Inclusion of p-sulfonatothiacalix[4]arene and its metal complexes.

As a new member of the water-soluble calixarene family, p-sulfonatothiacalix[4]arene possesses unique properties resulting from its inherent structural characteristics. In our recent research, we have investigated the self-assembly of bowl-like p-sulfonatothiacalix[4]arenes with or without transition-metal ions in the presence of suitable guests. We have obtained a series of compounds with different structural motifs, such as capsules, tetranuclear clusters, and molecular clefts. In addition, p-sulfonatothiacalix[4]arenes show good inclusion abilities and can capture different guests by utilizing their hydrophobic cavities through supramolecular interactions. Even when a cone-like conformation is fixed, the p-sulfonatothiacalix[4]arene can also splay its opposite aromatic rings apart to adjust its cone-like conformations from C4v to C2v and even lower symmetries. All of these show that it is a good candidate for the research of inclusion phenomena.