Conductance and geometry of pyridine-linked single-molecule junctions

M. Kamenetska, Su Ying Quek, A. C. Whalley, M. L. Steigerwald, H. J. Choi, Steven G. Louie, C. Nuckolls, M. S. Hybertsen, J. B. Neaton, L. Venkataraman

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175 Citations (Scopus)


We have measured the conductance and characterized molecule-electrode binding geometries of four pyridine-terminated molecules by elongating and then compressing gold point contacts in a solution of molecules. We have found that all pyridine-terminated molecules exhibit bistable conductance signatures, signifying that the nature of the pyridine-gold bond allows two distinct conductance states that are accessed as the gold-molecule-gold junction is elongated. We have identified the low-conductance state as corresponding to a molecule fully stretched out between the gold electrodes, where the distance between contacts correlates with the length of the molecule; the high-conductance state is due to a molecule bound at an angle. For all molecules, we have found that the distribution of junction elongations in the low-conductance state is the same, while in the high-conductance state, the most likely elongation length increases linearly with molecule length. The results of first-principles conductance calculations for the four molecules in the low-conductance geometry agree well with the experimental results and show that the dominant conducting channel in the conjugated pyridine-linked molecules is through the φ* orbital.

Original languageEnglish
Pages (from-to)6817-6821
Number of pages5
JournalJournal of the American Chemical Society
Issue number19
Publication statusPublished - 2010 May 19

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry


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