Ruthenium-based light-driven molecular machine prototypes: synthesis and properties.

In the past years, many dynamic systems often referred to as "molecular machines" have been elaborated. They are generally set in motion by external stimuli like chemical, electrochemical, or photochemical reactions. Light irradiation seems particularly promising since the input signal can be switched on and off fast and readily on a very small place. In this tutorial review, we will highlight recent advances in the design and synthesis of various ruthenium(II) complexed rotaxanes, catenanes, scorpionates or macrocycles. In these compounds, one part of the system is set in motion by photochemically expelling a given chelate. We will discuss the behaviour of various topologically non-trivial systems like catenanes and rotaxanes as well as acyclic and macrocyclic models.