Table 2.
EPR and Mössbauer parameters of observed FeIII complexes
| EPR | Mössbauer | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| D (cm−1) | E/D | Conc (mM)a | %Fe b | δ(mm/s) | ΔEQ (mm/s) | η | A0/gnβn (T) | %Feb | ||
| 1 + CHD | D1 (S = 5/2) | −1.5 | 0.18 | 1.08 | 54 | 0.36 | −1.56 | 1.7 | −19.5 | 58 |
| D2 (S = 5/2) | −1.5 | 0.24 | 0.56 | 28 | 0.36 | −1.56 | 1.7 | −20.1 | 28 | |
| D3 (S = 3/2) | −6 | 0.22 | 0.16 | 8 | - | |||||
| Self- Decay of 1 | D1 (S = 5/2) | −1.5 | 0.18 | 0.47 | 23 | 0.36 | −1.56 | 1.7 | −19.7 | 38c |
| D2 (S = 5/2) | −1.5 | 0.24 | 0.20 | 10 | ||||||
| D3 (S = 3/2) | −6 | 0.22 | 0.10 | 5 | ||||||
| C (S = 5/2) | −2.3 | 0.15 | 1.00 | 50 | 0.34 | −2.00d | 1 | −18.8 | 48c | |
a
As a result of the complexity of the model used in the fitting procedure, the quoted EPR concentrations are estimated to be ± 10%.
b
Samples of 1 typically contained 90% FeIV =O species, with the remainder of the iron belonging to an unreactive byproduct, which was also found in samples derived from 1.
c
A second Mössbauer sample for characterizing the self-decay of 1 contained ca. 40% of the Fe belonging to D1 +D2 and 40% to C. The uncertainties in the Mössbauer quantifications are ca. ± 5%.
d
The z axis of the EFG tensor is tilted by β = 50° (towards the x axis )with respect to the z-axis of the ZFS tensor.