Electrochemical Investigations of the Nickel(II)-Penicillamine System. Inert and Labile Complexes Detected by Polarography

Abstract

The effect of penicillamine on nickel diffusion current demonstrates that Ni22- is a kinetically inert complex whereas NiL is labile (L2- = (CH3)2C(S-)CH(NH2)COO-)). The difference in kinetic stability between the analogous bis-ligand complexes of Ni(II) with either penicillamine or cysteine is tentatively explained taking into account their structures. It is suggested that nickel detoxication by chelate ligands depends on the inert character rather than on the thermodynamic stability of the relevant nickel complex.