Dept. of Chemistry
Oregon Graduate Center
Resonance Raman spectra of the complex of FeIII-ethylenediamine-tetraacetate with hydrogen peroxide have been obtained in the region of the peroxidic O-O stretching vibration that occurs at 815 cm [superscript -1] in frozen solution. When the complex was prepared from nearly neat, mixed-isotope hydrogen peroxide, H216O18O, a single O-O vibration was observed at 794 cm [superscript -1]. This observation establishes that the two oxygen atoms of the bound peroxide are equivalent and that the peroxide is ligated in an Î·2 side-on configuration in this mononuclear complex. The absence of any shift in Ï (O-O) when the complex was prepared in D2O solvent provides further support for the Fe-OO geometry and rules out the alternative Î·1 end-on Fe-OOH configuration. In contrast, Ï (O-O) of free hydrogen peroxide in the frozen state occurs at 877 cm [superscript -1] in H2Oand at 879 cm [superscript -1] in D2O. The 2- cm [superscript -1] upshift in D2O is similar to that observed previously with oxyhemerythrin and appears to be characteristic of a hydrogen-bonded or protonated peroxide species.
Ahmad, Salman, "Raman spectroscopic evidence for side-on binding of peroxide ion to ferric EDTA" (1988). Scholar Archive. 274.