Mononuclear iron complexes relevant to nonheme iron oxygenases. Synthesis, characterizations and reactivity of Fe-Oxo and Fe-Peroxo intermediates.
The new ligand L(6)(2)4E (N,N,N',N'-tetrakis(5-ethyl-2-pyridylmethyl)ethane-1,2-diamine) was designed as a more robust analog of TPEN (N,N,N',N'-tetrakis(2-pyridylmethyl)ethane-1,2-diamine) for which the ability at stabilizing high valent Fe-Oxo and Fe-(hydro)peroxo has been reported. With respect to the latter, the pyridyl beta-substituents in L(6)(2)4E do not modify the Fe coordination chemistry. From the Fe(II) precursor, [FeO](2+) and Fe(III)-(hydro)peroxo intermediates are prepared using the same synthetic methods as those reported for the TPEN analogs. The spectroscopic characteristics of all L(6)(2)4E-Fe complexes are very similar to their TPEN analog. However, [(L(6)(2)4E)FeO](2+) has a greater lifetime than that of [(TPEN)FeO](2+). This can be explained by a restricted bimolecular autodegradation due to the bulkiness provided by the ethyl substituents. Regarding small organic molecule oxidation, [(L(6)(2)4E)FeO](2+) and [(L(6)(2)4E)FeOOH](2+) exhibit behaviours that seem to be general for the complexes built with ligands of the TPEN family: [FeO](2+) appears to be efficient to epoxidize olefins, whereas [FeOOH](2+) hydroxylates the aromatic ring of anisole with efficacy.
Thibon
Aurore
A
Institut de Chimie Moléculaire et des Matériaux d'Orsay, Laboratoire de Chimie Inorganique, Université Paris Sud 11, 91405, Orsay Cedex, France.
Bartoli
Jean-François
JF
Bourcier
Sophie
S
Banse
Frédéric
F
D032701:Biomimetics; D005021:Ethylamines / Q000737:chemistry*; D006838:Hydrocarbons / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D008024:Ligands; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D010084:Oxidation-Reduction; D010105:Oxygenases / Q000378:metabolism*; D010545:Peroxides / Q000737:chemistry; D011725:Pyridines / Q000737:chemistry*; D012996:Solutions; D013057:Spectrum Analysis
D005021:Ethylamines; D006838:Hydrocarbons; D008024:Ligands; C546109:N,N,N',N'-tetrakis(5-ethyl-2-pyridylmethyl)ethane-1,2-diamine; D009942:Organometallic Compounds; D010545:Peroxides; D011725:Pyridines; D012996:Solutions; D007501:Iron; D010105:Oxygenases; C433124:iron(II) oxygenase; C041564:ethylamine