Ratchet-free solid-state inertial rotation of a guest ball in a tight tubular host

Overview of the press release

Dynamics of molecules in the solid state holds promise for connecting molecular behaviors with properties of bulk materials. Solid-state dynamics of [60]fullerene (C₆₀) has previously been explored to reveal the presence of unique rotational motions. However, intimate intermolecular contacts between the polyhedral molecules result in restricted motions of a ratchet phase at low temperatures, which provides an interesting yet challenging problem in controlling the solid-state dynamics of molecules. Here we show that a tubular host for C₆₀ liberates the solid-state dynamics of the guest from the motional restrictions. Although the intermolecular contacts between the host and C₆₀ were present to enable a tight association with a large energy gain of –14 kcal mol^–1, the dynamic rotations of C₆₀ were simultaneously enabled by a small energy barrier of +2 kcal mol^–1 for the reorientation. The solid-state rotational motions that were dictated by the single energy barrier halted at a very low temperature of 50 K and, at a high temperature of 335 K, reached a non-Brownian, inertial regime with an extremely rapid rotational frequency of 213 GHz. Supramolecular methods adopting non-directional van der Waals interactions should be of interest to explore solid materials possessing unique dynamic characteristics.

Publication details

Journal	Nature Communications
Title	Ratchet-free solid-state inertial rotation of a guest ball in a tight tubular host
Authors	Taisuke Matsuno, Yusuke Nakai, Sota Sato, Yutaka Maniwa & Hiroyuki Isobe*
DOI	10.1038/s41467-018-04325-2
Paper link	https://doi.org/10.1038/s41467-018-04325-2

― Office of Communication ―