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A stable, ‘low impedance’ metal – molecule interface is highly desirable for the realization of molecular electronic devices. An alternative to the common thiol anchor group is offered by dithiocarbamates, and we show that they provide an improved contact to the metal due to the presence of delocalized electronic adsorbate states close to the Fermi level of gold. By photoelectron spectroscopy, a significantly increased density of states at the interface is observed and electronic structure calculations show that this can be attributed to resonant states on the dithiocarbamate anchor group, hybridized with metal d states. A low charge injection barrier between surface and molecular backbone is thus created. Charge transport measurements with interlinked nanoparticle networks show a one order of magnitude difference in the conductivity of films interlinked with thiol and dithiocarbamate derived compounds. Furthermore, thermal desorption experiments show an increased desorption stability of dithiocarbamates on gold. These results suggest that molecules coupled to metals via the dithiocarbamate group could significantly improve the interface between organic molecules and metal electrodes. |