Synthesis and Chiroptical Properties of Chiral Carbazole-Based BODIPYs

Chihiro Maeda, Keita Suka, Keiji Nagahata, Kazuto Takaishi, Tadashi Ema

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1 Citation (Scopus)

Abstract

A series of carbazole-based boron dipyrromethenes (BODIPYs) 2 a–g bearing binaphthyl units have been synthesized by the Et2AlCl-mediated reaction of the corresponding BODIPY difluorides 1 a–g with 1,1′-binaphthalene-2,2′-diol. Substituents such as halogen, nitrile, and amino groups were tolerated under the reaction conditions, and the reaction of the phenylethynyl-substituted 1 h gave (R,R)-3 h bearing two binaphthyl units. The chiroptical properties of these dyes with different substituents were investigated by UV/Vis, CD, fluorescence, and circularly polarized luminescence (CPL) spectroscopy. The CD spectra showed Cotton effects in the absorption region of the BODIPY moieties. In addition, they showed CPL both in solution and in the solid state. Interestingly, several dyes recorded higher glum values in the solid state, probably due to intermolecular interactions. Because (R,R)-3 h recorded relatively low glum values, the diastereomer (R,S)-3 h was prepared. The (R,S) diastereomer showed intense CPL, which suggests a synergetic effect of the two binaphthyl groups. Finally, chiral carbazole-based BODIPY dimers have been synthesized for the first time and their chiroptical properties were investigated. They showed redshifted fluorescence and CPL, which reached the near-IR (NIR) region in the solid state.

Original languageEnglish
Pages (from-to)4261-4268
Number of pages8
JournalChemistry - A European Journal
Volume26
Issue number19
DOIs
Publication statusPublished - Apr 1 2020

Keywords

  • chirality
  • dyes/pigments
  • heterocycles
  • luminescence
  • photophysics

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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