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

Abstract

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.

Modifying the STM Tip for the ' Ultimate ' Imaging of the Si(111)-7×7 Surface and Metal-supported Molecules

“…9e, unlike FePc, whose central iron atom appears as a protrusion. The FePc and ZnPc molecules show identical orientations on Au(111), with the 'cross' directed in the [1][2][3][4][5][6][7][8][9][10] and directions of the Au(111) surface. The enhanced brightness at the center of FePc is ascribed to a large tunneling current that results from orbitalmediated tunneling through the half-filled orbital of the Fe ion.…”

“…In the past several decades, various organicinorganic interfaces have been extensively investigated with the aim to construct molecular-based functional nanodevices. [2][3][4][5][6][7][8][9] Besides the observations of geometric superstructures in different dimensions [6,8,[10][11][12][13][14][15][16][17][18][19][20][21] or the configuration of individual molecules in self-assemblies, [22][23][24][25] researchers are seeking to explore molecular electronic structures with higher resolution, allowing direct imaging of intrinsic molecular orbitals and further providing a deeper understanding of the moleculesubstrate interaction. The majority of STM studies of individual molecules have so far been limited to molecules on metal or semiconductor substrates, since STM relies on nonzero conductance within the tunneling junction to produce an image.…”

Bright functional rotaxanes

“…Gao et al 20,21 have reported reversible, erasable, and rewritable nanorecording on rotaxane R4 (Fig. 5) Langmuir-Blodgett (LB) thin films, using a scanning tunneling microscope (STM) by inducing conductance transitions of this supramolecule.…”

Electroactive Molecules and Supramolecules for Information Processing and Storage

“…Accordingly, CBPQT 4 þ can be switched back to the TTF site and thus the recording nanodots become erasable. 75 Charge transfer complexes have also been investigated as the most attractive candidate materials for high-density electrical data storage. 76,77 For instance, silver-tetracyanoquinodimethane (Ag-TCNQ) and copper-tetracyanoquinodimethane (Cu-TCNQ) have been studied for data recording since they exhibit electrical bistability.…”