Synthesis of Purine-Containing Conjugated Polymers and their Optoelectronic Characteristics

Understanding the relationships between conjugated polymer properties and monomer design is vital when targeting specific properties for specific technologies. Purines are multifunctional heterocycles that have hardly been studied as building blocks for conjugated polymers because of synthetic challenges. The overarching goal for my dissertation was to design a viable synthetic route for purine-containing π-conjugated polymers and characterize their optoelectronic properties. Herein, purine-containing monomers containing thienyl flanking groups were synthesized, which enables fully conjugated, purine-containing polymers to be created and studied. Monomers were synthesized via Suzuki-Miyaura cross-coupling reactions, and connectivity across the purine scaffold was varied to synthesize conjugated copolymers. In this vein, the purine-containing units were copolymerized with a variety of comonomers, including electron accepting monomers, highly fluorescent monomers, electron donating monomers, and monomers that extend the conjugation. These copolymers were synthesized via direct arylation polymerization or, in a few cases, microwave-assisted Suzuki-Miyaura cross-coupling polymerizations. In addition, purine-containing homopolymers made via AB and AA+BB step-growth polymerizations were analyzed to understand how sequence regularity effects optoelectronic and physical properties. My work highlights the functionality of purine as a building block for conjugated polymers and describes fundamental properties of a series of purine-containing copolymers.