Peroxo complexes Raman spectra

The resonance Raman spectrum of [ Cu(L) 2(02)]2+, where L = tris(7V-benzylaminoethyl)-amine, contains vCuO features at 556 and 539 cm-1, suggesting the presence of two peroxo species in solution.387 There is resonance Raman evidence for the formation of peroxo and bis(p-oxo) species (from characteristic vCu02 and vCuOCu bands) on treatment of Cu 2 or Cun2 complexes of polyamine ligands with 02 or H202.388... 

There are few peroxide adducts of synthetic non-heme iron complexes that are well characterized (Table VI). Perhaps the best known adduct is that derived from Fe (EDTA) under basic conditions. This purple complex has an absorption maximum near 520 nm (e 528 M cm ) (163). These are absorptions characteristics associated with the peroxide-to-Fe" charge-transfer band in oxyHr however, the coordination mode of peroxide in the complex appears to be different from that in oxyFIr. After some debate in the literature, it has been concluded that the peroxide is T --bound on the basis of isotope effects observed in the Raman spectrum of the complex (158, 164). The v(O-O) of the H2 Oi complex is found at 815 cm". When is used, the v(O-O) shifts to 794 cm and appears as a peak of comparable line width. Were the peroxide only ri -bound, two peaks due to the Fe-O -O " and the Fe-" 0- 0 isotopomers would have been expected, as in oxyHr. An ri -peroxo structure is also proposed for [Fe(TPP)02] and has been determined for the corresponding [Mn(TPP)Oi] complex (165). 

The adsorption of O2 on iron supported on zeolite MFl produced an IR band at 730 cm (698 cm in 02) assigned to the bridging peroxo-species Fe(02)Fe. " The resonance Raman spectrum of a peroxide intermediate derived from iron diazacyclononane includes vOO of an iron(III) peroxide complex at 854 cm (consistent with side-on geometry). ... 

Lippard et al detected new intermediates, compounds L and Q in the catalytic cycle of MMOH from M. capsulatus (Bath) [65]. These are similar to the compounds P and Q, respectively, for MMOH from M. trichosporium OB3b. The intermediates were trapped by applying the same method as Lipscomb et al [61, 62]. After addition of dioxygen gas to the diferrous MMOH, the compound L was detected from the sample of 155 ms interval, and the compound Q was detected from the sample of 3 s interval. Resonance Raman spectrum of the compound L shows that the compound L is a diiron peroxo complex [66]. The detailed analysis of the Mossbauer spectrum of the compound L shows that the compound L has a synmietrical structure and suggests that the peroxo ligand of compound L coordinates in the I-T t or the I-T ti binding mode. 

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