Session: POLY/PMSE Poster Session:

In recent years, direct arylation polymerization (DArP) has become a leading cross-coupling method in conjugated polymer synthesis. Previously, most cross-coupling reactions were carried out through methods such as Stille, Suzuki, Kumada, Negishi, etc. While these older methods have their utility, stoichiometric amounts of main group elements and/or other reagents are typically required. With this issue comes the problem of increased toxicity and less environmentally friendly syntheses. DArP mitigates this issue by direct activation of the C-H, thus removing the need for such main group intermediates. Here, the necessary requirements are thus only C-H and a C-X (X= halogen) bonds that can couple and allow for the formation of a new C-C bond. These can exist on a single monomer to create a homopolymer or individually on two different monomers to create an alternating copolymer. A key experimental parameter that has been found to enhance the efficiency of these reactions is increased pressure during the polymerization, achieved by heating past the critical point of a given solvent system in a sealed vial. Under these conditions larger molecular weight polymers can be formed, resulting in enhanced delocalization and minimum bandgap energies. While the bulk of DArP studies have focused on reduced bandgap (E_g = 1.5-2.0 eV) materials, this presentation will present recent efforts to generate low bandgap (E_g < 1.5 eV) materials, with a focus on the types of polymeric systems that can be made via DArP, the variable experiment parameters, and results of successful implementation.

Mr. Evan W. Culver B.S. Chemistry

Graduate Student, North Dakota State University

Appearances