Abstract
S/N crosstalk species derived from the interconnected reactivity of H(2) S and NO facilitate the transport of reactive sulfur and nitrogen species in signaling, transport, and regulatory processes. We report here that simple Fe(2+) 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 FeCl(2) with SNO(-) we were able to isolate the unstable intermediate hydrosulfido mononitrosyl iron complex [FeCl(2) (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 PPh(3) to yield Roussin's Red Salt ([Fe(2) S(2) (NO)(4) ](2-) ), which highlights the role of S/N crosstalk species in the assembly of fundamental Fe-S motifs.