Stabilising effects on the 4Fe–4S core analogues for high-potential iron–sulphur proteins with a hydrophobic environment provided by macrocycles

Abstract

Studies of redox potentials and reactions with molecular oxygen of a series of 4Fe–4S complexes attached to a 36-membered macrocycle show that all three electron transfer processes, 1–/2–, 2–/3–, and 3–/4–, are reversible for the cyclic aryl-substituted clusters, and that half-wave potentials for alkyl derivatives with hydrophobic macrocycles showed largely positive shifts of the 1–/2– couples as given in high-potential iron–sulphur proteins as well as a stabilising effect of the cores towards molecular oxygen.