From nonconjugation to conjugation: novel meso-OH substituted dipyrromethanes as fluorescence turn-on Zn2+ probes

Org Biomol Chem. 2013 Apr 28;11(16):2685-92. doi: 10.1039/c3ob40121a.

Abstract

Most reported Zn(2+) probes suffer from the interference of background fluorescence originated from the conjugated structures of commonly utilized fluorophores. In this work, three novel meso-hydroxyl group substituted dipyrromethanes DPMOH1-DPMOH3 were synthesized and found to be colourless and nonfluorescent due to the interruption of the conjugated π system by an sp(3) carbon between the two pyrrolic units. Interestingly, only the addition of Zn(2+) to the solutions of DPMOH1-DPMOH3 promoted their oxidation to dipyrrin forms, and bright fluorescence "turn on" was observed due to the formation of corresponding dipyrrin complexes with the dipyrrin : zinc stoichiometry of 2 : 1. Zn(2+) detection mechanism was investigated by UV-Vis, fluorescence, (1)H NMR and HRMS analyses, which can be ascribed to the CHEF type fluorescence enhancement, resulting from good rigidity of the dipyrrin complexes. Hence, DPMOH1-DPMOH3 can be used as fluorescence turn-on Zn(2+) probes with the advantage of no background fluorescence.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cations, Divalent / analysis
  • Fluorescence
  • Fluorescent Dyes / chemistry*
  • Models, Molecular
  • Oxidation-Reduction
  • Pyrroles / chemistry*
  • Sensitivity and Specificity
  • Spectrometry, Fluorescence / methods*
  • Zinc / analysis*

Substances

  • Cations, Divalent
  • Fluorescent Dyes
  • Pyrroles
  • dipyrromethane
  • Zinc