Crystals (Sep 2021)

Pyrrolylquinoline-BF<sub>2</sub> and BPh<sub>2</sub> BODIPY-Type Analogues: Synthesis, Structural Analysis and Photophysical Properties

  • Abdulrahman A. Alsimaree,
  • Omar M. Alatawi,
  • Paul G. Waddell,
  • David P. Day,
  • Nawaf I. Alsenani,
  • Julian G. Knight

DOI
https://doi.org/10.3390/cryst11091103
Journal volume & issue
Vol. 11, no. 9
p. 1103

Abstract

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Two new pyrrolylquinoline-substituted heteroaromatic-containing compounds bearing a central boron bridge have been prepared by a short, high-yielding sequence consisting of Suzuki-coupling of 8-bromoquinoline and N-Boc 2-pyrroleboronic acid, thermolytic tert-butyloxycarbonyl deprotection, and subsequent boron chelation (either using boron trifluoride or triphenylborane). Both derivatives display longer wavelength absorption maxima (λabsmax) than a previously reported indolopyridine-BPh2 analogue, in agreement with the smaller HOMO-LUMO energy gap predicted by DFT quantum chemical calculations. Both of the pyrrolylquinoline-boron chelates display weak emission (quantum yields 0.3–0.9%) and the BPh2 complex displays a very broad, long-wavelength emission (λemmax = 715 nm, MeCN), which may be due to dimer emission and results in a large pseudo-Stokes’ shift (7753 cm−1) for this compound.

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