Electrostatically Driven CO−π Aromatic Interactions

A series
of N-aryl­imide molecular balances
were developed to study and measure carbonyl–aromatic (CO−π)
interactions. Carbonyl oxygens were observed to form repulsive interactions
with unsubstituted arenes and attractive interactions with electron-deficient
arenes with multiple electron-withdrawing groups. The repulsive and
attractive CO−π aromatic interactions were well-correlated
to electrostatic parameters, which allowed accurate predictions of
the interaction energies based on the electrostatic potentials of
the carbonyl and arene surfaces. Due to the pronounced electrostatic
polarization of the CO bond, the CO−π aromatic
interaction was stronger than the previously studied oxygen−π
and halogen−π aromatic interactions.