Coordination properties of polyamine-macrocycles containing terpyridine units

The insertion of 2,2′:6′,2″-terpyridine groups into macrocyclic polyamine structures gives rise to a considerable enhancement of molecular rigidity which affects their coordination properties. This review concerns some examples of both very rigid, shape-persistent Schiff-base macrocycles and less rigid polyamine-macrocycles in which the rigidity of terpyridine is associated with the flexibility of aliphatic polyamine chains. Structural, thermodynamic, electrochemical, and spectroscopic properties of transition metal complexes with these ligands are presented and correlated with the ligand structures. The ability of some complexes to bind and activate substrate molecules, in particular CO2 uptake and conversion into carbonate/carbamate, and ATPase mimicking, is also described. The review includes an introductive overview of the relevant terpyridine properties.