Dioxygen Reactivity of an Iron Complex of 2‑Aminophenol-Appended Ligand: Crystallographic Evidence of the Aromatic Ring Cleavage Product of the 2‑Aminophenol Unit

2-Aminophenol appended
pentadentate ligand H2GanAP was synthesized
by mixing equimolar amounts of 2-[bis­(2-pyridylmethyl)­aminomethyl]­aniline
(A) and 3,5-di-tert-butyl catechol in hexane in the
presence of Et3N under air. The ligand reacted with Fe­(ClO4)2·6H2O or Fe­(ClO4)3·6H2O in the presence of tetrabutylammonium
perchlorate, and Et3N under air and provided a μ2 oxo-bridged dinuclear iron complex (1). X-ray
single-crystal analysis of complex 1 revealed the presence
of a furan derivative, resulting from the oxidative aromatic C–C
bond cleavage product of 2-aminophenol derivative, in the coordination
sphere of each iron center. Mechanistic investigation for the formation
of complex 1 established that in the absence of molecular
oxygen no oxidation of the appended 2-amidophenolate unit took place.
An iron­(III)–amidophenolate complex, formed initially, further
reacted with molecular oxygen and caused oxidative aromatic C–C
bond cleavage via a putative alkylperoxo species.