Synthesis and properties of open fullerenes encapsulating ammonia and methane

We describe the synthesis and characterisation of open fullerene (1) and its reduced form (2) in which CH₄ and NH₃ are encapsulated, respectively. The ¹H NMR resonance of endohedral NH₃ is broadened by scalar coupling to the quadrupolar ¹⁴N nucleus, which relaxes rapidly. This broadening is absent f...

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Main Authors: Bloodworth, Sally, Gräsvik, John, Alom, Shamim, Kouril,, Karel, Elliott, Stuart J., Wells, Neil J., Horsewill, Anthony J., Mamone, Salvatore, Jimenez-Ruiz, Monica, Rols, Stéphane, Nagel, Urmas, Room, Toomas, Levitt, Malcolm H., Whitby, Richard J.
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Published: Wiley 2018
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Online Access:https://eprints.nottingham.ac.uk/50033/
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author Bloodworth, Sally
Gräsvik, John
Alom, Shamim
Kouril,, Karel
Elliott, Stuart J.
Wells, Neil J.
Horsewill, Anthony J.
Mamone, Salvatore
Jimenez-Ruiz, Monica
Rols, Stéphane
Nagel, Urmas
Room, Toomas
Levitt, Malcolm H.
Whitby, Richard J.
author_facet Bloodworth, Sally
Gräsvik, John
Alom, Shamim
Kouril,, Karel
Elliott, Stuart J.
Wells, Neil J.
Horsewill, Anthony J.
Mamone, Salvatore
Jimenez-Ruiz, Monica
Rols, Stéphane
Nagel, Urmas
Room, Toomas
Levitt, Malcolm H.
Whitby, Richard J.
author_sort Bloodworth, Sally
building Nottingham Research Data Repository
collection Online Access
description We describe the synthesis and characterisation of open fullerene (1) and its reduced form (2) in which CH₄ and NH₃ are encapsulated, respectively. The ¹H NMR resonance of endohedral NH₃ is broadened by scalar coupling to the quadrupolar ¹⁴N nucleus, which relaxes rapidly. This broadening is absent for small satellite peaks, which are attributed to natural abundance ¹⁵N. The influence of the scalar relaxation mechanism on the linewidth of the ¹H ammonia resonance is probed by variable temperature NMR. A rotational correlation time of τc= 1.5 ps. is determined for endohedral NH₃, and of τc=57±5 ps. for the open fullerene, indicating free rotation of the encapsulated molecule. IR spectroscopy of NH3@2 at 5 K identifies three vibrations of NH₃ (ν₁, ν₃ and ν₄) redshifted in comparison with free NH₃, and temperature dependence of the IR peak intensity indicates the presence of a large number of excited translational/ rotational states. Variable temperature ¹H NMR spectra indicate that endohedral CH4 is also able to rotate freely at 223 K, on the NMR timescale. Inelastic neutron scattering (INS) spectra of CH₄@1 show both rotational and translational modes of CH₄. Energy of the first excited rotational state (J=1) of CH₄@1 is significantly lower than that of free CH₄.
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spelling nottingham-500332020-05-04T19:30:50Z https://eprints.nottingham.ac.uk/50033/ Synthesis and properties of open fullerenes encapsulating ammonia and methane Bloodworth, Sally Gräsvik, John Alom, Shamim Kouril,, Karel Elliott, Stuart J. Wells, Neil J. Horsewill, Anthony J. Mamone, Salvatore Jimenez-Ruiz, Monica Rols, Stéphane Nagel, Urmas Room, Toomas Levitt, Malcolm H. Whitby, Richard J. We describe the synthesis and characterisation of open fullerene (1) and its reduced form (2) in which CH₄ and NH₃ are encapsulated, respectively. The ¹H NMR resonance of endohedral NH₃ is broadened by scalar coupling to the quadrupolar ¹⁴N nucleus, which relaxes rapidly. This broadening is absent for small satellite peaks, which are attributed to natural abundance ¹⁵N. The influence of the scalar relaxation mechanism on the linewidth of the ¹H ammonia resonance is probed by variable temperature NMR. A rotational correlation time of τc= 1.5 ps. is determined for endohedral NH₃, and of τc=57±5 ps. for the open fullerene, indicating free rotation of the encapsulated molecule. IR spectroscopy of NH3@2 at 5 K identifies three vibrations of NH₃ (ν₁, ν₃ and ν₄) redshifted in comparison with free NH₃, and temperature dependence of the IR peak intensity indicates the presence of a large number of excited translational/ rotational states. Variable temperature ¹H NMR spectra indicate that endohedral CH4 is also able to rotate freely at 223 K, on the NMR timescale. Inelastic neutron scattering (INS) spectra of CH₄@1 show both rotational and translational modes of CH₄. Energy of the first excited rotational state (J=1) of CH₄@1 is significantly lower than that of free CH₄. Wiley 2018-02-05 Article PeerReviewed Bloodworth, Sally, Gräsvik, John, Alom, Shamim, Kouril,, Karel, Elliott, Stuart J., Wells, Neil J., Horsewill, Anthony J., Mamone, Salvatore, Jimenez-Ruiz, Monica, Rols, Stéphane, Nagel, Urmas, Room, Toomas, Levitt, Malcolm H. and Whitby, Richard J. (2018) Synthesis and properties of open fullerenes encapsulating ammonia and methane. ChemPhysChem, 19 (3). pp. 266-276. ISSN 1439-7641 endofullerenes; inelastic neutron scattering spectroscopy; infra-red spectroscopy; NMR spectroscopy; SpinDynamica http://onlinelibrary.wiley.com/doi/10.1002/cphc.201701212/full doi:10.1002/cphc.201701212 doi:10.1002/cphc.201701212
spellingShingle endofullerenes; inelastic neutron scattering spectroscopy; infra-red spectroscopy; NMR spectroscopy; SpinDynamica
Bloodworth, Sally
Gräsvik, John
Alom, Shamim
Kouril,, Karel
Elliott, Stuart J.
Wells, Neil J.
Horsewill, Anthony J.
Mamone, Salvatore
Jimenez-Ruiz, Monica
Rols, Stéphane
Nagel, Urmas
Room, Toomas
Levitt, Malcolm H.
Whitby, Richard J.
Synthesis and properties of open fullerenes encapsulating ammonia and methane
title Synthesis and properties of open fullerenes encapsulating ammonia and methane
title_full Synthesis and properties of open fullerenes encapsulating ammonia and methane
title_fullStr Synthesis and properties of open fullerenes encapsulating ammonia and methane
title_full_unstemmed Synthesis and properties of open fullerenes encapsulating ammonia and methane
title_short Synthesis and properties of open fullerenes encapsulating ammonia and methane
title_sort synthesis and properties of open fullerenes encapsulating ammonia and methane
topic endofullerenes; inelastic neutron scattering spectroscopy; infra-red spectroscopy; NMR spectroscopy; SpinDynamica
url https://eprints.nottingham.ac.uk/50033/
https://eprints.nottingham.ac.uk/50033/
https://eprints.nottingham.ac.uk/50033/