Skip to main content

Thank you for visiting 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.

Magnetic ordering through itinerant ferromagnetism in a metal–organic framework


Materials that combine magnetic order with other desirable physical attributes could find transformative applications in spintronics, quantum sensing, low-density magnets and gas separations. Among potential multifunctional magnetic materials, metal–organic frameworks, in particular, bear structures that offer intrinsic porosity, vast chemical and structural programmability, and the tunability of electronic properties. Nevertheless, magnetic order within metal–organic frameworks has generally been limited to low temperatures, owing largely to challenges in creating a strong magnetic exchange. Here we employ the phenomenon of itinerant ferromagnetism to realize magnetic ordering at TC = 225 K in a mixed-valence chromium(ii/iii) triazolate compound, which represents the highest ferromagnetic ordering temperature yet observed in a metal–organic framework. The itinerant ferromagnetism proceeds through a double-exchange mechanism, which results in a barrierless charge transport below the Curie temperature and a large negative magnetoresistance of 23% at 5 K. These observations suggest applications for double-exchange-based coordination solids in the emergent fields of magnetoelectrics and spintronics.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Solid-state structures.
Fig. 2: Spectroscopic characterization.
Fig. 3: Magnetic properties of Cr(tri)2(CF3SO3)0.33.
Fig. 4: Electronic structure calculations and electronic conductivity of Cr(tri)2(CF3SO3)0.33.

Data availability

All data supporting the findings of this study are available within the paper and its Supplementary Information files. Source data are provided with this paper.


  1. 1.

    Gutfleicsch, O. et al. Magnetic materials and devices for the 21st century: stronger, lighter and more energy efficient. Adv. Mater. 23, 821–842 (2011).

    Article  Google Scholar 

  2. 2.

    Felser, C., Fecher, G. H. & Balke, B. Spintronics: a challenge for materials science and solid-state chemistry. Angew. Chem. Int. Ed. 46, 668–699 (2007).

    CAS  Article  Google Scholar 

  3. 3.

    Coronado, E., Palacio, F. & Veciana, J. Molecule-based magnetic materials. Angew. Chem. Int. Ed. 42, 2570–2572 (2003).

    CAS  Article  Google Scholar 

  4. 4.

    Kübler, J. Theory of Itinerant Electron Magnetism (Oxford Univ. Press, 2000).

  5. 5.

    Zener, C. Interaction between the d-shells in the transition metals. II. Ferromagnetic compounds of manganese with perovskite structure. Phys. Rev. 82, 403–405 (1951).

    CAS  Article  Google Scholar 

  6. 6.

    Briceño, G., Chang, H., Sun, X., Schultz, P. G. & Xiang, X.-D. A class of cobalt oxide magnetoresistance materials discovered with combinatorial synthesis. Science 270, 273–275 (1995).

    Article  Google Scholar 

  7. 7.

    Şaşıoğlu, E., Sandratskii, L. M. & Bruno, P. Role of conduction electrons in mediating exchange interactions in Mn-based Heusler alloys. Phys. Rev. B 77, 064417 (2008).

    Article  Google Scholar 

  8. 8.

    Yaghi, O. M. et al. Reticular synthesis and the design of new materials. Nature 423, 705–714 (2003).

    CAS  Article  Google Scholar 

  9. 9.

    Calbo, J., Golomb, M. J. & Walsh, A. Redox-active metalo-organic frameworks for energy conversion and storage. J. Mater. Chem. A 7, 16571–16597 (2019).

    CAS  Article  Google Scholar 

  10. 10.

    Yin, Z., Wan, S., Yang, J., Kurmoo, M. & Zeng, M.-H. Recent advances in post-synthetic modification of metal–organic frameworks: new types and tandem reactions. Coord. Chem. Rev. 378, 500–512 (2019).

    CAS  Article  Google Scholar 

  11. 11.

    Dechambenoit, P. & Long, J. R. Microporous magnets. Chem. Soc. Rev. 40, 3249–3265 (2011).

    CAS  Article  Google Scholar 

  12. 12.

    Thorarinsdottir, A. E. & Harris, T. D. Metal–organic framework magnets. Chem. Rev. 120, 8716–8789 (2020).

    CAS  Article  Google Scholar 

  13. 13.

    Kosaka, W. et al. Gas-responsive porous magnet distinguishes the electron spin of molecular oxygen. Nat. Commun. 9, 5420 (2018).

    CAS  Article  Google Scholar 

  14. 14.

