Abstract

GONCALVES, Norberto S. et al. Resonance Raman spectroscopy of Fe^IIFe^III and Fe^IIIFe^III model complexes containing an unsymmetrical dinucleating ligand: a biomimetic redox pair for uteroferrin. J. Braz. Chem. Soc. [online]. 2006, vol.17, n.8, pp. 1658-1663. ISSN 0103-5053.  http://dx.doi.org/10.1590/S0103-50532006000800025.

Raman excitation profiles for the complex [Fe^IIFe^III(bpbpmp)(C₂ H₃O₂)₂](ClO₄ ) (1), and its oxidized form, the new compound [Fe^IIIFe^III(bpbpmp)(C₂ H₃O₂)₂](ClO₄ )₂ (2), are reported. H₂bpbpmp is the proligand 2-bis[{(2-pyridylmethyl)-aminomethyl}-6-{(2-hydroxybenzyl)(2 -pyridylmethyl)}-aminomethyl]-4-methylphenol. For compound 1, the most enhanced vibrational mode in the Raman spectra is the n(Fe-O_{phen-terminal}), observed at 608 cm^-1. For compound 2, the n(CO_{phen-terminal}), which corresponds to the band at 1276 cm^-1, becomes the most enhanced one. These differences are ascribed to the changes in the electronic structure of the dinuclear phenolate bridged core upon oxidation. The phenolate bridge allows charge density transmission between the metal centers.

Keywords : Resonance Raman spectroscopy; purple acid phosphatase; biomimetic analogue; mixed-valence; unsymmetrical ligand.