A Molecular Shuttle with Fluorescence Output

A Molecular Shuttle with Fluorescence Output

Author: Richard Threlfall

Mechanically interlocked molecules (MIMs) have attracted chemists’ attention in the past few decades due to their applications in multicomponent molecular level devices and machines.

As one kind of MIM, bistable [2]rotaxanes play an important role in the design of molecular devices because of their adjustable physical and chemical properties. In this type of rotaxane, a macrocycle with two distinct, well-separated recognition sites on the thread component can be changed in response to external stimuli. Symmetrical functional [n]rotaxanes with repeating bistable [2]rotaxane arms have attracted much attention because of their charming structures, tunable properties, and synthetic challenge.

Da-Hui Qu and colleagues, East China University of Science and Technology, Shanghai, designed and constructed a bistable bis-branched [3]rotaxane with a perylene bisimide (PBI) chromophore core and two mechanically interlocked [2]rotaxane arms including a diferrocene-functionalized dibenzo-24-crown-8 ring (pictured).

 

 

The shuttling motion of the macrocycles along the thread component is accompanied by visual fluorescent change due to distance-dependent photoinduced electron transfer from the ferrocene units to the PBI fluorophore. This kind of rotaxane has potential value for constructing more sophisticated MIMs with controllable functions.


 

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