Concentration dependent ¹H-NMR chemical shifts of quinoline derivatives
- UNCW Author/Contributor (non-UNCW co-authors, if there are any, appear on document)
- Adam Beck (Creator)
- Institution
- The University of North Carolina Wilmington (UNCW )
- Web Site: http://library.uncw.edu/
- Advisor
- Paulo Almeida
Abstract: Quinolines are an important group of heterocyclic compounds that are found in many
biologically active natural products and synthetic molecules. The non-exchangeable
hydrogens of quinolines have been shown to have unusual concentration dependent
chemical shift changes in 1H-NMR studies. It is proposed that these changes are due to
dipole-dipole and p-p interactions between two or more quinolines. The approach used to
investigate the inter- and intramolecular p-p interactions of the quinoline protons in
solution was to synthesize quinoline monomers and dimers substituted at the 6 and 8
positions and compare their concentration dependent chemical shifts of their aromatic
protons. The quinoline dimers with C3, C6 and C10 tethers were evaluated with respect to
the substitution location, length of tether and functional group attaching the tether and the
quinoline ring.
The concentration dependent chemical shifts (?d/?C) of the quinoline protons on the
6-substituted diquinoline diesters were smaller than those of the equivalent 6-monoesters.
However, the 8-substituted diquinoline diesters had similar chemical shifts compared to
the 8-monoesters. This data is consistent with the 6-substituted dimers being able to
stack intramolecularly in an anti-parallel conformation. The ?d/?C of the 6-substituted
diethers and the 8-substituted diethers were similar to their respective 6 and 8-substituted
monoethers. This shows that while the position of the substituent contributes to interand
intramolecular interactions, it is not the only determining factor. The 6-substituted
monoethers supported p – p stacking in an anti-parallel conformation with longer ether
linkages creating more steric interference. The 8-substituted monoethers also supported p – p stacking in an anti-parallel conformation with longer ether linkages hindering
intermolecular lateral movement between rings.
Concentration dependent ¹H-NMR chemical shifts of quinoline derivatives
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Created on 1/1/2009
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Additional Information
- Publication
- Thesis
- A Thesis Submitted to the University of North Carolina at Wilmington in Partial Fulfillment of the Requirement for the Degree of Masters of Science
- Language: English
- Date: 2009
- Keywords
- Heterocyclic compounds, Quinoline
- Subjects
- Heterocyclic compounds
- Quinoline