The dynamics of three guests: benzene (ben), naphthalene (nap), and xylene (xyl) included in the isostructural cavities of tetrameric [(2fbe) 2 (bpy)⊃guest] 4 cages were examined using single-crystal X-ray diffraction, thermogravimetric analysis, variable-temperature solid-state 2 H NMR spectroscopy, and molecular dynamics simulations. The inclusion compounds were selected from a series of boron−nitrogen host adducts assembled in a 2:1 stoichiometric ratio from the catechol ester of 2,4difluorophenylboronic acid (2fbe) and 4,4′-bipyridine (bpy) in the presence of aromatic guests. The dynamic characterization studies revealed that ben is highly mobile with fast in-plane jumps around the C 6 -axis above T = 150 K, with a calculated activation energy, E a , of 4.9 kJ mol −1 . Surprisingly, the larger guest nap experiences 180°jumps above 296 K. On the contrary, xyl guests can only experience 120°in-plane jumps at temperatures close to the decomposition point because the methyl groups act as effective stoppers.
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