1 research outputs found
Aromatic Saddles Containing Two Heptagons
Soluble derivatives of C<sub>70</sub>H<sub>26</sub> (<b>1a</b>,<b>b</b>) and C<sub>70</sub>H<sub>30</sub> (<b>2a</b>,<b>b</b>), two new saddle-shaped
polycyclic arenes containing
two heptagons, were successfully synthesized from saddle-shaped diketones
(<b>3a</b>,<b>b</b>), whose carbonyl groups are the key
in the reactions to extend the polycyclic π-framework. As found
from the crystal structures, the polycyclic backbone of <b>1b</b> has a deep saddle shape, while that of <b>2b</b> is even more
distorted because of the existence of two [4]-helicene moieties. On
the basis of crystal structures, local aromaticity and nonplanarity
of individual rings in the saddle-shaped π-backbone were analyzed,
and were found to follow Clar’s rule in general. It was found
that <b>1b</b> and <b>3b</b> behaved as p-type semiconductors
in solution-processed thin film transistors while the amorphous films
of <b>2b</b> appeared insulating