. Author manuscript; available in PMC: 2017 Jan 25.

Published in final edited form as: J Biol Inorg Chem. 2015 Jun 5;20(5):875–883. doi: 10.1007/s00775-015-1272-4

Table 3.

Redox potentials for [2Fe-2S] clusters

Oxidized Cluster	Fe³⁺₂/Fe³⁺Fe²⁺ (V)^a	Fe³⁺Fe²⁺/Fe²⁺₂ (V)^a	Ref
[LFe(μ-S)]₂	−1.00	−1.36	This work
[N₂Fe(μ-S)]₂⁻²	−1.23	−2.20	17
[N₂Fe(μ-S)]₂⁻²	−1.43	−2.19	27
[N₂Fe(μ-S)₂FeS₂]⁻²	−2.38	-	16
[N₂Fe(μ-S)₂FeS₂]⁻²	−1.21	−2.17	25

Protein type	Fe³⁺₂/Fe³⁺Fe²⁺ (V)^b		Ref

Ferredoxin	−0.85 to −0.65		48
Rieske	−0.56 to −0.04		49

For entries 2–5, N₂ = bis(benzimidazolate) ligand; for entries 4 and 5, S₂ = 1,1′-biphenyl 2,2-dithiolate ligand

All reduction potentials referenced to [FeCp₂]^0/+. Entry 4 is referenced to [FeCp₂*]^0/+ and converted with E° = −0.48 V vs [FeCp₂]^0/+ in acetonitrile [50].

Protein values referenced to [FeCp₂]^0/+ using E° = +0.40 V. vs. SHE in water [51]. SHE = standard hydrogen electrode.