Regioselective Functionalization of Nitrogen-Embedded Perylene Diimides for High-Performance Organic Electron-Transporting Materials

Functionalization of pi-conjugated compounds is an important strategy to tune electronic states and aggregated structures, leading to development of high-performance organic optoelectronic materials ranging from small molecules to conjugated polymers. Regioselective functionalization can be particularly striking for highly ordered aggregated structures, which is crucial for excellent carrier-transport properties. Herein, we report the regioselective dibromination of the bay position of a nitrogen-embedded perylene diimide analogue, benzo[de]-isoquinolino[1,8-gh]quinolinetetracarboxylic diimide (BQQD1), via palladium(II)-catalyzed oxidation directed by the embedded nitrogen, followed by dicyanation. The dicyanated compound showed a remarkably deep lowest-unoccupied molecular orbital and redox stability, which were useful for air-stable n-channel transistors exhibiting the electron mobility of 1 cm(2) V-1 s(-1). In addition, the embedded nitrogen atoms play a significant role in making the bay functionalized pi-core planar, which promises advantages for future development of not only small-molecular compounds but also conjugated polymers as high-performance organic electron-transporting materials.