Electrochemical transformations of antimony(V) complexes containing tridentate O,N,O-donor ligands

Electrochemical transformations of antimony(V) complexes containing a tridentate redoxactive ligand, N,N-bis-(2-hydroxy-di-3,5-tert-butylphenyl)amine: R 3Sb(Cat-NH-Cat) (R = (1) Ph; (2) Et), (3) Et2Sb(Cat-N-Cat)) are studied. Electrochemical oxidation of complexes 1, 2 occurs irreversibly leading to formation of unstable radical cations. The next stage is the chemical process resulting in formation of neutral paramagnetic compounds. The Et2Sb(V)(Cat-N-Cat) complex is characterized by two reversible anodic redox processes corresponding to a change of in the ligand redox level. Stable paramagnetic derivatives are formed as a result of electrochemical oxidation of compounds 1, 3; this allows considering these compounds as potential radical scavengers. Interaction of complex 1 with electrogenerated superoxide radical anion led to formation of paramagnetic reaction products.