Organometallic cavitands: Cation–π interactions and anion binding via π-metallation

While metal coordination through functional groups on cavitands has been known for many years, the interaction of a range of metals with the π-electrons of the arene rings has triggered great interest in the last 15 years. This article reviews the occurrence of this type of bonding and its effect on the shape and properties of calixarenes and related macrocycles. The review covers both cation–π interactions involving labile metals and the synthesis and inclusion chemistry of inert transitional metal organometallic cavitands.