• Media type: E-Article
  • Title: Phenylpyridyl‐Fused Boroles: A Unique Coordination Mode and Weak B−N Coordination‐Induced Dual Fluorescence
  • Contributor: He, Jiang; Rauch, Florian; Friedrich, Alexandra; Krebs, Johannes; Krummenacher, Ivo; Bertermann, Rüdiger; Nitsch, Jörn; Braunschweig, Holger; Finze, Maik; Marder, Todd B.
  • imprint: Wiley, 2021
  • Published in: Angewandte Chemie International Edition
  • Language: English
  • DOI: 10.1002/anie.202013692
  • ISSN: 1433-7851; 1521-3773
  • Keywords: General Chemistry ; Catalysis
  • Origination:
  • Footnote:
  • Description: <jats:title>Abstract</jats:title><jats:p>Using 4‐phenylpyridine or 2‐phenylpyridine in place of biphenyl, two electron‐poor phenylpyridyl‐fused boroles, <jats:bold>[TipPBB1]<jats:sub>4</jats:sub></jats:bold> and <jats:bold>TipPBB2</jats:bold> were prepared. <jats:bold>[TipPBB1]<jats:sub>4</jats:sub></jats:bold> adopts a unique coordination mode and forms a tetramer with a cavity in both the solid state and solution. The boron center of <jats:bold>TipPBB2</jats:bold> is 4‐coordinate in the solid state but the system dissociates in solution, leading to 3‐coordinate borole species. Compared to its borafluorene analogues, the electron‐accepting ability of <jats:bold>TipPBB2</jats:bold> is largely enhanced by the pyridyl group. <jats:bold>TipPBB2</jats:bold> exhibits dual fluorescence in solution due to an equilibrium between free <jats:bold>TipPBB2</jats:bold> and a weak intermolecular coordination adduct with a second molecule. This equilibrium was further investigated by low‐temperature NMR spectroscopy and photophysical studies. Theoretical studies indicate that the highest occupied molecular orbital (HOMO) of <jats:bold>TipPBB2</jats:bold> localizes at the Tip group, in contrast to its borafluorene derivatives, wherein the HOMOs are localized on the borafluorene cores.</jats:p>