Giant Cavity Macrocycle: Synthesis, Structure, and Its Complexation with Pagoda[5]arene.

A novel stretched hexagon structure naphthalene diimides-extended-pillar[6]arene with a giant cavity size of 18.769 Å in width and 17.109 Å in height is reported. exhibits highly selective binding of pagoda[5]arene compared to pillar[5]arene and prism[5]arene. Size matching and charge transfer interactions play a key role in the formation of the ring-in-ring stable complex.