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.

Quantum nanomagnets in on-surface metal-free porphyrin chains

Nature Chemistry volume 15, pages 53–60 (2023)Cite this article

Subjects

Abstract

Unlike classic spins, quantum magnets are spin systems that interact via the exchange interaction and exhibit collective quantum behaviours, such as fractional excitations. Molecular magnetism often stems from d/f-transition metals, but their spin–orbit coupling and crystal field induce a significant magnetic anisotropy, breaking the rotation symmetry of quantum spins. Thus, it is of great importance to build quantum nanomagnets in metal-free systems. Here we have synthesized individual quantum nanomagnets based on metal-free multi-porphyrin systems. Covalent chains of two to five porphyrins were first prepared on Au(111) under ultrahigh vacuum, and hydrogen atoms were then removed from selected carbons using the tip of a scanning tunnelling microscope. The conversion of specific porphyrin units to their radical or biradical state enabled the tuning of intra- and inter-porphyrin magnetic coupling. Characterization of the collective magnetic properties of the resulting chains showed that the constructed S = 1/2 antiferromagnets display a gapped excitation, whereas the S = 1 antiferromagnets exhibit distinct end states between even- and odd-numbered spin chains, consistent with Heisenberg model calculations.

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

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Get just this article for as long as you need it

$39.95

Learn more

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

Fig. 1: Construction of molecular nanomagnets in metal-free porphyrins.
Fig. 2: Characterization of intra-unit magnetic coupling within porphyrin monomers.
Fig. 3: Characterization of inter-unit magnetic coupling within porphyrin dimers.
Fig. 4: Antiferromagnetic coupled finite S = 1/2 spin chain.
Fig. 5: Antiferromagnetic coupled finite S = 1 spin chains.

Data availability

Data supporting the findings of this study are available within the paper and its Supplementary Information. The Supplementary Information includes details of experiments, synthetic procedures and characterization data of the molecular precursor, as well as details of calculations. Source data are provided with this paper.

Code availability

The Heisenberg Hamiltonians were solved using Python. Details of this code are available from the corresponding author on request.

References

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

    Article  Google Scholar 

  2. Shimizu, D. & Osuka, A. Porphyrinoids as a platform of stable radicals. Chem. Sci. 9, 1408–1423 (2018).

    Article  CAS  Google Scholar 

  3. Li, J. et al. Survival of spin state in magnetic porphyrins contacted by graphene nanoribbons. Sci. Adv. 4, eaaq0582 (2018).

    Article  Google Scholar 

  4. Kadish, K., Smith, K. & Guilard, R. Handbook of Porphyrin Science (World Scientific, 2010).

  5. Baklanov, A. et al. On-surface synthesis of nonmetal porphyrins. J. Am. Chem. Soc. 142, 1871–1881 (2020).

    Article  CAS  Google Scholar 

  6. Mateo, L. M. et al. On-surface synthesis and characterization of triply fused porphyrin-graphene nanoribbon hybrids. Angew. Chem. Int. Ed. 59, 1334–1339 (2020).

    Article  CAS  Google Scholar 

  7. Fan, Q. et al. Template-controlled on-surface synthesis of a lanthanide supernaphthalocyanine and its open-chain polycyanine counterpart. Nat. Commun. 10, 5049 (2019).

    Article  Google Scholar 

  8. Doppagne, B. et al. Single-molecule tautomerization tracking through space- and time-resolved fluorescence spectroscopy. Nat. Nanotechnol. 15, 207–211 (2020).

    Article  CAS  Google Scholar 

  9. Köbke, A. et al. Reversible coordination-induced spin-state switching in complexes on metal surfaces. Nat. Nanotechnol. 15, 18–21 (2020).

    Article  Google Scholar 

  10. Cirera, B. et al. On-surface synthesis of gold porphyrin derivatives via a cascade of chemical interactions: planarization, self-metalation and intermolecular coupling. Chem. Mater. 31, 3248–3256 (2019).

    Article  CAS  Google Scholar 

  11. Su, X., Xue, Z., Li, G. & Yu, P. Edge state engineering of graphene nanoribbons. Nano Lett. 18, 5744–5751 (2018).

    Article  CAS  Google Scholar 

  12. Bischoff, F. et al. Exploration of interfacial porphine coupling schemes and hybrid systems by bond-resolved scanning probe microscopy. Angew. Chem. Int. Ed. 57, 16030–16035 (2018).

