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Non-chemisorbed gold–sulfur binding prevails in self-assembled monolayers


Gold–thiol contacts are ubiquitous across the physical and biological sciences in connecting organic molecules to surfaces. When thiols bind to gold in self-assembled monolayers (SAMs) the fate of the hydrogen remains a subject of profound debate—with implications for our understanding of their physical properties, spectroscopic features and formation mechanism(s). Exploiting measurements of the transmission through a molecular junction, which is highly sensitive to the nature of the molecule–electrode contact, we demonstrate here that the nature of the gold–sulfur bond in SAMs can be probed via single-molecule conductance measurements. Critically, we find that SAM measurements of dithiol-terminated molecular junctions yield a significantly lower conductance than solution measurements of the same molecule. Through numerous control experiments, conductance noise analysis and transport calculations based on density functional theory, we show that the gold–sulfur bond in SAMs prepared from the solution deposition of dithiols does not have chemisorbed character, which strongly suggests that under these widely used preparation conditions the hydrogen is retained.

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Fig. 1: Conductance histograms for solution or SAM measurements of C12-based single-molecule junctions that comprise different sulfur terminal groups.
Fig. 2: Conductance histograms for terphenyl (Ph3)-based single-molecule junctions that comprise different sulfur terminal groups.
Fig. 3: Noise analysis for Ph3- and Cn-based single-molecule junctions.
Fig. 4: Calculated transmission and measured conductance for alkanes with terminal sulfur groups.

Code availability

The data that support the findings were acquired using a custom instrument controlled by custom software (Igor Pro, Wavemetrics). The software is available from the corresponding author upon reasonable request.

Data availability

The data that support the findings of this study not included in the Supplementary Information are available from the corresponding author upon reasonable request.


  1. 1.

    Nuzzo, R. G. & Allara, D. L. Adsorption of bifunctional organic disulfides on gold surfaces. J. Am. Chem. Soc. 105, 4481–4483 (1983).

    CAS  Article  Google Scholar 

  2. 2.

    Bain, C. D. & Whitesides, G. M. Molecular-level control over surface order in self-assembled monolayer films of thiols on gold. Science 240, 62–63 (1988).

    CAS  Article  Google Scholar 

  3. 3.

    Love, J. C., Estroff, L. A., Kriebel, J. K., Nuzzo, R. G. & Whitesides, G. M. Self-assembled monolayers of thiolates on metals as a form of nanotechnology. Chem. Rev. 105, 1103–1170 (2005).

    CAS  Article  Google Scholar 

  4. 4.

    Hakkinen, H. The gold–sulfur interface at the nanoscale. Nat. Chem. 4, 443–455 (2012).

    Article  Google Scholar 

  5. 5.

    Bain, C. D., Biebuyck, H. A. & Whitesides, G. M. Comparison of self-assembled monolayers on gold: coadsorption of thiols and disulfides. Langmuir 5, 723–727 (1989).

    CAS  Article  Google Scholar 

  6. 6.

    Cossaro, A. et al. X-ray diffraction and computation yield the structure of alkanethiols on gold(111). Science 321, 943–946 (2008).

    CAS  Article  Google Scholar 

  7. 7.

    Walczak, M. M., Alves, C. A., Lamp, B. D. & Porter, M. D. Electrochemical and X-ray photoelectron spectroscopic evidence for differences in the binding sites of alkanethiolate monolayers chemisorbed at gold. J. Electroanal. Chem. 396, 103–114 (1995).

    Article  Google Scholar 

  8. 8.

    Poirier, G. E. & Pylant, E. D. The self-assembly mechanism of alkanethiols on Au(111). Science 272, 1145–1148 (1996).

    CAS  Article  Google Scholar 

  9. 9.

    Nuzzo, R. G., Zegarski, B. R. & Dubois, L. H. Fundamental studies of the chemisorption of organosulfur compounds on gold(111). Implications for molecular self-assembly on gold surfaces. J. Am. Chem. Soc. 109, 733–740 (1987).

    CAS  Article  Google Scholar 

  10. 10.

    Vericat, C., Vela, M. E., Benitez, G., Carro, P. & Salvarezza, R. C. Self-assembled monolayers of thiols and dithiols on gold: new challenges for a well-known system. Chem. Soc. Rev. 39, 1805–1834 (2010).

