Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

Shape-persistent ladder molecules exhibit nanogap-independent conductance in single-molecule junctions

Nature Chemistry (2024)Cite this article

Subjects

Abstract

Molecular electronic devices require precise control over the flow of current in single molecules. However, the electron transport properties of single molecules critically depend on dynamic molecular conformations in nanoscale junctions. Here we report a unique strategy for controlling molecular conductance using shape-persistent molecules. Chemically diverse, charged ladder molecules, synthesized via a one-pot multicomponent ladderization strategy, show a molecular conductance (d[log(G/G0)]/dx ≈ −0.1 nm−1) that is nearly independent of junction displacement, in stark contrast to the nanogap-dependent conductance (d[log(G/G0)]/dx ≈ −7 nm−1) observed for non-ladder analogues. Ladder molecules show an unusually narrow distribution of molecular conductance during dynamic junction displacement, which is attributed to the shape-persistent backbone and restricted rotation of terminal anchor groups. These principles are further extended to a butterfly-like molecule, thereby demonstrating the strategy’s generality for achieving gap-independent conductance. Overall, our work provides important avenues for controlling molecular conductance using shape-persistent molecules.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on SpringerLink
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Molecular design and synthesis for single-molecule electronics.
Fig. 2: Single-molecule conductance of ladder and non-ladder molecules.
Fig. 3: Voltage-regulated dual charge transport pathways in ladder molecules.
Fig. 4: Comparative analysis of structural and electronic properties.
Fig. 5: Single-molecule conductance of a butterfly-like molecule.

Similar content being viewed by others

Data availability

All data supporting the findings of this study are available within this Article and its Supplementary Information. Crystallographic data for structures reported in this Article have been deposited at the Cambridge Crystallographic Data Center (CCDC) under deposition numbers CCDC 2294843 (N1-PF6), 2334051 (L4-PF6) and 2334052 (L1-PF6). Copies of the data can be obtained free of charge via https://www.ccdc.cam.ac.uk/structures/. Source data are provided with this paper. These data are also available via figshare at https://doi.org/10.6084/m9.figshare.26314444 (ref. 68).

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 authors upon reasonable request.

References

  1. Kim, J., Ghaffari, R. & Kim, D.-H. The quest for miniaturized soft bioelectronic devices. Nat. Biomed. Eng. 1, 0049 (2017).

    Article  Google Scholar 

  2. Lundstrom, M. Moore’s law forever? Science 299, 210–211 (2003).

    Article  CAS  PubMed  Google Scholar 

  3. Toumey, C. Less is Moore. Nat. Nanotechnol. 11, 2–3 (2016).

    Article  CAS  PubMed  Google Scholar 

  4. Xiang, D., Wang, X., Jia, C., Lee, T. & Guo, X. Molecular-scale electronics: from concept to function. Chem. Rev. 116, 4318–4440 (2016).

    Article  CAS  PubMed  Google Scholar 

  5. Meng, L. et al. Dual-gated single-molecule field-effect transistors beyond Moore’s law. Nat. Commun. 13, 1410 (2022).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  6. Li, T., Bandari, V. K. & Schmidt, O. G. Molecular electronics: creating and bridging molecular junctions and promoting its commercialization. Adv. Mater. 35, 2209088 (2023).

    Article  CAS  Google Scholar 

  7. Chen, H. & Fraser Stoddart, J. From molecular to supramolecular electronics. Nat. Rev. Mater. 6, 804–828 (2021).

    Article  CAS  Google Scholar 

  8. Stone, I. et al. A single-molecule blueprint for synthesis. Nat. Rev. Chem. 5, 695–710 (2021).

    Article  PubMed  Google Scholar 

  9. Zou, Q., Qiu, J., Zang, Y., Tian, H. & Venkataraman, L. Modulating single-molecule charge transport through external stimulus. eScience 3, 100115 (2023).

    Article  Google Scholar 

  10. Li, T., Hu, W. & Zhu, D. Nanogap electrodes. Adv. Mater. 22, 286–300 (2010).

    Article  PubMed  Google Scholar 

  11. Luo, S., Hoff, B. H., Maier, S. A. & de Mello, J. C. Scalable fabrication of metallic nanogaps at the sub-10 nm level. Adv. Sci. 8, 2102756 (2021).