    Article  CAS  Google Scholar 

  13. Zeng, W. et al. Phenalenyl-fused porphyrins with different ground states. Chem. Sci. 6, 2427–2433 (2015).

    Article  CAS  Google Scholar 

  14. Sun, Q. et al. On-surface formation of two-dimensional polymer via direct C–H activation of metal phthalocyanine. Chem. Commun. 51, 2836–2839 (2015).

    Article  CAS  Google Scholar 

  15. Müllegger, S., Schöfberger, W., Rashidi, M., Reith, L. M. & Koch, R. Spectroscopic STM studies of single gold(III) porphyrin molecules. J. Am. Chem. Soc. 131, 17740–17741 (2009).

    Article  Google Scholar 

  16. Grill, L. & Hecht, S. Covalent on-surface polymerization. Nat. Chem. 12, 115–130 (2020).

    Article  CAS  Google Scholar 

  17. Grill, L. et al. Nano-architectures by covalent assembly of molecular building blocks. Nat. Nanotechnol. 2, 687–691 (2007).

    Article  CAS  Google Scholar 

  18. Zhao, Y. et al. Precise control of π-electron magnetism in metal-free porphyrins. J. Am. Chem. Soc. 142, 18532–18540 (2020).

    Article  CAS  Google Scholar 

  19. Rana, A. et al. Stable expanded porphycene‐based diradicaloid and tetraradicaloid. Angew. Chem. 130, 12714–12717 (2018).

    Article  Google Scholar 

  20. Sun, Q. et al. Inducing open-shell character in porphyrins through surface-assisted phenalenyl π-extension. J. Am. Chem. Soc. 142, 18109–18117 (2020).

    Article  CAS  Google Scholar 

  21. Clair, S. & de Oteyza, D. G. Controlling a chemical coupling reaction on a surface: tools and strategies for on-surface synthesis. Chem. Rev. 119, 4717–4776 (2019).

    Article  CAS  Google Scholar 

  22. Ruffieux, P. et al. On-surface synthesis of graphene nanoribbons with zigzag edge topology. Nature 531, 489–492 (2016).

    Article  CAS  Google Scholar 

  23. Cai, J. et al. Atomically precise bottom-up fabrication of graphene nanoribbons. Nature 466, 470–473 (2010).

    Article  CAS  Google Scholar 

  24. Gröning, O. et al. Engineering of robust topological quantum phases in graphene nanoribbons. Nature 560, 209–213 (2018).

    Article  Google Scholar 

  25. Zhong, D. et al. Linear alkane polymerization on a gold. Surf. Sci. 334, 213–216 (2011).

    CAS  Google Scholar 

  26. de Oteyza, D. G. et al. Direct imaging of covalent bond structure in single-molecule chemical reactions. Science 340, 1434–1437 (2013).

    Article  Google Scholar 

  27. Moreno, C. et al. Bottom-up synthesis of multifunctional nanoporous graphene. Science 360, 199–203 (2018).

    Article  CAS  Google Scholar 

  28. Mishra, S. et al. Topological frustration induces unconventional magnetism in a nanographene. Nat. Nanotechnol. 15, 22–28 (2020).

    Article  CAS  Google Scholar 

  29. Zheng, Y. et al. Designer spin order in diradical nanographenes. Nat. Commun. 11, 6076 (2020).

    Article  CAS  Google Scholar 

  30. Zheng, Y. et al. Engineering of magnetic coupling in nanographene. Phys. Rev. Lett. 124, 147206 (2020).

    Article  CAS  Google Scholar 

  31. Song, S. et al. On-surface synthesis of graphene nanostructures with π-magnetism. Chem. Soc. Rev. 50, 3238–3262 (2021).

    Article  CAS  Google Scholar 

  32. Hla, S.-W., Bartels, L., Meyer, G. & Rieder, K.-H. Inducing all steps of a chemical reaction with the scanning tunneling microscope tip: towards single molecule engineering. Phys. Rev. Lett. 85, 2777–2780 (2000).

    Article  CAS  Google Scholar 

  33. Kaiser, K. et al. An sp-hybridized molecular carbon allotrope, cyclo[18]carbon. Science 365, 1299–1301 (2019).

    Article  CAS  Google Scholar 

  34. Pavliček, N. et al. Synthesis and characterization of triangulene. Nat. Nanotechnol. 12, 308–311 (2017).

    Article  Google Scholar 

  35. Pavliček, N. et al. Polyyne formation via skeletal rearrangement induced by atomic manipulation. Nat. Chem. 10, 853–858 (2018).

