ARE SINGLE MOLECULAR WIRES CONDUCTING

Molecular wire candidates inserted into ''nonconducting'' n-dodecaneth iol self-assembled monolayers on Au{111} were probed by scanning tunne ling microscopy (STM) and microwave frequency alternating current STM at high tunnel junction impedance (100 gigohms) to assess their electr ical properties. The inserted conjugated molecules, which were 4,4'-di (phenylene-ethynylene)benzenethiolate derivatives, formed single molec ular wires that extended from the Au{111} substrate to about 7 angstro ms above and had very high conductivity as compared with that of the a lkanethiolate.