Self-Assembly of Charged Supramolecular Sandwiches Formed by Corannulene Tetraanions and Lithium Cations

The reduction of corannulene (C20H10) with excess lithium metal in a strong chelating O-donor solvent,
diglyme, leads to the formation of the highly reduced C20H104– anion. However, in contrast to
the formation of the sandwich-type supramolecular aggregate [Li5(C20H104–)2]3– observed in THF, corannulene tetraanions and
lithium counterions in diglyme form only contact ion pairs according
to 7Li NMR spectroscopy. Furthermore, the slow dissociation
of the premade sandwich [Li5(C20H104–)2]3– in neat diglyme
has been demonstrated by multinuclear NMR spectroscopy. In contrast,
the [Li5(C20H104–)2]3– sandwich can be crystallized from
the THF/diglyme mixture as the new crystalline product [Li­(THF)2(diglyme)]+­[Li2(THF)­(diglyme)//Li5(C20H104–)2]−, showing a complex 1D hybrid architecture according
to the single-crystal X-ray diffraction study.