    Article  Google Scholar 

  36. Beyer, D. et al. Graphene nanoribbons derived from zigzag edge-encased poly(para-2,9-dibenzo[bc,kl]coronenylene) polymer chains. J. Am. Chem. Soc. 141, 2843–2846 (2019).

    Article  CAS  Google Scholar 

  37. Gross, L., Mohn, F., Moll, N., Liljeroth, P. & Meyer, G. The chemical structure of a molecule resolved by atomic force microscopy. Science 325, 1110–1114 (2009).

    Article  CAS  Google Scholar 

  38. Ortiz, R. et al. Exchange rules for diradical π-conjugated hydrocarbons. Nano Lett. 19, 5991–5997 (2019).

    Article  CAS  Google Scholar 

  39. Ternes, M. Spin excitations and correlations in scanning tunneling spectroscopy. New J. Phys. 17, 063016 (2015).

    Article  Google Scholar 

  40. Choi, D.-J. et al. Colloquium: atomic spin chains on surfaces. Rev. Mod. Phys. 91, 041001 (2019).

    Article  CAS  Google Scholar 

  41. Li, J. et al. Uncovering the triplet ground state of triangular graphene nanoflakes engineered with atomic precision on a metal surface. Phys. Rev. Lett. 124, 177201 (2020).

    Article  CAS  Google Scholar 

  42. Su, X. et al. Atomically precise synthesis and characterization of heptauthrene with triplet ground state. Nano Lett. 20, 6859–6864 (2020).

    Article  CAS  Google Scholar 

  43. Žonda, M. et al. Resolving ambiguity of the Kondo temperature determination in mechanically tunable single-molecule Kondo systems. J. Phys. Chem. Lett. 12, 6320–6325 (2021).

    Article  Google Scholar 

  44. Toskovic, R. et al. Atomic spin-chain realization of a model for quantum criticality. Nat. Phys. 12, 656–660 (2016).

    Article  CAS  Google Scholar 

  45. Rubio-Verdú, C., Zaldívar, J., Žitko, R. & Pascual, J. I. Coupled Yu-Shiba-Rusinov states induced by a many-body molecular spin on a superconductor. Phys. Rev. Lett. 126, 017001 (2021).

    Article  Google Scholar 

  46. Haldane, F. D. M. Nonlinear field theory of large-spin Heisenberg antiferromagnets: semiclassically quantized solitons of the one-dimensional easy-axis Néel state. Phys. Rev. Lett. 50, 1153–1156 (1983).

    Article  Google Scholar 

  47. Taniguchi, M., Balakumar, A., Fan, D., McDowell, B. E. & Lindsey, J. S. Imine-substituted dipyrromethanes in the synthesis of porphyrins bearing one or two meso substituents. J. Porphyr. Phthalocyan. 09, 554–574 (2005).

    Article  CAS  Google Scholar 

  48. 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  Google Scholar 

  49. Weigend, F. & Ahlrichs, R. Balanced basis sets of split valence, triple zeta valence and quadruple zeta valence quality for H to Rn: design and assessment of accuracy. Phys. Chem. Chem. Phys. 7, 3297–3305 (2005).

    Article  CAS  Google Scholar 

  50. Lu, T. & Chen, F. Multiwfn: a multifunctional wavefunction analyzer. J. Comput. Chem. 33, 580–592 (2012).

    Article  Google Scholar 

  51. Momma, K. & Izumi, F. VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data. J. Appl. Crystallogr. 44, 1272–1276 (2011).

    Article  CAS  Google Scholar 

  52. Kresse, G. & Hafner, J. Ab initio molecular dynamics for liquid metals. Phys. Rev. B 47, 558–561 (1993).

    Article  CAS  Google Scholar 

  53. 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).

    Article  CAS  Google Scholar 

  54. Kresse, G. & Furthmüller, J. Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set. Comput. Mater. Sci. 6, 15–50 (1996).

    Article  CAS  Google Scholar 

  55. 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).

    Article  CAS  Google Scholar 

  56. Blöchl, P. E. Projector augmented-wave method. Phys. Rev. B 50, 17953–17979 (1994).

    Article  Google Scholar 

  57. Ternes, M., Heinrich, A. J. & Schneider, W.-D. Spectroscopic manifestations of the Kondo effect on single adatoms. J. Phys. Condens. Matter 21, 053001 (2009).

