Table 1.
Spectroscopic Characterization of Axially Ligated F8 and PIm Heme System (Porphyrinate)FeIV-Oxo Cmpd-II Complexesa
| UV-vis | Mössbauerb | Fe XAS | rR | ||
|---|---|---|---|---|---|
| Soret, Q-bands (nm) | δ (mm/s) | ΔEQ (mm/s) | pre-edge areaf | ν(57Fe=O) (Δ57−54Fe) (cm−1) | |
| F8Cmpd-II | 415, | 0.11 | 2.06 | 54.3 (2.6) | 833(5) |
| 544 | ν4: 1370 | ||||
| ν2: 1574 | |||||
| (DCHIm)F8Cmpd-II | 421, | 0.11 | 1.07 | 27.6 | 811(5) |
| 552 | (1.1) | ν4: 1370 | |||
| ν2: 1573 | |||||
| PImCmpd-IIc | 422, | 0.11 | 1.23 | N/A | -d |
| 554 | |||||
| (Im−)F8Cmpd-IIe | 420, | 0.12 | 1.550 | 33.6 | 828(6) |
| 556 | (0.7) | ν4: 1368 | |||
| ν2: 1571 | |||||
| (ArO−)F8Cmpd-II | 420, | 0.12 | 1.57 | 42.1 | 829(6) |
| 548 | (0–9) | ν4: 1369 | |||
| ν2: 1572 | |||||
a
All complexes are EPR silent as determined by using X-band EPR spectroscopy at 10 K.
b
The values for the major species are reported in this table. See SI for minor Mössbauer species fits and details.
c
The Mössbauer spectrum of PImCmpd-II is best fit to three ferryl species due to the flexibility of the tethered imidazole base; see the text for more details.
d
rR spectroscopic data for PImCmpd-II were not collected.
e
The Mössbauer spectrum of (Im−)F8Cmpd-II shows a 13% impurity of F8 Cmpd-II.
f
Pre-edge area (standard deviations for the fits).