Fe(III)-hydroperoxo and peroxo complexes with aminopyridyl ligands and the Resonance Raman spectroscopic identification of the Fe-O and O-O stretching modes

A.J. Simaan (1) , S. Döpner (2) , F. Banse (1) , Sophie Bourcier (3) , Guy Bouchoux (3) , A. Boussac (4) , P. Hildebrandt (2) , J.-J. Girerd (1)

1 Laboratoire de Chimie Inorganique
2 Max-Planck-Institut für Strahlenchemie
3 DCMR - Laboratoire des mécanismes réactionnels
4 Section de Bioénergétique

Nonheme Fe(III)-hydroperoxo and Fe(III)-peroxo complexes with aminopyridyl-type ligands have been prepared and characterized by UV/Vis, EPR, mass and Resonance Raman (RR) spectroscopy. The Fe(III)(OOH) species are low-spin and exhibit a deep purple color due to the ligand-to-metal charge transfer (LMCT) hand centered at ca. 550 nm. The RR spectra of the Fe(III)(OOH) complexes display two bands at ca. 620 and 800 cm-1 that are assigned to the respective Fe-O and O-O stretching modes on the basis of the characteristic H/D and 16O/18O frequency shifts. Upon deprotonation, Fe(III)(O2) species are obtained which possess a high-spin configuration of nearly axial symmetry and a LMCT transition in the near infrared (ca. 750 nm). The frequencies of the Fe-O and O-O stretching modes at ca. 465 and 820 cm-1, as well as their respective 16O/18O shifts of -16 and -45 cm-1, indicate an ?2 coordination geometry for the Fe(III)(O2) complex.

A.J. Simaan, S. Döpner, F. Banse, Sophie Bourcier, Guy Bouchoux, et al.. Fe(III)-hydroperoxo and peroxo complexes with aminopyridyl ligands and the Resonance Raman spectroscopic identification of the Fe-O and O-O stretching modes. European Journal of Inorganic Chemistry, 2000, 2000 (7), pp.1627-1633. ⟨hal-00922246⟩