Fluorescent half-salen phenoxy-imine zinc complexes to reveal exogenous and endogenous H2S

In this contribution, the synthesis and the reactivity with HS− of a family of half-salen Zn complexes are reported. We provide evidence that HS− binds the zinc center of all the complexes under investigation. DFT and CCSD(T) calculations were performed to model the reactivity of these complexes with HS− . We successfully applied a homoleptic zinc complex bearing a Schiff-based ligand with pyridine pendant arms as a probe for the monitoring of exogenous and endogenous H2S levels in live cells.