Non-heme iron polyazadentate complexes as catalysts for aromatic hydroxylation by H2O2: Particular efficiency of tetrakis(2-pyridylmethyl)ethylenediamine-iron(II) complexes

作者：Thibon Aurore; Bartoli Jean Francois; Guillot Regis; Sainton Joelle; Martinho Marlene; Mansuy Daniel; Banse Frederic^*

来源：Journal of Molecular Catalysis A: Chemical , 2008, 287(1-2): 115-120.

DOI：10.1016/j.molcata.2008.03.006

• monooxygenation
• aromatic substrates
• hexazadentate ligands
• reducing agent

Two iron(II) complexes with ligands related to TPEN, N,N,N',N'-tetrakis-(2-pyridylmethyl)ethane-1,2diamine, were prepared, characterized and compared as catalysts for the hydroxylation of aromatic compounds by H2O2. The (TPEN)Fell complex gave the best yields ever reported for such iron polyazadentate catalysts with yields up to 86, 59,59 and 38% for the hydroxylation of anisole, benzene, chlorobenzene and ethylbenzene, respectively.
Experiments using (H2O2)-O-18 and (H2O)-O-18 clearly showed that the oxygen atom incorporated in the aromatic substrates almost exclusively comes from H2O2. Preliminary experiments on the effects of O-2 and spintraps on the reactions suggested a minor contribution of uncontrolled radicals such as center dot OH. From the presently available data, a tentative mechanism based on the hydroxylation of substrates by a (FeOOH)-O-III intermediate or, more probably, by a species resulting from the O-O bond cleavage of this intermediate, such as [(FeO)-O-IV + center dot OH], is proposed.

• 出版日期2008-5-15