Title

Dendrimeric and polymeric rotaxanes incorporating the Loeb recognition motif.

Date of Award

2005

Degree Type

Dissertation

Degree Name

Ph.D.

Department

Chemistry and Biochemistry

Keywords

Chemistry, Organic.

Rights

CC BY-NC-ND 4.0

Abstract

Traditionally, dendrimeric and polymeric macromolecules have been pieced together using the strength of covalent and metal coordinative bonds. The incorporation of non-covalent interactions within these polymers may prove interesting in the fundamental role that interlocked components play in entanglements, rheology, elasticity and mechanical properties of the polymers in which they will be incorporated. The focus of this thesis is to explore the incorporation of the 1,2-bis(pyridinium)ethane (Loeb) rotaxane motif into various polymeric and dendrimeric architectures and study how these new interpenetrated and interlocked components affect the properties of the resulting systems. A series of molecules possessing both recognition elements covalently bound to one another, in a daisy chain fashion, were synthesized in order to study their self-complexing and oligomerizing abilities in competitive and non-competitive solvents. Proton nuclear magnetic resonance (1 H NMR) spectroscopy and high resolution electrospray ionization mass spectrometry (ESI-MS) were used to characterize these compounds and study their polymerization behavior. The same rotaxane motif was then used to synthesize a series of branched [n]rotaxanes. [2]-, [3]- and [4]Rotaxanes were obtained using a threading followed by stoppering approach and subsequently characterized by 1H NMR spectroscopy and ESI-MS. Isolated product yields and product distributions are discussed with respect to the core size and macrocyclic arrangement about the core. To study the effect of incorporating Frechet dendrons as stoppers and as macrocyclic appendages into this rotaxane motif, various dendrimeric [2]rotaxanes were synthesized. By altering the size of the dendrons employed, a 1H NMR spectroscopic study was performed in a variety of solvents of differing polarity. Their results as well as ESI-MS investigations will be discussed. Finally, Frechet dendrons were incorporated into a series of [3]rotaxanes and their [2]rotaxane molecular shuttle counterparts. This was done in order to study the effect dendrons have on the translational isomerism of shuttling [2]rotaxane systems. The systems were characterized by 1H NMR spectroscopy and ESI-MS. In addition, the rates of the shuttling process as well as the recognition site occupancy were measured using variable temperature NMR (VT-NMR) spectroscopy as well as NMR simulation software. These final results will be presented.Dept. of Chemistry and Biochemistry. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2005 .T73. Source: Dissertation Abstracts International, Volume: 66-11, Section: B, page: 5990. Thesis (Ph.D.)--University of Windsor (Canada), 2005.