    CAS  Article  Google Scholar 

  11. 11.

    Pensa, E. et al. The chemistry of the sulfur–gold interface: in search of a unified model. Acc. Chem. Res. 45, 1183–1192 (2012).

    CAS  Article  Google Scholar 

  12. 12.

    Reimers, J. R., Ford, M. J., Marcuccio, S. M., Ulstrup, J. & Hush, N. S. Competition of van der Waals and chemical forces on gold–sulfur surfaces and nanoparticles. Nat. Rev. Chem. 1, 0017 (2017).

    CAS  Article  Google Scholar 

  13. 13.

    Jadzinsky, P. D., Calero, G., Ackerson, C. J., Bushnell, D. A. & Kornberg, R. D. Structure of a thiol monolayer-protected gold nanoparticle at 1.1 Å resolution. Science 318, 430–433 (2007).

    CAS  Article  Google Scholar 

  14. 14.

    Xu, B. & Tao, N. J. Measurement of single-molecule resistance by repeated formation of molecular junctions. Science 301, 1221–1223 (2003).

    CAS  Article  Google Scholar 

  15. 15.

    Zhou, C., Muller, C., Burgin, T., Tour, J. & Reed, M. Conductance of a molecular junction. Science 278, 252–254 (1997).

    Article  Google Scholar 

  16. 16.

    Haiss, W. et al. Redox state dependence of single molecule conductivity. J. Am. Chem. Soc. 125, 15294–15295 (2003).

    CAS  Article  Google Scholar 

  17. 17.

    Li, C. et al. Charge transport in single Au | alkanedithiol | Au junctions: coordination geometries and conformational degrees of freedom. J. Am. Chem. Soc. 130, 318–326 (2008).

    CAS  Article  Google Scholar 

  18. 18.

    Inkpen, M. S. et al. New insights into single-molecule junctions using a robust, unsupervised approach to data collection and analysis. J. Am. Chem. Soc. 137, 9971–9981 (2015).

    CAS  Article  Google Scholar 

  19. 19.

    Haiss, W. et al. Anomalous length and voltage dependence of single molecule conductance. Phys. Chem. Chem. Phys. 11, 10831–10838 (2009).

    CAS  Article  Google Scholar 

  20. 20.

    Venkataraman, L., Klare, J. E., Nuckolls, C., Hybertsen, M. S. & Steigerwald, M. L. Dependence of single-molecule junction conductance on molecular conformation. Nature 442, 904–907 (2006).

    CAS  Article  Google Scholar 

  21. 21.

    Inkpen, M. S., Leroux, Y. R., Hapiot, P., Campos, L. M. & Venkataraman, L. Reversible on-surface wiring of resistive circuits. Chem. Sci. 8, 4340–4346 (2017).

    CAS  Article  Google Scholar 

  22. 22.

    Everret, D. H. Definitions, terminology and symbols in colloid and surface chemistry. Pure Appl. Chem. 31, 579–638 (1972).

    Google Scholar 

  23. 23.

    Zang, Y. et al. Electronically transparent Au–N bonds for molecular junctions. J. Am. Chem. Soc. 139, 14845–14848 (2017).

    CAS  Article  Google Scholar 

  24. 24.

    Park, Y. S. et al. Contact chemistry and single-molecule conductance: a comparison of phosphines, methyl sulfides, and amines. J. Am. Chem. Soc. 129, 15768–15769 (2007).

    CAS  Article  Google Scholar 

  25. 25.

    Cheng, Z. L. et al. In situ formation of highly conducting covalent Au–C contacts for single-molecule junctions. Nat. Nanotechnol. 6, 353–357 (2011).

    CAS  Article  Google Scholar 

  26. 26.

    Hybertsen, M. S. & Venkataraman, L. Structure–property relationships in atomic-scale junctions: histograms and beyond. Acc. Chem. Res. 49, 452–460 (2016).

    CAS  Article  Google Scholar 

  27. 27.

    Quek, S. Y. et al. Amine−gold linked single-molecule circuits: experiment and theory. Nano Lett. 7, 3477–3482 (2007).

    CAS  Article  Google Scholar 

  28. 28.

    Paulsson, M., Krag, C., Frederiksen, T. & Brandbyge, M. Conductance of alkanedithiol single-molecule junctions: a molecular dynamics study. Nano Lett. 9, 117–121 (2009).