    Ruiz, E., Rodríguez-Fortea, A., Alvarez, S. & Verdaguer, M. Is it possible to get high TC magnets with Prussian blue analogues? A theoretical prospect. Chem. Eur. J. 11, 2135–2144 (2005).

    CAS  Article  Google Scholar 

  15. 15.

    Mallah, T., Thiébaut, S., Verdaguer, M. & Veillet, P. High-TC molecular-based magnets: ferrimagnetic mixed-valence chromium(iii)–chromium(ii) cyanide with TC at 240 and 190 Kelvin. Science 262, 1554–1557 (1993).

    CAS  Article  Google Scholar 

  16. 16.

    Ferlay, S., Mallah, T., Ouahès, R., Veillet, P. & Verdaguer, M. A room-temperature organometallic magnet based on Prussian blue. Nature 378, 701–703 (1995).

    CAS  Article  Google Scholar 

  17. 17.

    Holmes, S. M. & Girolami, G. S. Sol–gel synthesis of KVii[Criii(CN)6]·2H2O: a crystalline molecule-based magnet with a magnetic ordering above 100 °C. J. Am. Chem. Soc. 121, 5593–5594 (1999).

    CAS  Article  Google Scholar 

  18. 18.

    Manriquez, J. M., Yee, G. T., McLean, R. S., Epstein, A. J. & Miller, J. S. A room-temperature molecular/organic-based magnet. Science 252, 1415–1417 (1991).

    CAS  Article  Google Scholar 

  19. 19.

    Bechlar, B. et al. High-spin ground states via electron delocalization in mixed-valence imidazolate-bridged divanadium complexes. Nat. Chem. 2, 362–368 (2010).

    Article  Google Scholar 

  20. 20.

    Gaudette, A. I. et al. Electron hopping through double-exchange coupling in a mixed-valence diiminobenzoquinone-bridged Fe2 complex. J. Am. Chem. Soc. 137, 12617–12626 (2015).

    CAS  Article  Google Scholar 

  21. 21.

    Schulze, B. & Schubert, U. S. Beyond click chemistry—supramolecular interactions of 1,2,3-triazoles. Chem. Soc. Rev. 43, 2522–2571 (2014).

    CAS  Article  Google Scholar 

  22. 22.

    Aubrey, M. L. et al. Electron delocalization and charge mobility as a function of reduction in a metal–organic framework. Nat. Mater. 17, 625–632 (2018).

    CAS  Article  Google Scholar 

  23. 23.

    Zhang, J. P., Zhang, Y. B., Lin, J. B. & Chen, X. M. Metal azolate frameworks: from crystal engineering to functional materials. Chem. Rev. 112, 1001–1033 (2012).

    CAS  Article  Google Scholar 

  24. 24.

    Park, J. G. et al. Charge delocalization and bulk electronic conductivity in the mixed-valence metal–organic framework Fe(1,2,3-triazolate)2(BF4)x. J. Am. Chem. Soc. 140, 8526–8534 (2018).

    CAS  Article  Google Scholar 

  25. 25.

    Brunschwig, B. S., Creutz, C. & Sutin, N. Optical transitions of symmetrical mixed-valence systems in the class II–III transition regime. Chem. Soc. Rev. 31, 168–184 (2002).

    CAS  Article  Google Scholar 

  26. 26.

    Gándara, F. et al. Porous, conductive metal–triazolates and their structural elucidation by the charge-flipping method. Chem. Eur. J. 18, 10595–10601 (2012).

    Article  Google Scholar 

  27. 27.

    Zhou, X.-H., Peng, Y.-H., Du, X.-D., Zuo, J.-L. & You, X.-Z. Hydrothermal syntheses and structures of three novel coordination polymers assembled from 1,2,3-triazolate ligands. Cryst. Eng. Comm. 11, 1964–1970 (2009).

    CAS  Article  Google Scholar 

  28. 28.

    Collman, J. P. et al. Synthetic, electrochemical, optical, and conductivity studies of coordination polymers of iron, ruthenium, and osmium octaethylporphyrin. J. Am. Chem. Soc. 109, 4606–4614 (1987).

    CAS  Article  Google Scholar 

  29. 29.

    Tanner, D. B., Jacobsen, C. S., Garito, A. F. & Heeger, A. J. Infrared studies of the energy gap in tetrathiofulvalene-tetracyanoquinodimethane (TTF-TCNQ). Phys. Rev. B 13, 3381–3404 (1976).

    CAS  Article  Google Scholar 

  30. 30.

