Abstract
Artificial molecular motors are designed to transform external energy into useful work in the form of unidirectional motion1. They have been studied mainly in solution2,3,4, but also on solid surfaces5,6, which provide fixed reference points, allowing for tracking of their movement. However, these molecules require sophisticated design and synthesis, because the motor function must be imprinted into the chemical structure, and show reduced functionality on surfaces compared with in solution5,6,7,8. DNA walkers9,10, on the other hand, impart high directionality as they include the surface as part of the motor function, but they require chemical surface patterning and sequential solvent modification for motor activation. Here we show how efficient motors can operate at much smaller length scales on a homogeneous metal surface without any liquid. This is realized by combining a surface with a simple molecule, which, by itself, does not contain any motor unit. The motion, which is tracked at the single-molecule level, is triggered by intramolecular proton transfer with a corresponding modulation of the potential energy surface. Each molecule moves with 100 percent unidirectionality along an atomically defined straight line. Proof of the motor performing meaningful work is shown by controlled transport of single carbon monoxide molecules. This simplistic concept could form the basis for the controlled bottom-up assembly of nanostructures at the atomic scale.
This is a preview of subscription content, access via your institution
Access options
Access Nature and 54 other Nature Portfolio journals
Get Nature+, our best-value online-access subscription
$29.99 / 30 days
cancel any time
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Rent or buy this article
Prices vary by article type
from$1.95
to$39.95
Prices may be subject to local taxes which are calculated during checkout
Data availability
All data needed to evaluate the conclusions in the paper are available in the main text or the Supplementary Information. Additional data related to this paper may be requested from the corresponding author.
References
Kassem, S. et al. Artificial molecular motors. Chem. Soc. Rev. 46, 2592–2621 (2017).
Koumura, N., Zijistra, R. W. J., Delden, R. A. V., Harada, N. & Feringa, B. L. Light-driven monodirectional molecular rotor. Nature 401, 152–155 (1999).
Badjic, J. D., Balzani, V., Credi, A., Silvi, S. & Stoddart, J. F. A molecular elevator. Science 303, 1845–1849 (2004).
Hernandez, J. V., Kay, E. R. & Leigh, D. A reversible synthetic rotary molecular motor. Science 306, 1532–1537 (2004).
Kudernac, T. et al. Electrically driven directional motion of a four-wheeled molecule on a metal surface. Nature 479, 208–211 (2011).
Saywell, A. et al. Light-induced translation of motorized molecules on a surface. ACS Nano 10, 10945–10952 (2016).
Coronado, E., Gavina, P. & Tatay, S. Catenanes and threaded systems: from solution to surfaces. Chem. Soc. Rev. 38, 1674–1689 (2009).
Schwarz, F. B., Heinrich, T., Lippitz, A., Unger, W. E. S. & Schalley, C. A. A photoswitchable rotaxane operating in monolayers on solid support. Chem. Commun. 52, 14458–14461 (2016).
Gu, H., Chao, J., Xiao, S.-J. & Seeman, N. C. A proximity-based programmable DNA nanoscale assembly line. Nature 465, 202–206 (2010).
Wickham, S. F. J. et al. Direct observation of stepwise movement of a synthetic molecular transporter. Nat. Nanotechnol. 6, 166–169 (2011).
Tolman, R. C. The principle of microscopic reversibility. Proc. Natl Acad. Sci. USA 11, 436–439 (1925).
Astumian, R. D. & Hänggi, P. Brownian motors. Phys. Today 55, 33–39 (2002).
Kodera, N., Yamamoto, D., Ishikawa, R. & Ando, T. Video imaging of walking myosin V by high-speed atomic force microscopy. Nature 468, 72–77 (2010).
Feringa, B. L. The art of building small: from molecular switches to motors (Nobel Lecture). Angew. Chem. Int. Edn 56, 11060–11078 (2017).
Stoddart, J. F. Mechanically interlocked molecules (MIMs)—molecular shuttles, switches and machines (Nobel Lecture). Angew. Chem. Int. Edn 56, 11094–11125 (2017).
Astumian, R. D. Microscopic reversibility as the organizing principle of molecular machines. Nat. Nanotechnol. 7, 684–688 (2012).
