Direct arylation polycondensation of thienothiophenes with various dibromoarylenes

Abstract

CH direct arylation reactions of thieno[3,2-b]thiophenes (TT) with dibromo-substituted aromatic compounds afforded five different kinds of TT-based conjugated polymers, including donoracceptor and dye-containing polymers. Although various thiophene-based polymers have been synthesized previously via polycondensation using direct arylation reactions, our research demonstrates the first direct arylation polycondensation procedure using a TT monomer. The physical properties of the obtained polymers were evaluated by using UVvis absorption spectroscopy and cyclic voltammetry. The dye-containing polymer showed photovoltaic responses in a bulk heterojunction solar cells with a fullerene derivative. light-emitting diodes (OLED), and organic field-effect transistors (OFET). In this research, we focused on the use of thieno- [3,2-b]thiophenes (TT) as a monomer in direct arylation polycondensation because TT-based polymers have shown excellent performance in OPV and OFET.24,25 To our best knowledge, there has been no report of direct arylation polycondensation of TT. Direct arylation polycondensation of TT leads to preparation of high-performance polymer in a practical way. Herein, we report synthesis of five different kinds of TT-based polymers including donoracceptor and dye-containing conjugated polymers, via direct arylation polycondensation. The obtained polymers were evaluated in terms of their absorption, electrochemical, and photovoltaic properties.