This tutorial review presents our strategy to control the rotation in a molecular rotary motor, and the family of star-shaped ruthenium complexes designed to perform such a task. The molecules have a piano-stool structure with a "stator" meant to be grafted on a surface, and a "rotor" bearing redox-active groups, so that addressing the molecule with nano-electrodes would trigger rotation.

A dicationic tweezer incorporating two acridinium moieties linked by a 2,6-diphenylpyridine spacer was shown to self-assemble in an entwined dimer both in acetonitrile and water. The reaction was studied according to solvent polarity, temperature and concentration conditions. The entwined structure was confirmed in the solid state via single-crystal X-ray diffraction.