Iron-sulfur cluster
Iron–sulfur clusters are molecular ensembles of iron and sulfide. They are most often discussed in the context of the biological role for iron-sulfur proteins, which are pervasive. Many Fe-S clusters are known in the area of organometallic chemistry and as precursors to synthetic analogues of the biological clusters (see Figure).
The most well characterized clusters have the formula [Fe4S4(SR)4]2-, which are known for many R substituents, and with many cations. Many variations have been prepared including the incomplete cubanes [Fe3S4(SR)3]3-.
Organometallic Fe-S clusters include the sulfido carbonyls with the formula Fe2S2(CO)6, H2Fe3S(CO)9, and Fe3S2(CO)9. Compounds are also know that incorporate cyclopentadienyl ligands, such as (C5H5)4Fe4S4.
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