Recent advances in phenoxyl radical complexes of salen-type ligands as mixed-valent galactose oxidase models

► We discuss metal-salen phenoxyl radical complexes in the context of galactose oxidase modeling. ► Synthetic strategies for tuning electronic properties of salen ligands are discussed. ► Emphasis is placed on spectroscopic and electrochemical characterization of phenoxyl radical complexes as mixed-valent species along with a Marcus-Hush analysis of their intervalence charge transfer bands.