Table 3.
EPR properties of S = ½ iron species related to the high-valent iron intermediates.
| Complex a | EPR gx,y,z | 57Fe Ax, Ay, Az (MHz) | % Fe | ref |
|---|---|---|---|---|
| (N4Py)FeIII–OOH | 2.16, 2.11, 1.98 | − 9, − 53, + 6 | 100 % | 65 |
| (TPA*)FeIII–OOAc (3a*) | 2.58, 2.38, 1.72 | − 62, + 26, + 42 | 50 % | 50 |
| (TPA)FeIII–OOAc (3a) | 2.74, 2.43, 1.52 | – | 23 % | b |
| 6a* | 2.22, 2.16, 1.94 | Ax = 60 | 4 % | 51/b |
| 6a | 2.21, 2.16, 1.96 | Ax = 60 | 5 % | b |
| 5a* | 2.07, 2.01, 1.96 | Ay = 65 | 9 % | 51/b |
| 5a | 2.07, 2.01, 1.96 | Ay = 65 | 10 % | b |
| [(PyNMe3)FeV(O)]3+ (5b) | 2.07, 2.01, 1.96 | Ax ≪ Ay = 47 ≫ Az | 40 % | 54 |
| [(TMC)FeV(O)(NC(O)Me)]+ | 2.05, 2.01, 1.97 | −47, −17, 0 | 50 % | 61 |
| [(TAML)FeV(O)]− | 1.99, 1.97. 1.74 | −67, −2, − 22 | 95 % | 64 |
| [(Me3TACN)FeIV(O)(Cl-acac•+)]2+ | 1.97, 1.93, 1.91 | – | 35 % | 70 |
| [(TBP8Cz•+)FeIV(O)] | 2.09, 2.05, 2.02 | – | 71 | |
| HRP-Cpd I | 1.99 (broad) | − 26, − 26, − 8 | 62 | |
| CPO-Cpd I | 1.72, 1.61, 2.00 | − 42, − 41, − 3 | 72 | |
| CYP119-Cpd I | 2.00, 1.96, 1.86 | − 38, − 44, − 4 | 72 |
a
Abbreviations used: CPO = chloroperoxidase; CYP119 = cytochrome P-450; HRP = horseradish peroxidase; Me3TACN = 1,4,7-trimethyl-1,4,7-triazacyclononane, Cl-acac = 3-chloro-acetylacetonate; N4Py = bis(2-pyridylmethyl)-bis(2-pyridyl)methylamine; PyNMe3 = 3,6,9-trimethyl-3,6,9-triaza-1(2,6)-pyridinacyclodecaphane; TAML = tetraamidate macrocyclic ligand; TBP8Cz = octakis(4-tert-butylphenyl)corrolazine; TMC = tetramethylcyclam, TPA* = tris(3,5-dimethyl-4-methoxypyridyl-2-methyl)amine.
b
This work.