Chemical shielding of H2O and HF encapsulated inside a C60 cage

Jarvis, Samuel and Sang, Hongqian and Junqueira, Filipe and Gordon, Oliver and Hodgkinson, Jo E and Saywell, Alex and Rahe, Philipp and Mamone, Salvatore and Taylor, Simon and Sweetman, Adam and Leaf, Jeremy and Duncan, David and Lee, Tien-Lin and Thakur, Pardeep and Hoffman, Gabriella and Whitby, Richard and Levitt, Malcolm and Held, Georg and Kantorovich, Lev and Moriarty, Philip and Jones, Robert (2021) Chemical shielding of H2O and HF encapsulated inside a C60 cage. Communications Chemistry, 4: 135. ISSN 2399-3669

Text (H2O-C60-accepted)
H2O_C60_accepted.pdf - Accepted Version
Available under License Creative Commons Attribution.
Download (2MB)

Abstract

Molecular surgery provides the opportunity to study relatively large molecules encapsulated within a fullerene cage. Here we determine the location of an H2O molecule isolated within an adsorbed buckminsterfullerene cage, and compare this to the intrafullerene position of HF. Using normal incidence X-ray standing wave (NIXSW) analysis, coupled with density functional theory and molecular dynamics simulations, we show that both H2O and HF are located at an off-centre position within the fullerene cage, caused by substantial intra-cage electrostatic fields generated by surface adsorption of the fullerene. The atomistic and electronic structure simulations also reveal significant internal rotational motion consistent with the NIXSW data. Despite this substantial intra-cage interaction, we find that neither HF or H2O contribute to the endofullerene frontier orbitals, confirming the chemical isolation of the encapsulated molecules. We also show that our experimental NIXSW measurements and theoretical data are best described by a mixed adsorption site model.