| Abstract: | Oxidative fusion reactions of ortho ‐phenylene‐bridged cyclic hexapyrroles and hexathiophenes furnished novel closed helicenes in a selective manner. X‐Ray diffraction analysis unambiguously revealed the structures to be a closed pentaaza9]helicene, the longest azahelicene reported so far, and an unexpected double‐helical structure of hexathia9]/5]helicene, whose formation was assumed to result from multiple oxidative fusion along with a 1,2‐aryl shift. The pentaaza9]helicene exhibited well‐defined emission with high fluorescence quantum yield (Φ F=0.31) among the known 9]helicenes. Chiral resolution of the racemic pentaaza9]helicene and hexathia9]/5]helicene were achieved by chiral‐phase HPLC and the enantiomers were characterized by circular dichroism spectra and DFT calculations. |
