Merging thiophene with boron: new building blocks for conjugated materials

This perspective highlights recent progress on the design, synthesis and applications of thienylboranes as building blocks for new functional materials. Well-controlled synthetic protocols, such as boron-tin and boron-silicon exchange reactions, hydroboration of alkynyl groups, and electrophilic borylations provide opportunities to access thiophene-boranes that are chemically robust and display desirable photophysical properties, redox characteristics, and solid-state assembly behavior. Diverse protocols for further functionalization allow for facile integration into larger conjugated structures and even polymeric systems. Moreover, the strong Lewis acid character that is characteristic of trivalent boranes facilitates intra- and intermolecular Lewis acid-base interactions that can further enrich the chemical and electronic properties of thiophene-borane materials. Recent advances with respect to applications in sensing, organic electronics, and the development of molecular switches are also discussed.