Fe(II) and Fe(III) Mononuclear Complexes with a Pentadentate Ligand Built on the 1,3-Diaminopropane Unit. Structures and Spectroscopic and Electrochemical Properties. Reaction with H2O2

Two new iron complexes, [L5 3FeIICl]PF6 (1·PF6) and [(L5 3H+)FeIIICl3]PF6 (2·PF6), were synthesized (L5 3 = N-methyl-N,N‘,N‘-tris(2-pyridylmethyl)propane-1,3-diamine), and their molecular structures were determined by X-ray crystallography. Their behavior in solution was studied by UV−vis spectroscopy and electrochemistry. Upon addition of a base to an acetonitrile solution of 2, the new unsymmetrical dinuclear complex [L5 3FeIIIOFeIIICl3]+ was detected. Treating 1 with hydrogen peroxide has allowed us to detect the low spin [L5 3FeIIIOOH]2+. Its spectroscopic properties (UV−vis, EPR and resonance Raman) are similar to those reported for related FeOOH complexes obtained with amine/pyridine ligands. Using stopped-flow absorption spectroscopy, the formation and degradation of [L5 3FeIIIOOH]2+ has been monitored, and a mechanism is proposed to reproduce the kinetic data.