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The Global ETD Search service is a free service for researchers
to find electronic theses and dissertations. This service is
provided by the
Networked Digital Library of Theses and Dissertations.
Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
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Showing 101 to 110 of 770 (0.033 seconds)| 101 |
Guanidine-mediated asymmetric epoxidation reactionsGenski, Thorsten January 2001 (has links)
No description available.
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Asymmetric synthesis using enantiopure dihydro-2H-1,4-oxazin-2-one templatesTyler, Simon Nicholas George January 1998 (has links)
No description available.
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| 103 |
Nonperturbative propagators in axial gauge QCDGentles, Andrew James January 1996 (has links)
No description available.
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| 104 |
Phosphorus functionalised polymeric supportsEdwards, Christopher January 2000 (has links)
No description available.
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| 105 |
Asymmetric synthesis using acyl-nitroso cycloadditions : applications to natural product synthesisPepper, Adrian Gordon January 2000 (has links)
No description available.
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| 106 |
Microbial biotransformation of 2-arylpropionic acidsHung, Yi-Feng January 1997 (has links)
No description available.
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| 107 |
Enantioselective synthesis of cyclic imidesAdams, David J. January 2000 (has links)
No description available.
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| 108 |
New stereoselective enolate chemistry using atropisomeric anilidesHughes, Adam D. January 1999 (has links)
No description available.
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| 109 |
Stereoselective synthesis of triacarbonyl(#eta#'6-arene)chromium(0) complexes and amine-borane complexes mediated by chiral basesAriffin, Azhar January 1999 (has links)
No description available.
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| 110 |
ENANTIO-SELECTIVE MECHANISM OF THE POLY-PROLINE CHIRAL STATIONARY PHASE: A MOLECULAR DYNAMICS STUDYAshtari, MOHAMMAD 29 January 2013 (has links)
Poly-proline-based chiral stationary phases are relatively new stationary phases and have shown to be competitive to other commercially available chiral stationary phases for high performance liquid chromatography (HPLC). The conformational studies, solvation properties and enantio-selective mechanism of this chiral stationary phase are the main focus of this thesis. Semi-flexible models are developed based on an extensive series of ab initio calculations for proline selectors from di- to hexa-proline and a series of six chiral analytes. Then molecular dynamics simulations are performed to study the solvation, conformational preferences at the interface, and the selectivity.
The solvation and conformational preferences of poly-proline selectors at the interface are examined in a normal phase n-hexane/-2propanol and a reverse phase water/methanol solvent. We noticed a significant difference between conformational preferences of poly-proline chains in these solvents indicating the effect of solvent polarity and hydrogen bonding on the relative stabilities of poly-proline conformers. Solvent partitioning occurs at the interface and this creates a polarity gradient between the stationary phase and the bulk that encourages analyte docking at the interface. Hydrogen bonding to the poly-proline selectors is shown to be a function of solvent composition and poly-proline conformation at the interface.
The selectivity of the poly-proline chains was studied by molecular dynamics simulations of chiral analytes docking into the interface. The selectivity factors for a set of enantiomers were predicted successfully. Enantio-resolution has been shown to mostly happen with hydrogen bonding to poly-proline carbonyl oxygens located close to the interface. Steric interactions and conformational flexibility of the analytes are also contributing factors for enantio-resolution. / Thesis (Ph.D, Chemistry) -- Queen's University, 2013-01-28 14:31:53.316
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