Investigation of PEPPSI precatalysts for controlled polymerization of -conjugated polymers from cheap starting materials
Abstract
Since the discovery of catalyst-transfer polymerization in 2004 there has been significant
research into expanding the scope from Kumada couplings of poly-thiophenes mediated
by nickel initiators. This thesis presents an investigation toward the synthesis of
-conjugated polymers by the elusive pseudo-living polymerization of chloroarene
monomers.
Chapter 1 sets the scene with an in-depth review of chain-growth polymerizations
mediated by palladium catalysts. In chapter 2, we report the first examples of exhaustive
substitution of poly-chloroarenes in the presence of a deficit of nucleophile in the sp3-sp2
Negishi coupling mediated by PEPPSI-IPr. These experiments demonstrated
intramolecular transfer of the active catalyst which is essential for catalyst-transfer
polymerization.
Chapter 3 describes the synthesis of the highly active PEPPSI-IPent precatalyst from
cheap commercially available starting materials with minimal purification. Subsequently
in chapter 4, it was demonstrated that PEPPSI-IPent undergoes exhaustive substitution of
poly-chloroarenes in the presence of a deficit of nucleophile in sp2-sp2 Kumada, Negishi
and Suzuki cross-couplings.
In chapter 5, optimization of current Kumada polymerization of bromo phenylene-based
monomer mediated by PEPPSI-IPr is described. Direct comparison of model reactions
and Kumada polycondensation confirmed high selectivity for exhaustive substitution is
required to achieve polycondensation in a chain-growth manner. Initial research into
catalyst-transfer polycondensation of chloroarene monomers did not achieve
polymerization in a chain-growth manner using modified conditions from bromoarene
monomers.
Authors
Groombridge, Benjamin JohnCollections
- Theses [3706]