Table 6.
Coupling constants (J) and EPR parameters for mixed-valent diiron(II,III) form in proteins and model compounds.
| Compound | J | g-values | gave (2–gave)a | ganisb | Ref |
|---|---|---|---|---|---|
| 1 | 22.5 | 1.96, 1.88, 1.75 | 1.86 (0.14) | 0.05 | This work |
| 1 (without D/J mixing) | ∞ | 2.00, 1.91, 1.80 | 1.90 (0.10) | 0.05 | This work |
| Mouse MIOX(II,III) c | 40 | 1.95, 1.66, 1.66 | 1.76 (0.24) | 0.10 | 29 |
| Mouse MIOX(II,III)·MI c | 20 | 1.95, 1.81, 1.81 | 1.85 (0.15) | 0.05 | 29 |
| uteroferrin(II,III) | 20 | 1.94, 1.73, 1.56 | 1.74 (0.26) | 0.10 | 36,37,62 |
| uteroferrin(II,III)·phosphate | 6 | 2.27, 1.51, 1.06 | 1.61 (0.39) | 0.33 | 36,73 |
| Diiron(II,III) form of methane monooxygenases [M. trichosporium] {M. capsulatus} | ~60 | [1.94, 1.86, 1.76] {1.92, 1.86, 1.71} |
[1.85 (0.15)] {1.83 (0.17)} |
[0.04] {0.06} |
[22,74] {23} |
| Synthetic (μ-oxo)diiron(II,III) complexes | ~200 | - | ~1.93–1.96 (~0.04–0.07) | ~0.01–0.02 | 67 |
| eg. [FeII,III2(O)(O2CtBu)2(Me3-TACN)2]+ d | 238 | 1.97, 1.93, 1.90 | 1.93 (0.07) | 0.02 | 46 |
| Synthetic (μ-hydroxo)diiron(II,III) complexes | ~20 | - | >1.87 (>0.13) | >0.05 | 67 |
| eg. [FeII,III2(OH)(O2CtBu)2(Me3TACN)2]2+ d | 1.95, 1.51, 1.43 | 1.65 (0.35) | 0.16 | 45 |
a
gave = (gx + gy + gz)/3.
b
ganis = |gz−(gx+gy)/2|/3 where gz has the largest deviation from gave.
c
MIOX = myo-inositol oxygenase; MI = myo-inositol.
d
Me3-TACN = 1,4,7-trimethyl-1,4,7-triazacyclononane