Astumian, R. D. & Derényi, I. Fluctuation driven transport and models of molecular motors and pumps. Eur. Biophys. J. 27, 474–489 (1998).
Astumian, R. D., Mukherjee, S. & Warshel, A. The physics and physical chemistry of molecular machines. ChemPhysChem 17, 1719–1741 (2016).
Erbas-Cakmak, S., Leigh, D. A., McTernan, C. T. & Nussbaumer, A. L. Artificial molecular machines. Chem. Rev. 115, 10081–10206 (2015).
Brasen, W. R., Holmquist, H. E. & Benson, R. E. N,N’-disubstituted-1-amino-7-imino-1,3,5-cycloheptatrienes, a non-classical aromatic system. J. Am. Chem. Soc. 83, 3125–3135 (1961).
Claramunt, R. M. et al. Solid-state structure and tautomerism of 2-aminotroponimines studied by X-ray crystallography and multinuclear NMR spectroscopy. Eur. J. Org. Chem. 2004, 4452–4466 (2004).
Schunack, M. et al. Long jumps in the surface diffusion of large molecules. Phys. Rev. Lett. 88, 156102 (2002).
Alemani, M. et al. Recording the intramolecular deformation of a 4-legs molecule during its STM manipulation on a Cu(211) surface. Chem. Phys. Lett. 402, 180–185 (2005).
Simpson, G. J., Garcia-Lopez, V., Petermeier, P., Grill, L. & Tour, J. M. How to build and race a fast nanocar. Nat. Nanotechnol. 12, 604–606 (2017).
Ho, W. Single-molecule chemistry. J. Chem. Phys. 117, 11033–11061 (2002).
Barth, J. V. Transport of adsorbates at metal surfaces: from thermal migration to hot precursors. Surf. Sci. Rep. 40, 75–149 (2000).
Pawin, G. et al. Surface diffusive motion in a periodic and asymmetric potential. J. Am. Chem. Soc. 130, 15244–15245 (2008).
Kumagai, T. et al. Thermally- and vibrationally induced tautomerization of single porphycene molecules on a Cu(110) surface. Phys. Rev. Lett. 111, 246101 (2013).
Stolz, S., Gröning, O., Prinz, J., Brune, H. & Widmer, R. Molecular motor crossing the frontier of classical to quantum tunneling motion. Proc. Natl Acad. Sci. USA 117, 14838–14842 (2020).
Torres, J. A. G., Finley, K. L., Früchtl, H. A., Webb, P. B. & Schaub, R. Strong substrate mediation of attractive lateral interactions of CO on Cu(110). Langmuir 35, 608–614 (2019).
Peng, C. S. et al. Nanometer-resolution long-term tracking of single cargos reveals dynein motor mechanisms. Preprint at bioRxiv https://doi.org/10.1101/2022.1101.1105.475120 (2022).
Kresse, G. & Furthmüller, J. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B 54, 11169–11186 (1996).
Kresse, G. & Joubert, D. From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B 59, 1758–1775 (1999).
Dion, M., Rydberg, H., Schröder, E., Langreth, D. C. & Lundqvist, B. I. van der Waals density functional for general geometries. Phys. Rev. Lett. 92, 246401 (2004).
Román-Pérez, G. & Soler, J. M. Efficient implementation of a van der Waals density functional: application to double-wall carbon nanotubes. Phys. Rev. Lett. 103, 096102 (2009).
Berland, K. & Hyldgaard, P. Exchange functional that tests the robustness of the plasmon description of the van der Waals density functional. Phys. Rev. B 89, 035412 (2014).
Gharaee, L., Erhart, P. & Hyldgaard, P. Finite-temperature properties of nonmagnetic transition metals: comparison of the performance of constraint-based semilocal and nonlocal functionals. Phys. Rev. B 95, 085147 (2017).
Mills, G., Jónsson, H. & Schenter, G. K. Reversible work transition state theory: application to dissociative adsorption of hydrogen. Surf. Sci. 324, 305–337 (1995).
Henkelman, G., Uberuaga, B. P. & Jónsson, H. A climbing image nudged elastic band method for finding saddle points and minimum energy paths. J. Chem. Phys. 113, 9901–9904 (2000).
