A Highly Luminescent Nitrogen-Doped Nanographene as an Acid- and Metal-Sensitive Fluorophore for Optical Imaging

J Am Chem Soc. 2021 Jul 14;143(27):10403-10412. doi: 10.1021/jacs.1c04880. Epub 2021 Jul 5.

Abstract

Dibenzo[hi,st]ovalene (DBOV) has excellent photophysical properties, including strong fluorescence and high ambient stability. Moreover, the optical blinking properties of DBOV have enabled optical super-resolution single-molecule localization microscopy with an imaging resolution beyond the diffraction limit. Various organic and inorganic fluorescent probes have been developed for super-resolution imaging, but those sensitive to pH and/or metal ions have remained elusive. Here, we report a diaza-derivative of DBOV (N-DBOV), synthesized in eight steps with a total yield of 15%. Nitrogen (N)-bearing zigzag edges were formed through oxidative cyclization of amino groups in the last step. UV-vis and fluorescence spectroscopy of N-DBOV revealed its promising optical properties comparable to those of the parent DBOV, while cyclic voltammetry and density functional theory calculations highlighted its lower orbital energy levels and potential n-type semiconductor character. Notably, in contrast to that of the parent DBOV, the strong luminescence of N-DBOV is dependent on pH and the presence of heavy metal ions, indicating the potential of N-DBOV in sensing applications. N-DBOV also exhibited pH-responsive blinking, which enables pH-sensitive super-resolution imaging. Therefore, N-DBOV appears to be a highly promising candidate for fluorescence sensing in biology and environmental analytics.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Copper / chemistry
  • Fluorescent Dyes / chemical synthesis*
  • Fluorescent Dyes / chemistry
  • Graphite / chemistry*
  • Iron / chemistry
  • Luminescent Measurements / methods*
  • Molecular Structure
  • Nanostructures / chemistry*
  • Nitrogen / chemistry*

Substances

  • Fluorescent Dyes
  • Graphite
  • Copper
  • Iron
  • Nitrogen