Reversible coordination-induced spin-state switching in complexes on metal surfaces

Abstract

Molecular spin switches are attractive candidates for controlling the spin polarization developing at the interface between molecules and magnetic metal surfaces1,2, which is relevant for molecular spintronics devices3,4,5. However, so far, intrinsic spin switches such as spin-crossover complexes have suffered from fragmentation or loss of functionality following adsorption on metal surfaces, with rare exceptions6,7,8,9. Robust metal–organic platforms, on the other hand, rely on external axial ligands to induce spin switching10,11,12,13,14. Here we integrate a spin switching functionality into robust complexes, relying on the mechanical movement of an axial ligand strapped to the porphyrin ring. Reversible interlocked switching of spin and coordination, induced by electron injection, is demonstrated on Ag(111) for this class of compounds. The stability of the two spin and coordination states of the molecules exceeds days at 4 K. The potential applications of this switching concept go beyond the spin functionality, and may turn out to be useful for controlling the catalytic activity of surfaces15.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Fig. 1: Molecular switch with interlocked coordination and spin degrees of freedom.
Fig. 2: Interlocking of coordination and spin states.
Fig. 3: Sub-monolayer coverage of 2 on Ag(111).
Fig. 4: Reversible coordination-induced spin-state switching of complexes 1–3 on Ag(111).

Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.

References

  1. 1.

    Djeghloul, F. et al. High spin polarization at ferromagnetic metal–organic interfaces: a generic property. J. Phys. Chem. Lett. 7, 2310–2315 (2016).

    CAS  Article  Google Scholar 

  2. 2.

    Gruber, M. et al. Spin-dependent hybridization between molecule and metal at room temperature through interlayer exchange coupling. Nano Lett. 15, 7921–7926 (2015).

    CAS  Article  Google Scholar 

  3. 3.

    Barraud, C. et al. Unravelling the role of the interface for spin injection into organic semiconductors. Nat. Phys. 6, 615–620 (2010).

    CAS  Article  Google Scholar 

  4. 4.

    Cinchetti, M., Dediu, V. A. & Hueso, L. E. Activating the molecular spinterface. Nat. Mater. 16, 507–515 (2017).

    CAS  Article  Google Scholar 

  5. 5.

    Delprat, S. et al. Molecular spintronics: the role of spin-dependent hybridization. J. Phys. D 51, 473001 (2018).

    Article  Google Scholar 

  6. 6.

    Gopakumar, T. G. et al. Electron-induced spin crossover of single molecules in a bilayer on gold. Angew. Chem. Int. Ed. 51, 6262–6266 (2012).

    CAS  Article  Google Scholar 

  7. 7.

    Miyamachi, T. et al. Robust spin crossover and memristance across a single molecule. Nat. Commun. 3, 938 (2012).

    Article  Google Scholar 

  8. 8.

    Bairagi, K. et al. Molecular-scale dynamics of light-induced spin cross-over in a two-dimensional layer. Nat. Commun. 7, 12212 (2016).

    CAS  Article  Google Scholar 

  9. 9.

    Knaak, T. et al. Fragmentation and distortion of terpyridine-based spin-crossover complexes on Au(111). J. Phys. Chem. C 123, 4178–4185 (2019).

    CAS  Article  Google Scholar 

  10. 10.

    Wäckerlin, C. et al. Controlling spins in adsorbed molecules by a chemical switch. Nat. Commun. 1, 61 (2010).

    Article  Google Scholar 

  11. 11.

    Seufert, K., Auwärter, W. & Barth, J. V. Discriminative response of surface-confined metalloporphyrin molecules to carbon and nitrogen monoxide. J. Am. Chem. Soc. 132, 18141–18146 (2010).

    CAS  Article  Google Scholar 

  12. 12.

    Wäckerlin, C. et al. Ammonia coordination introducing a magnetic moment in an on-surface low-spin porphyrin. Angew. Chem. Int. Ed. 52, 4568–4571 (2013).

