Synthesis and Characterization of Hexapole [7]Helicene, A Circularly Twisted Chiral Nanographene

We report the synthesis and characterization
of two hexapole [7]­helicenes
(H7Hs). Single crystal X-ray diffraction unambiguously confirms the
molecular structure. H7H absorbs light, with distinct Cotton effect,
from ultraviolet to the near-infrared (λmax = 618
nm). Cyclic voltammetry reveals nine reversible redox states, consecutively
from −2 to +6. These chiroptical and electronic properties
of H7H are inaccessible from helicene’s small homologues.