Resonance Raman spectroscopy of (FeFeIII)-Fe-II and (FeFeIII)-Fe-III model complexes containing an unsymmetrical dinucleating ligand: A biomimetic redox pair for uteroferrin

摘要

Raman excitation profiles for the complex [(FeFeIII)-Fe-II(bpbpmp)(C2H3O2)(2)](ClO4) (1), and its oxidized form, the new compound [(FeFeIII)-Fe-III(bpbpmp)(C2H3O2)(2)](ClO4)(2) (2), are reported. H-2 bpbpmp 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 v(Fe-O-phen_ terminal), observed at 608 cm(-1). For compound 2, the v(COphen_ 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.