    Article  CAS  Google Scholar 

  12. Chang, S., He, J., Zhang, P., Gyarfas, B. & Lindsay, S. Gap distance and interactions in a molecular tunnel junction. J. Am. Chem. Soc. 133, 14267–14269 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  13. McNaught, A. D. & Wilkinson, A. Compendium of Chemical Terminology Vol. 1669 (Blackwell Science, 1997).

  14. Cai, Z. et al. Exceptional single-molecule transport properties of ladder-type heteroacene molecular wires. J. Am. Chem. Soc. 138, 10630–10635 (2016).

    Article  CAS  PubMed  Google Scholar 

  15. Li, J. et al. Ladder-type conjugated molecules as robust multi-state single-molecule switches. Chem 9, 2282–2297 (2023).

  16. Moore, J. S. Shape-persistent molecular architectures of nanoscale dimension. Acc. Chem. Res. 30, 402–413 (1997).

    Article  CAS  Google Scholar 

  17. Cao, Z., Leng, M., Cao, Y., Gu, X. & Fang, L. How rigid are conjugated non-ladder and ladder polymers? J. Polym. Sci. 60, 298–310 (2022).

    Article  CAS  Google Scholar 

  18. Ikai, T. et al. Triptycene-based ladder polymers with one-handed helical geometry. J. Am. Chem. Soc. 141, 4696–4703 (2019).

    Article  CAS  PubMed  Google Scholar 

  19. Liu, X., Zhu, C. & Tang, B. Z. Bringing inherent charges into aggregation-induced emission research. Acc. Chem. Res. 55, 197–208 (2022).

    Article  CAS  PubMed  Google Scholar 

  20. Wan, X., Li, C., Zhang, M. & Chen, Y. Acceptor–donor–acceptor type molecules for high performance organic photovoltaics – chemistry and mechanism. Chem. Soc. Rev. 49, 2828–2842 (2020).

    Article  CAS  PubMed  Google Scholar 

  21. Li, Z. et al. Understanding the conductance dispersion of single-molecule junctions. J. Phys. Chem. C 125, 3406–3414 (2021).

    Article  CAS  Google Scholar 

  22. Ji, X. et al. Pauli paramagnetism of stable analogues of pernigraniline salt featuring ladder-type constitution. J. Am. Chem. Soc. 142, 641–648 (2020).

    Article  CAS  PubMed  Google Scholar 

  23. Maekawa, T., Ueno, H., Segawa, Y., Haley, M. M. & Itami, K. Synthesis of open-shell ladder π-systems by catalytic C–H annulation of diarylacetylenes. Chem. Sci. 7, 650–654 (2016).

    Article  CAS  PubMed  Google Scholar 

  24. Babel, A. & Jenekhe, S. A. High electron mobility in ladder polymer field-effect transistors. J. Am. Chem. Soc. 125, 13656–13657 (2003).

    Article  CAS  PubMed  Google Scholar 

  25. Teo, Y. C., Lai, H. W. H. & Xia, Y. Synthesis of ladder polymers: developments, challenges, and opportunities. Chem. Eur. J. 23, 14101–14112 (2017).

    Article  CAS  PubMed  Google Scholar 

  26. Lee, J., Kalin, A. J., Yuan, T., Al-Hashimi, M. & Fang, L. Fully conjugated ladder polymers. Chem. Sci. 8, 2503–2521 (2017).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  27. Cai, Z., Awais, M. A., Zhang, N. & Yu, L. Exploration of syntheses and functions of higher ladder-type π-conjugated heteroacenes. Chem 4, 2538–2570 (2018).

    Article  CAS  Google Scholar 

  28. Huang, C., Rudnev, A. V., Hong, W. & Wandlowski, T. Break junction under electrochemical gating: testbed for single-molecule electronics. Chem. Soc. Rev. 44, 889–901 (2015).

    Article  CAS  PubMed  Google Scholar 

  29. Li, L. et al. Highly conducting single-molecule topological insulators based on mono- and di-radical cations. Nat. Chem. 14, 1061–1067 (2022).

