Graphene and its derivatives have been widely used because of their remarkable electronic, mechanical, and thermal properties. Rotaxanes are a type of mechanically interlocked molecules that consist of one or more macrocyclic rings threaded onto a dumbbell-like component and trapped by bulky stoppers. They have promising potential for applications in the fabrication of molecular switches, molecular logic gates, and molecular wires. Combining the properties of both may open a new research avenue.

Yanli Zhao and colleagues, Nanyang Technological University, Singapore, report the construction of a photoswitchable α-cyclodextrin (α-CD)-based [2]rotaxane array on graphene oxide (GO).

They have used click chemistry to introduce light-responsive α-CD-based [2]rotaxanes onto the surface of GO.
The α-CD ring can be reversibly switched between two stations by alternating irradiation with UV and visible light. It can move back and forth along the dumbbell component driven by trans–cis isomerization of the azobenzene unit.

This provides a light-responsive platform for the potential fabrication of information storage and memory devices.

• A Photoswitchable [2]Rotaxane Array on Graphene Oxide,
  Hong Yan, Liangliang Zhu, Xing Li, Anna Kwok, Xiaoyong Pan, Yanli Zhao,
  Asian J. Org. Chem. 2012.
  DOI: 10.1002/ajoc.201200102