Part I: Strategies for the Synthesis of Monodisperse Polymers and Cyclic Polymers. Part II: Synthesis of Dipyrromethenes and Aza-dipyrromethenes from Aromatic Nitriles

This thesis is presented in two parts. Part I begins with an introduction to some contemporary problems in polymer chemistry, but also contains what is essentially a mini-review of catalyst transfer polymerization (CTP). This part of the chapter elucidates a number of common misunderstandings of CTP that are present in the literature. It goes onto suggest a new set of design principles to design new CTP systems for a wider variety of monomers. This leads into the first homogenous synthesis of monodisperse polymers. Through cycling between low and high temperatures and carefully controlling monomer activation, we show that it is possible to add exactly one monomer per temperature cycle to each chain in solution, resulting in monodisperse polymers with quantitatively controlled end groups. Part I also describes a project in which macrocyclic poly(3-hexylthiophene) (P3HT) and poly(3-heptylselenophene) (P37S) were synthesized from their linear counterparts. The approach used to accomplish this differs from more common syntheses of cyclic polymers, in that the relatively long persistence length of the polymers makes it unreasonable to assume 100\% cyclization. The approach presented in this chapter is meant to be as general as possible, and to have applications in other cases where polymers need to be separated based on chemical functionality. Part II is an introduction to dipyrromethene and aza-dipyrromethene dyes, along with common methods for their syntheses. It goes on to present a new synthesis of aza-dipyrromethene dyes, which provides an easy route to a number of previously inaccessible compounds, as the previously existing procedures for these dyes are very limited. During the course of this project, it was discovered that one of the starting materials reacted under the same conditions to give a completely different major product. Understanding the mechanism through which it is produced may enable the development of a previously unknown chemical transformation.

Department dc:contributor.department

Chemistry

Year dc:date.issued

2020

Author dc:creator

• McKeown, George Robert

Advisor dc:contributor.advisor

• Seferos, Dwight S

Handle dc:identifier.uri

http://hdl.handle.net/1807/101156

OAI identifier oai:identifier

oai:utoronto.scholaris.ca:1807/101156