Topological selectivity in a supramolecular self-assembled host-guest network at the solid-liquid interface

An oligopyridine forms a well-ordered two-dimensional network at the graphite-liquid interface stabilized by weak hydrogen bonds. This network offers two types of geometrically different voids of similar size, oval and circular in shape, respectively. Hierarchical coadsorption of C-60 fullerene onto the oligopyridine monolayer leads to a host-guest network in which the fullerene molecules adsorb exclusively in the circularly shaped voids. This is attributed to the fit of the spherical molecules to the round void according to a geometric lock-and-key principle.