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

As a new member of the water‐soluble calixarene family, p‐sulfonatothiacalix4]arene possesses unique properties resulting from its inherent structural characteristics. In our recent research, we have investigated the self‐assembly of bowl‐like p‐sulfonatothiacalix4]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‐sulfonatothiacalix4]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‐sulfonatothiacalix4]arene can also splay its opposite aromatic rings apart to adjust its cone‐like conformations from C_4v to C_2v and even lower symmetries. All of these show that it is a good candidate for the research of inclusion phenomena. © 2009 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 9: 155–168; 2009: Published online in Wiley InterScience ( www.interscience.wiley.com ) DOI 10.1002/tcr.200800033