Chiral Influence on Synthetic Systems
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2011
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ndltd-OhioLink-oai-etd.ohiolink.edu-osu12991704482021-08-03T06:01:44Z Chiral Influence on Synthetic Systems King, Eric David Chemistry Reported are the studies on chiral influence on synthetic molecules such asazobenzene containing oligomers, benzophenone derivatives, and 1, 4, 5, 8-perylenetetracarboxylic acid diimides. Amino acids and other simple, low-cost chiralinducers were used as readily available sources of asymmetric induction. The design ofthe folded azobenzene oligomer originated from the concept that the architecture of themeta- substituted aromatic groups would force the molecule to assemble into a helix.The stability of this helical formation would be assisted by both π-π stacking andhydrogen bonding. The resulting oligomer exists in two enantiomeric helical forms. Itwas hypothesized that a small chiral perturbation placed at a specific point at the end ofthe oligomer would then be amplified throughout the length of the entire moleculecreating a preference for one-handed sense of the helix over the other antipode. Thistheory was proven through the use of circular dichroism (CD) spectra. The chiraloligomers were synthesized in two and four turn variants and the induced chiralityincreased by more than two times with this increase in length. The oligomer wasdetermined to be right-handed or P sense. This conclusion was reached thoughinterpretation of the CD spectra, computer assisted molecular modeling, calculated CD’s,and through collaboration with Christopher M. Hadad’s research group.Benzophenone was envisioned as a ligand in asymmetric catalysis. Benzophenone isa chiral-racemic molecule that exists in two enantiomeric, propeller-like forms. It wasproposed that after the benzophenone scaffold was appended with a pair of phosphineatoms it can act as a ligand in transition metal catalysis. The ketone moiety could then bemanipulated with a chiral amine to form an imine and then this handed perturbation couldbe amplified through the molecule. The induced chirality would subsequently transfer tothe active site of the metal catalyst. Favorable hydrogen bonding interactions the assist instabilizing the catalyst in its preferred handed form. A benefit of this ligand would be themodularity granted to the catalyst by changing the identity or handedness of the aminoacid used for induction. It was observed via CD that the identity of the amine employedhad a great effect on the resulting signal and therefore the chiral environment of the precatalyst.Finally, the self-assembly of several one-dimensional nanostructures comprised of 1,4, 5, 8-perylenetetracarboxylic acid diimides with various imide groups was studied. Theimides were altered from simple alkyl chains or several combinations of protected lysineto form amphiphiles and bola-amphiphiles. Perylene was selected because of its manyopto-electronic properties that are frequently exploited in intermolecular charge transfer.It was observed through various analytical techniques that the perylene diimides stronglyassembled in numerous solvent conditions with the exception of 2,2,2-trifluoroethanol(TFE). 2011-07-20 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1299170448 http://rave.ohiolink.edu/etdc/view?acc_num=osu1299170448 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |
| collection |
NDLTD |
| language |
English |
| sources |
NDLTD |
| topic |
Chemistry |
| spellingShingle |
Chemistry King, Eric David Chiral Influence on Synthetic Systems |
| author |
King, Eric David |
| author_facet |
King, Eric David |
| author_sort |
King, Eric David |
| title |
Chiral Influence on Synthetic Systems |
| title_short |
Chiral Influence on Synthetic Systems |
| title_full |
Chiral Influence on Synthetic Systems |
| title_fullStr |
Chiral Influence on Synthetic Systems |
| title_full_unstemmed |
Chiral Influence on Synthetic Systems |
| title_sort |
chiral influence on synthetic systems |
| publisher |
The Ohio State University / OhioLINK |
| publishDate |
2011 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=osu1299170448 |
| work_keys_str_mv |
AT kingericdavid chiralinfluenceonsyntheticsystems |
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