Rotaxanes electrochemically controlled switching

Figure 13.25 Stmcture formula of rotaxane 284+ and its electrochemically controlled switching process.

Electrochemically Controlled Switching of TTF/DNP-based [2]Rotaxanes 8.4.2.1 Solution-phase Switching... 

Another synthetic strategy is based on self-assembly driven by molecular recognition between complementary 7t-donors and 7T-acceptors. Examples include the synthesis of catenanes and rotaxanes that can act as controllable molecular shuttles (6,236). The 7t-donors in the shuttles are located in the dumb-bell shaped component of the rotaxane and the 7T-acceptors in the macrocydic component, or vice versa. The shuttles may be switched by chemical, electrochemical, or photochemical means. 

A Redox and Chemically Controllable Bistable Neutral [2]Rotaxane 8.4.3.1 Electrochemical Switching... 

Like rotaxanes, catenanes are mechanically interlocked molecules. However, instead of interlocking one ring shaped macrocycle and a dumbbell shape, catenanes consist of interlocked macrocycles. The number of macrocycles contained in a catenane is indicated by the numeral that precedes it. Catenanes have bistable and multistable forms and a switchable, bistable [2]catenane is commonly exploited in nanotechnology and molecular electronics because its behavior can be controlled by electrochemical processes [89]. Collier et al. was the first to demonstrate the electroactivity of interlocked catenanes [90]. The authors affixed phospholipid counterions to a monolayer of [2]catenanes and then sandwiched this system between two electrodes. This work resulted in a molecular switching device that opened at a positive potential of 2 V and closed at a negative potential of 2 V. 

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