Functional model oxygenations by nonheme iron complexes - Advances in Catalytic Activation of Dioxygen by Metal Complexes - page 188

The type was proposed to correspond to the high-valent species in
nonheme diiron enzymes. 237, 238 Few examples of this type of complexes, however,
are known and characterized by crystallographic analysis. 239-241 The reaction

between and forms quantitatively
that is converted to In
addition to the diiron(III) complex, a series
of metastable complex with the diamond core was synthesized
with using the tetradentate tripodal ligand (TPA and its methylated derivatives). 237,
238, 243-245 Reactivity of the TPA complex demonstrated that a species
could carry out oxidation reactions of hydrocarbons. 246 Cumene is converted to
cumyl alcohol and and ethylbenzene to 1-phenylethanol and
styrene, but cycloheptane is not oxidized. Two-step mechanism has been proposed
to explain the product distribution: formation of alkyl radical in the first and rate-
determining step by the abstraction of a hydrogen atom from the substrate followed
by the reaction of the intermediate radical either with the diamond core
species or Crystal structure of the high-valent complex with a
diamond core was characterized with
Resonance Raman evidence for an structure derived from the

isomerization of the diamond core was obtained with the complex

(Fig. 13). 247 Recently, formation of the

and TBHP has been shown. 248

diamond core species from

On the other hand, the reactivity of peroxo complexes toward a
variety of substrates was investigated by LeCloux et a l .. 249, 250 The nucleophilic/
basic complex (L = m-xylenediamine
bis(Kemp's triacid imide dinuleating ligand system) reacts with phenols
and carboxylic acids to liberate hydrogen peroxide, but not with electrophilic
reagents such as olefins or triphenylphosphine, or even with a weak hydrogen
donors such as dimethyl benzylamine at -77 °C. At room temperature, the complex
reacts with solvents such as THF, toluene, and cyclopentane, to form mixtures of
alcohol and ketone products by a radical autoxidation pathway. The complex with