Oligoyne Single Molecule Wires

Abstract

We report the electrical conductance at the single molecule level of the oligoyne molecular wires Py-(CtC)n-Py (n ) 1, 2 and 4; Py ) 4-pyridyl) using STM-molecular break junction techniques in Au|molecule|Au configurations. All three conduction groups in the oligoyne series show a remarkably low value of (0.06 ( 0.03) Å-1, that is, the conductance is almost independent of molecular length. 4,4′-Bipyridyl studied under the same conditions does not follow this exponential decay series. Theoretical calculations using a combination of density functional theory and nonequilibrium Green’s function formalism support the experimental results. We conclude that oligoynes and polyynes are a very promising class of molecular wires for integration into electronic circuits