Palladium-templated subcomponent self-assembly of macrocycles, catenanes, and rotaxanes.

The reaction of 2,6-diformylpyridine with diverse amines and Pd(II) ions gave rise to a variety of metallosupramolecular species, in which the Pd(II) ion is observed to template a tridentate bis(imino)pyridine ligand. These species included a mononuclear complex as well as [2+2] and [3+3] macrocycles. The addition of pyridine-containing macrocyclic capping ligands allows for topological complexity to arise, thereby enabling the straightforward preparation of structures that include a [2]catenane, a [2]rotaxane, and a doubly threaded [3]rotaxane.