    Motokawa, N., Miyasaka, H., Yamashita, M. & Dunbar, K. R. An electron-transfer ferromagnet with TC = 107 K based on a three-dimensional [Ru2]2/TCNQ system. Angew. Chem. Int. Ed. 47, 7760–7763 (2008).

    CAS  Article  Google Scholar 

  31. 31.

    Stone, K. H. et al. Mnii(TCNE)3/2(I3)1/2—a 3D network-structured organic-based magnet and comparison to a 2D analog. Adv. Mater. 22, 2514–2519 (2010).

    CAS  Article  Google Scholar 

  32. 32.

    Kessler, J. Polarized Electrons (Springer, 1985).

  33. 33.

    Efros, A. L. & Shklovskii, B. I. Coulomb gap and low temperature conductivity of disordered systems. J. Phys. C 8, L49–L56 (1975).

    CAS  Article  Google Scholar 

  34. 34.

    Raju, N. P. et al. Anomalous magnetoresistance in high-temperature organic-based magnetic semiconducting V(TCNE)x films. J. Appl. Phys. 93, 6799 (2003).

    CAS  Article  Google Scholar 

  35. 35.

    Coronado, E., Prieto-Ruiz, J. P. & Prima-Garcia, H. Spin polarization in electrodeposited thin films of the molecule-based magnetic semiconductor Cr5.5(CN)12·11.5H2O. Chem. Commun. 49, 10145–10147 (2013).

    CAS  Article  Google Scholar 

  36. 36.

    Lu, Y. et al. Thin-film deposition of an organic magnet based on vanadium methyl tricyanoethylenecarboxylate. Adv. Mater. 26, 7632–7636 (2014).

    CAS  Article  Google Scholar 

  37. 37.

    Black, N. et al. Giant negative magnetoresistance in Ni(quinoline-8-selenoate)2. Phys. Chem. Chem. Phys. 20, 514–519 (2018).

    CAS  Article  Google Scholar 

  38. 38.

    Coey, J. M. D. & Venkatesan, M. Half-metallic ferromagnetism: example of CrO2. J. Appl. Phys. 91, 8345–8350 (2002).

    CAS  Article  Google Scholar 

  39. 39.

    Xiao, J. Q., Jian, J. S. & Chien, C. L. Giant magnetoresistance in nonmultilayer magnetic systems. Phys. Rev. Lett. 68, 3749–3752 (1992).

    CAS  Article  Google Scholar 

  40. 40.

    Coelho, A. A. TOPAS-Academic v. 5 (Coelho Software, 2017).

  41. 41.

    Huq, A. et al. POWGEN: rebuild of a third-generation powder diffractometer at the Spallation Neutron Source. J. Appl. Cryst. 52, 1199–1201 (2019).

    Article  Google Scholar 

Download references


This research was supported by the National Science Foundation (NSF) Award no. DMR-1611525, with the exception of the measurement and analysis of the magnetic data, which were supported by the Nanoporous Materials Genome Center of the US Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences under Award no. DE-FG02-17ER16362. Powder X-ray diffraction data were collected at Beamline 11-BM at the APS, operated by Argonne National Laboratory, and beamline BM31 at the ESRF. We are grateful to our local contact at the ESRF for providing assistance in using beamline BM31. Use of the APS at Argonne National Laboratory was supported by US Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract no. DE-AC02-06CH11357. Data from Beamline 11-BM were collected as part of the 2018 Modern Methods in Rietveld Refinement and Structural Analysis workshop, a school supported by the US National Committee for Crystallography and the American Crystallographic Association. Neutron diffraction data were collected at the POWGEN beamline at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. Soft X-ray absorption spectroscopy data were collected at Beamline 8.0.1 at the Advanced Light Source of Lawrence Berkeley National Laboratory, a Department of Energy Office of Science User Facility under Contract no. DE-AC02-05CH11231. Electronic structure calculations utilized an award of computer time provided by the ASCR Leadership Computing Challenge (ALCC) program and resources of the National Energy Research Scientific Computing Center, a US Department of Energy Office of Science User Facility operated under Contract no. DE-AC02-05CH11231. Additional computation resources were provided by the Minnesota Supercomputing Institute at the University of Minnesota. T.R. thanks the Welch Foundation (Grant no. N-2012-20190330) for funding. In addition, we thank J. Oktawiec, S. H. Lapidus, X. Wenqian, P. Khalifah, Q. Zhang, M. J. Kirkham, Y.-S. Liu and G. Ren for discussions and experimental assistance, and T.D.H. for editorial assistance. We also thank the National Science Foundation and National GEM Consortium for providing graduate fellowship supports for J.G.P. and B.A.C., respectively.

