ABSTRACT
This chapter focuses on the controlled synthesis of regioregular, group 16 poly(3-alkylchalcogenophene)s, which are soluble and processable semiconducting polymers. It discusses key properties and some applications of the materials. The chapter provides an introduction to the controlled synthesis and properties of polyfurans, polyselenophenes, and polytellurophenes and more comprehensive review articles can be found elsewhere. The synthesis of polyhalogenated derivatives followed by dehalogenation can be adopted to afford 3-halochalcogenophenes. The synthesis of 3-alkylselenophenes, and 3-alkyltellurophenes by a ring-closing reaction has been developed, which offers improved yields. The regioregularity of conjugated polymers greatly impacts properties. Due to the asymmetry of 3-alkylchalcogenophenes, specific strategies need to be employed to achieve high regioregularity. Polymerization of chalcogenophenes can be classified into two categories: electrochemical/chemical oxidative and cross-coupling. Electrochemical oxidative polymerization was historically used to synthesize polychalcogenophenes. Cross-coupling polymerizations are based on reactions of various organometallic reagents and aryl halides to form new carbon-carbon bonds.
