Effect of internal oxygen substituents on the properties of bowl-shaped aromatic hydrocarbons

Internally substituted π-systems have remained somewhat underexplored in contrast to their peripherally functionalized counterparts. In this study, we compare a bowl-shaped aromatic hydrocarbon with internal methoxy groups to related derivatives with hydrogen, methyl, and anisyl groups, evaluating their electron-accepting properties, electronic absorption spectra, and fullerene-binding behavior. The methoxy-substituted derivative exhibits enhanced electron-accepting properties and positively shifted electrostatic potential mapping on its concave surface due to the inductive effect of the oxygen atoms. The σ* orbitals of the internal C–O bonds participate in π-conjugation to change the absorption properties of the bowl-shaped π-skeleton. As hydrocarbons internally substituted with oxygen are key fragments of graphene oxide, these results can be expected to aid the understanding of the structure–property relationships in graphene oxide. Furthermore, internal substitution with oxygen atoms decreases the efficiency of fullerene-binding, thus affording fundamental insights into the design of advanced fullerene-receptors.