Charge transport in nanoscale aromatic and antiaromatic systems

Abstract

Molecules such as benzene, that have six pi electrons cyclically delocalized, have the special stability that chemists call aromaticity. When electricity passes through a molecular wire containing a benzene ring a quinone-like structure is induced, and there is some loss of aromaticity. The conductance of such systems correlates with the magnitude of this effect. A molecule such as cyclobutadiene with only four cyclically delocalized pi electrons has special instability, called antiaromaticity. Evidence that such antiaromatic systems could convey high conductance in appropriate systems is derived from electrochemical studies, which also detect geometric changes in some thiophene-derived nanolength wires.