Squeezing formaldehyde into C60 fullerene

Abstract

The cavity inside fullerene C60 provides a highly symmetric and inert environment for housing atoms and small molecules. Here we report the encapsulation of formaldehyde inside C60 by molecular surgery, yielding the supermolecular complex CH2O@C60, despite the 4.4 Å van der Waals length of CH2O exceeding the 3.7 Å internal diameter of C60. The presence of CH2O significantly reduces the cage HOMO-LUMO gap. Nuclear spin-spin couplings are observed between the fullerene host and the formaldehyde guest. The rapid spin-lattice relaxation of the formaldehyde 13C nuclei is attributed to a dominant spin-rotation mechanism. Despite being squeezed so tightly, the encapsulated formaldehyde molecules rotate freely about their long axes even at cryogenic temperatures, allowing observation of the ortho-to-para spin isomer conversion by infrared spectroscopy. The particle in a box nature of the system is demonstrated by the observation of two quantised translational modes in the cryogenic THz spectra.

More information

Identifiers

ORCID for Vijyesh K. Vyas: orcid.org/0000-0003-3603-722X

ORCID for Murari Soundararajan: orcid.org/0000-0003-0767-8263

ORCID for Mark E. Light: orcid.org/0000-0002-0585-0843

ORCID for Malcolm H. Levitt: orcid.org/0000-0001-9878-1180

ORCID for Richard J. Whitby: orcid.org/0000-0002-9891-5502

Catalogue record

Export record

Altmetrics