From Binuclear Complexes to Molecular Necklaces: Incorporating Flexible Ligands into Rotaxanes.

The conversion of binuclear complexes into larger molecular necklaces can be achieved through rigidifying flexible ligands by threading them through a crown ether to form either an interpenetrated [2]pseudorotaxane or a permanently interlocked [2]rotaxane. The resulting complexes and assemblies are characterized by (1) H and DOSY NMR in solution and single-crystal X-ray diffraction in the solid-state.