Cation-Templated Assembly of 6 1 3 and 6 2 3 Metalla-Links.

Facilitated by multiple stacking interactions between components, two kinds of metalla-links containing molecular Borromean rings (6 2 3 links) and head-to-tail cyclic [3]catenanes (6 1 3 links), as isomers, were constructed in high yield by introducing tri- μ -methoxyl-dinuclear complexes [(Cp*M) 2 ( μ -OCH 3 ) 3 ][OTf] (M = Rh III or Ir III , Cp* = η 5 -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.