The study of weak non-covalent interactions is crucial for the development of supramolecular chemistry. Since the emergency of supramolecular chemistry, the exploration on every new type of weak non-covalent interactions, such as hydrogen bonding, π-π interactions, hydrophobic effect, halogen bonding and cation-π interactions, has greatly promoted the development of (Supramolecular) Chemistry and related disciplines including Materials and Life Sciences. Seeking for new non-covalent interactions, as it were, provides us the opportunity for deeply understanding the material world and so as to advance Chemistry and related fields.
Anion-π interactions, as a new type of non-covalent interactions, have emerged since the beginning of this century. However, its existence was disputed in the supramolecular society due to lack of direct experimental evidence. To address this challenge, our research group has taken the unique electron-deficient macrocyclic hosts, tetraoxacalixarenetriazines, as a probe and detailedly investigated their interactions with various anions. The success of this system provides the first experimental evidence for sole anion-π interactions with neutral organic receptors, both in solid states and in solution. Further studies have revealed the generality, binding strength and structure of such interactions, and built the basis for their applications in supramolecular assembly and catalysis. With this regard, our current interests are devoted to further disclosing the nature of anion-π interactions, the design and synthesis of novel electron-deficient π systems, the anion-π interactions driven assembly and disassembly, and their applications in anion transportation and catalysis.