Understanding Reactive Sulfur Species Storage from Hybrid S/N Crosstalk Species: Perthionitrite (SSNO^–) and Thionitrite (SNO^–) Activation by a Mononuclear Nonheme Fe^II Complex

S/N hybrid species, such as perthionitrite (SSNO^-) and thionitrite (SNO^-), play intricate roles in nitric oxide (NO^•) and hydrogen sulfide (H₂S) biological signaling and transport pathways. Despite this emerging significance, the fundamental reactivities of these species remain largely unexplored. In particular, a significant gap remains in understanding how these S/N hybrid species react with redox active metal centers. Building from this gap, we report here the reactivity of SSNO^- and SNO^- toward tripodal Fe²⁺ complex [Fe(³CF₃-baTren)]^- (<b>1</b>) and examine the associated reactive nitrogen and sulfur species output pathways from these reactions using both spectroscopic and chemical trapping techniques. Specifically, we observe that complex <b>1</b> facilitates S-N bond homolysis of SSNO^- to give {Fe-NO}⁷ complex [Fe(³CF₃-baTren)(NO)]^- (<b>2</b>) and polysulfide radicals, whereas SNO^- reacts with <b>1</b> to undergo S-centered reduction to give S^2- and NO^•. Taken together, these results advance our understanding of how small molecule S/N hybrids react with redox active metal centers and may contribute to metal nitrosyl formation.