Cation-Templated Assembly of 6 and 6 Metalla-Links.

Facilitated by multiple stacking interactions between components, two kinds of metalla-links containing molecular Borromean rings (6 links) and head-to-tail cyclic [3]catenanes (6 links), as isomers, were constructed in high yield by introducing tri--methoxyl-dinuclear complexes [(CpM)(-OCH)][OTf] (M = Rh or Ir, Cp = -pentamethylcyclopentadienyl, OTf = triflate) as unusual cationic guests during coordination-driven assembly. The topology of these intricate structures was controlled by strategically selecting two dipyridyl ligands that differ in their coordination orientations, as evidenced by X-ray crystallography and electrospray ionization-time-of-flight/mass spectrometry analysis. The behavior of the abovementioned metalla-links in solution was monitored and further studied by the detailed NMR techniques.