Author information




J.G.P. and J.R.L. formulated the project. J.G.P. synthesized the compound. B.A.C. and J.D.G. performed electronic structure calculations and analysed the data. J.G.P. and L.E.D. collected and analysed the magnetic data. M.E.Z. collected X-ray absorption spectroscopy data. J.G.P. and M.L.A. collected and analysed conductivity data. E.V. collected scanning electron microscopy images. H.Z.H.J. collected and analysed the infrared spectra. J.G.P. collected and analysed powder X-ray diffraction data from the APS, with assistance from T.R. M.A.G. collected and analysed powder X-ray diffraction data from the ESRF. M.A.G. and J.G.P. collected and analysed powder neutron diffraction data. J.G.P. and J.R.L. wrote the paper, and all the authors contributed to revising it.

Corresponding author

Correspondence to Jeffrey R. Long.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Peer review information Nature Chemistry thanks Talal Mallah 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 Fig. 1 Scanning electron microscopy images of Cr(tri)2(CF3SO3)0.33 crystals.

a,b Scanning electron microscopy images of microcrystalline Cr(tri)2(CF3SO3)0.33 powder. Octahedron-shaped crystals have an average edge dimension of ~0.5 μm. Scale bars 2 μm (a) and 1 μm (b).

Extended Data Fig. 2 Analyses of the Cr mixed-valency.

a, N2 adsorption isotherm collected at 77 K for Cr(tri)2(CF3SO3)0.33. Closed and open data points represent adsorption and desorption, respectively. b, Infrared data collected at 150 K (blue) and 300 K (red) and the difference plot (green) for Cr(tri)2(CF3SO3)0.33. Source data

Extended Data Fig. 3 Magnetic data.

a, Variable-temperature magnetic susceptibility data (χM) for Cr(tri)2(CF3SO3)0.33 collected under the applied dc field of 25 Oe. Data plotted as 1/χM versus temperature. Curie-Weiss fit to the data between 300 K and 350 K is shown by a black solid line, with fitting parameters described in the main text. b-f, Variable-temperature in-phase (χ”) and out-of-phase (χ”) ac magnetic susceptibility of Cr(tri)2(CF3SO3)0.33 at selected frequencies of 4 Oe ac oscillating magnetic field and zero dc magnetic field. Source data

Extended Data Fig. 4 Charge analysis.

a, Magnetic moments (µB mol−1) for the ferromagnetic state. b, Atomic charge for the ferromagnetic state in atomic units. c, Magnetic moments (µB mol−1) for the antiferromagnetic state. d, Atomic charge for the antiferromagnetic state in atomic units. Atomic properties shown as a gradient from blue to white to red. Negative magnetic moments indicate spin-down contributions.

Extended Data Fig. 5 Variable temperature conductivity data modeling.

a-d, Variable-temperature log(σ) data of Cr(tri)2(CF3SO3)0.33 plotted versus 1/T0.25 (a), 1/T0.5 (b), and 1/T and fitted with three-dimensional variable-range hopping, Efros-Shklovskii variable-range hopping, and Arrhenius models, respectively (c, d). For clarity, log(σ) versus 1/T plot (c) has been zoomed-in to the intermediate temperature region (d) where conductivity exhibits a weak temperature dependence. Source data

Supplementary information

Supplementary Information

Definition of compound, additional methods, additional discussion, references, Supplementary Tables 1 and 2 and Figs. 1–7.

Supplementary Data 1

Supplementary PXRD Data containing synchrotron powder X-ray diffraction data (.xye) and input (.inp) files used for performing Rietveld refinements in Supplementary Figure 1.

Supplementary Data 2

Supplementary computational data, source data for Supplementary Figure 4.

Source data

Source Data Fig. 2

Statistical source data for Figure 2a,b.

Source Data Fig. 3

Statistical source data for Figure 3a,b,c.

Source Data Fig. 4

Statistical source data for Figure 4e,f.

Source Data Extended Data Fig. 2

Statistical source data for Extended Data Figure 2.

Source Data Extended Data Fig. 3

Statistical source data for Extended Data Figure 3.

Source Data Extended Data Fig. 5

Statistical source data for Extended Data Figure 5.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Park, J.G., Collins, B.A., Darago, L.E. et al. Magnetic ordering through itinerant ferromagnetism in a metal–organic framework. Nat. Chem. (2021).

Download citation


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