    Article  CAS  PubMed  Google Scholar 

  30. Liu, J., Huang, X., Wang, F. & Hong, W. Quantum interference effects in charge transport through single-molecule junctions: detection, manipulation, and application. Acc. Chem. Res. 52, 151–160 (2019).

    Article  CAS  PubMed  Google Scholar 

  31. Su, T. A., Neupane, M., Steigerwald, M. L., Venkataraman, L. & Nuckolls, C. Chemical principles of single-molecule electronics. Nat. Rev. Mater. 1, 16002 (2016).

    Article  CAS  Google Scholar 

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

    Article  CAS  PubMed  Google Scholar 

  33. Dantus, M., Bowman, R. M. & Zewail, A. H. Femtosecond laser observations of molecular vibration and rotation. Nature 343, 737–739 (1990).

    Article  CAS  Google Scholar 

  34. Feng, A. et al. σ–σ Stacked supramolecular junctions. Nat. Chem. 14, 1158–1164 (2022).

    Article  CAS  PubMed  Google Scholar 

  35. Li, J. et al. Achieving multiple quantum-interfered states via through-space and through-bond synergistic effect in foldamer-based single-molecule junctions. J. Am. Chem. Soc. 144, 8073–8083 (2022).

    Article  CAS  PubMed  Google Scholar 

  36. Lee, W. et al. Increased molecular conductance in oligo[n]phenylene wires by thermally enhanced dihedral planarization. Nano Lett. 22, 4919–4924 (2022).

    Article  CAS  PubMed  Google Scholar 

  37. Yu, H. et al. Efficient intermolecular charge transport in π-stacked pyridinium dimers using cucurbit[8]uril supramolecular complexes. J. Am. Chem. Soc. 144, 3162–3173 (2022).

    Article  CAS  PubMed  Google Scholar 

  38. 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).

    Article  CAS  PubMed  Google Scholar 

  39. Yao, X., Sun, X., Lafolet, F. & Lacroix, J.-C. Long-range charge transport in diazonium-based single-molecule junctions. Nano Lett. 20, 6899–6907 (2020).

    Article  CAS  PubMed  Google Scholar 

  40. Kadam, V. D. et al. Cascade C–H annulation reaction of benzaldehydes, anilines, and alkynes toward dibenzo[a,f]quinolizinium salts: discovery of photostable mitochondrial trackers at the nanomolar level. Org. Lett. 20, 7071–7075 (2018).

    Article  CAS  PubMed  Google Scholar 

  41. Capozzi, B. et al. Length-dependent conductance of oligothiophenes. J. Am. Chem. Soc. 136, 10486–10492 (2014).

    Article  CAS  PubMed  Google Scholar 

  42. Kamenetska, M. et al. Formation and evolution of single-molecule junctions. Phys. Rev. Lett. 102, 126803 (2009).

    Article  CAS  PubMed  Google Scholar 

  43. 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  PubMed  Google Scholar 

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

    Article  CAS  PubMed  Google Scholar 

  45. Stefani, D. et al. Conformation-dependent charge transport through short peptides. Nanoscale 13, 3002–3009 (2021).

    Article  CAS  PubMed  Google Scholar 

  46. Chen, H. et al. Single-molecule charge transport through positively charged electrostatic anchors. J. Am. Chem. Soc. 143, 2886–2895 (2021).

    Article  CAS  PubMed  Google Scholar 

  47. Li, J. et al. Reversible switching of molecular conductance in viologens is controlled by the electrochemical environment. J. Phys. Chem. C 125, 21862–21872 (2021).

    Article  CAS  Google Scholar 

  48. Yang, J. S.-J. & Fang, L. Conjugated ladder polymers: advances from syntheses to applications. Chem 10, 1668–1724 (2024).

  49. 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 

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

    Article  Google Scholar 

  51. Papior, N., Lorente, N., Frederiksen, T., García, A. & Brandbyge, M. Improvements on non-equilibrium and transport Green function techniques: the next-generation transiesta. Comput. Phys. Commun. 212, 8–24 (2017).

