Molecular hysteresis by linkage isomerizations induced by electrochemical processes

The redox behavior of [Ru(NH3)(5)(sulfoxide)](2+/3+) has been characterized . Kinetic parameters and mechanisms of linkage isomerizations for Ru2+ O -- > S and Ru3+ S --> O induced by electrochemical processes are reviewed. The properties of molecules specifically designed to exhibit a hysteresis loop on being addressed electrochemically are described. These molecules compri se a combination of two Ru3+/Ru2+ couples, one with the metal attached to a n electrochemically reversible group and the other with the metal attached to the sulfoxide by a bridging ligand. Their redox and kinetic behaviors ar e presented and their memory lives are determined as the rates of the conve rsions between two isomeric intermediate states. Reading out the memory by intervalence bands is also discussed. Some considerations are also presente d for linkage isomerizations and molecular hysteresis.