methoxyphenyl)-phenyl phosphine and (S)-ferrocenyl-(2-methoxyphenyl)-phenyl phosphine. The iridium complexes are shown to reduce a range of prochiral olefins, including Z-methyl-2-acetylamino-3-phenylpropenoate (MAC) in up to 19% e.e. The di-(R,R)-(ferrocenyl-(2-methoxyphenyl)-phenyl phosphine) rhodium complex is more selective, reducing MAC in 54% e.e., while the rhodium complex of (S)-t-butyl-(2-methoxyphenyl)-phenyl phosphine reduces MAC in 24% e.e.

Thesis (Ph.D.)--Memorial University of Newfoundland, 1999. / Bibliography: leaves 236-258.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 205-214). Also available via the Internet.

Thesis (Ph. D. in Chemistry)--Vanderbilt University, Dec. 2005. / Title from title screen. Includes bibliographical references.