title: Oxygen atom transfer mediated by an iron(IV)/iron(II) macrocyclic complex containing pyridine and tertiary amine donors.
abstract: A new non-heme iron model complex containing a high-spin iron(II) complexed with N-methylated pyridine-containing macrocycle was synthesized and crystallographically characterized. The complex generates peroxo- and high-valent iron-oxo intermediates in reactions with tert-butylhydroperoxide and isopropyl 2-iodoxybenzoate, respectively, allowing to gain insight into the formation and reactivity of enzyme-like intermediates related to biological oxygen activation. The formation and reactivity of these intermediate species were investigated by the stopped-flow methodology. The mechanism of oxygen transfer to organic substrates involving reaction of oxoiron(IV) intermediate was elucidated on the basis of spectroscopic and kinetic data. Incorporation of a pyridine ring into the macrocycle increased the reactivity of the Fe(IV)=O intermediates in comparison with polyamine tetraaza macrocyclic complexes: ferryl (Fe(IV)=O) species derived from 3 demonstrated electrophilic reactivity in transferring an oxygen atom to substituted triarylphosphines and to olefins (such as cyclooctene). However, iron(III) alkylperoxo intermediate was unreactive with cyclooctene.
authors.affiliation: Department of Chemistry, Tufts University, Medford, MA 02155, USA.
authors.forename: Wanhua
authors.initials: W
authors.lastname: Ye
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Staples
authors.forename: Elena V
authors.initials: EV
authors.lastname: Rybak-Akimova
mesh_terms: D000588:Amines / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D047028:Macrocyclic Compounds / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*
chemical_list: D000588:Amines; D047028:Macrocyclic Compounds; D011725:Pyridines; D007501:Iron; C023666:pyridine; D010100:Oxygen