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Ultra‐Fast Molecular Rotors within Porous Organic Cages
Author(s) -
Hughes Ashlea R.,
Brownbill Nick J.,
Lalek Rachel C.,
Briggs Michael E.,
Slater Anna G.,
Cooper Andrew I.,
Blanc Frédéric
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201704964
Subject(s) - porosity , materials science , phenylene , molecule , activation energy , relaxation (psychology) , atmospheric temperature range , spectral line , crystallography , chemical physics , chemistry , polymer , organic chemistry , physics , thermodynamics , composite material , psychology , social psychology , astronomy
Using variable temperature 2 H static NMR spectra and 13 C spin‐lattice relaxation times (T 1 ), we show that two different porous organic cages with tubular architectures are ultra‐fast molecular rotors. The central para ‐phenylene rings that frame the “windows” to the cage voids display very rapid rotational rates of the order of 1.2–8×10 6 Hz at 230 K with low activation energy barriers in the 12–18 kJ mol −1 range. These cages act as hosts to iodine guest molecules, which dramatically slows down the rotational rates of the phenylene groups (5–10×10 4 Hz at 230 K), demonstrating potential use in applications that require molecular capture and release.