    Article  CAS  Google Scholar 

  52. Bai, J. et al. Anti-resonance features of destructive quantum interference in single-molecule thiophene junctions achieved by electrochemical gating. Nat. Mater. 18, 364–369 (2019).

    Article  CAS  PubMed  Google Scholar 

  53. Chen, Y. et al. Regio- and steric effects on single molecule conductance of phenanthrenes. Nano Lett. 21, 10333–10340 (2021).

    Article  CAS  PubMed  Google Scholar 

  54. Gómez-Gallego, M., Martín-Ortiz, M. & Sierra, M. A. Concerning the electronic control of torsion angles in biphenyls. Eur. J. Org. Chem. 2011, 6502–6506 (2011).

    Article  Google Scholar 

  55. Yin, J. et al. Acyl radical to rhodacycle addition and cyclization relay to access butterfly flavylium fluorophores. Nat. Commun. 10, 5664 (2019).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  56. Frisch, M. et al. Gaussian 16, revision C.01 (Gaussian, Inc., 2019).

  57. Becke, A. D. A new mixing of Hartree–Fock and local density‐functional theories. J. Chem. Phys. 98, 1372–1377 (1993).

    Article  CAS  Google Scholar 

  58. Becke, A. D. Density‐functional thermochemistry. I. The effect of the exchange‐only gradient correction. J. Chem. Phys. 96, 2155–2160 (1992).

    Article  CAS  Google Scholar 

  59. Becke, A. D. Density‐functional thermochemistry. II. The effect of the Perdew–Wang generalized‐gradient correlation correction. J. Chem. Phys. 97, 9173–9177 (1992).

    Article  CAS  Google Scholar 

  60. Becke, A. D. Density‐functional thermochemistry. III. The role of exact exchange. J. Chem. Phys. 98, 5648–5652 (1993).

    Article  CAS  Google Scholar 

  61. Becke, A. D. Density‐functional thermochemistry. IV. A new dynamical correlation functional and implications for exact‐exchange mixing. J. Chem. Phys. 104, 1040–1046 (1996).

    Article  CAS  Google Scholar 

  62. Krishnan, R., Binkley, J. S., Seeger, R. & Pople, J. A. Self‐consistent molecular orbital methods. XX. A basis set for correlated wave functions. J. Chem. Phys. 72, 650–654 (2008).

    Article  Google Scholar 

  63. Grimme, S., Antony, J., Ehrlich, S. & Krieg, H. A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu. J. Chem. Phys. 132, 154104 (2010).

    Article  PubMed  Google Scholar 

  64. Barone, V. & Cossi, M. Quantum calculation of molecular energies and energy gradients in solution by a conductor solvent model. J. Phys. Chem. A 102, 1995–2001 (1998).

    Article  CAS  Google Scholar 

  65. Hratchian, H. P. & Schlegel, H. B. in Theory and Applications of Computational Chemistry (eds Dykstra, C. E. et al.) 195–249 (Elsevier, 2005).

  66. Brisendine, J. M. et al. Probing charge transport through peptide bonds. J. Phys. Chem. Lett. 9, 763–767 (2018).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  67. Perdew, J. P., Burke, K. & Ernzerhof, M. Generalized gradient approximation made simple. Phys. Rev. Lett. 77, 3865–3868 (1996).

    Article  CAS  PubMed  Google Scholar 

  68. Liu, X. et al. Shape-persistent ladder molecules exhibit nanogap-independent conductance in single-molecule junctions. figshare https://doi.org/10.6084/m9.figshare.26314444 (2024).

Download references

Acknowledgements

This research was supported by the US Department of Energy (DE-SC0022035). We express our gratitude to the Mass Spectrometry Laboratory and the 3M Materials Chemistry Laboratory at the University of Illinois for their assistance with mass spectrometry and X-ray experiments, respectively. Major funding for the 500 MHz Bruker CryoProbe was provided by the Roy J. Carver Charitable Trust (Muscatine, Iowa; grant no. 15-4521) to the School of Chemical Sciences NMR Lab. R.S.A. and H.H. acknowledge Laboratory Directed Research and Development (LDRD) funding from Argonne National Laboratory, provided by the Director, Office of Science, of the US Department of Energy under contract no. DE-AC02-06CH11357. H.H. and R.S.A. acknowledge the computing resources provided on ‘BEBOP’ and ‘IMPROV’, two computing clusters operated by the Laboratory Computing Resource Center at Argonne National Laboratory. X.L. acknowledges Y. Diao at the University of Illinois Urbana-Champaign for offering the use of the UV–visible spectrophotometer. X.L. acknowledges N. Jackson, B. A. Suslick and R. Zhang at the University of Illinois Urbana-Champaign for constructive suggestions.

