Molecular Shuttling of a Compact and Rigid H-Shaped [2]Rotaxane

摘要

Bistable [2]rotaxanes (molecular shuttles) are mechanically interlocked molecules (MIMs) that can be switched between different translational co-conformations in response to an external stimulus. Chemical, electrochemical, and photochemical inputs have been used to control the actions of these systems in solution and some very efficient and sophisticated examples are known, including those that occupy non-equilibrium states and function using a ratchet-type mechanism. Since most [2]rotaxane molecular shuttles are large, flexible molecules with multiple functional groups they operate with efficiency in solution where the interlocked components enjoy a high degree of structural and dynamic freedom. The size and flexibility of the molecular structure are rarely a problem, however, these attributes make them much less practical for highly condensed phases where the size, positional orientation and degree of aggregation of the MIM components are crucial to optimum switching efficiency. To incorporate efficient molecular switches into materials and devices with a high density of functional components, a compact structure with a rigid axle and short, linear track for translational motion would be most desirable.