Abstract
With the goal of gaining insight into the structures of peroxo intermediates observed for oxygen-activating nonheme diiron enzymes, a series of metastable synthetic diiron(III)-peroxo complexes with [FeIII 2(μ-O)(μ- 1, 2-O2)] cores has been characterized by X-ray absorption and resonance Raman spectroscopies, EXAFS analysis shows that this basic core structure gives rise to an Fe-Fe distance of ~3.15 Å; the distance is decreased by 0.1 Å upon introduction of an additional carboxylate bridge. In corresponding resonance Raman studies, vibrations arising from both the Fe-O-Fe and the Fe-O-O-Fe units can be observed. Importantly a linear correlation can be discerned between the v(O-O) frequency of a complex and its Fe-Fe distance among the subset of complexes with [FeIII 2(μ-OR)(μ-1, 2-O2)] cores (R = H, alkyl, aryl, or no substituent). These experimental studies are complemented by a normal coordinate analysis and DFT calculations.
Original language | English (US) |
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Pages (from-to) | 13037-13044 |
Number of pages | 8 |
Journal | Journal of Physical Chemistry A |
Volume | 112 |
Issue number | 50 |
DOIs | |
State | Published - Dec 18 2008 |