Fast motion of molecular rotors in metal–organic framework struts at very low temperatures


The solid state is typically not well suited to sustaining fast molecular motion, but in recent years a variety of molecular machines, switches and rotors have been successfully engineered within porous crystals and on surfaces. Here we show a fast-rotating molecular rotor within the bicyclopentane–dicarboxylate struts of a zinc-based metal–organic framework—the carboxylate groups anchored to the metal clusters act as an axle while the bicyclic unit is free to rotate. The three-fold bipyramidal symmetry of the rotator conflicts with the four-fold symmetry of the struts within the cubic crystal cell of the zinc metal–organic framework. This frustrates the formation of stable conformations, allowing for the continuous, unidirectional, hyperfast rotation of the bicyclic units with an energy barrier of 6.2 cal mol−1 and a high frequency persistent for several turns even at very low temperatures (1010 Hz below 2 K). Using zirconium instead of zinc led to a different metal cluster–carboxylate coordination arrangement in the resulting metal–organic framework, and much slower rotation of the bicyclic units.

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Fig. 1: Factors influencing the molecular rotor dynamics, conformations of the rotator and stator in the ligand and the resulting energy profiles.
Fig. 2: Crystal structure, cavity geometry and rotors in the frameworks.
Fig. 3: Crossed (Zn) and in-plane (Zr) conformations with torsional energy profiles of the ligands.
Fig. 4: Solid-state NMR spectra and 1H T1 spin–lattice relaxation times of the molecular rotor in the MOFs recorded at various magnetic fields.
Fig. 5: Molecular dynamics results for Zn-FTR calculated at various temperatures.

Data availability

X-ray crystallographic data have been deposited at the Cambridge Crystallographic Data Centre ( with reference numbers CCDC 1994502 (single-crystal Zn-FTR), 1994503 (Zn-FTR refined from PXRD) and 1994504 (Zr-FTR refined from PXRD). A copy of the data can be obtained free of charge via All other data supporting the findings of this study are available within the article and its Supplementary Information. Data are also available from the corresponding author upon reasonable request. Raw data are available for Fig. 5. Source data are provided with this paper.


  1. 1.

    Saibil, H. Chaperone machines for protein folding, unfolding and disaggregation. Nat. Rev. Mol. Cell Biol. 14, 630–642 (2013).

    CAS  PubMed  PubMed Central  Google Scholar 

  2. 2.

    Kinbara, K. & Aida, T. Towards intelligent molecular machines: Directed motions of biological and artificial molecules and assemblies. Chem. Rev. 105, 1377–1400 (2005).

    CAS  PubMed  Google Scholar 

  3. 3.

    Olesen, C. et al. The structural basis of calcium transport by the calcium pump. Nature 450, 1036–1042 (2007).

    CAS  PubMed  Google Scholar 

  4. 4.

    Howard, J., Hudspeth, A. J. & Vale, R. D. Movement of microtubules by single kinesin molecules. Nature 342, 154–158 (1989).

    CAS  PubMed  Google Scholar 

  5. 5.

    Preben Morth, J. et al. A structural overview of the plasma membrane Na+,K+-ATPase and H+-ATPase ion pumps. Nat. Rev. Mol. Cell Biol. 12, 60–70 (2011).

    PubMed  Google Scholar 

  6. 6.

    Vogelsberg, C. S. & Garcia-Garibay, M. A. Crystalline molecular machines: function, phase order, dimensionality, and composition. Chem. Soc. Rev. 41, 1892–1910 (2012).

    CAS  PubMed  Google Scholar 

  7. 7.

    Bracco, S., Comotti, A. & Sozzani, P. Molecular rotors built in porous materials. Acc. Chem. Res. 49, 1701–1710 (2016).

    PubMed  Google Scholar 

  8. 8.

    Danowski, W. et al. Unidirectional rotary motion in a metal-organic framework. Nat. Nanotechnol. 488, 488–494 (2019).

    Google Scholar 

  9. 9.

    Deng, H., Olson, M. A., Stoddart, J. F. & Yaghi, O. M. Robust dynamics. Nat. Chem. 2, 439–443 (2010).

    CAS  PubMed  Google Scholar 

  10. 10.

    Zhu, K., O’Keefe, C. A., Vukotic, V. N., Schurko, R. W. & Loeb, S. J. A molecular shuttle that operates inside a metal-organic framework. Nat. Chem. 7, 514–519 (2015).

