Carbazole- and Fluorene-Fused Aza-BODIPYs: NIR Fluorophores with High Brightness and Photostability

Tanja Rappitsch, Sergey M. Borisov*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Three new aza-BODIPY dyes incorporating fused fluorene or carbazole moieties have been prepared. The dyes show significant enhancement of photophysical properties compared to the parent 1,3,5,7-tetraphenyl aza-BODIPY (TPAB): a bathochromic shift of the absorption maximum (up to 2700 cm−1) and emission maximum (up to 2270 cm−1); an almost threefold increase in molar absorption coefficients (to ca. 230 000 M−1 cm−1) and a significant increase in the fluorescence quantum yield to 49–66 %. Owing to the combination of these properties, the new aza-BODIPY dyes belong to the brightest NIR dyes reported. The dyes also show excellent photostability. Due to their outstanding properties, the new dyes represent a promising platform for further exploration in biomedical research. A pH indicator containing only one fused carbazole unit was also prepared and shows absorption and emission spectra that are bathochromically shifted by about 110 and 100 nm, respectively, compared to the indicator dye based on the TPAB chromophore.

Original languageEnglish
Pages (from-to)10685-10692
Number of pages8
JournalChemistry - a European Journal
Issue number41
Publication statusPublished - 21 Jul 2021


  • dyes
  • fluorescence
  • near-infrared
  • pH
  • sensing

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry


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