Metal-based [2] and [3]rotaxanes.

The focus of this thesis is to synthesize, characterize and investigate the properties of [2]rotaxanes and [3]rotaxanes for the purposes of developing molecular level machines. In the first part of the thesis the coordination chemistry of the [2]rotaxane 1,2-bis(4,4\u27-dipyridinium)ethane/dibenzo-24-crown-8 is investigated. The production of zwitterionic and dizwitterionic [2]rotaxanes produced upon capping with an anionic metal complex is described. The complexes are studied in solution using UV/vis spectroscopy and characterized by X-ray crystallography. The same system, 1,2-bis(4,4\u27-dipyridinium)ethane/dibenzo-24-crown-8, is then used for the development of 1- and 2-dimensional infinite networks. The networks are characterized by X-ray crystallography and their stability is studied using thermogravimetric analysis. The second part of the thesis focuses on a new class of [2]rotaxanes in which a chelating group has been incorporated into the cationic thread portion. The chelating group is sufficiently bulky making it an adequate stopper. This allows for the incorporation of metal ions in competitive solvents and at high temperature without compromising the integrity of the [2]rotaxanes. The use of a 2,2\u27, 6\u27,2″ -terpyridine unit as the chelating group allowed for investigation of homoleptic iron(II) and heteroleptic ruthenium(II) complexes. The synthesis and characterization of all species using NMR spectroscopy, UV/vis spectroscopy, mass spectrometry and X-ray crystallography are described. The final part of this thesis introduces the new concept of flip switching using the 1,2-bis(4,4\u27-dipyridinium)ethane/dibenzo-24-crown-8 motif. The synthesis of two model compounds, one with a square planar geometry the other with an octahedral arrangement, is described. These complexes were characterized using standard techniques and investigated for \u27 flipping\u27 at low temperature using 1H NMR spectroscopy. The result of the model complexes lead to the development of a molecular level machine, in which, the flipping can be controlled by the geometry of the metal centre and monitored at room temperature using 1H NMR spectroscopy.Dept. of Chemistry and Biochemistry. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2004 .D38. Source: Dissertation Abstracts International, Volume: 65-10, Section: B, page: 5142. Adviser: S. J. Loeb. Thesis (Ph.D.)--University of Windsor (Canada), 2004