Publication Date

2024

Document Type

Dissertation/Thesis

First Advisor

Nesterov, Evgueni E.

Degree Name

Ph.D. (Doctor of Philosophy)

Legacy Department

Department of Chemistry and Biochemistry

Abstract

Semiconducting organic conjugated polymers show major promise for the manufacturing of organic electronic and optoelectronic devices. Their utility comes from inherent conductivity, elasticity, processability and low weight paving the way towards novel materials and applications. The molecular weight, polydispersity, and precise incorporation of structural elements into the conjugated backbone are among the important parameters that affect a conjugated polymer’s mechanical and electrical properties. Therefore, precise control over such parameters provides a path for electronic materials with tunable properties tailored for a specific application. Recent success in this endeavor has been achieved with Suzuki-Miyaura Catalyst-Transfer Polymerization (SCTP) which is a transition metal catalyzed approach toward the controlled synthesis of conjugated polymers. Despite some recent breakthroughs, SCTP is still limited in its application. The goal of this dissertation is to expand the mechanistic understanding of SCTP by investigating the controlled synthesis of the challenging polymer, poly(9,9-dioctylfluorene), using Buchwald-type Pd catalysts. The N-methyliminodiacetic acid boronate ester protecting group (BMIDA) is employed as the nucleophilic coupling “handle”, and its impact on SCTP is examined through the lens of the traditional Suzuki-Miyaura reaction’s transmetalation step. Extensive discussion of the two possible transmetalation pathways, boronate and oxo-Pd, is extended based on the current research findings. The BMIDA fluorenyl monomer proved to be less reactive towards SCTP. However, based on understanding of the transmetalation step of Suzuki-Miyaura coupling, the chemistry can be directed to a more efficient coupling regime involving the oxo-Pd transmetalation pathway through halogen abstraction with Ag+ salts. Furthermore, the discovery of a novel direct transmetalation pathway of the BMIDA monomer without prior need for hydrolysis is discussed and followed by an in-depth exploration of the impact this discovery may have on the polymerization. Mechanistic considerations and catalyst design are provided to enhance the possibility of using less reactive BMIDA monomers. Novel concepts stemming from this work may aid the development of improved controlled polymerization reaction methods for the synthesis of organic conjugated polymers. With an advanced understanding of the mechanisms behind such polymer synthesis, the preparation of novel and unique conjugated polymer structures and morphologies may be accessed, studied, and implemented for technological progress and for the benefit of society.

Extent

228 pages

Language

en

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type

Text

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