Epoxidation of alkenes catalyzed by iron(III) Schiff base chelates. A monooxygenase model

Abstract

Iron(III) Schiff base chelates [Fe₂(PA₂ppd)₂C_l4]C_l2 (1), [Fe₂(PA₂mpd)₂C_l4]Cl2 (2), and [Fe(PA₂opd)C_l2]Cl (3), were synthesized, where (PA₂ppd), (PA₂mpd), and (PA₂opd) are the Schiff bases derived from 2-pyridinecarbaldehyde (PA), and p-phenylenediamine (ppd), m-phenylenediamine (mpd), and o-phenylenediamine (opd) respectively. The complexes 1, 2, and 3 catalyzed the epoxidation of alkenes with iodosylbenzene as an oxidant providing a chemical model for cytochrome P-450. The binuclear complexes (1, 2) were superior to the mononuclear complex (3) as the catalyst for epoxidation of norbornene. Addition of pyridine bases increased the rates, and yields of epoxidation.