Molecular Junctions Bridged by Metal Ion Complexes
Article appeared in: Chemistry - A European Journal, 17, (2011) 13166; DOI: 10.1002/chem.201102915
Dong Xiang, Yi Zhang, Feliks Pyatkov, Florian Schröper, Andreas Offenhäusser and Dirk Mayer
Published: November 2011
Metal ions play a crucial role in biological charge transport, however only little is known about electron transport via metal ions entrapped between ligand molecules on the single molecule level. For metal complexes, it can be envisioned that the charge transport depends on nature of ligands and on the kind of metal ion entrapped between the ligands. In this manuscript, metal-molecule-ion-molecule-metal junctions were realized by mechanically controllable break junction (MCBJ) experiments. We investigated the influence of different metal ion on conductivity, for the first time, while leaving the ligands mainly unchanged. We demonstrate that the conductance of the junctions depends strongly on the kind of integrated metal ion in the order: Ca2+ > Zn2+ > Ni2+. The observed relation between type of metal ion and conductivity may reveal a deeper insight into biological charge transport processes. Furthermore, it may pave the way for novel design strategies for molecule based devices. In this context, the metal ions may act as dopant that can tailor the conductivity of the molecule based functional unit.