Single-molecular switch

Franco I, George CB, Solomon GC, Schatz GC, Ratner MA (2011) Mechanically activated molecular switch through single-molecule pulling. J Am Chem Soc 133(7) 2242-2249... 

Information technology has revolutionized daily life in the last decades and the continuously increasing amount of data to be stored and manipulated strongly stimulated the search for switching and memory elements as tiny as a single molecule. Molecular switches can be converted from one state to another by an external stimulus such as light, electricity or a chemical reaction. Like with their macroscopic counterparts, one is able to control numerous functions and properties of materials and devices. 

Key questions ahead of us concern new concepts for addressing individual molecular switches and the construction of more complex systems which incorporate several switchable functions. Advances in scanning - probe techniques and single molecule spectroscopy as well as supramolecular chemistry will play an important role in this endeavor. 

A further step towards the implementation of a molecular switch is to use manipulation techniques to reversibly modify the molecular conformation. The switching of a single leg in and out of the porphyrin plane is possible by lateral and vertical movement of the tip to push the leg down. By measuring the current passing through a single leg in real time during its... 

A combined computational and electrochemical investigation revealed that arylated TEEs may also have potential as electrochemically driven molecular switches [27]. The electrochemical studies showed that the first reduction potentials of mono- and bis(4-nitrophenyl)-substituted TEEs occur at similar values (around —1.35 to —1.38 V versus the ferrocene/ ferricinium couple, Fc/Fc+) on steps involving one and two electrons, respectively. Moreover, the first reduction potential of nitrophenyl-substituted TEEs is hardly affected by the presence of other aryl substituents, such as the DMA donor groups, attached to the TEE frame. These findings suggest that the nitrophenyl redox centers behave as independent redox centers. However, ab initio calculations on singly-reduced trans-13 (Figure 4)... 

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