Brightening Up Circularly Polarized Luminescence of [6]Helicenes by Fusion with BN-Heterocycles

We here disclose synthesis and properties of a series of BN-heterocycle-fused [6]helicenes. The fusion of the BN-heterocycle is helpful to extend π-conjugation and increase absorptivity and fluorescence efficiency of the first excited state. Especially, the double [6]helicene BiBN-BiHC shows outstanding circularly polarized luminescence performance with BCPL up to 49.0 M–1 cm–1, owing to its very high ΦF (0.87), large ε (5.47 × 104 M–1 cm–1), and fairly good |glum| (2.06 × 10–3).