Interaction of monohydrogensulfide with a family of fluorescent pyridoxal-based Zn(ii) receptors

Dalton Trans. 2018 Dec 28;47(48):17392-17400. doi: 10.1039/c8dt03969k. Epub 2018 Nov 27.

Abstract

H2S and its conjugate base HS- have recently gained increasing attention for their reactivity with bioinorganic targets. However, so far, stable adducts of bioinorganic compounds with H2S/HS- are still scarce due to the propensity of sulfide to form insoluble metal sulfides. In this work, we studied the reactivity of HS- with a family of fluorescent zinc complexes via a variety of spectroscopic techniques. The complexes selected for this study feature a pyridoxal moiety with different substituent groups on the ligand framework. Interaction of the complexes under investigation with HS- results in the displacement of the coordinated ligand from the Zn center with the concomitant precipitation of ZnS in the case of complexes 1 and 3, whereas for complex 2 our data points to the coordination of HS- to the metal center likely assisted by hydrogen bonding with the OH of the pyridoxal moiety. In the presence of HS-, the fluorescence emission of complex 2 is enhanced, whereas the fluorescence emission of complexes 1 and 3 is quenched. The results highlight the potential of complex 2 to be implemented as a HS- fluorescent sensor via a coordinative-based approach.

MeSH terms

  • Coordination Complexes / chemical synthesis
  • Coordination Complexes / chemistry*
  • Fluorescent Dyes / chemistry*
  • Hydrogen Sulfide / chemistry*
  • Molecular Structure
  • Pyridoxal / chemistry*
  • Spectrometry, Fluorescence
  • Spectrophotometry, Ultraviolet
  • Zinc / chemistry*

Substances

  • Coordination Complexes
  • Fluorescent Dyes
  • Pyridoxal
  • Zinc
  • Hydrogen Sulfide