title: A Vicinal Electrophilic Diborylation Reaction Furnishes Doubly Boron-Doped Polycyclic Aromatic Hydrocarbons.
abstract: Ten examples of unsymmetrically benzannulated, boron-doped polycyclic aromatic hydrocarbons (B-PAHs) were prepared by a one-pot protocol using 4,5-dichloro-1,2-bis(trimethylsilyl)benzene (1), BBr3, and selected PAHs-among them anthracene, benzo[a]pyrene, biphenylene, and fluoranthene. After mesitylation at the boron centers, the resulting air- and water-stable products were investigated by1H/11B{1H}/13C{1H} NMR spectroscopy, X-ray crystallography, cyclic voltammetry, and UV/Vis absorption/emission spectroscopy. The experiments were augmented by DFT calculations. Most of the B-PAHs are brightly luminescent (ΦPLup to 90 %) and undergo reversible reduction at moderate half-wave potentials. The two chloro substituents of 1 are not only mandatory for accomplishing efficient diborylation, but can subsequently be used for Stille-type coupling reactions to introduce 2-thienyl moieties. Alternatively, Cl/H exchange is achievable with HSiEt3in a quantitative, Pd-catalyzed transformation.
authors.affiliation: Institut für Anorganische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, 60438, Frankfurt am Main, Germany.
authors.forename: Alexandra
authors.initials: A
authors.lastname: John
authors.affiliation: Institut für Anorganische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, 60438, Frankfurt am Main, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Bolte
authors.affiliation: Institut für Anorganische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, 60438, Frankfurt am Main, Germany.
authors.forename: Hans-Wolfram
authors.identifier: 0000-0003-1803-7947
authors.initials: HW
authors.lastname: Lerner
authors.affiliation: Institut für Anorganische Chemie, Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, 60438, Frankfurt am Main, Germany.
authors.forename: Matthias
authors.identifier: 0000-0001-5806-8276
authors.initials: M
authors.lastname: Wagner
keywords: arenes; aromatic substitution; boron; electrophilic substitution; fluorescence spectroscopy