Observation of Structural and Conductance Transition of Rotaxane Molecules at a Submolecular Scale

Rotaxane molecules have attracted considerable interest because of their good performance in both molecular electronic devices and nanoscale data‐storage media. Low‐temperature scanning tunneling microscopy is used to investigate the structure and conductance of single H2 rotaxane molecules on a buffer‐layered Au(111) substrate at 77 K. It is demonstrated that the conductance switching in rotaxane‐based, solid‐state devices is an inherent property of the rotaxane molecules. These results provide evidence that the conductance switching might arise from the movement of the cyclobis(paraquat‐p‐phenylene) ring along the rod section of the dumbbell‐shaped backbone of the rotaxane molecule. Rotaxane molecules have attracted considerable interest because of their performance in molecular electronic devices and nanoscale data‐storage media. Low‐temperature scanning tunneling microscopy is used to investigate the structure and conductance of single H2 rotaxane molecules (see figure) on a buffered Au(111) substrate at 77 K.