Synthesis, characterization, and reactivities of high valent metal–corrole (M = Cr, Mn, and Fe) complexes

Abstract

For the first-row middle transition metals (Cr, Mn, and Fe), the formal oxidation states are relatively lower. However, biological systems in various enzymatic reactions rely extensively on the higher oxidation states of these first-row middle transition metals. Thus there is a constant strive to achieve the higher oxidation states of these metals in various ligand frameworks in order to mimic the naturally occurring metallo-enzymes. Thus it is clearly understood that the ligand design has a vital role in order to achieve the higher oxidation states (HOS) of these metals. In this context, corrole, a trianionic ligand has a great potential. Corrole, a contracted version of porphyrin, is more anionic in nature and has a smaller cavity size than porphyrin. Thus it stabilizes higher oxidation states of metals. In this review, recent advances in the field of higher oxidation states of chromium, manganese, and iron corroles are summarized. Special emphasis has been given in the area of various redox catalysis reactions of these high valent corrole-metal (M = Cr, Mn, and Fe) complexes.