Molecular Rotors in a Metal-Organic Framework: Muons on a Hyper-Fast Carousel.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 32870690.
- Also identified by DOI 10.1021/acs.nanolett.0c03140 and PMC identifier 8011913.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Using muon-spin spectroscopy, we study the exceptional dynamical properties of rotating molecular struts engineered within a Zn-based metal-organic framework at cryogenic temperatures, where the internal motions of almost any other organic substance are quenched. Muon-spin spectroscopy is particularly suited for this aim, as the experimental evidence suggests several implantation sites for the muons, among which at least one directly onto the rotating moiety. The dynamics of the molecular rotors are characterized by the exceptionally low activation energy <i>E</i><sub>A</sub> ∼ 30 cal mol<sup>-1</sup>. At the same time, we evidence a highly unusual temperature dependence of the dipolar interaction of muons with nuclear magnetic moments on the rotors, suggesting a complex influence of the rotations on the muon implantation and diffusion.