Thionitrite (SNO-) and Perthionitrite (SSNO-) are Simple Synthons for Nitrosylated Iron Sulfur Clusters

S/N crosstalk species derived from the interconnected reactivity of H2S and NO facilitate the transport of reactive sulfur and nitrogen species in signaling, transport, and regulatory processes. We report here that simple Fe2+ ions, such as those that are bioavailable in the labile iron pool (LIP), react with thionitrite (SNO-) and perthionitrite (SSNO-) to yield the dinitrosyl iron complex [Fe(NO)(2)(S-5)](-). In the reaction of FeCl2 with SNO- we were able to isolate the unstable intermediate hydrosulfido mononitrosyl iron complex [FeCl2(NO)(SH)](-), which was characterized by X-ray crystallography. We also show that [Fe(NO)(2)(S-5)](-) is a simple synthon for nitrosylated Fe-S clusters via its reduction with PPh3 to yield Roussin's Red Salt ([Fe2S2(NO)(4)](2-)), which highlights the role of S/N crosstalk species in the assembly of fundamental Fe-S motifs.

Automated summary

S/N crosstalk species derived from the interconnected reactivity of H2S and NO play important roles in signaling, transport, and regulatory processes. Simple Fe2+ ions react with thionitrite and perthionitrite to form a dinitrosyl iron complex, and can also produce a hydrosulfido mononitrosyl iron complex through specific reactions. Furthermore, the dinitrosyl iron complex serves as a precursor for nitrosylated Fe-S clusters.