L. A. Bumm, J. J. Arnold, M. T Cygan, T. D. Dunbar, T. P. Burgin, L. Jones II, D. L. Allara,* J. M. Tour,* and P. S. Weiss*
Science 271, 1705 (1996).
Molecular wire candidates inserted into nonconducting" n-dodecanethiol self-assembled monolayers on Au{111} have been probed by scanning tunneling microscopy (STM) and microwave frequency alternating current STM (ACSTM) at high tunnel junction impedance (100 GOhms) to assess their electrical properties. The inserted conjugated molecules, 4,4-di(phenylene-ethynylene)benzenethiolate derivatives, form single molecular wires (MWs) which extend from the Au{111} substrate to ca. 7Å above and have very high conductivity compared to the alkanethiolate.