Redox properties of NN′-X-phenylenebis(Y-salicyli-deneiminato)iron(II) complexes and reactivity of the corresponding iron(III) complexes towards catecholates

The electrochemical behaviour of a series of iron(II) complexes with the tetradentate ligand NN′-1,2-phenylenebis(salicylideneimine), Fe(II)L], was studied in non-aqueous solvents. The redox properties of the complexes were related to the nature of the substituents in the aromatic rings. Attention was devoted to dioxygen reactivity of the complexes. The electrode activity of the catechol—NN′-1,2-phenylenebis(salicylidene-iminato) iron(III)] system, Fe(III)L(catH)], was also studied; the results gave evidence that both the electrochemical oxidation and the chemical oxidation by dioxygen of Fe(II)L] in the presence of catechol lead to the complex Fe(III)L(catH)].