Hydrogen atom abstraction by a high-spin [Fe^III=S] complex

Iron-sulfur clusters are critical to a plethora of biological processes; however, little is known about the elementary unit of these clusters, namely, the [Fe=S]ⁿ⁺ fragment. Here, we report the synthesis and characterization of a terminal iron sulfido complex. Despite its high-spin (S = 5/2) ground state, structural, spectroscopic, and computational characterization provide evidence for iron sulfur multiple bond character. Intriguingly, the complex reacts with additional sulfur to afford an S = 3/2 iron(III) disulfido (S₂²⁻) complex. Preliminary studies reveal that the sulfido complex reacts with dihydroanthracene to afford an iron(II) hydrosulfido complex, akin to the reactivity of iron oxo complexes. By contrast, there is no reaction with the disulfido complex. These results provide important insight into the nature of the iron sulfide unit.