Molecular hysteresis

Examples of individual molecules showing hysteresis even though they have simple (unsegmented) structure are described. The mechanism of the molecular hysteresis has been studied in detail for (1,5-dithiacyclooctane 1-oxide)bis(pentaammineruthenium(II)). Thermodynamics and kinetic parameters for the complex and the interconversion rate between the members of the bistable system have been obtained, and show that the memory life of the system is about 5 seconds at room temperature. Features of the molecular hysteresis are discussed.