Imidazo-pyridine-based zinc(ii) complexes as fluorescent hydrogen sulfide probes

In this work we explore the interaction of HS- with a family of fluorescent zinc complexes. In particular we selected a family of complexes with N,O-bidentate ligands aiming at assessing whether the zinc-chelating ligand plays a role in influencing the reactivity of HS- with the complexes under investigation. Different experiments, performed by diverse spectroscopic techniques, provide evidence that HS- binds the zinc center of all the complexes included in this study. The results highlight the potential of the devised systems to be used as HS-/H2S fluorescent sensors via a coordinative-based approach. To shed light on the species formed in solution when HS-/H2S interacts with the title complexes and aiming to rationalize the photophysical properties of the sensing constructs, we performed a computational analysis based on the time dependent density functional theory (TD-DFT). Preliminary bio-imaging experiments were also performed and the results indicate the potential of this class of compounds as probes for the detection of H2S in living cells.

Automated summary

This study investigates the interaction of a family of fluorescent zinc complexes with HS-, showing the potential of these complexes to be used as HS-/H2S fluorescent sensors and probes for detecting H2S in living cells. Computational analysis based on TD-DFT was performed to shed light on the species formed in solution and elucidate the photophysical properties of the sensing constructs. Preliminary bio-imaging experiments indicate the promising potential of this class of compounds for H2S detection in living cells.