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.

Colour coding the co-conformations of a [2]rotaxane flip-switch.

Fine-tuning the charge transfer chromophores in a series of [2]rotaxane flip-switches yields a unique optical signal (purple colour) for one of the interactions allowing for facile determination of the position of the flip-switch equilibrium.

Eliminating the need for independent counterions in the construction of metal-organic rotaxane frameworks (MORFs).

The combination of a disulfonated-dibenzo-24crown-8 ether wheel and a dicationic 1,2-bis(pyridinium)ethane axle yields a neutral [2]pseudorotaxane which in combination with neutral metallic units such as a Cu(II)benzoate paddlewheel or Cu(I)Br unit yields one-dimensional coordination polymers (linear and bent) which are the first examples of charge neutral, metal-organic rotaxane frameworks.