Fluorescent salen-type Zn(II) Complexes As Probes for Detecting Hydrogen Sulfide and Its Anion: Bioimaging...

In this work, we investigate the mode of interaction of a family of fluorescent zinc complexes with HS^- and H₂S. Different experiments, performed by diverse spectroscopic techniques, provide evidence that HS^- binds the zinc center of all the complexes under investigation. Treatment with neutral H₂S exhibits a markedly different reactivity which indicates selectivity for HS^- over H₂S of the systems under investigation. Striking color changes, visible to the naked eye, occur when treating the systems with HS^- or by an H₂S flow. Accordingly, also the fluorescence is modulated by the presence of HS^-, with the possible formation of multiple adducts. The results highlight the potential of the devised systems to be implemented as HS^-/H₂S colorimetric and fluorescent sensors. Bioimaging experiments indicate the potential of using this class of compounds as probes for the detection of H₂S in living cells.