Novel clay-like and helical superstructures generated using arene-arene interactions

Two novel supramolecular arrays are reported, which rely upon the noncovalent linking of cationic 4,4′-pyridylpyridinium units by enclathrated benzene (PhH) molecules through aromatic π-π interactions. Dicationic clathrands, consisting of two 4,4′-pyridylpyridinium units connected via aryldimethylene spacers, are cocrystallized with PhH to generate clathrated supramolecular arrays. A p-xylyl-spaced dicationic clathrand crystallizes with PhH to produce a layered solid, in which π-stacked dication-PhH layers are separated by bands containing PF₆^- anions and PhH molecules to form a superstructure that is reminiscent of an organic clay. On the other hand, its p,′-bitolyl-spaced congener cocrystallizes with PhH to create a novel helical supramolecular array.