Author information

Author notes

  1. These authors contributed equally: Xiaolin Liu, Hao Yang, Hassan Harb.

Authors and Affiliations

  1. Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, IL, USA

    Xiaolin Liu, Hao Yang, Rajarshi Samajdar, Qian Chen, Adolfo I. B. Romo, Joaquín Rodríguez-López, Jeffrey S. Moore & Charles M. Schroeder

  2. Department of Chemistry, University of Illinois Urbana-Champaign, Urbana, IL, USA

    Xiaolin Liu, Toby J. Woods, Oliver Lin, Qian Chen, Adolfo I. B. Romo, Joaquín Rodríguez-López, Jeffrey S. Moore & Charles M. Schroeder

  3. Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, IL, USA

    Hao Yang, Qian Chen, Jeffrey S. Moore & Charles M. Schroeder

  4. Materials Science Division, Argonne National Laboratory, Lemont, IL, USA

    Hassan Harb & Rajeev S. Assary

  5. Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, IL, USA

    Rajarshi Samajdar & Charles M. Schroeder

Authors
  1. Xiaolin Liu
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Hao Yang
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Hassan Harb
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Rajarshi Samajdar
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Toby J. Woods
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Oliver Lin
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Qian Chen
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Adolfo I. B. Romo
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. Joaquín Rodríguez-López
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. Rajeev S. Assary
    View author publications

    You can also search for this author in PubMed Google Scholar

  11. Jeffrey S. Moore
    View author publications

    You can also search for this author in PubMed Google Scholar

  12. Charles M. Schroeder
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

X.L. and H.Y. conceived the idea, designed the experiments and wrote the paper. C.M.S., J.S.M. and R.S.A. co-supervised the project and revised the paper. X.L. designed and synthesized the molecules and conducted structural, optical and magnetic property and redox activity characterizations and analyses. H.Y. performed the break-junction experiments and analyses. H.H. carried out electronic structure calculations. R.S. carried out transmission calculations. T.J.W. performed single-crystal characterizations and analyses, and also provided technical guidance for EPR measurements. O.L. and Q.C. contributed constructive discussions. A.I.B.R. and J.R.-L. provided technical guidance for the cyclic voltammetry measurements.

Corresponding authors

Correspondence to Rajeev S. Assary, Jeffrey S. Moore or Charles M. Schroeder.

Ethics declarations

Competing interests

The authors declare no competing interests.

Peer review

Peer review information

Nature Chemistry thanks Daniel Paley and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Figs. 1–88, Tables 1–3, Materials and instrument information, and synthetic procedure and characterization data.

Supplementary Crystallographic Data 1

X-ray structure for L1-PF6.

Supplementary Crystallographic Data 2

X-ray structure for L4-PF6.

Supplementary Crystallographic Data 3

X-ray structure for N1-PF6.

Supplementary Computational Data 1

DFT optimized structures for L1-C3H7-PF6, L1-Cl, L1-neutral, L1-PF6, L2-PF6, L3-PF6, L4-PF6, N1-PF6, N2-PF6 and N3-PF6.

Source data

Source Data Fig. 2

Statistical source data.

Source Data Fig. 3

Statistical source data.

Source Data Fig. 4

Statistical source data.

Source Data Fig. 5

Statistical source data.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Liu, X., Yang, H., Harb, H. et al. Shape-persistent ladder molecules exhibit nanogap-independent conductance in single-molecule junctions. Nat. Chem. (2024). https://doi.org/10.1038/s41557-024-01619-5

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1038/s41557-024-01619-5

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing