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.

  • Letter
  • Published:

A molecular force probe

Abstract

Force probes1 allow reaction rates to be measured as a function of the restoring force in a molecule that has been stretched or compressed. Unlike strain energy2, approaches based on restoring force allow quantitative molecular understanding3 of phenomena as diverse as translation of microscopic objects by reacting molecules4,5,6, crack propagation7,8 and mechanosensing9. Conceptually, localized reactions offer the best opportunity to gain fundamental insights into how rates vary with restoring forces, but such reactions are particularly difficult to study systematically using microscopic force probes10,11,12,13,14. Here, we show how a molecular force probe, stiff stilbene, simplifies force spectroscopy of localized reactions. We illustrate the capabilities of our approach by validating the central postulate of chemomechanical kinetics15—force lowers the activation barrier proportionally to the difference in a single internuclear distance between the ground and transition states projected on the force vector—on a paradigmatic unimolecular reaction: concerted dissociation of the C–C bond.

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

Access options

Buy this article

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

Figure 1: Microscopic versus molecular force probes.
Figure 2: The experimental system used to illustrate the use of a molecular force probe, stiff stilbene (red), for studies of the chemomechanical kinetics of localized reactions.
Figure 3: Kinetic and force data for macrocycles 1–9.
Figure 4: Validation of the single-coordinate model of chemomechanical kinetics.

Similar content being viewed by others

References

  1. Neuman, K. C. & Nagy, A. Single-molecule force spectroscopy: Optical tweezers, magnetic tweezers and atomic force microscopy. Nature Methods 5, 491–505 (2008).

    Article  CAS  Google Scholar 

  2. Cremer, D. & Kraka, E. The concept of molecular strain: Basic principles, utility and limitations, in Molecular Structure and Energetics (eds Liebman, J. F. & Greenberg, A.) Vol. 7, 65–138 (VCH, 1988).

  3. Reimann, P. Brownian motors: Noisy transport far from equilibrium. Phys. Rep. 361, 57–265 (2002).

    Article  CAS  Google Scholar 

  4. Schliwa, M. (ed.) Molecular Motors (Wiley, 2003).

    Google Scholar 

  5. Browne, W. R. & Feringa, B. L. Making molecular machines work. Nature Nanotech. 1, 25–35 (2006).

    Article  CAS  Google Scholar 

  6. Hugel, T. et al. Single-molecule optomechanical cycle. Science 296, 1103–1106 (2002).

    Article  Google Scholar 

  7. Casale, A. & Porter, R. S. Polymer Stress Reactions (Academic Press, 1979).

    Google Scholar 

  8. Granick, S. & Bae, S. C. Stressed molecules break down. Nature 440, 160 (2006).

    Article  CAS  Google Scholar 

  9. Vogel, V. Mechanotransduction involving multimodular proteins: Converting force into biochemical signals. Ann. Rev. Biophys. Biomol. Struct. 35, 459–488 (2006).

    Article  CAS  Google Scholar 

  10. Schmidt, S. W., Beyer, M. K. & Clausen-Schaumann, H. Dynamic strength of the silicon–carbon bond observed over three decades of force-loading rates. J. Am. Chem. Soc. 130, 3664–3668 (2008).

    Article  CAS  Google Scholar 

  11. Koti Ainavarapu, S. R. et al. Single-molecule force spectroscopy measurements of bond elongation during a bimolecular reaction. J. Am. Chem. Soc. 130, 6479–6487 (2008).

    Article  Google Scholar 

  12. Wiita, A. P. et al. Probing the chemistry of thioredoxin catalysis with force. Nature 450, 124–127 (2007).

    Article  CAS  Google Scholar 

  13. Kersey, F. R., Yount, W. C. & Craig, S. L. Single-molecule force spectroscopy of bimolecular reactions: System homology in the mechanical activation of ligand substitution reactions. J. Am. Chem. Soc. 128, 3886–3887 (2006).