    CAS  PubMed  Google Scholar 

  11. 11.

    Kobr, L. et al. Inclusion compound based approach to arrays of artificial dipolar molecular rotors. A surface inclusion. J. Am. Chem. Soc. 134, 10122–10131 (2012).

    CAS  PubMed  Google Scholar 

  12. 12.

    Inukai, M. et al. Control of molecular rotor rotational frequencies in porous coordination polymers using a solid-solution approach. J. Am. Chem. Soc. 137, 12183–12186 (2015).

    CAS  PubMed  Google Scholar 

  13. 13.

    Vogelsberg, C. S. et al. Ultrafast rotation in an amphidynamic crystalline metal organic framework. Proc. Natl Acad. Sci. USA 114, 13613–13618 (2017).

    CAS  PubMed  Google Scholar 

  14. 14.

    Michl, J., Charles, E. & Sykes, H. Molecular rotors and motors: recent advances and future challenges. ACS Nano 3, 1042–1048 (2009).

    CAS  PubMed  Google Scholar 

  15. 15.

    Prokop, A., Vacek, J. & Michl, J. Friction in carborane-based molecular rotors driven by gas flow or electric field: classical molecular dynamics. ACS Nano 6, 1901–1914 (2012).

    CAS  PubMed  Google Scholar 

  16. 16.

    Coskun, A., Banaszak, M., Astumian, R. D., Stoddart, J. F. & Grzybowski, B. A. Great expectations: can artificial molecular machines deliver on their promise? Chem. Soc. Rev. 41, 19–30 (2012).

    CAS  PubMed  Google Scholar 

  17. 17.

    Steuerman, D. W. et al. Molecular-mechanical switch-based solid-state electrochromic devices. Angew. Chem. Int. Ed. 43, 6486–6491 (2004).

    CAS  Google Scholar 

  18. 18.

    Collier, C. P. et al. A [2]catenane-based solid state electronically reconfigurable switch. Science 289, 1172–1175 (2000).

    CAS  PubMed  Google Scholar 

  19. 19.

    Kaleta, J. et al. Surface inclusion of unidirectional molecular motors in hexagonal tris(o‑phenylene) cyclotriphosphazene. J. Am. Chem. Soc. 139, 10486–10498 (2017).

    CAS  PubMed  Google Scholar 

  20. 20.

    Jiang, X. et al. Crystal fluidity reflected by fast rotational motion at the core, branches, and peripheral aromatic groups of a dendrimeric molecular rotor. J. Am. Chem. Soc. 138, 4650–4656 (2016).

    CAS  PubMed  PubMed Central  Google Scholar 

  21. 21.

    Comotti, A., Bracco, S., Ben, T., Qiu, S. & Sozzani, P. Molecular rotors in porous organic frameworks. Angew. Chem. Int. Ed. 53, 1043–1047 (2014).

    CAS  Google Scholar 

  22. 22.

    Comotti, A. et al. & . Engineering switchable rotors in molecular crystals with open porosity. J. Am. Chem. Soc. 136, 618–621 (2014).

    CAS  PubMed  Google Scholar 

  23. 23.

    Bracco, S. et al. CO2 regulates molecular rotor dynamics in porous materials. Chem. Commun. 53, 7776–7779 (2017).

    CAS  Google Scholar 

  24. 24.

    Bracco, S. et al. Ultrafast molecular rotors and their CO2 tuning in MOFs with rod-like ligands. Chem. Eur. J. 23, 11210–11215 (2017).

    CAS  PubMed  Google Scholar 

  25. 25.

    Bracco, S. et al. & . Dipolar rotors orderly aligned in mesoporous fluorinated organosilica architectures. Angew. Chem. Int. Ed. 54, 4773–4777 (2015).

    CAS  Google Scholar 

  26. 26.

    Horike, S. et al. & . Dynamic motion of building blocks in porous coordination polymers. Angew. Chem. Int. Ed. 45, 7226–7230 (2006).

    CAS  Google Scholar 

  27. 27.

    Zhu, K., Vukotic, V. N., Okeefe, C. A., Schurko, R. W. & Loeb, S. J. Metal–organic frameworks with mechanically interlocked pillars: controlling ring dynamics in the solid-state via a reversible phase change. J. Am. Chem. Soc. 136, 7403–7409 (2014).

    CAS  PubMed  Google Scholar 

  28. 28.

