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 pentaazahelicene, the longest azahelicene reported so far, and an unexpected double-helical structure of hexathia/helicene, whose formation was assumed to result from multiple oxidative fusion along with a 1,2-aryl shift. The pentaazahelicene exhibited well-defined emission with high fluorescence quantum yield (ΦF=0.31) among the known helicenes. Chiral resolution of the racemic pentaazahelicene and hexathia/helicene were achieved by chiral-phase HPLC and the enantiomers were characterized by circular dichroism spectra and DFT calculations.
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