Synthesis of μ-oxo-bisiron(III)porphyrin compounds and their catalysis for cyclohexane hydroxylation

Fourteen substituted mu-oxo-bis[tetraphenylporphinatoiron(III)] derivants ([TXPPFeIII](2)O) were synthesized by passing chlorotetraphenylporphinatoiron(III) ((TPPFeCl)-Cl-III) through a neutral alumina chromatographic column, and nine of which were used in cyclohexane hydroxylation with PhIO as a new type of catalyst under moderate conditions. The experiments have shown that the yields, rate constants k of the cyclohexane hydroxylation have a linear relationship to characteristic constants sigma of substituents on porphyrin rings, a physical constant characterizing the electronic effects and steric effects of a substituent group, and that the product distributions and kinetic properties of the reactions are dependent on the reaction temperature, solvent as well as air. In contrast with monoironporphyrin (TPPFeCl)-Cl-III, mu-oxo-bisironporphyrin [TPPFeIII](2)O is shown to have the better catalytic power for cyclohexane hydroxylation with PhIO under moderate conditions and stability to PhIO. The research results show that mu-oxo-bisironporphyrin can be used as the model compound of cytochrome P-450 monooxygenase. (C) 1998 Academic Press.