Anion interactions of pseudorotaxanes and rotaxanes.
Date of Award
Chemistry and Biochemistry
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This thesis describes studies on the interactions of anions with pseudorotaxanes and rotaxanes comprised of 24-membered crown ether wheels and bis(pyridinium)ethane axles which incorporate an amide anion receptor. Eight nicotinamide-based threads containing a bis(pyridinium)ethane recognition motif were synthesized. Their ability to form pseudorotaxane complexes with 24-membered crown ethers was determined by 1H NMR spectroscopy. The effect of anion binding on the stability of the pseudorotaxanes was investigated using 1H NMR titrations. Nine rotaxanes were synthesized from the combination of three threads and three crown ethers---dibenzo-, dinaphtho-, and naphtho-24-crown-8. The selectivity of the amide receptor towards small inorganic anions---halides and dihydrogenphosphate---were determined by titrations with a rotaxane from the dibenzo class. The anion binding ability of each rotaxane was then tested by titrations with chloride, bromide, and iodide. The steric impact of anion binding on the rotaxane structure was estimated from X-ray crystallography and 1H NMR titration spectra by comparing the chemical shifts. Comparisons between rotaxanes within a certain crown class---dibenzo-, dinaphtho-, or naphtho-, are presented in Chapter 3, Chapter 4 and Chapter 5 respectively. Comparisons among rotaxanes of a certain thread and various crown ethers are presented in Chapter 6. A rotaxane with 24-crown-8 ether was synthesized from one of the threads, and its titration shift data used as a baseline. The studies did not provide conclusive evidence of wheel transformation from an "S" shape to a "C" shape in the symmetrical rotaxanes. Quantitative chemical shift comparisons indicated an alteration in the isomer ratio in naphthorotaxanes, induced by anion binding. Synthetic attempts towards transforming the rotaxanes into molecular shuttles are described in Chapter 7. Synthetic strategies for future work are outlined.* *This dissertation is a compound document (contains both a paper copy and a CD as part of the dissertation).Dept. of Chemistry and Biochemistry. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2006 .M54. Source: Dissertation Abstracts International, Volume: 67-07, Section: B, page: 3805. Thesis (Ph.D.)--University of Windsor (Canada), 2006.
Mihalkov, Iavor S., "Anion interactions of pseudorotaxanes and rotaxanes." (2006). Electronic Theses and Dissertations. 1185.