Bistable rotaxanes

In order to make the copper central core as easy as possible to rotate, we thought that the bulky stoppers should be located far away from the central complex. We thus prepared and studied a new bistable rotaxane, depicted in Fig. 14.10, whose stoppers are indeed very remote from the copper center.31 This new dynamic system can indeed be set in motion more rapidly than the previously described systems. 

Figure 17.7 A molecular valve based on redox switchable bistable rotaxane 84 1 77 (Adapted with permission from V. Balzani et al., ChemPhysChem 2008, 9, 202-220. Copyright Wiley-VCH Verlag GmbH Co. KGaA.)...

In the following sections, bistable rotaxanes will be discussed and classified based on the types of the energy inputs utilized to power their mechanical motions. Since many of these compounds have already made their way into the device world, the prospects for their further development in an applied sense will also be addressed. 

The earliest examples of mechanically bonded molecular switches were two-station rotaxanes and catenanes (a station is a recognition site for the macrocyclic component) that could be switched by these common stimuli. Our group reported a bistable rotaxane in 1994 that could be switched chemically and electrochemi-cally, utilizing a n-n donor/acceptor recognition motif (see Scheme 2 and explanation in corresponding caption) [107]. Many of the recognition motifs in MIMs that... 

Photo-driven molecular devices (light-powered bistable rotaxanes and catenanes) 07CSR77. 

A Slow Amphiphilic Bistable Rotaxane-based Device... 

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