Table 4.
Selected Fe-N bond distance, g values and 1H-NMR of heme-FeIII complexes.
| Heme-FeIIIComplex | Fe–N (Å) | g˔ value | pyrrole-H (δ, ppm) |
spin state | reference |
|---|---|---|---|---|---|
| 5-coordinate | |||||
| (OEP)FeCl | 2.063 | 5.76(toluene) | 80.3(CDCl3) | h.s. (a) | 73,75,76 |
| (TPP)FeCl | 2.040 (9) 2.070 (9) |
5.66(toluene) | 80.8(toluene-d8) | h.s. | 75,77,78 |
| (F8)FeCl | 2.089(4) | 6.16(CH2Cl2) | 81.0(CDCl3) | h.s. | 29,30 |
| [(OEP)Fe](ClO4) | 1.994(10) | 5.83 (CH2Cl2) | --- | i.s. (b) | 79,80 |
| [(TPP)Fe](ClO4) | 2.001(5) | 4.72(CH2Cl2) 5.84(2- metTHF) |
−10 | h.s. + i.s. | 35,74 |
| [(F8)Fe](ClO4) | --- | 5.72(CH2Cl2) | ~15 | h.s. + i.s. | 74 |
| [(F8)Fe](SbF6) | --- | 5.84(CH2Cl2) | 27.2, 11.6 | h.s. + i.s. | this work |
| 6-coordinate | |||||
| [(OEP)Fe(DMSO)2]+ | 2.035(9) | --- | --- | h.s. | 81 |
| [(TPP)Fe(H2O)2]+ | 2.045(8) 2.029(5) |
~6(solid) | --- | h.s. | 82,83 |
| [(OEP)Fe(1-MeIm)2]+ | 2.004(2) | --- | --- | l.s. (c) | 81 |
| [(TPP)Fe(1-MeIm)2]+ | 1.982(3) | gz = 2.890, gy= 2.291, gx=1.554 |
--- | l.s. | 84 |
| [(OEP)Fe(THF)2]+ | 1.999(2) 1.978(12) |
4.68(CH2Cl2) | --- | i.s. | 85,86 |
| [(TPP)Fe(THF)2]+ (d) | 2.00(1) | --- | --- | i.s. | 87 |
| [(F8)Fe(THF)2](SbF6) | 2.027(3) | 6.12(THF) | 54.7, 14.8 | h.s + i.s. | this work |
(a)
: h.s. = high spin, S=5/2;
(b)
: i.s. = intermediate spin, S=3/2;
(c)
: l.s. = low spin, S=1/2;
(d)
: derived from a dinuclear heme-FeIII-CuII complex, [(TPP)Fe(THF)2]-{[(TPP)Fe(THF)][Cu(MNT)2]} •2THF (MNT = cis-1,2-dicyanoethylenedithiolate) OEP = octaethylporphine; TPP = meso-tetraphenylporphyrin; 2-metTHF = 2-methytetrahydrofuran; 1-MeIm = 1-methylimidazole; DMSO = dimethyl sulfoxide.