Selective <i>Endo</i> and <i>Exo</i> Binding of Alkali Metals to Corannulene

Abstract

The ion size matters: the structures of corannulene monoanions crystallized with Cs(+) and Rb(+) ions in the presence of [18]crown-6 reveal the intrinsic binding preferences of alkali metals and allow evaluation of the bowl deformation caused by negative charge distribution and metal binding. The large cesium cation coordinates exclusively to the concave face of C(20) H(10)(-), whereas the smaller rubidium cation exhibits convex binding.