Comparable Inclusion and Aggregation Structures of p-Sulfonatothiacalix[4]arene and p-Sulfonatocalix[4]arene upon Complexation with Quinoline Guests

Four supramolecular complexes of p-sulfonatocalix[4]arene and p-sulfonatothiacalix[4]arene with 8-hydroxyquinolinium (HQ⁺) and 8-aminoquinolinium (AQ⁺) guests were prepared, and their structures were determined by single-crystal X-ray diffraction as [HQ⁺]_3.5[p-sulfonatocalix[4]arene⁴⁻ + 0.5H⁺]·13.5H₂O (1), [HQ⁺]₄[p-sulfonatothiacalix[4]arene⁴⁻]·6.75H₂O (2), [HQ⁺]_2.5[p-sulfonatothiacalix[4]arene⁴⁻ + 1.5H⁺]·7.75H₂O (3), and [AQ⁺]_1.25[p-sulfonatocalix[4]arene⁴⁻ + 2.75H⁺]·9H₂O (4), respectively. The results obtained show that p-sulfonatothiacalix[4]arene can offer different inclusion structures with a HQ⁺ guest from p-sulfonatocalix[4]arene, and the formation of a molecular capsule based on p-sulfonatothiacalix[4]arene and HQ⁺ is pH-dependent. Furthermore, the aggregation structures of complexes 1−4 are comparatively discussed from the viewpoint of the manner of aggregation and driving forces.