Cobalt(III) complex with a redox non-innocent bis (o-aminophenol)

The redox non-innocent ligand bis(o-aminophenol) N,N '-bis(3,5-di-tertbutyl-2-hydroxy-phenyl)-1,2-phenyl-enediamine, H₄L, reacts with CoCl₂.6H₂O in a methanol solution under aerobic conditions to form [Co(HL)₂]. Both bis(o-aminophenol) ligands coordinate as tridentate and the ligand set can be described as a resonance structure of two partially oxidized ligands, while the formal oxidation state of the metal centre appears as + III. In this resonance structure, one ligand carries an odd electron, which makes the Co(III) complex paramagnetic.