    Elsaidi, S. K. et al. Effect of ring rotation upon gas adsorption in SIFSIX-3-M (M = Fe, Ni) pillared square grid networks. Chem. Sci. 8, 2373–2380 (2017).

    CAS  PubMed  Google Scholar 

  29. 29.

    Gonzalez-Nelson, A., Coudert, F. X. & van der Veen, M. Rotational dynamics of linkers in metal–organic frameworks. Nanomaterials 9, 330–366 (2019).

    CAS  PubMed Central  Google Scholar 

  30. 30.

    Li, H., Eddaoudi, M., O’Keeffe, M. & Yaghi, O. M. Design and synthesis of an exceptionally stable and highly porous metal–organic framework. Nature 402, 276–279 (1999).

    CAS  Google Scholar 

  31. 31.

    Cavka, J. H. et al. & . A new zirconium inorganic building brick forming metal–organic frameworks with exceptional stability. J. Am. Chem. Soc. 130, 13850–13851 (2008).

    PubMed  Google Scholar 

  32. 32.

    Yuan, S., Qin, J.-S., Lollar, C. T. & Zhou, H.-C. Stable metal−organic frameworks with group 4 metals: Current status and trends. ACS Cent. Sci. 4, 440–450 (2018).

    CAS  PubMed  PubMed Central  Google Scholar 

  33. 33.

    Owen, N. L. in Internal Rotation in Molecules (ed. Orville‐Thomas, W. J.) Ch. 6 (Wiley, 1974).

  34. 34.

    Nakagawa, J. & Hayashi, M. Microwave spectrum and internal rotation of 2‐butyne‐1, 1, 1‐d3(dimethylacetylene), CH3C≡CCD3. J. Chem. Phys. 80, 5922–5925 (1984).

    CAS  Google Scholar 

  35. 35.

    Ilyushin, V. et al. Almost free methyl top internal rotation: Rotational spectrum of 2-butynoic acid. J. Mol Spectrosc. 267, 186–190 (2011).

    CAS  Google Scholar 

  36. 36.

    Hensel, K. D. & Gerry, M. C. L. Microwave spectrum of tetrolyl fluoride. J. Chem. Soc. Faraday Trans. 90, 3023–3027 (1994).

    CAS  Google Scholar 

  37. 37.

    Facelli, J. C. et al. & . Low-temperature carbon-13 magnetic resonance in solids. 5. Chemical shielding anisotropy of the 13CH2 group. J. Am. Chem. Soc. 107, 6749–6754 (1985).

    CAS  Google Scholar 

  38. 38.

    Gil, A. M. & Alberti, E. The effect of magic angle spinning on proton spin–lattice relaxation times in some organic solids. Solid State Nucl. Magn. Reson. 11, 203–209 (1998).

    CAS  PubMed  Google Scholar 

  39. 39.

    Ticko, R. et al. & . Molecular dynamics and the phase transition in solid C60. Phys. Rev. Lett. 67, 1886–1889 (1991).

    Google Scholar 

  40. 40.

    Panich, A. M. & Panich, E. A. NMR lineshape of a six-spin system with dipole-dipole interactions. Application to benzene. J. Magn. Res. Series A 116, 113–116 (1995).

    CAS  Google Scholar 

  41. 41.

    Goc, R. Computer calculation of the Van Vleck second moment for materials with internal rotation of spin groups. Comput. Phys. Commun. 162, 102–112 (2004).

    CAS  Google Scholar 

  42. 42.

    Kubo, R. & Tomita, K. A general theory of magnetic resonance adsorption. J. Phys. Soc. Jpn 9, 888–919 (1954).

    CAS  Google Scholar 

  43. 43.

    Koksal, F. & Rossler, E. Spin–lattice relaxation by tunneling motions of methyl groups in some organic compounds. Solid State Commun. 44, 233–235 (1982).

    Google Scholar 

  44. 44.

    Layanowicz, L. Spin–lattice NMR relaxation and second moment of NMR line in solids containing CH3 groups. Concepts Magn. Reson. 44A, 214–225 (2015).

    Google Scholar 

  45. 45.

    Eibl, K., Kannengießer, R., Stahl, W., Nguyen, H. V. L. & Kleiner, I. Low barrier methyl rotation in 3-pentyn-1-ol as observed by microwave spectroscopy. Molecular Phys. 114, 3483–3489 (2016).

    CAS  Google Scholar 

  46. 46.

    Coelho, A. A. Indexing of powder diffraction patterns by iterative use of singular value decomposition. J. Appl. Cryst. 36, 86–95 (2003).