Sheppard, D., Terrell, R. & Henkelman, G. Optimization methods for finding minimum energy paths. J. Chem. Phys. 128, 134106 (2007).
Smidstrup, S., Pedersen, A., Stokbro, K. & Jónsson, H. Improved initial guess for minimum energy path calculations. J. Chem. Phys. 140, 214106 (2014).
Tersoff, J. & Hamann, D. R. Theory and application for the scanning tunneling microscope. Phys. Rev. Lett. 50, 1998–2001 (1983).
Lorente, N. & Persson, M. Theoretical aspects of tunneling-current-induced bond excitation and breaking at surfaces. Faraday Discuss. 117, 277–290 (2000).
Acknowledgements
We acknowledge J. Schachner for deuteration of the molecules and B. Werner for NMR measurements. We also thank L. Gross for careful reading of the manuscript and valuable feedback during the review process. We acknowledge The European Commission (FET open project no. 766864) as well as the Austrian Science fund FWF (Lise Meitner project no. M 2021-N36) for financial support and Barkla at the University of Liverpool for providing computer resources.
Author information
Authors and Affiliations
Contributions
G.J.S. performed the experiments, G.J.S. and L.G. analysed the data. M.P. did the calculations. G.J.S. and L.G. wrote the paper with feedback from M.P.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing interests.
Peer review
Peer review information
Nature thanks R. Dean Astumian, Leo Gross 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
This file contains details about molecular configurations of ditolyl-ATI, thermally activated diffusion, unidirectional motion as well as calculated vibrational energies, molecular states and reaction pathways, Supplementary Figs. 1–15, Table 1 and References.
Supplementary Video 1
STM tip-induced hopping of ditolyl-ATI on Cu(110). 44 consecutively acquired STM images (V = 690 mV, I = 150 pA, 368 × 368 Å2) showing ditolyl-ATI adsorbed on a Cu(110) surface. Hopping of individual molecules is induced by scanning with a bias above the threshold of about 390 mV and occurs along the close-packed rows of the surface (surface lattice overlaid as a grid).
Supplementary Video 2
Thermally activated diffusion of ditolyl-ATI on Cu(110). 74 consecutively acquired STM images (V = 100 mV, I = 250 pA, 368 × 368 Å2) in the temperature range 47.4–43.7 K showing random thermally induced diffusion of ditolyl-ATI along the close-packed Cu(110) rows. The numbering of the molecules corresponds to the numbering shown in Supplementary Fig. 6b.
Supplementary Video 3
Reaction pathway for unidirectional motion. The mechanism of unidirectional motion of ditolyl-ATI along the \(\left[\bar{1}10\right]\) direction on Cu(110). The molecule progresses from \({{\rm{R}}}_{{\rm{o}}}\to \,{\widetilde{{\rm{R}}}}_{{\rm{o}}}\to \,{{\rm{L}}}_{\downarrow }\to \,{{\rm{R}}}_{\downarrow }\) in one full hop along a close-packed row. This process then repeats. For simplicity, the molecule ends on the blue curve of the L tautomer after proton transfer (indicated by a vertical arrow). It is noted that this is different from the instantaneously created L* state that is higher in energy (see Supplementary Fig. 11 for details).
Supplementary Video 4
Unidirectional hopping of molecules moving in opposite directions. 24 consecutively acquired STM images (V = 390 mV, I = 20 pA). The two ditolyl-ATI molecules in the centre of the frame point in opposite directions (\(\left[1\bar{1}0\right]\) and \([\bar{1}10]\)). Accordingly, the two molecules translate in opposite directions when unidirectional hopping is induced.
Supplementary Video 5
Cargo transport by a single ditolyl-ATI molecule. STM images (V = 110 mV, I = 10 pA) showing a single ditolyl-ATI molecule moving over the Cu(110) surface. Individual hops are induced by voltage pulses from the STM tip. A CO molecule lies along the path of the molecule and is subsequently pushed further in the same direction in a snowplough-like manner.
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.
About this article
Cite this article
Simpson, G.J., Persson, M. & Grill, L. Adsorbate motors for unidirectional translation and transport. Nature 621, 82–86 (2023). https://doi.org/10.1038/s41586-023-06384-y
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/s41586-023-06384-y
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.
