A Molecular Low-Coordinate [Fe-S-Fe] Unit in Three Oxidation States

A [Fe-S-Fe] subunit with a single sulfide bridging two low-coordinate iron ions is the supposed active site of the iron-molybdenum co-factor (FeMoco) of nitrogenase. Here we report a dinuclear monosulfido bridged diiron(II) complex with a similar complex geometry that can be oxidized stepwise to diiron(II/III) and diiron(III/III) complexes while retaining the [Fe-S-Fe] core. The series of complexes has been characterized crystallographically, and electronic structures have been studied using, inter alia, Fe-57 Mossbauer spectroscopy and SQUID magnetometry. Further, cleavage of the [Fe-S-Fe] unit by CS2 is presented.

Automated summary

This study reports a dinuclear monosulfido bridged diiron(II) complex with a similar [Fe-S-Fe] core geometry that can be stepwise oxidized to different oxidation states while retaining the core structure. The cleavage of the [Fe-S-Fe] unit by CS2 is also demonstrated in this research. The complexes have been characterized crystallographically and electron structures have been studied using various techniques such as Fe-57 Mossbauer spectroscopy and SQUID magnetometry.