    CAS  Google Scholar 

  47. 47.

    Coelho, A. A. & Kern, A. Discussion of the indexing algorithms within TOPAS. CPD Newsletter 32, 43–45 (2005).

    Google Scholar 

  48. 48.

    Macrae, C. F. et al. & . Mercury CSD 2.0 - new features for the vsualization and investigation of crystal structures. J. Appl. Cryst. 41, 466–470 (2008).

    CAS  Google Scholar 

  49. 49.

    Krause, L., Herbst-Irmer, R., Sheldrick, G. M. & Stalke, D. Comparison of silver and molybdenum microfocus X-ray sources for single-crystal structure determination. J. Appl. Cryst 48, 3–10 (2015).

    CAS  Google Scholar 

  50. 50.

    Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. OLEX2: A complete structure solution, refinement and analysis program. J. Appl. Cryst 42, 339–341 (2009).

    CAS  Google Scholar 

  51. 51.

    Sheldrick, G. M. A short history of SHELX. Acta Cryst. A64, 112–122 (2008).

    Google Scholar 

  52. 52.

    Sheldrick, G. M. Crystal structure refinement with SHELXL. Acta Cryst. C71, 3–8 (2015).

    Google Scholar 

  53. 53.

    Frisch, M. J. et al. Gaussian 16, Revision B.01 (Gaussian, 2016).

  54. 54.

    Zhao, Y., Mouhib, H., Li, G., Kleiner, I. & Stahl, W. Conformational analysis of tert-butyl acetate using a combination of microwave spectroscopy and quantum chemical calculations. J. Mol. Spectrosc. 322, 38–42 (2016).

    CAS  Google Scholar 

  55. 55.

    Macho, V., Brombacher, L. & Spiess, H. W. The NMR-WEBLAB: An internet approach to NMR lineshape analysis. Appl. Magn. Reson. 20, 405–432 (2001).

    CAS  Google Scholar 

  56. 56.

    Pecul, M., Dodziuk, H., Jaszunski, M., Lukin, O. & Leszezynski, J. Ab initio calculations of the NMR spectra of [1.1.1]propellane and bicyclo[1.1.1]pentane. Phys. Chem. Chem. Phys. 3, 1986–1991 (1985).

    Google Scholar 

  57. 57.

    Kubo, R. & Tomita, K. A general theory of magnetic resonance absorption. J. Phys. Soc. Jpn 9, 888–919 (1954).

    CAS  Google Scholar 

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Financial support from the Italian Ministry of University and Research (MIUR) through the grant ‘Dipartimenti di Eccellenza-2017 Materials For Energy’ is acknowledged. This research was funded by the PRIN-2015CTEBBA-003 and PRIN-20173L7W8K grants. I. Supino is acknowledged for her help during sample preparation.

Author information




A.C. and P.S. conceived the study. J.P. designed the materials synthesis and characterization. S.B., G.P., M.N., and P.C. carried out the NMR measurements and C.B., the theoretical calculations. A.C., P.S. and S.B. wrote the manuscript with suggestions from all the authors.

Corresponding authors

Correspondence to Angiolina Comotti or Piero Sozzani.

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The authors declare no competing interests.

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Supplementary information

Supplementary Information

Methods for solid-state NMR spectroscopy measurements. Characterization of Zn-FTR and Zr-FTR MOFs (TGA, SEM, IR, gas adsorption, PXRD and single-crystal diffraction measurement and solid-state NMR). Additional details on rotor dynamics (solid-state NMR data, muon spin relaxation measurements and molecular dynamics simulations). Supplementary Figs. 1–49 and Tables 1–15.

Supplementary Data 1

CIF for Zn-FTR (CCDC reference 1994502).

Supplementary Data 2

Structure factors for Zn-FTR (CCDC reference 1994502).

Supplementary Data 3

CIF for Zn-FTR refined from XRPD (CCDC reference 1994503).

Supplementary Data 4

CIF for Zr-FTR refined from XRPD (CCDC reference 1994504).

Source data

Source Data Fig. 5

Zn-FTR rotor speeds and accumulative rotor turns at 298 K and 10 K; Zn-FTR rotor rotation angle at 298 K, 10 K and 2.3 K.

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Perego, J., Bracco, S., Negroni, M. et al. Fast motion of molecular rotors in metal–organic framework struts at very low temperatures. Nat. Chem. 12, 845–851 (2020).

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