Oxidation of a Dihydrophenazine Molecular Wire Attenuates Molecular Conductance

The concept of aromaticity is one of the most fundamental principles for understanding the properties and reactivities of organic molecules. However, in molecular electronics research, it has been shown that aromaticity is not necessarily advantageous for electron transmission across electrode-molecule-electrode junctions. In this work, we introduce formally antiaromatic, yet planar <i>N</i>,<i>N</i>'-disubstituted dihydrophenazines as a compelling building block for exploring molecular conductance properties beyond the scope of classical aromatic molecules and compare anchor group-modified dihydrophenazines and structurally closely related anthracenes. We find that molecular conductance increases by 1.5 orders of magnitude from aromatic anthracenes to their phenazine congeners, where the central ring attains partially antiaromatic character. Oxidation of the dihydrophenazine core results accordingly in conductance attenuation.