Bowl-Shaped Polyarenes as Concave–Convex Shape Complementary Hosts for C₆₀- and C₇₀-Fullerenes

The X-ray crystal structures of two new co-crystals comprised of C60 and C70 fullerenes and a dibenzo­[a,g]­corannulene bowl, namely, (C28H14)·(C60) and (C28H14)2·(C70), are reported. A clear difference is observed between C60 to C70, with the latter fullerene molecule being fully ordered and lacking the orientational disorder found in many fullerene co-crystallized products. In the solid state structure of (C28H14)2·(C70), two bowl-shaped C28H14 molecules encapsulate the C70-cage and exhibit a preferential spatial alignment parallel to the longer axis of the fullerene. In this case, dibenzo­[a,g]­corannulene utilizes only its concave surface for binding, showing a staggered conformation of carbon atoms over the convex surface of C70-fullerene. In the solid-state structure of (C28H14)·(C60), both convex–convex and convex–concave π···π interactions are observed between the curved surfaces of C28H14 and C60. The C60-core is disordered showing no preferential orientation. In both cases, the formation of π···π adducts was not observed in solutions of chlorinated benzene solvents from which the co-crystals were grown.