Inelastic neutron scattering spectroscopy of C60@calix[8]arene

The vibrational dynamics of the p-tert-butylcalix[8]arene and the 1:1 inclusion complex C60@p-tert-butylcalix[8]arene are investigated by a combination of inelastic neutron scattering (INS) and MM3 molecular mechanics calculations. The results show that the isolated, single molecule approximation breaks down and is not sufficient to explain the features observed experimentally. The origin of the line broadening in the low energy region is discussed in terms of intermolecular interactions: this effect is sharper in the case of the complex with the C60 molecule, due to the high number of co-conformers allowed by the mismatch between the circumferences of the host and the guest. The successful interpretation of the INS spectra validates the use of the model adopted.