A series of 2:1 fluorinated arylboronic ester adducts with 4,4′-bipyridine sustained by N→B dative bonds have been synthesized. The degree of fluorination in the arylboronic esters derived from catechol is shown to modulate the molecular conformation of the coordinated boronic ester moieties and the intermolecular interactions by means of C−H•••F and F•••F contacts that sustain the crystal lattices. The adduct derived from the catechol ester of 2,4-difluorophenylboronic acid was chosen to examine the formation of inclusion complexes with a large number of aromatic guests, affording solvates, cocrystals, and a cocrystal solvate. Six different crystal structure types with 1:1, 1:2, and 1:2:2 N→B adduct−guest ratios were observed, whose supramolecular organization is strongly influenced by the formation of sandwich-type complexes between the host and guest molecules. The host−guest interactions involve π•••π interactions with the bipyridine linkers and additional contacts with the catecholate and Baryl F substituents, indicating a large flexibility of the N→B adducts to adapt to the guest stereochemistry. The versatility of the crystallization system was employed to isolate o-xylene from an equimolar mixture of o-, m-, and p-xylene.

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8-Hydroxyquinolin-5-sulfonic acid (8HQSA) was combined with 3-pyridineboronic acid (3PBA) or 4-pyridineboronic acid (4PBA) to give two zwitterionic monoboron complexes in crystalline form. The compounds were characterized by elemental analysis, single-crystal X-ray diffraction studies, and IR, 1H NMR, UV-Visible, and luminescence spectroscopy. The analyses revealed compounds with boron atoms adopting tetrahedral geometry. In the solid state, the molecular components are linked by charge-assisted (B)(O-H···−O(S) and N+-H···O(S) hydrogen bonds aside from C-H···O contacts and π···π interactions, as shown by Hirshfeld surface analyses and 2D fingerprint plots. The luminescence properties were characterized in terms of the emission behavior in solution and the solid state, showing emission in the bluish-green region in solution and large positive solvatofluorochromism, caused by intramolecular charge transfer. According to TD-DFT calculations at the M06-2X/6-31G(d) level of theory simulating an ethanol solvent environment, the emission properties are originated from π-π * and n-π * HOMO-LUMO transitions.

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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