RESUMEN
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 (λem =684â 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 700â nm. Notably, compared to the reported small organic molecules, EP9H displays an outstanding |glum | value of 4.50×10-2 and BCPL as 304â M-1 cm-1 .
RESUMEN
A chiral W-shaped fully π-extended double [7]helicene (ED7H) has been synthesized and fully characterized. It displays fluorescence emission (λem = 636 nm) with a quantum yield (Φf) of 0.10. In comparison to its X-shaped and monomict π-extended [7]helicene analogues, enantiopure W-shaped ED7H exhibited superior chiral optical characteristics, including distinct circular dichroism signals from 400 to 650 nm, a good dissymmetric emission factor |glum| of 4 × 10-3, and a circularly polarized luminescence brightness value BCPL of 42 M-1 cm-1.