Stepwise reduction of a corannulene-based helical molecular nanographene with Na metal.

The chemical reduction of a corannulene-based molecular nanographene, C 76 H 64 (1), with Na metal in the presence of 18-crown-6 afforded the doubly-reduced state of 1. This reduction provokes a distortion of the helicene core and has a significant impact on the aromaticity of the system.