Table 3.

Reduction potentials (in V) relative to the standard hydrogen electrode (SHE). Column “s.p.” indicates the spin projection correction using the two spin system model. The contributions under ΔG°_solute reflect the difference between the zero-point energy (ZPE), enthalpy and entropy corrections to the reduced and oxidized solvated species as a result of structural optimizations. Reduction potentials were calculated from Δε_SCF^s.p., ΔG°_solute and ΔΔG°_solvation, as described in Eqs. (1)-(3). The models labeled “+H” are the O_hydroxyl-protonated models. All numbers are given in V.

model	gas phasea			solute corrections				Δ Δ G ° solv		Ε° vs. SHE
	Δ ε SCF	s.p.	Δ ε SCFs.p.	ΔZPE	Δ H °	T Δ S °	Δ G °	Δ Δ Gelec	Δ Δ Gnon
[6FeII-1FeIII-N3−]5−	−6.37							8.14	−0.02	−2.68
[4FeII-3FeIII-C4−]4−	−4.96							7.79	−0.02	−1.62
[4FeII-3FeIII-C4−+H]3−	−2.81							6.07	−0.03	−1.19
[4FeII-3FeIII-N3−]3−	−2.33			−0.01	0.00	0.04	−0.04	6.00	−0.03	−0.83
[4FeII-3FeIII-N3−+H]2−	0.30	−0.02	0.28	−0.02	−0.02	−0.09	0.05	3.78	−0.02	−0.34
[4FeII-3FeIII-O2−]2−	0.77			−0.01	15 -0.04	−0.13	0.08	3.58	−0.04	−0.05
[4FeII-3FeIII-O2−+H]1−	3.45			−0.01	−0.02	−0.06	0.03	1.31	−0.04	0.31
[2FeII-5FeIII-C4−]2−	0.68	−0.03	0.65	0.06	−0.03	−0.12	0.15	3.66	−0.03	0.00
[2FeII-5FeIII-C4−+H]1−	3.46	−0.04	3.43	0.04	0.00	−0.03	0.07	1.34	−0.03	0.38
[2FeII-5FeIII-N3−]1−	3.81	−0.03	3.77	0.04	0.03	0.06	0.01	1.25	−0.01	0.59
experiment (Ref. 11)										−0.042

^aIn vacuo electronic energy (⟨Ψ(0) ∣ Ĥ ∣ Ψ(0)⟩)⁵⁰ with PCM-optimized geometry.