Oxo- and hydroxo-bridged diiron(III) porphyrin dimers: Inorganic and bio-inorganic perspectives and effects of intermacrocyclic interactions

Abstract

Oxo- and hydroxo-bridged diiron active centers are common structural motifs found in a variety of proteins in biology. The highly versatile oxo/hydroxo-bridged dimetallic centers, regulated by a simple protonation/deprotonation process, permit the enzyme a natural way to control the intermediates in the catalytic cycles. The fascinating chemistry of the oxo and hydroxo-bridged diheme centers, covalently connected through bridges varying in lengths and flexibility, has attracted much attention in recent times and a comprehensive review on their syntheses, structures and spectral properties is presented here. The chemical and electrochemical nature of the Fe–O–Fe/Fe–O(H)–Fe unit are suitably controlled by the inter-macrocyclic interaction between two heme centers and thereby influence the structure, property and reactivity of the molecule to a large extent.