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

S/N crosstalk species derived from the interconnected reactivity of H S and NO facilitate the transport of reactive sulfur and nitrogen species in signaling, transport, and regulatory processes. We report here that simple Fe 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) (S )] . In the reaction of FeCl with SNO we were able to isolate the unstable intermediate hydrosulfido mononitrosyl iron complex [FeCl (NO)(SH)] , which was characterized by X-ray crystallography. We also show that [Fe(NO) (S )] is a simple synthon for nitrosylated Fe-S clusters via its reduction with PPh to yield Roussin's Red Salt ([Fe S (NO) ] ), which highlights the role of S/N crosstalk species in the assembly of fundamental Fe-S motifs.