    Article  Google Scholar 

  13. 13.

    Hermanns, C. F. et al. Huge magnetically coupled orbital moments of Co porphyrin molecules and their control by CO adsorption. Phys. Rev. B 88, 104420 (2013).

    Article  Google Scholar 

  14. 14.

    Gopakumar, T. G., Tang, H., Morillo, J. & Berndt, R. Transfer of Cl ligands between adsorbed iron tetraphenylporphyrin molecules. J. Am. Chem. Soc. 134, 11844–11847 (2012).

    CAS  Article  Google Scholar 

  15. 15.

    Sugiyasu, K., Ogi, S. & Takeuchi, M. Strapped porphyrin-based polymeric systems. Polym. J. 46, 674–681 (2014).

    CAS  Article  Google Scholar 

  16. 16.

    Venkataramani, S. et al. Magnetic bistability of molecules in homogeneous solution at room temperature. Science 331, 445–448 (2011).

    CAS  Article  Google Scholar 

  17. 17.

    Matino, F. et al. Single azopyridine-substituted porphyrin molecules for configurational and electronic switching. Chem. Commun. 46, 6780–6782 (2010).

    CAS  Article  Google Scholar 

  18. 18.

    Momenteau, M. & Reed, C. A. Synthetic heme–dioxygen complexes. Chem. Rev. 94, 659–698 (1994).

    CAS  Article  Google Scholar 

  19. 19.

    Gazeau S., Pecaut J. & Marchon J.-C. Nickel porphyrin nanotweezers. Chem. Commun. 1644–1645 (2001).

  20. 20.

    Zhang, X. et al. Ultrafast stimulated emission and structural dynamics in nickel porphyrins. J. Phys. Chem. A 111, 11736–11742 (2007).

    CAS  Article  Google Scholar 

  21. 21.

    Duval, H., Bulach, V., Fischer, J. & Weiss, R. Four-coordinate, low-spin (S = 0) and six-coordinate, high-spin (S = 1) nickel(ii) complexes of tetraphenylporphyrins with β-pyrrole electron-withdrawing substituents: porphyrin-core expansion and conformation. Inorg. Chem. 38, 5495–5501 (1999).

    CAS  Article  Google Scholar 

  22. 22.

    Jia, S.-L. et al. Axial coordination and conformational heterogeneity of nickel(ii) tetraphenylporphyrin complexes with nitrogenous bases. Inorg. Chem. 37, 4402–4412 (1998).

    CAS  Article  Google Scholar 

  23. 23.

    Gutzeit, F. et al. Structure and properties of a five-coordinate Ni(ii) porphyrin. Inorg. Chem. 58, 12542–12546 (2019).

    CAS  Article  Google Scholar 

  24. 24.

    Krasnikov, S. A. et al. Electronic structure of Ni(ii) porphyrins and phthalocyanine studied by soft X-ray absorption spectroscopy. Chem. Phys. 332, 318–324 (2007).

    CAS  Article  Google Scholar 

  25. 25.

    Gottfried, J. M. Surface chemistry of porphyrins and phthalocyanines. Surf. Sci. Rep. 70, 259–379 (2015).

    CAS  Article  Google Scholar 

  26. 26.

    Auwärter, W., Écija, D., Klappenberger, F. & Barth, J. V. Porphyrins at interfaces. Nat. Chem. 7, 105–120 (2015).

    Article  Google Scholar 

  27. 27.

    Ohresser, P. et al. DEIMOS: a beamline dedicated to dichroism measurements in the 350–2,500 eV energy range. Rev. Sci. Instrum. 85, 013106 (2014).

    CAS  Article  Google Scholar 

  28. 28.

    Joly, L. et al. Fast continuous energy scan with dynamic coupling of the monochromator and undulator at the DEIMOS beamline. J. Synchrotron Radiat. 21, 502–506 (2014).

    CAS  Article  Google Scholar 

  29. 29.

