Stabilization of a Zn(II) hydrosulfido complex utilizing a hydrogen-bond accepting ligand

Hydrogen sulfide (H2S) has gained recent attention as an important biological analyte that interacts with bioinorganic targets. Despite this importance, stable H2S or HS- adducts of bioinorganic metal complexes remain rare due to the redox activity of sulfide and its propensity to form insoluble metal sulfides. We report here reversible coordination of HS- to Zn(didpa)Cl-2, which is enabled by an intramolecular hydrogen bond between the zinc hydrosulfido product and the pendant tertiary amine of the didpa ligand.