The Fascination of Large Rings: Cyclic Metal Complexes of Polydendate Ligands

Coupling reactions in the coordination spheres of metal ions are the most important steps in the synthesis of very large inorganic ring complexes. The majority of such compounds can be categorized as coordination complexes. In addition, there are also examples from organometallic chemistry, such as the ferrocene scoop wheel presented by F. H. Köhler et al. in this issue. Before a planned synthesis of these compounds can be achieved, principles that govern the formation of these unusually large macrocycles must be determined. Insights into these principles are given herein.