Intermolecular hydrogen bonding in calix[5]arene derived cavitands regulates the molecular recognition of fullerenes.

We present a readily available calix[5]arene derived cavitand receptor that is stabilized in the closed cone conformer through intermolecular hydrogen bonding with methanol molecules. The receptor features a highly spherical aromatic surface that binds C 60 and C 70 fullerenes effectively, and the binding event can be regulated allosterically by the addition of methanol.