Rotaxanes Ruthenium complexes

A special issue devoted to molecular machines appeared in Accounts of Chemical Research in 2001. It reflects the current interest for this field in which ruthenium complexes act as important tools. Molecular machines are characterized by a mobile part and a stationary part. Photochemical and electrochemical inputs can make a machine work, offering the advantage of being switched on and off easily and rapidly. Mechanically interlocked molecules, such as rotaxanes and catenanes, are suitable candidates. Crown ethers, cyclophanes, and calixarenes are representative families of the cyclic... 

Tire second half of the book concerns measurements and particular molecular structures. After a general overview, this section concentrates on specifics, ranging from complex molecules like catanenes and rotaxanes through ruthenium complexes and organometallics. More materials-oriented contributions on carbon nanotubes. 

It is, thus, important that the ruthenium(II) complexes that are to be used as building blocks of the future machines contain sterically hindering chelates so as to force the coordination sphere of the metal to be distorted from the perfect octahedral geometry. We will discuss the photochemical reactivity of rotaxanes and catenanes of this family as well as non-interlocking systems like scorpionates since the lability of bulky monodentate ligands could also lead to useful photosubstitution reactions. 

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