Title

Phosphonium stoppered [2]rotaxanes and molecular shuttles.

Date of Award

2004

Degree Type

Thesis

Degree Name

M.Sc.

Department

Chemistry and Biochemistry

First Advisor

Loeb, Stephen J.,

Keywords

Chemistry, Organic.

Rights

CC BY-NC-ND 4.0

Abstract

This thesis deals with the synthesis of [2]rotaxanes with single and double sites of recognition, containing pyridinium ethane units in their linear components. In the first part, one pyridinium ethane axle with a triethylphosphonium group on one end was synthesized and the possibility of its complexation with 24C8 derivatives was investigated. Although [2]pseudorotaxane formation was limited due to the bulk of the PR4+ stopper, [2]rotaxanes were formed utilising 24-crown-8 ether, benzo-24-crown-8 ether and naphtho-24-crown-8 ether. The crystal structure of the [2]rotaxane containing 24C8 was determined. The dynamic "flip-switch" activity of the asymmetric crown ethers was analysed by variable temperature NMR experiments and two translational isomers for each were observed. The second part of the thesis describes the novel synthesis of a [2]rotaxane molecular shuttle containing two identical ethane sites connected by a bipyridinium centre in the thread component. The symmetrical DB24C8 ring shuttles between the two sites. The originality of the method consists of first creating one bonding site, then introducing the crown ether, the second site and stopper at the same time. In addition, the effect of the solvent on the motion of the crown was investigated. It was determined that the shuttling of the crown between the two sites is faster in acetonitrile than in methylene chloride. (Abstract shortened by UMI.)Dept. of Chemistry and Biochemistry. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2003 .G4674. Source: Masters Abstracts International, Volume: 43-01, page: 0218. Adviser: Stephen J. Loeb. Thesis (M.Sc.)--University of Windsor (Canada), 2004.