Gating the conductance of a single-molecule junction with ion-π interaction.

The single molecular conductance of viologen derivative VSMe and supramolecular compound VSMe-PA[5] (pillararene[5]) was investigated. The difference of their conductance demonstrated the gating effect of cation-π interaction. Theoretical calculations showed that the higher conductance of VSMe-PA[5] is a result of the planar structure of the VSMe component and the narrowed HOMO-LUMO bandgap of VSMe-PA[5], which is due to the cation-π interaction between the VSMe and PA[5] components.