    Kappler, J.-P. et al. Ultralow-temperature device dedicated to soft X-ray magnetic circular dichroism experiments. J. Synchrotron Radiat. 25, 1727–1735 (2018).

    CAS  Article  Google Scholar 

  30. 30.

    Piamonteze, C. et al. X-treme beamline at SLS: X-ray magnetic circular and linear dichroism at high field and low temperature. J. Synchrotron Radiat. 19, 661–674 (2012).

    CAS  Article  Google Scholar 

Download references

Acknowledgements

We are grateful to the SOLEIL staff for the smooth running of the facility and to F. Leduc for technical assistance. We acknowledge funding by the Deutsche Forschungsgemeinschaft (DFG) via SFB 677. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant no. 766726.

Author information

Affiliations

Authors

Contributions

F.G. and R.H. conceived and synthesized the molecules. M.G., S.R., T.J.-T., S.J., F.D., A.S., J.G. and M.S. carried out the NEXAFS measurements. M.G. analysed the corresponding data. F.G. and F.R. carried out the DFT calculations. A.K., M.G. and A.W. performed the STM measurements and analysed the data. All authors discussed the data and their interpretation. M.G. wrote the manuscript with input from R.B., A.K., F.G. and R.H.

Corresponding authors

Correspondence to Rainer Herges or Manuel Gruber.

Additional information

Peer Review Information Nature Nanotechnology thanks Mirko Cinchetti and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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

Extended data

Extended Data Figure 1 Description of the switching procedure of complex 2.

Examples of switching procedures ab from the LS to the HS state and cd from the HS to the LS state. The tip is positioned over the center of the complex experiencing the switching, and the current feedback loop is active while the voltage is gradually varied as a function of time. While the switching from the LS to the HS state (HS to LS) occurs at a sample voltage of 2.5 V (\(-1.7\) V) for these examples, the voltage required to induce a transition varies from 2.1 to 2.7 V (\(-1.6\) to \(-2.1\) V), and the large voltage may need to be applied for several seconds to several minutes for transitions from the LS to the HS state. The large spread in the threshold voltages may be due to the exact positioning of the tip and details of the molecule’s environment. To increase the success rate of the switching from the LS to the HS state, we usually applied a sample voltage between 2.5 and 2.7 V with a current between 30 pA and 1 nA for approximately 5 min. While this procedure is very effective, it is at the cost of selectivity as neighboring molecules were usually switched as well. In contrast, HS to LS switching is relatively efficient. Sub-pA currents may be sufficient to induce the corresponding transition (see Extended Data Fig. 2). The arrows indicate the time at which the switching takes place.

Extended Data Figure 2 Switching sequence of two complexes.

ae Constant-height STM topographs (1 V, 10 pA, 4.65 nm wide) describing the switching sequence of two complexes (compound 2) on Ag(111). In this example, a sample voltage of 2.7 V was applied for 30 s between the acquisition of topographs a and b, and between topographs b and c (tunneling current of 30 pA) to induce transitions from the LS to the HS state of the lower left and lower right complexes. The topographs a and b illustrate that the switching can be induced in neighboring molecules upon application of large voltages. Indeed, the tip was positioned on the top right molecule (white disk in a) while the lower right molecule is switched (lower right molecule in b). f, \(I-V\) curve recorded atop the lower right molecule in c leading to the switching from the HS to the LS state. Note that a current of \(\approx 250\) fA was sufficient to induce the transition highlighting the efficiency of the backward switching process.

Supplementary information

Supplementary Information

Supplementary Figs. 1–12, Tables 1–4 and refs. 31–56.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Köbke, A., Gutzeit, F., Röhricht, F. et al. Reversible coordination-induced spin-state switching in complexes on metal surfaces. Nat. Nanotechnol. 15, 18–21 (2020). https://doi.org/10.1038/s41565-019-0594-8

Download citation

Further reading

Search

Find nanotechnology articles, nanomaterial data and patents all in one place. Visit Nano by Nature Research