What is the coordination number of copper(ii) in metallosupramolecular chemistry?

Analysis of structural and solution data shows a specific stabilisation of copper(II) in ternary complexes containing one 2,2′:6′,2″-terpyridine and one 2,2′-bipyridine ligand. This is not a general phenomenon relating to five-coordinate copper(II), but rather a specific consequence of the two ligand donor sets. The consequences of this observation for metallosupramolecular chemistry are discussed.