A π-Extended Pentadecabenzo[9]Helicene.

A novel chiral nanographene (i.e. EP9H) with a pentadecabenzo[9]helicene core fragment has been synthesized and fully characterized. Single-crystal X-ray diffraction unambiguously confirms the helical structure. The fluorescence emission of EP9H is located in the near infrared region (λ em =684 nm) with a medium quantum yield (0.10) for helicene derivatives. Cyclic voltammetry reveals its seven quasi-reversible redox states from -2 to +5. Furthermore, enantiopure EP9H displays distinct CD signals in a broad spectral range from 300 to 700 nm. Notably, compared to the reported small organic molecules, EP9H displays an outstanding |g lum | value of 4.50×10 -2 and B CPL as 304 M -1 cm -1 .