Host-guest chemistry with bi- and tetra-nuclear macrocyclic metallasupramolecules.

Among the reported two-dimension macrocycles, bi- and tetra-nuclear macrocyclic metallasupramolecules are designed to have novel specific cavities with different shapes and dimensions, and demonstrate good selectivity and binding for planar aromatic guests and small organic molecules. This feature article focus on the progress in the development of host-guest behavior of bi- and tetra-nuclear macrocyclic metallasupramolecules. Examples in which X-ray structural determination is essential for establishing the real composition and geometry of the host-guest systems are highlighted.