    Article  CAS  Google Scholar 

  14. Grandbois, M. et al. How strong is a covalent bond? Science 283, 1727–1730 (1999).

    Article  CAS  Google Scholar 

  15. Hyeon, C. & Thirumalai, D. Measuring the energy landscape roughness and the transition state location of biomolecules using single molecule mechanical unfolding experiments. J. Phys. Condens. Matter 19, 113101 (2007).

    Article  Google Scholar 

  16. Eelkema, R. et al. Molecular machines: Nanomotor rotates microscale objects. Nature 440, 163 (2006).

    Article  CAS  Google Scholar 

  17. Nguyen, T. Q. & Kausch, H. H. (eds) Flexible Polymer Chains in Elongational Flow: Theory and Experiment (Springer, 1999).

    Book  Google Scholar 

  18. Hickenboth, C. R. et al. Biasing reaction pathways with mechanical force. Nature 446, 423–427 (2007).

    Article  CAS  Google Scholar 

  19. Sheiko, S. S. et al. Adsorption-induced scission of carbon–carbon bonds. Nature 440, 191–194 (2006).

    Article  CAS  Google Scholar 

  20. Sotomayor, M. & Schulten, K. Single-molecule experiments in vitro and in silico. Science 316, 1144–1148 (2007).

  21. Stirling, C. J. M. Evaluation of the effect of strain upon reactivity. Tetrahedron 41, 1613–1666 (1985).

    Article  CAS  Google Scholar 

  22. Tani, K. & Stoltz, B. M. Synthesis and structural analysis of 2-quinuclidonium tetrafluoroborate. Nature 441, 731–734 (2006).

    Article  CAS  Google Scholar 

  23. Carey, F. A. & Sundberg, R. J. Advanced Organic Chemistry (Springer, 2007).

    Google Scholar 

  24. Tobe, M. L. & Burgess, J. Inorganic Reaction Mechanisms (Longman, 1999).

    Google Scholar 

  25. Gajewski, J. J. Hydrocarbon Thermal Isomerizations (Elsevier, 2004).

    Google Scholar 

  26. Guner, V. et al. A standard set of pericyclic reactions of hydrocarbons for the benchmarking of computational methods. J. Phys. Chem. A 107, 11445–11459 (2003).

    Article  CAS  Google Scholar 

  27. McMurry, J. E. Carbonyl-coupling reactions using low-valent titanium. Chem. Rev. 89, 1513–1524 (1989).

    Article  CAS  Google Scholar 

  28. Cramer, C. J. Essentials of Computational Chemistry: Theories and Models (Wiley, 2002).

    Google Scholar 

  29. Jencks, W. P. A primer for the bema hapothle. An empirical approach to the characterization of changing transition-state structures. Chem. Rev. 85, 511–527 (1985).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

The authors would like to thank J. I. Brauman, M. Gruebele, J. F. Hartwig, J. S. Moore, T. J. Martinez, K. S. Suslick and G. M. Whitesides for helpful discussions. The work was supported by the National Science Foundation (NSF) CAREER Award (CHE-0748281), the US Air Force Office of the Scientific Research Young Investigator Award (FA9550-08-1-0072), the American Chemical Society Petroleum Research Fund (48454-AC3 and 43354-G3) and the University of Illinois. T.K. thanks the Office of the Naval Research and the NSF for pre-doctoral fellowships. We gratefully acknowledge grants of computational time by the Air Force Research Lab Major Shared Resource Center and the National Center for Supercomputing Applications.

Author information

Authors and Affiliations

Authors

Contributions

Q.Y. designed and synthesized the macrocycles, Z.H. measured the kinetics, T.K. synthesized the macrocycles, D.K. carried out DFT computations of thermodynamic parameters and reaction coordinates, J.C. carried out preliminary MM and DFT calculations, R.B. designed the experiments, developed methods for calculating the restoring forces, analysed the results and wrote the paper.

Corresponding author

Correspondence to Roman Boulatov.

Supplementary information

Supplementary Information

Supplementary Information (PDF 6647 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Yang, QZ., Huang, Z., Kucharski, T. et al. A molecular force probe. Nature Nanotech 4, 302–306 (2009). https://doi.org/10.1038/nnano.2009.55

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nnano.2009.55

This article is cited by

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