    CAS  Article  Google Scholar 

  29. 29.

    Kim, Y.-H., Kim, H. S., Lee, J., Tsutsui, M. & Kawai, T. Stretching-induced conductance variations as fingerprints of contact configurations in single-molecule junctions. J. Am. Chem. Soc. 139, 8286–8294 (2017).

    CAS  Article  Google Scholar 

  30. 30.

    Rascón-Ramos, H., Artés, J. M., Li, Y. & Hihath, J. Binding configurations and intramolecular strain in single-molecule devices. Nat. Mater. 14, 517–522 (2015).

    Article  Google Scholar 

  31. 31.

    Adak, O. et al. Flicker noise as a probe of electronic interaction at metal–single molecule interfaces. Nano Lett. 15, 4143–4149 (2015).

    CAS  Article  Google Scholar 

  32. 32.

    Brandbyge, M., Mozos, J.-L., Ordejón, P., Taylor, J. & Stokbro, K. Density-functional method for nonequilibrium electron transport. Phys. Rev. B 65, 165401 (2002).

    Article  Google Scholar 

  33. 33.

    Koentopp, M., Burke, K. & Evers, F. Zero-bias molecular electronics: exchange-correlation corrections to Landauer’s formula. Phys. Rev. B 73, 121403 (2006).

    Article  Google Scholar 

  34. 34.

    Quek, S. Y. et al. Amine–gold linked single-molecule circuits: experiment and theory. Nano Lett. 7, 3477–3482 (2007).

    CAS  Article  Google Scholar 

  35. 35.

    Quek, S. Y., Choi, H. J., Louie, S. G. & Neaton, J. B. Length dependence of conductance in aromatic single-molecule junctions. Nano Lett. 9, 3949–3953 (2009).

    CAS  Article  Google Scholar 

  36. 36.

    Hybertsen, M. S. et al. Amine-linked single-molecule circuits: systematic trends across molecular families. J. Phys. Condens. Matter 20, 374115 (2008).

    Article  Google Scholar 

  37. 37.

    Widrig, C. A., Chung, C. & Porter, M. D. The electrochemical desorption of n-alkanethiol monolayers from polycrystalline Au and Ag electrodes. J. Electroanal. Chem. Interfacial Electrochem. 310, 335–359 (1991).

    CAS  Article  Google Scholar 

  38. 38.

    Angelova, P. et al. Chemisorbed monolayers of corannulene penta-thioethers on gold. Langmuir 29, 2217–2223 (2013).

    CAS  Article  Google Scholar 

  39. 39.

    Piotrowski, P. et al. Self-assembly of thioether functionalized fullerenes on gold and their activity in electropolymerization of styrene. RSC Adv. 5, 86771–86778 (2015).

    CAS  Article  Google Scholar 

  40. 40.

    Noh, J. et al. High-resolution STM and XPS studies of thiophene self-assembled monolayers on Au(111). J. Phys. Chem. B 106, 7139–7141 (2002).

    CAS  Article  Google Scholar 

  41. 41.

    Zhong, C.-J., Brush, R. C., Anderegg, J. & Porter, M. D. Organosulfur monolayers at gold surfaces: reexamination of the case for sulfide adsorption and implications to the formation of monolayers from thiols and disulfides. Langmuir 15, 518–525 (1998).

    Article  Google Scholar 

  42. 42.

    He, J. et al. Measuring single molecule conductance with break junctions. Faraday Discuss. 131, 145–154 (2006).

    CAS  Article  Google Scholar 

  43. 43.

    Haiss, W. et al. Impact of junction formation method and surface roughness on single molecule conductance. J. Phys. Chem. C 113, 5823–5833 (2009).

    CAS  Article  Google Scholar 

  44. 44.

    Li, X. et al. Conductance of single alkanedithiols: conduction mechanism and effect of molecule−electrode contacts. J. Am. Chem. Soc. 128, 2135–2141 (2006).

    CAS  Article  Google Scholar 

  45. 45.

    Burgi, T. Properties of the gold–sulphur interface: from self-assembled monolayers to clusters. Nanoscale 7, 15553–15567 (2015).

    CAS  Article  Google Scholar 

  46. 46.

    Hasan, M., Bethell, D. & Brust, M. The fate of sulfur-bound hydrogen on formation of self-assembled thiol monolayers on gold: 1H NMR spectroscopic evidence from solutions of gold clusters. J. Am. Chem. Soc. 124, 1132–1133 (2002).

