An 11 nm molecular wire that switches electrochemically between an insulating and a fully conjugated conducting state

Molecular wires consisting of oligothiophenes and oligothiophenylethynes, ranging in length from 2 to 11 nm, are synthesized and examined by spectroscopy and electrochemistry. UV spectroscopy shows that the longest wires are not fully conjugated, but twisted. However, cyclic voltammetry indicates that their monocations are now flattened and conjugated over the entire length range. In appropriate systems, the wires will link to two electrodes across a nanoscale gap and conduct current.