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

Area of Science:

• Coordination Chemistry
• Supramolecular Chemistry
• Chemical Sensing

Background:

• The biological significance of hydrosulfide (HS^-) and hydrogen sulfide (H₂S) necessitates sensitive detection methods.
• Fluorescent sensors offer advantages in sensitivity and real-time monitoring for biological analytes.

Purpose of the Study:

• To investigate the interaction between hydrosulfide (HS^-) and a series of fluorescent zinc complexes featuring N,O-bidentate ligands.
• To determine if the nature of the zinc-chelating ligand influences the reactivity of HS^-.
• To evaluate the potential of these zinc complexes as fluorescent sensors for HS^-/H₂S.

Main Methods:

• Spectroscopic techniques (e.g., fluorescence spectroscopy, NMR) were employed to study the binding interactions.
• Computational analysis using time-dependent density functional theory (TD-DFT) was performed to understand electronic structures and photophysical properties.
• Preliminary bio-imaging experiments were conducted in living cells.

Main Results:

• Experimental evidence confirmed that HS^- binds to the zinc center in all investigated complexes.
• The study demonstrated that the N,O-bidentate ligands facilitate HS^- binding.
• Computational and preliminary bio-imaging results support the sensing capabilities of these complexes for H₂S.

Conclusions:

• The explored fluorescent zinc complexes effectively bind HS^-, validating their potential as fluorescent sensors.
• A coordinative-based sensing mechanism is proposed for HS^-/H₂S detection.
• These compounds show promise as fluorescent probes for H₂S detection in living cells, paving the way for advanced bio-imaging applications.