摘要：

Two kinds of biomimetic systems based on metalloporphyrin catalysts are able to perform the selective oxidation of alkanes. The first systems associate a Fe(III) or Mn(III) porphyrin catalyst and an oxygen atom donor (PhIO, H 2 O 2 and O 2 + a reducing agent). Their mechanisms are of the monooxygenase type and involve the transfer of an oxygen atom from high-valent metal-oxo active species to the alkane. Iron porphyrins bearing electron-withdrawing substituents on the β-pyrrole positions are highly active for alkane hydroxylation. The second systems oxidize alkanes to the corresponding ketones (and alcohols) by O 2 itself, without consumption of any reducing agent, in the presence of a (porphyrin) Fe(III)-OH catalyst after photochemical or thermal activation of its Fe-OH bond. Oxidation of alkanes by these systems seem to involve a "dioxygenase-like" mechanism with radicals like OH as active species and the intermediate formation of alkylperoxy radicals.

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