Extended fused-ring analogs of poly(thieno[3,4-b]pyrazine)s and the effect on polymer band gap

ORGN 589

Jon P. Nietfeld, jon.nietfeld@ndsu.edu, Christopher L. Heth, christopher.heth@ndsu.edu, and Seth C. Rasmussen, seth.rasmussen@ndsu.edu. Department of Chemistry and Molecular Biology, North Dakota State University, Fargo, ND 58105
Conjugated organic polymers continue to attract attention due to their commercial application including organic light emitting diodes, photovoltaic devices and field effect transistors. An advantage of using conjugated polymers is the ability to tune the polymer properties at the molecular level, including the polymers band gap. One approach to lowering the band gap is via annulation of aromatic rings to the polymer repeat units. This has been successfully shown through several polythiophene derivatives including poly(isothianapthene), poly(thieno[3,4-b]thiophene)s, and poly(thieno[3,4-b]pyrazine)s. Recently, investigation of extended fused-ring analogues of thieno[3,4-b]pyrazine has led to the discovery of the stable new fused-ring species acenaptho[1,2-b]thieno[3,4-e]pyrazine. Electropolymerization results in a stable new conjugated polymer with a bandgap around 0.5 eV. Synthetic details for the production of new extended fused-ring analogues of thieno[3,4-b]pyrazines, including acenaptho[1,2-b]thieno[3,4-e]pyrazine and its 3,4-disubstituted analogues, will be presented, along with their optical and electrochemical characterization. Supporting calculations and polymerization studies will also be discussed.