Ball-, bowl-, and belt-shaped conjugated systems and their complexing abilities:: Exploration of the concave-convex π-π interaction

An overview is given of the supramolecular properties of the curved conjugated systems possessing a ball-shaped, bowl-shaped, or belt-shaped structure to explore the nature of the concave-convex π-π interaction. Under ball-shaped systems, emphasis is on complexes with small molecules, complexes with traditional hosts and designed host molecules. For ball-shaped systems, discussion covers stacking structure and host properties. With regards to belt-shaped systems, focus is on cyclacene and related compounds, open-cage fullerenes, cyclocarbon, cyclo-para-phenylene and the hybrid compounds and carbon nanorings. The complexing abilities of carbon nanorings are also discussed.