A Monkey-Saddle-Shaped Nanographene Embedding a Dicyclohepta[cd,fg]-as-Indacene Core and Two Additional Heptagons, and Its Paddle-Wheel Co-Assembly With Fullerenes.

We present a novel nanographene 1 that embeds a dicyclohepta[cd,fg]-as-indacene (DCH-as-I) motif and two additional heptagons. This defective π-skeleton was efficiently synthesized from the oligophenylene precursors via the Scholl reaction, affording four heptagons in one shot. The integration of DCH-as-I and heptagons endows 1 with excellent solubility, superior fluorescence emission, multiple reversible redox processes, and exceptional supramolecular behavior. X-ray crystallographic analysis shows that 1 adopts a chiral monkey-saddle-shaped conformation and exists as a pair of enantiomers in the crystal lattice. The saddles of 1 stack through π-π overlap into slipped π-dimers, which further assemble into linear arrays with ellipsoidal cavities that encapsulate chloroform molecules, forming clathrate-like structures. The supramolecular co-assembly of saddle 1 with C60 was confirmed both in solution and crystal states. Single-crystal structures unequivocally revealed an unprecedented 4:4 complex (C60)4⊂(1)4, in which four saddles of identical configuration and four C60 spheres are alternately arranged into a chiral paddle-wheel structure. Two such complexes of opposite chirality further dimerize in a staggered fashion to form an aesthetically-striking octameric nanocubular supramolecular architecture. This study offers profound insights into the joint influence of DCH-as-I and heptagonal defects on the topology, electronic structure, photophysical properties, and supramolecular assembly behavior of nanographenes.