Electronic structures and spectroscopic signatures of diiron intermediates generated by O activation of nonheme iron(II)-thiolate complexes.

The activation of O at thiolate-ligated iron(II) sites is essential to the function of numerous metalloenzymes and synthetic catalysts. Iron-thiolate bonds in the active sites of nonheme iron enzymes arise from either coordination of an endogenous cysteinate residue or binding of a deprotonated thiol-containing substrate. Examples of the latter include sulfoxide synthases, such as EgtB and OvoA, that utilize O to catalyze tandem S-C bond formation and -oxygenation steps in thiohistidine biosyntheses.