Metallomacrocycles: Supramolecular chemistry with hard and soft metal cations in action

It has been shown in this review that complexes with both hard and soft metal cations can be used for bimetallic catalysis and activation, the formation of supramolecular aggregates, allosteric effects, and changing the redox properties of the transition metal cation. The molecular structures used to achieve these goals reflect the variety of approaches used. Although in some cases potential applications have been suggested, until now they have not evolved into prototypes. The authors feel that supramolecular structures with several different metal cations at well-defined places will be the major challenge for the next decade.