Proton‐Induced Perthionitrite‐Mediated Zinc Thiolate Persulfidation

ABSTRACT

The perthionitrite anion, SSNO ⁻ , has been proposed as a S ⁰ source for persulfidation of biological thiol and thiolate compounds. Here, SSNO ⁻ reacts with an iminopyridine‐supported zinc thiolate complex to form a perthiolate‐supported zinc perthionitrite complex, acting as both a ligand to zinc and as a sulfur source for persulfidation of the thiolate moiety. A related zinc thionitrite complex was also prepared, enabling comparison of zinc thionitrite and zinc thiolate persulfidation. In these compounds, the zinc‐bound SNO ⁻ ligand is selectively persulfidated over the zinc‐bound thiolate moiety upon addition of S ₈ , cleanly forming SSNO ⁻ rather than the perthiolate. This work therefore demonstrates that direct S ⁰ transfer from SSNO ⁻ to thiolate anions is thermodynamically unfavorable and must instead be mediated by preceding SSNO ⁻ decomposition.