    CAS  Article  Google Scholar 

  47. 47.

    Crudden, C. M. et al. Ultra stable self-assembled monolayers of N-heterocyclic carbenes on gold. Nat. Chem. 6, 409–414 (2014).

    CAS  Article  Google Scholar 

  48. 48.

    Lavrich, D. J., Wetterer, S. M., Bernasek, S. L. & Scoles, G. Physisorption and chemisorption of alkanethiols and alkyl sulfides on Au(111). J. Phys. Chem. B 102, 3456–3465 (1998).

    CAS  Article  Google Scholar 

  49. 49.

    Xie, Z., Bâldea, I., Smith, C. E., Wu, Y. & Frisbie, C. D. Experimental and theoretical analysis of nanotransport in oligophenylene dithiol junctions as a function of molecular length and contact work function. ACS Nano 9, 8022–8036 (2015).

    CAS  Article  Google Scholar 

  50. 50.

    Li, H. et al. Extreme conductance suppression in molecular siloxanes. J. Am. Chem. Soc. 139, 10212–10215 (2017).

    CAS  Article  Google Scholar 

  51. 51.

    Li, H. et al. Electric field breakdown in single molecule junctions. J. Am. Chem. Soc. 137, 5028–5033 (2015).

    CAS  Article  Google Scholar 

  52. 52.

    Kirihara, M. et al. A mild and environmentally benign oxidation of thiols to disulfides. Synthesis 2007, 3286–3289 (2007).

    Article  Google Scholar 

  53. 53.

    Forward, J. M., Bohmann, D., Fackler, J. P. & Staples, R. J. Luminescence studies of gold(i) thiolate complexes. Inorg. Chem. 34, 6330–6336 (1995).

    CAS  Article  Google Scholar 

  54. 54.

    Monzittu, F. M. et al. Different emissive properties in dithiolate gold(i) complexes as a function of the presence of phenylene spacers. Dalton. Trans. 43, 6212–6220 (2014).

    CAS  Article  Google Scholar 

  55. 55.

    Atsushi, S. et al. Solvent diversity in the preparation of alkanethiol-capped gold nanoparticles. An approach with a gold(i) thiolate complex. Chem. Lett. 39, 319319–319321 (2010).

    Google Scholar 

  56. 56.

    Perdew, J. P., Burke, K. & Ernzerhof, M. Generalized gradient approximation made simple. Phys. Rev. Lett. 78, 1396–1396 (1997).

    CAS  Article  Google Scholar 

  57. 57.

    José, M. S. et al. The SIESTA method for ab initio order-N materials simulation. J. Phys. Condens. Matter 14, 2745–2779 (2002).

    Article  Google Scholar 

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We acknowledge discussions with M. L. Steigerwald, G. Lovat, T. Albrecht, Y. R. Leroux and P. Hapiot, and thank M. C. Buzzeo for the use of electrochemical equipment. This research was supported primarily by a Marie Skłodowska Curie Global Fellowship (M.S.I., MOLCLICK: 657247) within the Horizon 2020 Programme. This work was supported in part by the National Science Foundation grants DMR-1507440 and DMR-1807580. The computational work was supported by the US Department of Energy, Office of Basic Energy Sciences, Materials Sciences and Engineering Division, under contract no. DE–AC02–05CH11231, within the Theory FWP. This work was also supported by the Molecular Foundry through the US Department of Energy, Office of Basic Energy Sciences, under the same contract number. Portions of the computational work were performed at the National Energy Research Scientific Computing Center.

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M.S.I. and L.V. conceived and led the project. M.S.I. synthesized the compounds and performed STM, XPS and electrochemical experiments. L.V. carried out the noise analyses. Z.-F.L. and J.B.N. undertook first-principles calculations. The paper was written by M.S.I. and L.V. with contributions from all the other authors.

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Correspondence to Michael S. Inkpen or Latha Venkataraman.

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Supplementary Methods, Supplementary Data, Supplementary Figs 1–28, Supplementary Tables 1–3

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Inkpen, M.S., Liu, Z., Li, H. et al. Non-chemisorbed gold–sulfur binding prevails in self-assembled monolayers. Nat. Chem. 11, 351–358 (2019).

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