Abstract

The cavity inside fullerenes provides a unique environment for the study of isolated atoms and molecules. We report the encapsulation of hydrogen fluoride inside C60 using molecular surgery to give the endohedral fullerene HF@C60. The key synthetic step is the closure of the open fullerene cage with the escape of HF minimized. The encapsulated HF molecule moves freely inside the cage and exhibits quantization of its translational and rotational degrees of freedom, as revealed by inelastic neutron scattering and infrared spectroscopy. The rotational and vibrational constants of the encapsulated HF molecules were found to be redshifted relative to free HF. The NMR spectra display a large 1H–19F J coupling typical of an isolated species. The dipole moment of HF@C60 was estimated from the temperature dependence of the dielectric constant at cryogenic temperatures and showed that the cage shields around 75% of the HF dipole.

  • Compound

    hemiacetal

  • Compound

    tetraketone

  • Compound

    ylid

  • Compound

    diketone

  • Compound

    DA-adduct

  • Compound

    HF@hemiacetal

  • Compound

    HF@tetraketone

  • Compound

    HF@ylid

  • Compound

    HF@diketone

  • Compound

    HF@DA-adduct

  • Compound

    HF@fullerene-C60

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Acknowledgements

This research was supported by the Engineering and Physics Science Research Council (EP/1029451, M001962, M001970) including core capability (EP/K039466), and the European Regional Development Fund Interreg-IVB, MEET project. M.Ca. thanks the Royal Society for a University Research Fellowship. We are grateful to the UK 850 MHz solid-state NMR Facility at Warwick. The research in Tallinn was sponsored by the Estonian Ministry of Education and Research grant IUT23-3 and the European Regional Development Fund project TK134.

Author information

Affiliations

  1. Chemistry, University of Southampton, Southampton SO17 1BJ, UK

    • Andrea Krachmalnicoff
    • , Richard Bounds
    • , Shamim Alom
    • , Maria Concistrè
    • , Benno Meier
    • , Karel Kouřil
    • , Mark E. Light
    • , Marina Carravetta
    • , Malcolm H. Levitt
    •  & Richard J. Whitby
  2. School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK

    • Salvatore Mamone
    •  & Anthony J. Horsewill
  3. Institut Laue-Langevin, CS 20156, 38042 Grenoble, France

    • Mark R. Johnson
    •  & Stéphane Rols
  4. National Institute of Chemical Physics and Biophysics, Akadeemia Tee 23, Tallinn 12618, Estonia

    • Anna Shugai
    • , Urmas Nagel
    •  & Toomas Rõõm

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Contributions

The project was conceived by R.J.W. with the research and analysis coordinated by R.J.W., M.H.L., A.J.H., M.Ca. and T.R. The manuscript was written by R.J.W., A.K., M.H.L., A.J.H., S.M., R.B., T.R. and M.Co. R.J.W. conceived and A.K. and S.A. carried out the synthesis and basic characterization (solution NMR, electrochemistry, ultraviolet and mass spectroscopy and HPLC). The solid-state NMR was coordinated by M.Ca. and carried out by R.B. with assistance from M.Co. for the analysis. T.R. coordinated and A.S. and U.N. carried out the infrared measurements. A.J.H. coordinated and A.J.H., S.M., M.R.J. and S.R. carried out the INS experiments. S.M., T.R. and A.J.H. analysed the INS and infrared measurements, with modelling of the quantum dynamics of the confined HF carried out by S.M., A.J.H., T.R. and M.H.L. B.M. coordinated and B.M., K.K. and S.A. carried out the dielectric constant measurements. The crystal structure was acquired and solved by M.L.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Richard J. Whitby.

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Crystallographic information files

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    Supplementary information

    Crystallographic data for compound HFatC60.

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DOI

https://doi.org/10.1038/nchem.2563

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