Date of Degree

5-2019

Document Type

Dissertation

Degree Name

Ph.D.

Program

Chemistry

Advisor

Qiao-Sheng Hu

Committee Members

Michal Kruk

David Mootoo

Subject Categories

Polymer Chemistry

Keywords

Borylation, Cross-Coupling, Controlled Polymerization, Polymerization, Palladium(0), Nickel(0)

Abstract

Transition metal-catalyzed cross-coupling reactions such as Suzuki-Miyaura cross-couplings, are among the most powerful transformations in organic synthesis. They have been extensively used for the synthesis of a wide variety of organic compounds. Recently the Suzuki cross-coupling reaction has been extended to conjugated polymer synthesis, especially the controlled Suzuki cross-coupling polymerization for polymers with the desired length. My research is on developing highly efficient monophosphine-coordinated palladacycle complexes for cross-coupling reactions/polymerizations.

Based on the understanding of transition metal-catalyzed Suzuki cross-coupling reactions including polymerization, my dissertation started with Pd(0)- and Ni(0)-catalyzed borylation reactions of aryl halides and tosylates with bis(pinacolato)diboron to access arylboronates at room temperature. Pd(0)-catalyzed cross-coupling reactions of aryl halides with bis(pinacolato)-diboron are described. Monophosphine-coordinated palladacycle complexes, proved to be an efficient catalyst system for the Miyaura borylation reactions of a variety of aryl halides with bis(pinacolato)diboron. Ni(0)/PCy3-catalyzed cross-coupling reactions of aryl arenesulfonates with bis(pinacolato)diboron are also described. The Ni(0)/PCy3 catalysts, generated from Ni(COD)2 and PCy3, or air-stable 4-MeOC6H4Ni(II)(PCy3)2OTs, were efficient catalyst systems for the Miyaura borylation reactions of a variety of aryl arenesulfonates with bis(pinacolato)diboron. The mild reaction conditions, the easy availability of the catalyst and good coupling yields make these reactions potentially useful in organic synthesis.

In Chapter 3, a new polymerization catalyst was developed for Pd(0)-catalyzed Suzuki cross-coupling polymerization to generate conjugated polymers with high molecular weights at room temperature. The one-pot polymerizations of aryl dibromides and bis(pinacolato)diboron with monodentate phosphine as the ligand is also described. Such monophosphine-coordinated palladacycle complexes afforded polymers with yields and the molecular weights comparable to or higher than that of polymers obtained by using other palladium catalysts.

Chapter 4 describes, the development of two initiator systems for controlled Pd(0)-catalyzed Suzuki cross-coupling polymerization of AB-type monomers. Ad3P-coordinated acetanilide-based palladacycle complex and t-Bu2PCy-coordinated 2-phenylaniline-based palladacycle complexes were demonstrated to be efficient initiators for controlled Suzuki cross-coupling polymerization, affording polymers with narrow PDIs and well-controlled end groups. Collectively these studies provide a clearer understanding of Pd(0)-catalyzed Suzuki cross-coupling polymerizations and pave the road for diverse cross-coupling polymerizations.

This work is embargoed and will be available for download on Monday, May 31, 2021

Graduate Center users:
To read this work, log in to your GC ILL account and place a thesis request.

Non-GC Users:
See the GC’s lending policies to learn more.

Share

COinS