Journal of the American Chemical Society, Vol.133, No.9, 3014-3022, 2011
Nature of Electron Transport by Pyridine-Based Tripodal Anchors: Potential for Robust and Conductive Single-Molecule Junctions with Gold Electrodes
We have designed and synthesized a pyridine-based tripodal anchor unit to construct a single-molecule junction with a gold electrode. The advantage of tripodal anchoring to a gold surface was unambiguously demonstrated by cyclic voltanunetry measurements. X-ray photoelectron spectroscopy measurements indicated that the A orbital of pyridine contributes to the physical adsorption of the tripodal anchor unit to the gold surface, The conductance of a single-molecule junction that consists of the tripodal anchor and diphenyl acetylene was measured by modified scanning tunneling microscope techniques and successfully determined to be 5 +/- 1 x 10(-4) G(0.) Finally, by analyzing the transport mechanism based on ab initio calculations, the participation of the pi orbital of the anchor moieties was predicted. The tripodal structure is expected to form a robust junction, and pyridine is predicted to achieve pi-channel electric transport.