Considerable efforts have been devoted to mesoscopic devices due to the rapid advancement in the chemical synthesis of molecular junctions and their potential use as devices in molecular electronics.[1-5]One of the most important challenges in molecularscale electronics is the search for well-defined molecule-electrode bonding.To date,the most widely used molecular wire junctions have been formed by the chemisorption of thiols on Au,a simple yet versatile approach for preparing surfaces with tunable physical or chemical properties.[6,7] However,thiol linkage also has limitations,as it is considered to be only structural and lacks any subsequent useful "chemistry";[8] thiols can be displaced from the metal surface[9] or may be incompatible with other functional groups associated with the ligand.