    Article  Google Scholar 

Download references

Acknowledgements

S.W. acknowledges financial support from the National Key R&D Program of China (no. 2020YFA0309000), the National Natural Science Foundation of China (nos. 11874258 and 12074247), the Shanghai Municipal Science and Technology Qi Ming Xing Project (no. 20QA1405100), Fok Ying Tung Foundation for young researchers and SJTU (no. 21×010200846). This work is also partially supported by the Ministry of Science and Technology of China (grants nos. 2019YFA0308600, 2016YFA0301003 and 2016YFA0300403), NSFC (grants nos. 11521404, 11634009, 92065201, 11874256, 11790313 and 11861161003), the Strategic Priority Research Program of Chinese Academy of Sciences (grant no. XDB28000000) and the Science and Technology Commission of Shanghai Municipality (grants nos. 2019SHZDZX01, 19JC1412701 and 20QA1405100). We acknowledge the π 2.0 cluster of the Center for High Performance Computing at Shanghai Jiao Tong University.

Author information

Author notes

  1. These authors contributed equally: Yan Zhao, Kaiyue Jiang, Can Li.

Authors and Affiliations

  1. Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China

    Yan Zhao, Can Li, Yufeng Liu, Gucheng Zhu, Dandan Guan, Yaoyi Li, Hao Zheng, Canhua Liu, Jinfeng Jia, Mingpu Qin & Shiyong Wang

  2. The meso-Entropy Matter Lab, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, China

    Kaiyue Jiang & Xiaodong Zhuang

  3. School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA

    Michele Pizzochero & Efthimios Kaxiras

  4. Department of Physics, Harvard University, Cambridge, MA, USA

    Efthimios Kaxiras

  5. Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai, China

    Dandan Guan, Yaoyi Li, Hao Zheng, Canhua Liu, Jinfeng Jia, Mingpu Qin & Shiyong Wang

  6. Shanghai Research Center for Quantum Sciences, Shanghai, China

    Dandan Guan, Yaoyi Li, Hao Zheng, Canhua Liu, Jinfeng Jia & Shiyong Wang

Authors
  1. Yan Zhao
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Kaiyue Jiang
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Can Li
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Yufeng Liu
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Gucheng Zhu
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Michele Pizzochero
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Efthimios Kaxiras
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Dandan Guan
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. Yaoyi Li
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. Hao Zheng
    View author publications

    You can also search for this author in PubMed Google Scholar

  11. Canhua Liu
    View author publications

    You can also search for this author in PubMed Google Scholar

  12. Jinfeng Jia
    View author publications

    You can also search for this author in PubMed Google Scholar

  13. Mingpu Qin
    View author publications

    You can also search for this author in PubMed Google Scholar

  14. Xiaodong Zhuang
    View author publications

    You can also search for this author in PubMed Google Scholar

  15. Shiyong Wang
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

S.W. conceived the experiments. Y.Z., C. Li and G.Z. performed the SPM experiments. K.J. and X.Z. synthesized the molecular precursors. Y. Liu performed the DFT calculations in the gas phase. M.P. and E.K. performed the DFT calculations on Au(111). C. Li and M.Q. performed the modelling calculations. D.G., Y. Li, H.Z., C. Liu and J.J. analysed the STS data. S.W., Y.Z. and C. Li wrote the paper. All authors discussed the results and implications and commented on the manuscript at all stages.

Corresponding authors

Correspondence to Xiaodong Zhuang or Shiyong Wang.

Ethics declarations

Competing interests

The authors declare no competing interests.

Peer review

Peer review information

Nature Chemistry thanks Pavel Jelinek, Jiong Lu, Oleg Yazyev 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. 1–22, molecular precursor synthesis details and calculation details.

Supplementary Data 1

Raw NMR data, unprocessed STM and AFM images, source dI/dV spectroscopic data and computational data for supplementary information.

Source data

Source Data Fig. 1

Unprocessed STM and AFM images.

Source Data Fig. 2

Unprocessed STM images, AFM images, source dI/dV spectra and DFT electronic geometries.

Source Data Fig. 3

Unprocessed STM images and source dI/dV spectra.

Source Data Fig. 4

Unprocessed STM images and source dI/dV spectra.

Source Data Fig. 5

Unprocessed STM images, AFM images, source dI/dV spectra and Heisenberg calculations.

Rights and permissions

Springer Nature or its licensor 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

Verify currency and authenticity via CrossMark

Cite this article

Zhao, Y., Jiang, K., Li, C. et al. Quantum nanomagnets in on-surface metal-free porphyrin chains. Nat. Chem. 15, 53–60 (2023). https://doi.org/10.1038/s41557-022-01061-5

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41557-022-01061-5

This article is cited by

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